Sample records for ankle dorsiflexor motoneurons

  1. Feedback-controlled and programmed stretching of the ankle plantarflexors and dorsiflexors in stroke: effects of a 4-week intervention program.

    PubMed

    Selles, Ruud W; Li, Xiaoyan; Lin, Fang; Chung, Sun G; Roth, Elliot J; Zhang, Li-Qun

    2005-12-01

    To investigate the effect of repeated feedback-controlled and programmed "intelligent" stretching of the ankle plantar- and dorsiflexors to treat subjects with ankle spasticity and/or contracture in stroke. Noncontrolled trial. Institutional research center. Subjects with spasticity and/or contracture after stroke. Stretching of the plantar- and dorsiflexors of the ankle 3 times a week for 45 minutes during a 4-week period by using a feedback-controlled and programmed stretching device. Passive and active range of motion (ROM), muscle strength, joint stiffness, joint viscous damping, reflex excitability, comfortable walking speed, and subjective experiences of the subjects. Significant improvements were found in the passive ROM, maximum voluntary contraction, ankle stiffness, and comfortable walking speed. The visual analog scales indicated very positive subjective evaluation in terms of the comfort of stretching and the effect on their involved ankle. Repeated feedback-controlled or intelligent stretching had a positive influence on the joint properties of the ankle with spasticity and/or contracture after stroke. The stretching device may be an effective and safe alternative to manual passive motion treatment by a therapist and has potential to be used to repeatedly and regularly stretch the ankle of subjects with spasticity and/or contracture without daily involvement of clinicians or physical therapists.

  2. Resistance Training for Muscle Weakness in Multiple Sclerosis: Direct Versus Contralateral Approach in Individuals With Ankle Dorsiflexors' Disparity in Strength.

    PubMed

    Manca, Andrea; Cabboi, Maria Paola; Dragone, Daniele; Ginatempo, Francesca; Ortu, Enzo; De Natale, Edoardo Rosario; Mercante, Beniamina; Mureddu, Giovanni; Bua, Guido; Deriu, Franca

    2017-07-01

    To compare effects of contralateral strength training (CST) and direct strength training of the more affected ankle dorsiflexors on muscle performance and clinical functional outcomes in people with multiple sclerosis (MS) exhibiting interlimb strength asymmetry. Randomized controlled trial. University hospital. Individuals with relapsing-remitting MS (N=30) and mild-to-moderate disability (Expanded Disability Status Scale score ≤6) presenting with ankle dorsiflexors' strength disparity. Participants were randomly assigned to a CST (n=15) or direct strength training (n=15) group performing 6 weeks of maximal intensity strength training of the less or more affected dorsiflexors, respectively. Maximal strength, endurance to fatigue, and mobility outcomes were assessed before, at the intervention end, and at 12-week follow-up. Strength and fatigue parameters were measured after 3 weeks of training (midintervention). In the more affected limb of both groups, pre- to postintervention significant increases in maximal strength (P≤.006) and fatigue endurance (P≤.04) were detected along with consistent retention of these improvements at follow-up (P≤.04). At midintervention, the direct strength training group showed significant improvements (P≤.002), with no further increase at postintervention, despite training continuation. Conversely, the CST group showed nonsignificant strength gains, increasing to significance at postintervention (P≤.003). In both groups, significant pre- to postintervention improvements in mobility outcomes (P≤.03), not retained at follow-up, were observed. After 6 weeks of training, CST proved as effective as direct strength training in enhancing performance of the more affected limb with a different time course, which may have practical implications in management of severely weakened limbs where direct strength training is not initially possible. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc

  3. A parametric model of muscle moment arm as a function of joint angle: application to the dorsiflexor muscle group in mice.

    PubMed

    Miller, S W; Dennis, R G

    1996-12-01

    A parametric model was developed to describe the relationship between muscle moment arm and joint angle. The model was applied to the dorsiflexor muscle group in mice, for which the moment arm was determined as a function of ankle angle. The moment arm was calculated from the torque measured about the ankle upon application of a known force along the line of action of the dorsiflexor muscle group. The dependence of the dorsiflexor moment arm on ankle angle was modeled as r = R sin(a + delta), where r is the moment arm calculated from the measured torque and a is the joint angle. A least-squares curve fit yielded values for R, the maximum moment arm, and delta, the angle at which the maximum moment arm occurs as offset from 90 degrees. Parametric models were developed for two strains of mice, and no differences were found between the moment arms determined for each strain. Values for the maximum moment arm, R, for the two different strains were 0.99 and 1.14 mm, in agreement with the limited data available from the literature. While in some cases moment arm data may be better fitted by a polynomial, use of the parametric model provides a moment arm relationship with meaningful anatomical constants, allowing for the direct comparison of moment arm characteristics between different strains and species.

  4. Muscular activity and torque of the foot dorsiflexor muscles during decremental isometric test: A cross-sectional study.

    PubMed

    Ruiz-Muñoz, Maria; González-Sánchez, Manuel; Martín-Martín, Jaime; Cuesta-Vargas, Antonio I

    2017-06-01

    To analyse the torque variation level that could be explained by the muscle activation (EMG) amplitude of the three major foot dorsiflexor muscles (tibialis anterior (TA), extensor digitorum longus (EDL), extensor hallucis longus (EHL)) during isometric foot dorsiflexion at different intensities. In a cross-sectional study, forty-one subjects performed foot dorsiflexion at 100%, 75%, 50% and 25% of maximal voluntary contractions (MVC) with the hip and knee flexed 90° and the ankle in neutral position (90° between leg and foot). Three foot dorsiflexions were performed for each intensity. Outcome variables were: maximum (100% MVC) and relative torque (75%, 50%, 25% MVC), maximum and relative EMG amplitude. A linear regression analysis was calculated for each intensity of the isometric foot dorsiflexion. The degree of torque variation (dependent variable) from the independent variables explain (EMG amplitude of the three major foot dorsiflexor muscles) the increases when the foot dorsiflexion intensity is increased, with values of R 2 that range from 0.194 (during 25% MVC) to 0.753 (during 100% MVC). The reliability of the outcome variables was excellent. The EMG amplitude of the three main foot dorsiflexors exhibited more variance in the dependent variable (torque) when foot dorsiflexion intensity increases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Control of paraplegic ankle joint stiffness using FES while standing.

    PubMed

    Hunt, K J; Gollee, H; Jaime, R P

    2001-10-01

    The goal of this work was to investigate the feasibility of ankle stiffness control using functional electrical stimulation (FES) while standing, as relevant to the development of feedback systems for balance control in paraplegia. The work was carried out using apparatus in which the subject stands with all joints above the ankles braced, and where ankle moment is provided via FES of the ankle flexor and extensor muscles. A feedback control strategy for ankle stiffness control is proposed in which the ankle moment is controlled to a reference value equal to the product of the desired stiffness and the measured ankle angle. Two subjects participated in the study: one neurologically-intact person, and one paraplegic person with a complete thoracic spinal cord lesion. The results show that during forward-leaning postures, when the plantarflexor muscles are stimulated, relatively high ankle moments of up to 60 Nm can be generated and accurate moment tracking is achieved. As a consequence, ankle stiffness is close to the desired value. During backward lean, on the other hand, the dorsiflexor muscles are stimulated. These muscles are relatively weak and only modest ankle moments of up to around 15 Nm can be produced. As a result, dorsiflexor stimulation readily saturates giving poor stiffness control. It was further observed that when the desired stiffness is higher more external force has to be applied to perturb the body away from the neutral (upright) position. We conclude that: (i) accurate ankle stiffness control, up to the fundamental strength limits of the muscles, can be achieved with controlled FES; (ii) ankle stiffness control using FES in paraplegia has the potential to ease the task of stabilising upright posture by application of additional upper-body forces.

  6. Development of a method for fabricating polypropylene non-articulated dorsiflexion assist ankle foot orthoses with predetermined stiffness.

    PubMed

    Ramsey, Jason Allan

    2011-03-01

    A non-articulated plantarflexion resist ankle foot orthosis (AFO), commonly known as a posterior leaf spring AFO, is indicated for patients with motor impairment to the dorsiflexors. The AFO is often custom molded to a patient's lower limb anatomy and fabricated from polypropylene. There are no established guidelines for fabricating this type of AFO with predetermined stiffness of the ankle region for normal walking speeds. Therefore an AFO may not meet the biomechanical needs of the patient. Quantify the biomechanical ankle stiffness requirement for an individual with complete dorsiflexor impairment and develop a method for fabricating an AFO with ankle stiffness to meet that requirement. Experimental, bench research. The literature on sagittal biomechanics of non-pathological adults was reviewed to derive the stiffness of the ankle during loading response. Computer models of 144 AFOs were created with geometric variations to account for differences in human anthropometrics. Computer-based finite element analysis was employed to determine the stiffness and safety factor of the models. Stiffness of the AFOs ranged from 0.04 to 1.8 Nm/deg. This ample range is expected to account for the stiffness required for most adults with complete dorsiflexor impairment. At 5° deflection the factor of safety (ratio of strength to stress) ranged from 2.8 to 9.1. A computer program was generated that computes AFO stiffness from user-input variables of AFO geometry. The stiffness is compared to a theoretically appropriate stiffness based on the patient mass. The geometric variables can be modified until there is a close match, resulting in AFO design specification that is appropriate for the patient. Through validation on human subjects, this method may benefit patient outcomes in clinical practice by avoiding the current uncertainty surrounding AFO performance and reducing the labor and time involved in rectifying a custom AFO post-fabrication. This method provides an avenue for

  7. Ankle and knee kinetics between strike patterns at common training speeds in competitive male runners.

    PubMed

    Kuhman, Daniel; Melcher, Daniel; Paquette, Max R

    2016-01-01

    The purpose of this study was to investigate the interaction of foot strike and common speeds on sagittal plane ankle and knee joint kinetics in competitive rear foot strike (RFS) runners when running with a RFS pattern and an imposed forefoot strike (FFS) pattern. Sixteen competitive habitual male RFS runners ran at two different speeds (i.e. 8 and 6 min mile(-1)) using their habitual RFS and an imposed FFS pattern. A repeated measures analysis of variance was used to assess a potential interaction between strike pattern and speed for selected ground reaction force (GRF) variables and, sagittal plane ankle and knee kinematic and kinetic variables. No foot strike and speed interaction was observed for any of the kinetic variables. Habitual RFS yielded a greater loading rate of the vertical GRF, peak ankle dorsiflexor moment, peak knee extensor moment, peak knee eccentric extensor power, peak dorsiflexion and sagittal plane knee range of motion compared to imposed FFS. Imposed FFS yielded greater maximum vertical GRF, peak ankle plantarflexor moment, peak ankle eccentric plantarflexor power and sagittal plane ankle ROM compared to habitual RFS. Consistent with previous literature, imposed FFS in habitual RFS reduces eccentric knee extensor and ankle dorsiflexor involvement but produce greater eccentric ankle plantarflexor action compared to RFS. These acute differences between strike patterns were independent of running speeds equivalent to typical easy and hard training runs in competitive male runners. Current findings along with previous literature suggest differences in lower extremity kinetics between habitual RFS and imposed FFS running are consistent among a variety of runner populations.

  8. The association between physical characteristics of the ankle joint and the mobility performance in elderly people with type 2 diabetes mellitus.

    PubMed

    Ng, Thomas Ka-Wai; Lo, Sing-Kai; Cheing, Gladys Lai-Ying

    2014-01-01

    Previous studies showed that older adults with diabetes have a worse mobility performance as compared with those without diabetes. Studies also demonstrated that older adults with diabetes have weakened ankle muscle strength, reduced joint range in ankle dorsiflexion and worsened ankle joint proprioception as compared with control population. The purpose of the present study was to examine the relationship between the physical characteristics of the ankle joint and the mobility performance in older adults with type 2 diabetes. Older adults with type 2 diabetes (n=85) were recruited, and Timed Up and Go test (TUG) for mobility assessment was performed. Active ankle joint repositioning test was used for assessing the ankle joint proprioception sense; peak torque of ankle dorsiflexors and plantar flexors were tested by using a Cybex Norm dynamometer, and weight-bearing lunge test (WBLT) was used for assessing the stiffness of ankle dorsiflexion. Our results showed that age, body mass index (BMI), normalized peak torque of plantar flexors and dorsiflexors, active ankle joint repositioning test errors and the WBLT distance were significantly correlated with the TUG (all p<0.001). These ankle characteristics, together with the demographic data of the subjects, contributed 59.9% of the variance in the TUG by multiple regression analysis. Body mass, ankle plantar flexors strength and ankle joint proprioception are important factors contributing to the physical mobility of the older adults with type 2 diabetes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. A comprehensive assessment of the cross-training effect in ankle dorsiflexors of healthy subjects: A randomized controlled study.

    PubMed

    Manca, Andrea; Pisanu, Francesco; Ortu, Enzo; De Natale, Edoardo Rosario; Ginatempo, Francesca; Dragone, Daniele; Tolu, Eusebio; Deriu, Franca

    2015-06-01

    To investigate the cross-training effect, induced on ankle dorsiflexors (AD) by unilateral strength-training of the contralateral muscles, as transfer of peak torque (PT) and muscle work (MW) and their relative contributions to muscle performance. Thirty healthy volunteers were randomly assigned to a training or control group. The trained group sustained a 4-week maximal isokinetic training of the stronger AD at 90 and 45°/s. At both angular velocities, PT, MW and MW/PT ratio were measured from both legs at baseline and after intervention (trained group) or no-intervention (controls). The familiarization/learning-effect was calculated and subtracted by PT and MW measures to obtain their net changes. Net PT increased in both legs (untrained: +27.5% at 90°/s and +17.9% at 45°/s; trained: +15% at 90°/s and +16.3% at 45°/s). Similarly, net MW increased in both the untrained (90°/s: +29.6%; 45°/s: +37%) and trained (90°/s: +23.4%; 45°/s: +18.3%) legs. PT and MW gains were larger in the untrained than trained AD (p<0.0005), with MW improving more than PT at 45°/s (p=0.04). The MW/PT ratio increased bilaterally only in the trained group (p<0.05), depending on the angular velocity. The cross-training effect occurred in AD muscles in terms of both PT and MW, with MW adding valuable information to PT-analysis in describing muscle performance. Moreover, the MW/PT ratio allowed estimating the contributions of these parameters to muscle capability and may represent a novel index in isokinetic testing. The greater improvements in the untrained than trained limb raises interesting clinical implications in asymmetric conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Shank Muscle Strength Training Changes Foot Behaviour during a Sudden Ankle Supination

    PubMed Central

    Hagen, Marco; Lescher, Stephanie; Gerhardt, Andreas; Lahner, Matthias; Felber, Stephan; Hennig, Ewald M.

    2015-01-01

    Background The peroneal muscles are the most effective lateral stabilisers whose tension braces the ankle joint complex against excessive supination. The purpose of this study was to identify the morphological and biomechanical effects of two machine-based shank muscle training methods. Methods Twenty-two healthy male recreationally active sports students performed ten weeks of single-set high resistance strength training with 3 training sessions per week. The subjects conducted subtalar pronator/supinator muscle training (ST) with the right leg by using a custom-made apparatus; the left foot muscles were exercised with machine-based talocrural plantar and dorsiflexor training (TT). Muscle strength (MVIC), muscle volume and foot biomechanics (rearfoot motion, ground reaction forces, muscle reaction times) during a sudden ankle supination were recorded before and after the intervention. Results Compared to TT, ST resulted in significantly higher pronator (14% vs. 8%, P<0.01) and supinator MVIC (25% vs. 12%, P<0.01). During sudden foot inversions, both ST and TT resulted in reduced supination velocity (-12%; P<0.01). The muscle reaction onset time was faster after the training in peroneus longus (PL) (P<0.01). Muscle volume of PL (P<0.01) and TA (P<0.01) increased significantly after both ST and TT. Conclusion After both ST and TT, the ankle joint complex is mechanically more stabilised against sudden supinations due to the muscle volume increase of PL and TA. As the reduced supination velocities indicate, the strength training effects are already present during free-fall. According to a sudden ankle supination in standing position, both machine-based dorsiflexor and pronator strength training is recommended for enhancing the mechanical stability of the ankle. PMID:26110847

  11. An Ankle-Foot Orthosis Powered by Artificial Pneumatic Muscles

    PubMed Central

    Ferris, Daniel P.; Czerniecki, Joseph M.; Hannaford, Blake

    2005-01-01

    We developed a pneumatically powered orthosis for the human ankle joint. The orthosis consisted of a carbon fiber shell, hinge joint, and two artificial pneumatic muscles. One artificial pneumatic muscle provided plantar flexion torque and the second one provided dorsiflexion torque. Computer software adjusted air pressure in each artificial muscle independently so that artificial muscle force was proportional to rectified low-pass-filtered electromyography (EMG) amplitude (i.e., proportional myoelectric control). Tibialis anterior EMG activated the artificial dorsiflexor and soleus EMG activated the artificial plantar flexor. We collected joint kinematic and artificial muscle force data as one healthy participant walked on a treadmill with the orthosis. Peak plantar flexor torque provided by the orthosis was 70 Nm, and peak dorsiflexor torque provided by the orthosis was 38 Nm. The orthosis could be useful for basic science studies on human locomotion or possibly for gait rehabilitation after neurological injury. PMID:16082019

  12. Skin Cooling and Force Replication at the Ankle in Healthy Individuals: A Crossover Randomized Controlled Trial

    PubMed Central

    Haupenthal, Daniela Pacheco dos Santos; de Noronha, Marcos; Haupenthal, Alessandro; Ruschel, Caroline; Nunes, Guilherme S.

    2015-01-01

    Context Proprioception of the ankle is determined by the ability to perceive the sense of position of the ankle structures, as well as the speed and direction of movement. Few researchers have investigated proprioception by force-replication ability and particularly after skin cooling. Objective To analyze the ability of the ankle-dorsiflexor muscles to replicate isometric force after a period of skin cooling. Design Randomized controlled clinical trial. Setting Laboratory. Patients or Other Participants Twenty healthy individuals (10 men, 10 women; age = 26.8 ± 5.2 years, height = 171 ± 7 cm, mass = 66.8 ± 10.5 kg). Intervention(s) Skin cooling was carried out using 2 ice applications: (1) after maximal voluntary isometric contraction (MVIC) performance and before data collection for the first target force, maintained for 20 minutes; and (2) before data collection for the second target force, maintained for 10 minutes. We measured skin temperature before and after ice applications to ensure skin cooling. Main Outcome Measure(s) A load cell was placed under an inclined board for data collection, and 10 attempts of force replication were carried out for 2 values of MVIC (20%, 50%) in each condition (ice, no ice). We assessed force sense with absolute and root mean square errors (the difference between the force developed by the dorsiflexors and the target force measured with the raw data and after root mean square analysis, respectively) and variable error (the variance around the mean absolute error score). A repeated-measures multivariate analysis of variance was used for statistical analysis. Results The absolute error was greater for the ice than for the no-ice condition (F1,19 = 9.05, P = .007) and for the target force at 50% of MVIC than at 20% of MVIC (F1,19 = 26.01, P < .001). Conclusions The error was greater in the ice condition and at 50% of MVIC. Skin cooling reduced the proprioceptive ability of the ankle-dorsiflexor muscles to replicate isometric

  13. Effect of Wiihabilitation on strength ratio of ankle muscles in adults

    PubMed Central

    Khalil, Aya A.; Mohamed, Ghada A.; El Rahman, Soheir M. Abd; Elhafez, Salam M.; Nassif, Nagui S.

    2016-01-01

    [Purpose] This study was conducted to investigate the effect of Wiihabilitation on the ankle dorsiflexion/plantar flexion strength ratio in adults. [Subjects and Methods] Thirty-two healthy male volunteers were randomly assigned to two equal groups (experimental and control). Participants in the experimental group received a Wiihabilitation training program for six weeks. Data were collected using a Biodex system 3 Isokinetic dynamometer. Peak torques of the dorsiflexors and plantar flexors were measured at an angular velocity of 60°/sec which in turn were used to derive the ankle dorsiflexion/plantar flexion strength ratio. [Results] The mean values of the ankle dorsiflexion/plantar flexion strength ratio decreased significantly between before and after the training in the experimental group, meanwhile there was no significant difference between before and after the training period in the control group . [Conclusion] Wiihabilitation has an impact on the ankle dorsiflexion/plantar flexion strength ratio, so it can be considered an effective training tool in terms of the ankle strength ratio. Thus, it could be recommended for both prevention and rehabilitation of ankle instability patients. PMID:27821951

  14. Effect of Wiihabilitation on strength ratio of ankle muscles in adults.

    PubMed

    Khalil, Aya A; Mohamed, Ghada A; El Rahman, Soheir M Abd; Elhafez, Salam M; Nassif, Nagui S

    2016-10-01

    [Purpose] This study was conducted to investigate the effect of Wiihabilitation on the ankle dorsiflexion/plantar flexion strength ratio in adults. [Subjects and Methods] Thirty-two healthy male volunteers were randomly assigned to two equal groups (experimental and control). Participants in the experimental group received a Wiihabilitation training program for six weeks. Data were collected using a Biodex system 3 Isokinetic dynamometer. Peak torques of the dorsiflexors and plantar flexors were measured at an angular velocity of 60°/sec which in turn were used to derive the ankle dorsiflexion/plantar flexion strength ratio. [Results] The mean values of the ankle dorsiflexion/plantar flexion strength ratio decreased significantly between before and after the training in the experimental group, meanwhile there was no significant difference between before and after the training period in the control group . [Conclusion] Wiihabilitation has an impact on the ankle dorsiflexion/plantar flexion strength ratio, so it can be considered an effective training tool in terms of the ankle strength ratio. Thus, it could be recommended for both prevention and rehabilitation of ankle instability patients.

  15. Eight weeks of local vibration training increases dorsiflexor muscle cortical voluntary activation.

    PubMed

    Souron, Robin; Farabet, Adrien; Féasson, Léonard; Belli, Alain; Millet, Guillaume Y; Lapole, Thomas

    2017-06-01

    The aim of this study was to evaluate the effects of an 8-wk local vibration training (LVT) program on functional and corticospinal properties of dorsiflexor muscles. Forty-four young subjects were allocated to a training (VIB, n = 22) or control (CON, n = 22 ) group. The VIB group performed twenty-four 1-h sessions (3 sessions/wk) of 100-Hz vibration applied to the right tibialis anterior. Both legs were tested in each group before training (PRE), after 4 (MID) and 8 (POST) wk of training, and 2 wk after training (POST 2W ). Maximal voluntary contraction (MVC) torque was assessed, and transcranial magnetic stimulation (TMS) was used to evaluate cortical voluntary activation (VA TMS ), motor evoked potential (MEP), cortical silent period (CSP), and input-output curve parameters. MVC was significantly increased for VIB at MID for right and left legs [+7.4% ( P = 0.001) and +6.2% ( P < 0.01), respectively] and remained significantly greater than PRE at POST [+12.0% ( P < 0.001) and +10.1% ( P < 0.001), respectively]. VA TMS was significantly increased for right and left legs at MID [+4.4% ( P < 0.01) and +4.7% ( P < 0.01), respectively] and at POST [+4.9% ( P = 0.001) and +6.2% ( P = 0.001), respectively]. These parameters remained enhanced in both legs at POST 2W MEP and CSP recorded during MVC and input-output curve parameters did not change at any time point for either leg. Despite no changes in excitability or inhibition being observed, LVT seems to be a promising method to improve strength through an increase of maximal voluntary activation, i.e., neural adaptations. Local vibration may thus be further considered for clinical or aging populations. NEW & NOTEWORTHY The effects of a local vibration training program on cortical voluntary activation measured with transcranial magnetic stimulation were assessed for the first time in dorsiflexors, a functionally important muscle group. We observed that training increased maximal voluntary strength likely because of

  16. Cocontraction of Ankle Dorsiflexors and Transversus Abdominis Function in Patients With Low Back Pain

    PubMed Central

    Chon, Seung-Chul; You, Joshua H.; Saliba, Susan A.

    2012-01-01

    difference was observed in RF onset time (t38 = 1.63, P = .11) or the cocontracted TrA/IO peak (t38 = −1.90, P = .07) and mean (t38 = −1.81, P = .08). The test-retest reliability for the muscle thickness measure revealed excellent correlations (intraclass correlation coefficient range, 0.95–0.99). Conclusions We are the first to demonstrate that a cocontraction of the ankle dorsiflexors with ADIM training might result in a thickness change in the TrA muscle and associated pain management in patients with chronic LBP. PMID:22889653

  17. Unique Positioning for Using Elastic Resistance Band in Providing Strengthening Exercise to the Muscles Surrounding the Ankle

    PubMed Central

    Bandy, William D.

    2007-01-01

    Ankle sprains are among the most common injuries incurred by participants in athletics. Conservative management of the patient after an ankle sprain includes a comprehensive rehabilitation program of which the resistance exercises are a part and are frequently advised by the clinician, many times as part of a home exercise program. The purpose of this Clinical Suggestion is to present a unique method of using elastic resistance band to provide strengthening activities to the inverters, ever-tors, plantarflexors, and dorsiflexors of the ankle. The method is unique, as well as convenient and efficient, as it allows the subject to perform all four exercises with a minimum of change in position, while staying seated in a chair. PMID:21522203

  18. Whither motoneurons?

    PubMed

    Brownstone, Robert M; Stuart, Douglas G

    2011-08-29

    In the preceding series of articles, the history of vertebrate motoneuron and motor unit neurobiological studies has been discussed. In this article, we select a few examples of recent advances in neuroscience and discuss their application or potential application to the study of motoneurons and the control of movement. We conclude, like Sherrington, that in order to understand normal, traumatized, and diseased human behavior, it is critical to continue to study motoneuron biology using all available and emerging tools. This article is part of a Special Issue entitled Historical Review. 2011 Elsevier B.V. All rights reserved.

  19. Monkey extensor digitorum communis motoneuron pool: Proximal dendritic trees and small motoneurons.

    PubMed

    Jenny, Arthur B; Cheney, Paul D; Jenny, Andrew K

    2018-05-14

    Transverse sections of the monkey cervical spinal cord from a previous study (Jenny and Inukai, 1983) were reanalyzed using Neurolucida to create a three-dimensional display of extensor digitorum communis (EDC) motoneurons and proximal dendrites that had been labeled with horse radish peroxidase (HRP). The EDC motoneuron pool was located primarily in the C8 and T1 segments of the spinal cord. Small motoneurons (cell body areas less than 500 μm 2 and presumed to be gamma motoneurons) comprised about ten percent of the motoneurons and were located throughout the length of the motoneuron pool. Most small motoneurons were oblong in shape and had one or two major dendrites originating from the cell body in the transverse plane of section. The majority of the HRP labeled dendritic trees were directed either superiorly, dorsal-medially to the mid zone area between the base of the dorsal horn and the upper portion of the ventral horn, or medially to the ventromedial gray matter. The longer HRP labeled dendrites usually continued in the same radial direction as when originating from the cell body. As such we considered the radial direction of the longer proximal HRP labeled dendrites to be a reasonable estimate of the radial direction of the more distal dendritic tree. Our data suggest that the motoneuron dendritic tree as seen in transverse section has direction-oriented dendrites that extend toward functional terminal regions. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Robot-guided ankle sensorimotor rehabilitation of patients with multiple sclerosis.

    PubMed

    Lee, Yunju; Chen, Kai; Ren, Yupeng; Son, Jongsang; Cohen, Bruce A; Sliwa, James A; Zhang, Li-Qun

    2017-01-01

    People with multiple sclerosis (MS) often develop symptoms including muscle weakness, spasticity, imbalance, and sensory loss in the lower limbs, especially at the ankle, which result in impaired balance and locomotion and increased risk of falls. Rehabilitation strategies that improve ankle function may improve mobility and safety of ambulation in patients with MS. This pilot study investigated effectiveness of a robot-guided ankle passive-active movement training in reducing motor and sensory impairments and improving balance and gait functions. Seven patients with MS participated in combined passive stretching and active movement training using an ankle rehabilitation robot. Six of the patients finished robotic training 3 sessions per week over 6 weeks for a total of 18 sessions. Biomechanical and clinical outcome evaluations were done before and after the 6-week treatment, and at a follow-up six weeks afterwards. After six-week ankle sensorimotor training, there were increases in active range of motion in dorsiflexion, dorsiflexor and plantar flexor muscle strength, and balance and locomotion (p<0.05). Proprioception acuity showed a trend of improvement. Improvements in four biomechanical outcome measures and two of the clinical outcome measures were maintained at the 6-week follow-up. The study showed the six-week training duration was appropriate to see improvement of range of motion and strength for MS patients with ankle impairment. Robot-guided ankle training is potentially a useful therapeutic intervention to improve mobility in patients with MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Reduced effects of tendon vibration with increased task demand during active, cyclical ankle movements

    PubMed Central

    Floyd, Lisa M.; Holmes, Taylor C.; Dean, Jesse C.

    2013-01-01

    Tendon vibration can alter proprioceptive feedback, one source of sensory information which humans can use to produce accurate movements. However, the effects of tendon vibration during functional movement vary depending on the task. For example, ankle tendon vibration has considerably smaller effects during walking than standing posture. The purpose of this study was to test whether the effects of ankle tendon vibration are predictably influenced by the mechanical demands of a task, as quantified by peak velocity. Twelve participants performed symmetric, cyclical ankle plantarflexion/dorsiflexion movements while lying prone with their ankle motion unconstrained. The prescribed movement period (1s, 3s) and peak-to-peak amplitude (10°, 15°, 20°) were varied across trials; shorter movement periods or larger amplitudes increased the peak velocity. In some trials, vibration was continuously and simultaneously applied to the right ankle plantarflexor and dorsiflexor tendons, while the left ankle tendons were never vibrated. The vibration frequency (40, 80, 120, 160 Hz) was varied across trials. During trials without vibration, participants accurately matched the movement of their ankles. The application of 80 Hz vibration to the right ankle tendons significantly reduced the amplitude of right ankle movement. However, the effect of vibration was smaller during more mechanically demanding (i.e. higher peak velocity) movements. Higher vibration frequencies had larger effects on movement accuracy, possibly due to parallel increases in vibration amplitude. These results demonstrate that the effects of ankle tendon vibration are dependent on the mechanical demand of the task being performed, but cannot definitively identify the underlying physiological mechanism. PMID:24136344

  2. Correlations between ankle-foot impairments and dropped foot gait deviations among stroke survivors.

    PubMed

    Chisholm, Amanda E; Perry, Stephen D; McIlroy, William E

    2013-01-01

    The purpose of this paper is to 1) evaluate the relationship between ankle kinematics during gait and standardized measures of ankle impairments among sub-acute stroke survivors, and 2) compare the degree of stroke-related ankle impairment between individuals with and without dropped foot gait deviations. Fifty-five independently ambulating stroke survivors participated in this study. Dropped foot was defined as decreased peak dorsiflexion during the swing phase and reduced ankle joint motion in stance. Standardized outcome measures included the Chedoke-McMaster Stroke Assessment (motor impairment), Modified Ashworth Scale (spasticity), Medical Research Council (muscle strength), passive and active range of motion, and isometric muscle force. Foot impairment was not related to peak dorsiflexion during swing (r=-0.17, P=0.247) and joint motion during stance (r=0.05, P=0.735). Active (r=0.45, P<0.001) and passive (r=0.48, P<0.001) range of motion was associated with stance phase joint motion. Peak dorsiflexion during swing was related to isometric dorsiflexor muscle force (r=-0.32, P=0.039). Individuals with dropped foot demonstrated greater motor impairment, plantarflexor spasticity and ankle muscle weakness compared to those without dropped foot. Our investigation suggests that ankle-foot impairments are related to ankle deviations during gait, as indicated by greater impairment among individuals with dropped foot. These findings contribute to a better understanding of gait-specific ankle deviations, and may lead to the development of a more effective clinical assessment of dropped foot impairment. © 2013.

  3. Compensatory strategies during walking in response to excessive muscle co-contraction at the ankle joint.

    PubMed

    Wang, Ruoli; Gutierrez-Farewik, Elena M

    2014-03-01

    Excessive co-contraction causes inefficient or abnormal movement in several neuromuscular pathologies. How synergistic muscles spanning the ankle, knee and hip adapt to co-contraction of ankle muscles is not well understood. This study aimed to identify the compensation strategies required to retain normal walking with excessive antagonistic ankle muscle co-contraction. Muscle-actuated simulations of normal walking were performed to quantify compensatory mechanisms of ankle and knee muscles during stance in the presence of normal, medium and high levels of co-contraction of antagonistic pairs gastrocnemius+tibialis anterior and soleus+tibialis anterior. The study showed that if co-contraction increases, the synergistic ankle muscles can compensate; with gastrocmemius+tibialis anterior co-contraction, the soleus will increase its contribution to ankle plantarflexion acceleration. At the knee, however, almost all muscles spanning the knee and hip are involved in compensation. We also found that ankle and knee muscles alone can provide sufficient compensation at the ankle joint, but hip muscles must be involved to generate sufficient knee moment. Our findings imply that subjects with a rather high level of dorsiflexor+plantarflexor co-contraction can still perform normal walking. This also suggests that capacity of other lower limb muscles to compensate is important to retain normal walking in co-contracted persons. The compensatory mechanisms can be useful in clinical interpretation of motion analyses, when secondary muscle co-contraction or other deficits may present simultaneously in subjects with motion disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Precraniate origin of cranial motoneurons

    PubMed Central

    Dufour, Héloïse D.; Chettouh, Zoubida; Deyts, Carole; de Rosa, Renaud; Goridis, Christo; Joly, Jean-Stéphane; Brunet, Jean-François

    2006-01-01

    The craniate head is innervated by cranial sensory and motor neurons. Cranial sensory neurons stem from the neurogenic placodes and neural crest and are seen as evolutionary innovations crucial in fulfilling the feeding and respiratory needs of the craniate “new head.” In contrast, cranial motoneurons that are located in the hindbrain and motorize the head have an unclear phylogenetic status. Here we show that these motoneurons are in fact homologous to the motoneurons of the sessile postmetamorphic form of ascidians. The motoneurons of adult Ciona intestinalis, located in the cerebral ganglion and innervating muscles associated with the huge “branchial basket,” express the transcription factors CiPhox2 and CiTbx20, whose vertebrate orthologues collectively define cranial motoneurons of the branchiovisceral class. Moreover, Ciona's postmetamorphic motoneurons arise from a hindbrain set aside during larval life and defined as such by its position (caudal to the prosensephalic sensory vesicle) and coexpression of CiPhox2 and CiHox1, whose orthologues collectively mark the vertebrate hindbrain. These data unveil that the postmetamorphic ascidian brain, assumed to be a derived feature, in fact corresponds to the vertebrate hindbrain and push back the evolutionary origin of cranial nerves to before the origin of craniates. PMID:16735475

  5. Extraocular motoneurons of the adult rat show higher levels of vascular endothelial growth factor and its receptor Flk-1 than other cranial motoneurons.

    PubMed

    Silva-Hucha, Silvia; Hernández, Rosendo G; Benítez-Temiño, Beatriz; Pastor, Ángel M; de la Cruz, Rosa R; Morcuende, Sara

    2017-01-01

    Recent studies show a relationship between the deficit of vascular endothelial growth factor (VEGF) and motoneuronal degeneration, such as that occurring in amyotrophic lateral sclerosis (ALS). VEGF delivery protects motoneurons from cell death and delayed neurodegeneration in animal models of ALS. Strikingly, extraocular motoneurons show lesser vulnerability to neurodegeneration in ALS compared to other cranial or spinal motoneurons. Therefore, the present study investigates possible differences in VEGF and its main receptor VEGFR-2 or Flk-1 between extraocular and non-extraocular brainstem motoneurons. We performed immunohistochemistry and Western blot to determine the presence of VEGF and Flk-1 in rat motoneurons located in the three extraocular motor nuclei (abducens, trochlear and oculomotor) and to compare it to that observed in two other brainstem nuclei (hypoglossal and facial) that are vulnerable to degeneration. Extraocular motoneurons presented higher amounts of VEGF and its receptor Flk-1 than other brainstem motoneurons, and thus these molecules could be participating in their higher resistance to neurodegeneration. In conclusion, we hypothesize that differences in VEGF availability and signaling could be a contributing factor to the different susceptibility of extraocular motoneurons, when compared with other motoneurons, in neurodegenerative diseases.

  6. HuD and the Survival Motor Neuron Protein Interact in Motoneurons and Are Essential for Motoneuron Development, Function, and mRNA Regulation.

    PubMed

    Hao le, Thi; Duy, Phan Q; An, Min; Talbot, Jared; Iyer, Chitra C; Wolman, Marc; Beattie, Christine E

    2017-11-29

    Motoneurons establish a critical link between the CNS and muscles. If motoneurons do not develop correctly, they cannot form the required connections, resulting in movement defects or paralysis. Compromised development can also lead to degeneration because the motoneuron is not set up to function properly. Little is known, however, regarding the mechanisms that control vertebrate motoneuron development, particularly the later stages of axon branch and dendrite formation. The motoneuron disease spinal muscular atrophy (SMA) is caused by low levels of the survival motor neuron (SMN) protein leading to defects in vertebrate motoneuron development and synapse formation. Here we show using zebrafish as a model system that SMN interacts with the RNA binding protein (RBP) HuD in motoneurons in vivo during formation of axonal branches and dendrites. To determine the function of HuD in motoneurons, we generated zebrafish HuD mutants and found that they exhibited decreased motor axon branches, dramatically fewer dendrites, and movement defects. These same phenotypes are present in animals expressing low levels of SMN, indicating that both proteins function in motoneuron development. HuD binds and transports mRNAs and one of its target mRNAs, Gap43 , is involved in axonal outgrowth. We found that Gap43 was decreased in both HuD and SMN mutants. Importantly, transgenic expression of HuD in motoneurons of SMN mutants rescued the motoneuron defects, the movement defects, and Gap43 mRNA levels. These data support that the interaction between SMN and HuD is critical for motoneuron development and point to a role for RBPs in SMA. SIGNIFICANCE STATEMENT In zebrafish models of the motoneuron disease spinal muscular atrophy (SMA), motor axons fail to form the normal extent of axonal branches and dendrites leading to decreased motor function. SMA is caused by low levels of the survival motor neuron (SMN) protein. We show in motoneurons in vivo that SMN interacts with the RNA binding

  7. Adaptability of the oxidative capacity of motoneurons

    NASA Technical Reports Server (NTRS)

    Chalmers, G. R.; Roy, R. R.; Edgerton, V. R.

    1992-01-01

    Previous studies have demonstrated that a chronic change in neuronal activation can produce a change in soma oxidative capacity, suggesting that: (i) these 2 variables are directly related in neurons and (ii) ion pumping is an important energy requiring activity of a neuron. Most of these studies, however, have focused on reduced activation levels of sensory systems. In the present study the effect of a chronic increase or decrease in motoneuronal activity on motoneuron oxidative capacity and soma size was studied. In addition, the effect of chronic axotomy was studied as an indicator of whether cytoplasmic volume may also be related to the oxidative capacity of motoneurons. A quantitative histochemical assay for succinate dehydrogenase activity was used as a measure of motoneuron oxidative capacity in experimental models in which chronic electromyography has been used to verify neuronal activity levels. Spinal transection reduced, and spinal isolation virtually eliminated lumbar motoneuron electrical activity. Functional overload of the plantaris by removal of its major synergists was used to chronically increase neural activity of the plantaris motor pool. No change in oxidative capacity or soma size resulted from either a chronic increase or decrease in neuronal activity level. These data indicate that the chronic modulation of ionic transport and neurotransmitter turnover associated with action potentials do not induce compensatory metabolic responses in the metabolic capacity of the soma of lumbar motoneurons. Soma oxidative capacity was reduced in the axotomized motoneurons, suggesting that a combination of axoplasmic transport, intracellular biosynthesis and perhaps neurotransmitter turnover represent the major energy demands on a motoneuron. While soma oxidative capacity may be closely related to neural activity in some neural systems, e.g. visual and auditory, lumbar motoneurons appear to be much less sensitive to modulations in chronic activity levels.

  8. Gait and physical impairments in patients with acute ankle sprains who did not receive physical therapy.

    PubMed

    Punt, Ilona M; Ziltener, Jean-Luc; Laidet, Magali; Armand, Stéphane; Allet, Lara

    2015-01-01

    To assess ankle function 4 weeks after conservative management and to examine the correlation of function with gait. A prospective comparison study. Thirty patients with grade I or II acute ankle sprains were followed up after 4 weeks of conservative management not involving physical therapy. Participants underwent a clinical assessment and had to walk at a normal self-selected walking speed. Their results were compared with the data of 15 healthy subjects. Participants' joint swelling, muscle strength, passive mobility, and pain were assessed. In addition, patients' temporal-spatial, kinematic, and kinetic gait data were measured while walking. Muscle strength and passive mobility were significantly reduced on the injured side compared with the noninjured side (P < .001). During gait analysis, patients with ankle sprains showed slower walking speed, shorter step length, shorter single support time, reduced and delayed maximum plantar flexion, decreased maximum power, and decreased maximum moment (P < .050) compared with healthy persons. Decreased walking speed was mainly correlated with pain (R = -0.566, P = .001) and deficits in muscle strength of dorsiflexors (R = 0.506, P = .004). Four weeks after an ankle sprain, patients who did not receive physical therapy showed physical impairments of the ankle that were correlated with gait parameters. These findings might help fine-tune rehabilitation protocols. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  9. Gait mode recognition and control for a portable-powered ankle-foot orthosis.

    PubMed

    David Li, Yifan; Hsiao-Wecksler, Elizabeth T

    2013-06-01

    Ankle foot orthoses (AFOs) are widely used as assistive/rehabilitation devices to correct the gait of people with lower leg neuromuscular dysfunction and muscle weakness. We have developed a portable powered ankle-foot orthosis (PPAFO), which uses a pneumatic bi-directional rotary actuator powered by compressed CO2 to provide untethered dorsiflexor and plantarflexor assistance at the ankle joint. Since portability is a key to the success of the PPAFO as an assist device, it is critical to recognize and control for gait modes (i.e. level walking, stair ascent/descent). While manual mode switching is implemented in most powered orthotic/prosthetic device control algorithms, we propose an automatic gait mode recognition scheme by tracking the 3D position of the PPAFO from an inertial measurement unit (IMU). The control scheme was designed to match the torque profile of physiological gait data during different gait modes. Experimental results indicate that, with an optimized threshold, the controller was able to identify the position, orientation and gait mode in real time, and properly control the actuation. It was also illustrated that during stair descent, a mode-specific actuation control scheme could better restore gait kinematic and kinetic patterns, compared to using the level ground controller.

  10. Neuroprotective effects of testosterone metabolites and dependency on receptor action on the morphology of somatic motoneurons following the death of neighboring motoneurons.

    PubMed

    Cai, Yi; Chew, Cory; Muñoz, Fernando; Sengelaub, Dale R

    2017-06-01

    Partial depletion of spinal motoneuron populations induces dendritic atrophy in neighboring motoneurons, and treatment with testosterone is neuroprotective, attenuating induced dendritic atrophy. In this study we examined whether the protective effects of testosterone could be mediated via its androgenic or estrogenic metabolites. Furthermore, to assess whether these neuroprotective effects were mediated through steroid hormone receptors, we used receptor antagonists to attempt to prevent the neuroprotective effects of hormones after partial motoneuron depletion. Motoneurons innervating the vastus medialis muscles of adult male rats were selectively killed by intramuscular injection of cholera toxin-conjugated saporin. Simultaneously, some saporin-injected rats were treated with either dihydrotestosterone or estradiol, alone or in combination with their respective receptor antagonists, or left untreated. Four weeks later, motoneurons innervating the ipsilateral vastus lateralis muscle were labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed in three dimensions. Compared with intact normal animals, partial motoneuron depletion resulted in decreased dendritic length in remaining quadriceps motoneurons. Dendritic atrophy was attenuated with both dihydrotestosterone and estradiol treatment to a degree similar to that seen with testosterone, and attenuation of atrophy was prevented by receptor blockade. Together, these findings suggest that neuroprotective effects on motoneurons can be mediated by either androgenic or estrogenic hormones and require action via steroid hormone receptors, further supporting a role for hormones as neurotherapeutic agents in the injured nervous system. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 691-707, 2017. © 2016 Wiley Periodicals, Inc.

  11. Persistence of long term isokinetic strength deficits in subjects with lateral ankle sprain as measured with a protocol including maximal preloading.

    PubMed

    Perron, Marc; Moffet, Hélène; Nadeau, Sylvie; Hébert, Luc J; Belzile, Sylvain

    2014-12-01

    The assessment of muscle function is a cornerstone in the management of subjects who have sustained a lateral ankle sprain. The ankle range of motion being relatively small, the use of preloading allows to measure maximal strength throughout the whole amplitude and therefore to better characterize ankle muscles weaknesses. This study aimed to assess muscle strength of the injured and uninjured ankles in subjects with a lateral ankle sprain, to document the timeline of strength recovery, and to determine the influence of sprain grade on strength loss. Maximal torque of the periarticular muscles of the ankle in a concentric mode using a protocol with maximal preloading was tested in 32 male soldiers at 8 weeks and 6 months post-injury. The evertor muscles of the injured ankles were weaker than the uninjured ones at 8 weeks and 6 months post-injury (P<0.0001, effect size=0.31-0.42). Muscle weaknesses also persisted in the plantarflexors of the injured ankles at 8 weeks (P=0.0014, effect size=0.52-0.58) while at 6 months, only the subjects with a grade II sprain displayed such weaknesses (P<0.0001, effect size 0.27-0.31). The strength of the invertor and dorsiflexor muscles did not differ between sides. The use of an isokinetic protocol with preloading demonstrates significant but small strength deficits in the evertor and plantarflexor muscles. These impairments may contribute to the high incidence of recurrence of lateral ankle sprain in very active individuals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Feedback Signal from Motoneurons Influences a Rhythmic Pattern Generator.

    PubMed

    Rotstein, Horacio G; Schneider, Elisa; Szczupak, Lidia

    2017-09-20

    Motoneurons are not mere output units of neuronal circuits that control motor behavior but participate in pattern generation. Research on the circuit that controls the crawling motor behavior in leeches indicated that motoneurons participate as modulators of this rhythmic motor pattern. Crawling results from successive bouts of elongation and contraction of the whole leech body. In the isolated segmental ganglia, dopamine can induce a rhythmic antiphasic activity of the motoneurons that control contraction (DE-3 motoneurons) and elongation (CV motoneurons). The study was performed in isolated ganglia where manipulation of the activity of specific motoneurons was performed in the course of fictive crawling ( crawling ). In this study, the membrane potential of CV was manipulated while crawling was monitored through the rhythmic activity of DE-3. Matching behavioral observations that show that elongation dominates the rhythmic pattern, the electrophysiological activity of CV motoneurons dominates the cycle. Brief excitation of CV motoneurons during crawling episodes resets the rhythmic activity of DE-3, indicating that CV feeds back to the rhythmic pattern generator. CV hyperpolarization accelerated the rhythm to an extent that depended on the magnitude of the cycle period, suggesting that CV exerted a positive feedback on the unit(s) of the pattern generator that controls the elongation phase. A simple computational model was implemented to test the consequences of such feedback. The simulations indicate that the duty cycle of CV depended on the strength of the positive feedback between CV and the pattern generator circuit. SIGNIFICANCE STATEMENT Rhythmic movements of animals are controlled by neuronal networks that have been conceived as hierarchical structures. At the basis of this hierarchy, we find the motoneurons, few neurons at the top control global aspects of the behavior (e.g., onset, duration); and within these two ends, specific neuronal circuits control

  13. Bilateral effects of 6 weeks' unilateral acupuncture and electroacupuncture on ankle dorsiflexors muscle strength: a pilot study.

    PubMed

    Zhou, Shi; Huang, Li-Ping; Liu, Jun; Yu, Jun-Hai; Tian, Qiang; Cao, Long-Jun

    2012-01-01

    To determine the effect of unilateral manual acupuncture at selected acupoints on ankle dorsiflexion strength of both limbs, and compare the effect with that of electroacupuncture at the same acupoints and sham points. Randomized controlled trial. Rehabilitation laboratory of a university. Young men (N=43) were randomly allocated into 4 groups: control; manual acupuncture and electroacupuncture on 2 acupoints (ST-36 and ST-39); and electroacupuncture on 2 nonacupoints. These points were located on the tibialis anterior muscle. The participants in the experimental groups received 15 to 30 minutes of acupuncture or electroacupuncture on the right leg in each session, 3 sessions per week for 6 weeks. The maximal strength in isometric ankle dorsiflexion of both legs was assessed before and after the experimental period. Repeated-measures analysis of variance identified significant and similar strength gains (range, 35%-64% in the right leg and 32%-49% in the left leg; P<.01) in all acupuncture groups, but not in the control group (-2% to 2%, P>.05). Unilateral manual acupuncture and electroacupuncture at the acupoints can improve muscle strength in both limbs, and electroacupuncture at the nonacupoints as used in this study can also induce similar strength gains. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  14. The effects of aging on hypoglossal motoneurons in rats.

    PubMed

    Schwarz, Emilie C; Thompson, Jodi M; Connor, Nadine P; Behan, Mary

    2009-03-01

    Aging can result in a loss of neuronal cell bodies and a decrease in neuronal size in some regions of the brain and spinal cord. Motoneuron loss in the spinal cord is thought to contribute to the progressive decline in muscle mass and strength that occurs with age (sarcopenia). Swallowing disorders represent a large clinical problem in elderly persons; however, age-related alterations in cranial motoneurons that innervate muscles involved in swallowing have been understudied. We aimed to determine if age-related alterations occurred in the hypoglossal nucleus in the brainstem. If present, these changes might help explain alterations at the neuromuscular junction and changes in the contractile properties of tongue muscle that have been reported in older rats. We hypothesized that with increasing age there would be a loss of motoneurons and a reduction in neuronal size and the number of primary dendrites associated with each hypoglossal motoneuron. Neurons in the hypoglossal nucleus were visualized with the neuronal marker NeuN in young (9-10 months), middle-aged (24-25 months), and old (32-33 months) male F344/BN rats. Hypoglossal motoneurons were retrograde-labeled with injections of Cholera Toxin beta into the genioglossus muscle of the tongue and visualized using immunocytochemistry. Results indicated that the number of primary dendrites of hypoglossal motoneurons decreased significantly with age, while no age-associated changes were found in the number or size of hypoglossal motoneurons. Loss of primary dendrites could reduce the number of synaptic inputs and thereby impair function.

  15. The Effects of Aging on Hypoglossal Motoneurons in Rats

    PubMed Central

    Schwarz, Emilie C.; Thompson, Jodi M.; Connor, Nadine P.; Behan, Mary

    2008-01-01

    Aging can result in a loss of neuronal cell bodies and a decrease in neuronal size in some regions of the brain and spinal cord. Motoneuron loss in the spinal cord is thought to contribute to the progressive decline in muscle mass and strength that occurs with age (sarcopenia). Swallowing disorders represent a large clinical problem in elderly persons; however, age-related alterations in cranial motoneurons that innervate muscles involved in swallowing have been understudied. We aimed to determine if age-related alterations occurred in the hypoglossal nucleus in the brainstem. If present, these changes might help explain alterations at the neuromuscular junction and changes in the contractile properties of tongue muscle that have been reported in older rats. We hypothesized that with increasing age, there would be a loss of motoneurons and a reduction in neuronal size and the number of primary dendrites associated with each hypoglossal motoneuron. Neurons in the hypoglossal nucleus were visualized with the neuronal marker NeuN in young (9–10 months), middle-aged (24–25 months), and old (32–33 months) male F344/BN rats. Hypoglossal motoneurons were retrograde labeled with injections of Cholera Toxin β into the genioglossus muscle of the tongue and visualized using immunocytochemistry. Results indicated that the number of primary dendrites of hypoglossal motoneurons decreased significantly with age, while no age-associated changes were found in the number or size of hypoglossal motoneurons. Loss of primary dendrites could reduce the number of synaptic inputs and thereby impair function. PMID:18716837

  16. Absolute Reliability and Concurrent Validity of Hand Held Dynamometry and Isokinetic Dynamometry in the Hip, Knee and Ankle Joint: Systematic Review and Meta-analysis

    PubMed Central

    Chamorro, Claudio; Armijo-Olivo, Susan; De la Fuente, Carlos; Fuentes, Javiera; Javier Chirosa, Luis

    2017-01-01

    Abstract The purpose of the study is to establish absolute reliability and concurrent validity between hand-held dynamometers (HHDs) and isokinetic dynamometers (IDs) in lower extremity peak torque assessment. Medline, Embase, CINAHL databases were searched for studies related to psychometric properties in muscle dynamometry. Studies considering standard error of measurement SEM (%) or limit of agreement LOA (%) expressed as percentage of the mean, were considered to establish absolute reliability while studies using intra-class correlation coefficient (ICC) were considered to establish concurrent validity between dynamometers. In total, 17 studies were included in the meta-analysis. The COSMIN checklist classified them between fair and poor. Using HHDs, knee extension LOA (%) was 33.59%, 95% confidence interval (CI) 23.91 to 43.26 and ankle plantar flexion LOA (%) was 48.87%, CI 35.19 to 62.56. Using IDs, hip adduction and extension; knee flexion and extension; and ankle dorsiflexion showed LOA (%) under 15%. Lower hip, knee, and ankle LOA (%) were obtained using an ID compared to HHD. ICC between devices ranged between 0.62, CI (0.37 to 0.87) for ankle dorsiflexion to 0.94, IC (0.91to 0.98) for hip adduction. Very high correlation were found for hip adductors and hip flexors and moderate correlations for knee flexors/extensors and ankle plantar/dorsiflexors. PMID:29071305

  17. Simultaneous characterizations of reflex and nonreflex dynamic and static changes in spastic hemiparesis

    PubMed Central

    Chung, Sun G.; Ren, Yupeng; Liu, Lin; Roth, Elliot J.; Rymer, W. Zev

    2013-01-01

    This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping. Tendon reflex was characterized with reflex gain and threshold. Reflexively, tonic reflex gain was increased in spastic ankles at rest (P < 0.038) and was not regulated with muscle contraction, indicating impaired tonic stretch reflex. Phasic-reflex gain in spastic plantar flexors was higher and increased faster with plantar flexor contraction (P < 0.012) than controls (P < 0.023) and higher in dorsi-flexors at lower torques (P < 0.038), primarily because of its increase at rest (P = 0.045), indicating exaggerated phasic stretch reflex especially in more spastic plantar flexors, which showed higher phasic stretch reflex gain than dorsi-flexors (P < 0.032). Spasticity was associated with increased tendon reflex gain (P = 0.002) and decreased threshold (P < 0.001). Mechanically, stiffness in spastic ankles was higher than that in controls across plantar flexion/dorsi-flexion torque levels (P < 0.032), and the more spastic plantar flexors were stiffer than dorsi-flexors at comparable torques (P < 0.031). Increased stiffness in spastic ankles was mainly due to passive stiffness increase (P < 0.001), indicating increased connective tissues/shortened fascicles. Viscous damping in spastic ankles was increased across the plantar flexion torque levels and at lower dorsi-flexion torques, reflecting increased passive viscous damping (P = 0.033). The more spastic plantar flexors showed higher viscous damping than dorsi-flexors at comparable torque levels (P < 0.047). Simultaneous characterizations of reflex and nonreflex changes in spastic hemiparesis may help to evaluate and treat

  18. Saccular and utricular inputs to sternocleidomastoid motoneurons of decerebrate cats.

    PubMed

    Kushiro, K; Zakir, M; Ogawa, Y; Sato, H; Uchino, Y

    1999-06-01

    Connections from the otolithic organs to sternocleidomastoid (SCM) motoneurons were studied in 20 decerebrate cats. The electrical stimulation was selective for the saccular or the utricular nerves. Postsynaptic potentials were recorded from antidromically identified SCM motoneurons; these muscles participate mainly in neck rotation and flexion. Partial transections of the brainstem at the level of the obex were performed to identify the possible pathway from the otolithic organs to the SCM motoneurons. Saccular or utricular nerve stimulation mainly evoked inhibitory postsynaptic potentials (IPSPs) in the ipsilateral SCM motoneurons. Some of the sacculus-induced IPSPs were preceded by small-amplitude excitatory PSPs (EPSPs). The latencies of the PSPs ranged from 1.8 to 3.1 ms after saccular nerve stimulation and from 1.7 to 2.8 ms after utricular nerve stimulation, indicating that most of the ipsilateral connections were disynaptic. In the contralateral SCM motoneurons, saccular nerve stimulation had no or faint effects, whereas utricular nerve stimulation evoked EPSPs in about two-thirds of neurons, and no visible PSPs in about one-third of neurons. The latencies of the EPSPs ranged from 1.5 to 2.0 ms, indicating the disynaptic connection. Thus, the results suggest a difference between the two otolithic innervating patterns of SCM motoneurons. After transection of the medial vestibulospinal tract (MVST), saccular nerve stimulation did not evoke IPSPs at all in ipsilateral SCM motoneurons, but some (11/40) neurons showed small-amplitude EPSPs. Most (24/33) of the utricular-activated IPSPs disappeared after transection, whereas the other 9 neurons still indicated IPSPs. In the contralateral SCM motoneurons, no utricular-activated EPSPs were recorded after transection. These MVST transection results suggest that most of the otolith-SCM pathways are located in the MVST at the obex level. However, the results also suggest the possibility that other otolith-SCM pathways

  19. Inhibitory motoneurons in arthropod motor control: organisation, function, evolution.

    PubMed

    Wolf, Harald

    2014-08-01

    Miniaturisation of somatic cells in animals is limited, for reasons ranging from the accommodation of organelles to surface-to-volume ratio. Consequently, muscle and nerve cells vary in diameters by about two orders of magnitude, in animals covering 12 orders of magnitude in body mass. Small animals thus have to control their behaviour with few muscle fibres and neurons. Hexapod leg muscles, for instance, may consist of a single to a few 100 fibres, and they are controlled by one to, rarely, 19 motoneurons. A typical mammal has thousands of fibres per muscle supplied by hundreds of motoneurons for comparable behavioural performances. Arthopods--crustaceans, hexapods, spiders, and their kin--are on average much smaller than vertebrates, and they possess inhibitory motoneurons for a motor control strategy that allows a broad performance spectrum despite necessarily small cell numbers. This arthropod motor control strategy is reviewed from functional and evolutionary perspectives and its components are described with a focus on inhibitory motoneurons. Inhibitory motoneurons are particularly interesting for a number of reasons: evolutionary and phylogenetic comparison of functional specialisations, evolutionary and developmental origin and diversification, and muscle fibre recruitment strategies.

  20. Electrical stimulation of transplanted motoneurons improves motor unit formation

    PubMed Central

    Liu, Yang; Grumbles, Robert M.

    2014-01-01

    Motoneurons die following spinal cord trauma and with neurological disease. Intact axons reinnervate nearby muscle fibers to compensate for the death of motoneurons, but when an entire motoneuron pool dies, there is complete denervation. To reduce denervation atrophy, we have reinnervated muscles in Fisher rats from local transplants of embryonic motoneurons in peripheral nerve. Since growth of axons from embryonic neurons is activity dependent, our aim was to test whether brief electrical stimulation of the neurons immediately after transplantation altered motor unit numbers and muscle properties 10 wk later. All surgical procedures and recordings were done in anesthetized animals. The muscle consequences of motoneuron death were mimicked by unilateral sciatic nerve section. One week later, 200,000 embryonic day 14 and 15 ventral spinal cord cells, purified for motoneurons, were injected into the tibial nerve 10–15 mm from the gastrocnemii muscles as the only neuron source for muscle reinnervation. The cells were stimulated immediately after transplantation for up to 1 h using protocols designed to examine differential effects due to pulse number, stimulation frequency, pattern, and duration. Electrical stimulation that included short rests and lasted for 1 h resulted in higher motor unit counts. Muscles with higher motor unit counts had more reinnervated fibers and were stronger. Denervated muscles had to be stimulated directly to evoke contractions. These results show that brief electrical stimulation of embryonic neurons, in vivo, has long-term effects on motor unit formation and muscle force. This muscle reinnervation provides the opportunity to use patterned electrical stimulation to produce functional movements. PMID:24848463

  1. Myosin phosphatase Fine-tunes Zebrafish Motoneuron Position during Axonogenesis

    PubMed Central

    Granato, Michael

    2016-01-01

    During embryogenesis the spinal cord shifts position along the anterior-posterior axis relative to adjacent tissues. How motor neurons whose cell bodies are located in the spinal cord while their axons reside in adjacent tissues compensate for such tissue shift is not well understood. Using live cell imaging in zebrafish, we show that as motor axons exit from the spinal cord and extend through extracellular matrix produced by adjacent notochord cells, these cells shift several cell diameters caudally. Despite this pronounced shift, individual motoneuron cell bodies stay aligned with their extending axons. We find that this alignment requires myosin phosphatase activity within motoneurons, and that mutations in the myosin phosphatase subunit mypt1 increase myosin phosphorylation causing a displacement between motoneuron cell bodies and their axons. Thus, we demonstrate that spinal motoneurons fine-tune their position during axonogenesis and we identify the myosin II regulatory network as a key regulator. PMID:27855159

  2. Motoneuron excitability of the quadriceps decreases during a fatiguing submaximal isometric contraction.

    PubMed

    Finn, Harrison T; Rouffet, David M; Kennedy, David S; Green, Simon; Taylor, Janet L

    2018-04-01

    During fatiguing voluntary contractions, the excitability of motoneurons innervating arm muscles decreases. However, the behavior of motoneurons innervating quadriceps muscles is unclear. Findings may be inconsistent because descending cortical input influences motoneuron excitability and confounds measures during exercise. To overcome this limitation, we examined effects of fatigue on quadriceps motoneuron excitability tested during brief pauses in descending cortical drive after transcranial magnetic stimulation (TMS). Participants ( n = 14) performed brief (~5-s) isometric knee extension contractions before and after a 10-min sustained contraction at ~25% maximal electromyogram (EMG) of vastus medialis (VM) on one ( n = 5) or two ( n = 9) days. Electrical stimulation over thoracic spine elicited thoracic motor evoked potentials (TMEP) in quadriceps muscles during ongoing voluntary drive and 100 ms into the silent period following TMS (TMS-TMEP). Femoral nerve stimulation elicited maximal M-waves (M max ). On the 2 days, either large (~50% M max ) or small (~15% M max ) TMS-TMEPs were elicited. During the 10-min contraction, VM EMG was maintained ( P = 0.39), whereas force decreased by 52% (SD 13%) ( P < 0.001). TMEP area remained unchanged ( P = 0.9), whereas large TMS-TMEPs decreased by 49% (SD 28%) ( P = 0.001) and small TMS-TMEPs by 71% (SD 22%) ( P < 0.001). This decline was greater for small TMS-TMEPs ( P = 0.019; n = 9). Therefore, without the influence of descending drive, quadriceps TMS-TMEPs decreased during fatigue. The greater reduction for smaller responses, which tested motoneurons that were most active during the contraction, suggests a mechanism related to repetitive activity contributes to reduced quadriceps motoneuron excitability during fatigue. By contrast, the unchanged TMEP suggests that ongoing drive compensates for altered motoneuron excitability. NEW & NOTEWORTHY We provide evidence that the excitability of quadriceps

  3. Direct connection of the nucleus reticularis gigantocellularis neurons with neck motoneurons in cats.

    PubMed

    Sasaki, S

    1999-10-01

    Functional connections of single reticulospinal neurons (RSNs) in the nucleus reticularis gigantocellularis (NRG) with ipsilateral dorsal neck motoneurons were examined with the spike-triggered averaging technique. Extracellular spikes of single NRG-RSNs activated antidromically from the C6, but not from the L1 segment (C-RSNs) were used as the trigger. These neurons were monosynaptically activated from the superior colliculus and the cerebral peduncle. Single-RSN PSPs were recorded in 43 dorsal neck motoneurons [biventer cervicis and complexus (BCC) and splenius (SPL)] for 21 NRG-RSNs and 135 motoneurons tested. All synaptic potentials were EPSPs, and most of their latencies, measured from the triggering spikes, were 0.8-1.5 ms, which is in a monosynaptic range. The amplitudes of single-RSN EPSPs were 10-360 microV. Spike-triggered averaging revealed single-RSN EPSPs in multiple motoneurons of the same species (SPL or BCC), their locations extending up to nearly 1 mm rostrocaudally. Synaptic connections of single RSNs with both SPL and BCC motoneurons were also found with some predominance for one of them. The results provide direct evidence that NRG-RSNs make monosynaptic excitatory connections with SPL and BCC motoneurons. It appears that some NRG-RSNs connect predominantly with SPL motoneurons and others with BCC motoneurons.

  4. Permanent reorganization of Ia afferent synapses on motoneurons after peripheral nerve injuries

    PubMed Central

    Alvarez, Francisco J.; Bullinger, Katie L.; Titus, Haley E.; Nardelli, Paul; Cope, Timothy C.

    2010-01-01

    After peripheral nerve injuries to a motor nerve the axons of motoneurons and proprioceptors are disconnected from the periphery and monosynaptic connections from group I afferents and motoneurons become diminished in the spinal cord. Following successful reinnervation in the periphery, motor strength, proprioceptive sensory encoding, and Ia afferent synaptic transmission on motoneurons partially recover. Muscle stretch reflexes, however, never recover and motor behaviors remain uncoordinated. In this review, we summarize recent findings that suggest that lingering motor dysfunction might be in part related to decreased connectivity of Ia afferents centrally. First, sensory afferent synapses retract from lamina IX causing a permanent relocation of the inputs to more distal locations and significant disconnection from motoneurons. Second, peripheral reconnection between proprioceptive afferents and muscle spindles is imperfect. As a result, a proportion of sensory afferents that retain central connections with motoneurons might not reconnect appropriately in the periphery. A hypothetical model is proposed in which the combined effect of peripheral and central reconnection deficits might explain the failure of muscle stretch to initiate or modulate firing of many homonymous motoneurons. PMID:20536938

  5. Reflexes in cat ankle muscles after landing from falls.

    PubMed Central

    Prochazka, A; Schofield, P; Westerman, R A; Ziccone, S P

    1977-01-01

    1. Electrical activity and length of ankle muscles were recorded by telemetry during free fall and landing in cats. 2. After foot contact, there was a delay in onset of stretch of ankle extensors of between 8 and 11 ms. High-speed cinematography showed the delay to be associated with rapid initial dorsiflexion of the toes. 3. Electromyograms (e.m.g.) from lateral gastrocnemius increased in amplitude prior to landing. An early depression of lateral gastrocnemius e.m.g. commenced at 8 ms after foot contact, and was followed by a large peak of activity commencing some 8 ms after the first increase in lateral gastrocnemius length. 4. Local anaesthesia of the plantar cushion did not alter this pattern of response. 5. The early inhibition of lateral gastrocnemius was attributed to the action on lateral gastrocnemius motoneurones of non-cutaneous afferents responding to the initial toe dorsiflexion. Additional autogenetic inhibition may also have contributed. 6. The subsequent peak of e.m.g. was at a latenty consistent with a rapid stretch reflex, and occurred soon enough for the resulting active tension to contribute significantly to the extensor force during body deceleration. PMID:592210

  6. Changes in the estimated time course of the motoneuron afterhyperpolarization induced by tendon vibration.

    PubMed

    MacDonell, Christopher W; Ivanova, Tanya D; Garland, S Jayne

    2010-12-01

    Group Ia afferents are activated vigorously with high-frequency tendon vibration and provide excitatory input to the agonist muscle and inhibitory input to the antagonist muscle group via inhibitory interneurons. The purpose of this experiment was to determine whether the afterhyperpolarization (AHP) time course in humans is altered in response to tendon vibration. The AHP time course is estimated using the interval death rate (IDR) analysis, a transform of the motor unit action potential train. Single motor units from tibialis anterior (TA) were recorded as subjects held low force dorsiflexor contractions for 600 s with and without vibration. The vibratory stimulus was superimposed on the low force contraction either to the tendon of the TA or the antagonist Achilles tendon. During TA tendon vibration, the time course of the AHP, as expressed by its time constant (τ), decreased from 35.5 ms in the previbration control condition to 31.3 ms during the vibration (P = 0.003) and returned to 36.3 ms after the vibration was removed (P = 0.002). The AHP τ during vibration of the antagonist Achilles tendon (38.6 ms) was greater than the previbration control condition (33.6 ms; P = 0.001). It is speculated that the reduction in AHP time constant with TA vibration may have resulted alone or in combination with a modulation of motoneuron gain, an alteration of persistent inward currents and/or the restructuring of synaptic noise. A decrease in firing probability, possibly reflecting Ia reciprocal inhibition, may have been responsible for the larger AHP time constant.

  7. The alpha-motoneuron pool as transmitter of rhythmicities in cortical motor drive.

    PubMed

    Stegeman, Dick F; van de Ven, Wendy J M; van Elswijk, Gijs A; Oostenveld, Robert; Kleine, Bert U

    2010-10-01

    Investigate the effectiveness and frequency dependence of central drive transmission via the alpha-motoneuron pool to the muscle. We describe a model for the simulation of alpha-motoneuron firing and the EMG signal as response to central drive input. The transfer in the frequency domain is investigated. Coherence between stochastical central input and EMG is also evaluated. The transmission of central rhythmicities to the EMG signal relates to the spectral content of the latter. Coherence between central input to the alpha-motoneuron pool and the EMG signal is significant whereby the coupling strength hardly depends on the frequency in a range from 1 to 100 Hz. Common central input to pairs of alpha-motoneurons strongly increases the coherence levels. The often-used rectification of the EMG signal introduces a clear frequency dependence. Oscillatory phenomena are strongly transmitted via the alpha-motoneuron pool. The motoneuron firing frequencies do play a role in the transmission gain, but do not influence the coherence levels. Rectification of the EMG signal enhances the transmission gain, but lowers coherence and introduces a strong frequency dependency. We think that it should be avoided. Our findings show that rhythmicities are translated into alpha-motoneuron activity without strong non-linearities. Copyright 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  8. Inhibition of Sirt1 promotes neural progenitors toward motoneuron differentiation from human embryonic stem cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Yun; Wang, Jing; Clinical Stem Cell Center, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing 100191

    2011-01-14

    Research highlights: {yields} Nicotinamide inhibit Sirt1. {yields} MASH1 and Ngn2 activation. {yields} Increase the expression of HB9. {yields} Motoneurons formation increases significantly. -- Abstract: Several protocols direct human embryonic stem cells (hESCs) toward differentiation into functional motoneurons, but the efficiency of motoneuron generation varies based on the human ESC line used. We aimed to develop a novel protocol to increase the formation of motoneurons from human ESCs. In this study, we tested a nuclear histone deacetylase protein, Sirt1, to promote neural precursor cell (NPC) development during differentiation of human ESCs into motoneurons. A specific inhibitor of Sirt1, nicotinamide, dramatically increasedmore » motoneuron formation. We found that about 60% of the cells from the total NPCs expressed HB9 and {beta}III-tubulin, commonly used motoneuronal markers found in neurons derived from ESCs following nicotinamide treatment. Motoneurons derived from ESC expressed choline acetyltransferase (ChAT), a positive marker of mature motoneuron. Moreover, we also examined the transcript levels of Mash1, Ngn2, and HB9 mRNA in the differentiated NPCs treated with the Sirt1 activator resveratrol (50 {mu}M) or inhibitor nicotinamide (100 {mu}M). The levels of Mash1, Ngn2, and HB9 mRNA were significantly increased after nicotinamide treatment compared with control groups, which used the traditional protocol. These results suggested that increasing Mash1 and Ngn2 levels by inhibiting Sirt1 could elevate HB9 expression, which promotes motoneuron differentiation. This study provides an alternative method for the production of transplantable motoneurons, a key requirement in the development of hESC-based cell therapy in motoneuron disease.« less

  9. Phrenic motoneuron expression of serotonergic and glutamatergic receptors following upper cervical spinal cord injury

    PubMed Central

    Mantilla, Carlos B.; Bailey, Jeffrey P.; Zhan, Wen-Zhi; Sieck, Gary C.

    2012-01-01

    Following cervical spinal cord injury at C2 (SH hemisection model) there is progressive recovery of phrenic activity. Neuroplasticity in the postsynaptic expression of neurotransmitter receptors may contribute to functional recovery. Phrenic motoneurons express multiple serotonergic (5-HTR) and glutamatergic (GluR) receptors, but the timing and possible role of these different neurotransmitter receptor subtypes in the neuroplasticity following SH are not clear. The current study was designed to test the hypothesis that there is an increased expression of serotonergic and glutamatergic neurotransmitter receptors within phrenic motoneurons after SH. In adult male rats, phrenic motoneurons were labeled retrogradely by intrapleural injection of Alexa 488-conjugated cholera toxin B. In thin (10 μm) frozen sections of the spinal cord, fluorescently-labeled phrenic motoneurons were visualized for laser capture microdissection (LCM). Using quantitative real-time RT-PCR in LCM samples, the time course of changes in 5-HTR and GluR mRNA expression was determined in phrenic motoneurons up to 21 days post-SH. Expression of 5-HTR subtypes 1b, 2a and 2c and GluR subtypes AMPA, NMDA, mGluR1 and mGluR5 was evident in phrenic motoneurons from control and SH rats. Phrenic motoneuron expression of 5-HTR2a increased ~8-fold (relative to control) at 14 days post-SH, whereas NMDA expression increased ~16-fold by 21-days post-SH. There were no other significant changes in receptor expression at any time post-SH. This is the first study to systematically document changes in motoneuron expression of multiple neurotransmitter receptors involved in regulation of motoneuron excitability. By providing information on the neuroplasticity of receptors expressed in a motoneuron pool that is inactivated by a higher-level spinal cord injury, appropriate pharmacological targets can be identified to alter motoneuron excitability. PMID:22227062

  10. Synaptic control of the shape of the motoneuron pool input-output function

    PubMed Central

    Heckman, Charles J.

    2017-01-01

    Although motoneurons have often been considered to be fairly linear transducers of synaptic input, recent evidence suggests that strong persistent inward currents (PICs) in motoneurons allow neuromodulatory and inhibitory synaptic inputs to induce large nonlinearities in the relation between the level of excitatory input and motor output. To try to estimate the possible extent of this nonlinearity, we developed a pool of model motoneurons designed to replicate the characteristics of motoneuron input-output properties measured in medial gastrocnemius motoneurons in the decerebrate cat with voltage-clamp and current-clamp techniques. We drove the model pool with a range of synaptic inputs consisting of various mixtures of excitation, inhibition, and neuromodulation. We then looked at the relation between excitatory drive and total pool output. Our results revealed that the PICs not only enhance gain but also induce a strong nonlinearity in the relation between the average firing rate of the motoneuron pool and the level of excitatory input. The relation between the total simulated force output and input was somewhat more linear because of higher force outputs in later-recruited units. We also found that the nonlinearity can be increased by increasing neuromodulatory input and/or balanced inhibitory input and minimized by a reciprocal, push-pull pattern of inhibition. We consider the possibility that a flexible input-output function may allow motor output to be tuned to match the widely varying demands of the normal motor repertoire. NEW & NOTEWORTHY Motoneuron activity is generally considered to reflect the level of excitatory drive. However, the activation of voltage-dependent intrinsic conductances can distort the relation between excitatory drive and the total output of a pool of motoneurons. Using a pool of realistic motoneuron models, we show that pool output can be a highly nonlinear function of synaptic input but linearity can be achieved through adjusting the

  11. The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

    PubMed Central

    Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan RT

    2016-01-01

    Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep

  12. The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint.

    PubMed

    Sopher, Ran S; Amis, Andrew A; Davies, D Ceri; Jeffers, Jonathan Rt

    2017-01-01

    Data about a muscle's fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep

  13. The effects of model composition design choices on high-fidelity simulations of motoneuron recruitment and firing behaviors

    NASA Astrophysics Data System (ADS)

    Allen, John M.; Elbasiouny, Sherif M.

    2018-06-01

    Objective. Computational models often require tradeoffs, such as balancing detail with efficiency; yet optimal balance should incorporate sound design features that do not bias the results of the specific scientific question under investigation. The present study examines how model design choices impact simulation results. Approach. We developed a rigorously-validated high-fidelity computational model of the spinal motoneuron pool to study three long-standing model design practices which have yet to be examined for their impact on motoneuron recruitment, firing rate, and force simulations. The practices examined were the use of: (1) generic cell models to simulate different motoneuron types, (2) discrete property ranges for different motoneuron types, and (3) biological homogeneity of cell properties within motoneuron types. Main results. Our results show that each of these practices accentuates conditions of motoneuron recruitment based on the size principle, and minimizes conditions of mixed and reversed recruitment orders, which have been observed in animal and human recordings. Specifically, strict motoneuron orderly size recruitment occurs, but in a compressed range, after which mixed and reverse motoneuron recruitment occurs due to the overlap in electrical properties of different motoneuron types. Additionally, these practices underestimate the motoneuron firing rates and force data simulated by existing models. Significance. Our results indicate that current modeling practices increase conditions of motoneuron recruitment based on the size principle, and decrease conditions of mixed and reversed recruitment order, which, in turn, impacts the predictions made by existing models on motoneuron recruitment, firing rate, and force. Additionally, mixed and reverse motoneuron recruitment generated higher muscle force than orderly size motoneuron recruitment in these simulations and represents one potential scheme to increase muscle efficiency. The examined model

  14. The effects of model composition design choices on high-fidelity simulations of motoneuron recruitment and firing behaviors.

    PubMed

    Allen, John M; Elbasiouny, Sherif M

    2018-06-01

    Computational models often require tradeoffs, such as balancing detail with efficiency; yet optimal balance should incorporate sound design features that do not bias the results of the specific scientific question under investigation. The present study examines how model design choices impact simulation results. We developed a rigorously-validated high-fidelity computational model of the spinal motoneuron pool to study three long-standing model design practices which have yet to be examined for their impact on motoneuron recruitment, firing rate, and force simulations. The practices examined were the use of: (1) generic cell models to simulate different motoneuron types, (2) discrete property ranges for different motoneuron types, and (3) biological homogeneity of cell properties within motoneuron types. Our results show that each of these practices accentuates conditions of motoneuron recruitment based on the size principle, and minimizes conditions of mixed and reversed recruitment orders, which have been observed in animal and human recordings. Specifically, strict motoneuron orderly size recruitment occurs, but in a compressed range, after which mixed and reverse motoneuron recruitment occurs due to the overlap in electrical properties of different motoneuron types. Additionally, these practices underestimate the motoneuron firing rates and force data simulated by existing models. Our results indicate that current modeling practices increase conditions of motoneuron recruitment based on the size principle, and decrease conditions of mixed and reversed recruitment order, which, in turn, impacts the predictions made by existing models on motoneuron recruitment, firing rate, and force. Additionally, mixed and reverse motoneuron recruitment generated higher muscle force than orderly size motoneuron recruitment in these simulations and represents one potential scheme to increase muscle efficiency. The examined model design practices, as well as the present results

  15. Expression of vesicular glutamate transporters, VGLUT1 and VGLUT2, in cholinergic spinal motoneurons.

    PubMed

    Herzog, E; Landry, M; Buhler, E; Bouali-Benazzouz, R; Legay, C; Henderson, C E; Nagy, F; Dreyfus, P; Giros, B; El Mestikawy, S

    2004-10-01

    Mammalian spinal motoneurons are cholinergic neurons that have long been suspected to use also glutamate as a neurotransmitter. We report that VGLUT1 and VGLUT2, two subtypes of vesicular glutamate transporters, are expressed in rat spinal motoneurons. Both proteins are present in somato-dendritic compartments as well as in axon terminals in primary cultures of immunopurified motoneurons and sections of spinal cord from adult rat. However, VGLUT1 and VGLUT2 are not found at neuromuscular junctions of skeletal muscles. After intracellular injection of biocytin in motoneurons, VGLUT2 is observed in anterogradely labelled terminals contacting Renshaw inhibitory interneurons. These VGLUT2- and VGLUT1-positive terminals do not express VAChT, the vesicular acetylcholine transporter. Overall, our study establishes for the first time that (i) mammalian spinal motoneurons express vesicular glutamate transporters, (ii) these motoneurons have the potential to release glutamate (in addition to acetylcholine) at terminals contacting Renshaw cells, and finally (iii) the VGLUTs are not present at neuromuscular synapses of skeletal muscles.

  16. Succinate dehydrogenase activity and soma size of motoneurons innervating different portions of the rat tibialis anterior

    NASA Technical Reports Server (NTRS)

    Ishihara, A.; Roy, R. R.; Edgerton, V. R.

    1995-01-01

    The spatial distribution, soma size and oxidative enzyme activity of gamma and alpha motoneurons innervating muscle fibres in the deep (away from the surface of the muscle) and superficial (close to the surface of the muscle) portions of the tibialis anterior in normal rats were determined. The deep portion had a higher percentage of high oxidative fibres than the superficial portion of the muscle. Motoneurons were labelled by retrograde neuronal transport of fluorescent tracers: Fast Blue and Nuclear Yellow were injected into the deep portion and Nuclear Yellow into the superficial portion of the muscle. Therefore, motoneurons innervating the deep portion were identified by both a blue fluorescent cytoplasm and a golden-yellow fluorescent nucleus, while motoneurons innervating the superficial portion were identified by only a golden-yellow fluorescent nucleus. After staining for succinate dehydrogenase activity on the same section used for the identification of the motoneurons, soma size and succinate dehydrogenase activity of the motoneurons were measured. The gamma and alpha motoneurons innervating both the deep and superficial portions were located primarily at L4 and were intermingled within the same region of the dorsolateral portion of the ventral horn in the spinal cord. Mean soma size was similar for either gamma or alpha motoneurons in the two portions of the muscle. The alpha motoneurons innervating the superficial portion had a lower mean succinate dehydrogenase activity than those innervating the deep portion of the muscle. An inverse relationship between soma size and succinate dehydrogenase activity of alpha, but not gamma, motoneurons innervating both the deep and superficial portions was observed. Based on three-dimensional reconstructions within the spinal cord, there were no apparent differences in the spatial distribution of the motoneurons, either gamma or alpha, associated with the deep and superficial compartments of the muscle. The data

  17. Resistance of extraocular motoneuron terminals to effects of amyotrophic lateral sclerosis sera

    NASA Technical Reports Server (NTRS)

    Mosier, D. R.; Siklos, L.; Appel, S. H.

    2000-01-01

    In sporadic ALS (s-ALS), axon terminals contain increased intracellular calcium. Passively transferred sera from patients with s-ALS increase intracellular calcium in spinal motoneuron terminals in vivo and enhance spontaneous transmitter release, a calcium-dependent process. In this study, passive transfer of s-ALS sera increased spontaneous release from spinal but not extraocular motoneuron terminals, suggesting that the resistance to physiologic abnormalities induced by s-ALS sera in mice parallels the resistance of extraocular motoneurons to dysfunction and degeneration in ALS.

  18. Mechanisms of spinal motoneurons survival in rats under simulated hypogravity on earth

    NASA Astrophysics Data System (ADS)

    Islamov, R. R.; Mishagina, E. A.; Tyapkina, O. V.; Shajmardanova, G. F.; Eremeev, A. A.; Kozlovskaya, I. B.; Nikolskij, E. E.; Grigorjev, A. I.

    2011-05-01

    It was previously shown that different cell types in vivo and in vitro may die via apoptosis under weightlessness conditions in space as well as in simulated hypogravity on the Earth. We assessed survivability of spinal motoneurons of rats after 35-day antiorthostatic hind limb suspension. Following weight bearing, unloading the total protein content in lumbar spinal cord is dropped by 21%. The electrophysiological studies of m. gastrocnemius revealed an elevated motoneurons' reflex excitability and conduction disturbances in the sciatic nerve axons. The number of myelinated fibers in the ventral root of experimental animals was insignificantly increased by 35-day of antiorthostatic hind limb suspension, although the retrograde axonal transport was significantly decreased during the first week of simulated hypogravity. The results of the immunohistochemical assay with antibodies against proapoptotic protein caspase 9 and cytotoxicity marker neuron specific nitric oxide synthase (nNOS) and the TUNEL staining did not reveal any signs of apoptosis in motoneurons of suspended and control animals. To examine the possible adaptation mechanisms activated in motoneurons in response to simulated hypogravity we investigated immunoexpression of Hsp25 and Hsp70 in lumbar spinal cord of the rats after 35-day antiorthostatic hind limb suspension. Comparative analysis of the immunohistochemical reaction with anti-Hsp25 antibodies revealed differential staining of motoneurons in intact and experimental animals. The density of immunoprecipitate with anti-Hsp25 antibodies was substantially higher in motoneurons of the 35-day suspended than control rats and the more intensive precipitate in this reaction was observed in motoneuron neuritis. Quantitative analysis of Hsp25 expression demonstrated an increase in the Hsp25 level by 95% in experimental rats compared to the control. The immunoexpression of Hsp70 found no qualitative and quantitative differences in control and experimental

  19. Motoneurons secrete angiogenin to induce RNA cleavage in astroglia.

    PubMed

    Skorupa, Alexandra; King, Matthew A; Aparicio, Isabela M; Dussmann, Heiko; Coughlan, Karen; Breen, Bridget; Kieran, Dairin; Concannon, Caoimhin G; Marin, Philippe; Prehn, Jochen H M

    2012-04-11

    Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disorder affecting motoneurons. Mutations in angiogenin, encoding a member of the pancreatic RNase A superfamily, segregate with ALS. We previously demonstrated that angiogenin administration shows promise as a neuroprotective therapeutic in studies using transgenic ALS mice and primary motoneuron cultures. Its mechanism of action and target cells in the spinal cord, however, are largely unknown. Using mixed motoneuron cultures, motoneuron-like NSC34 cells, and primary astroglia cultures as model systems, we here demonstrate that angiogenin is a neuronally secreted factor that is endocytosed by astroglia and mediates neuroprotection in paracrine. We show that wild-type angiogenin acts unidirectionally to induce RNA cleavage in astroglia, while the ALS-associated K40I mutant is also secreted and endocytosed, but fails to induce RNA cleavage. Angiogenin uptake into astroglia requires heparan sulfate proteoglycans, and engages clathrin-mediated endocytosis. We show that this uptake mechanism exists for mouse and human angiogenin, and delivers a functional RNase output. Moreover, we identify syndecan 4 as the angiogenin receptor mediating the selective uptake of angiogenin into astroglia. Our data provide new insights into the paracrine activities of angiogenin in the nervous system, and further highlight the critical role of non-neuronal cells in the pathogenesis of ALS.

  20. Unexpected factors affecting the excitability of human motoneurones in voluntary and stimulated contractions

    PubMed Central

    Khan, Serajul I.; Taylor, Janet L.

    2016-01-01

    Key points The output of human motoneurone pools decreases with fatiguing exercise, but the mechanisms involved are uncertain. We explored depression of recurrent motoneurone discharges (F‐waves) after sustained maximal voluntary contractions (MVCs).MVC depressed the size and frequency of F‐waves in a hand muscle but a submaximal contraction (at 50% MVC) did not.Surprisingly, activation of the motoneurones antidromically by stimulation of the ulnar nerve (at 20 or 40 Hz) did not depress F‐wave area or persistence.Furthermore, a sustained (3 min) MVC of a hand muscle depressed F‐waves in its antagonist but not in a remote hand muscle.Our findings suggest that depression of F‐waves after voluntary contractions is not simply due to repetitive activation of the motoneurones but requires descending voluntary drive.  Furthermore, this effect may depress nearby, but not distant, spinal motoneurone pools. Abstract There are major spinal changes induced by repetitive activity and fatigue that could contribute to ‘central’ fatigue but the mechanisms involved are poorly understood in humans. Here we confirmed that the recurrent motoneuronal discharge (F‐wave) is reduced during relaxation immediately after a sustained maximal voluntary contraction (MVC) of an intrinsic hand muscle (abductor digiti minimi, ADM) and explored the relationship between motoneurone firing and the depression of F‐waves in three ways. First, the depression (in both F‐wave area and F‐wave persistence) was present after a 10 s MVC (initial decrease 36.4 ± 19.1%; mean ± SD) but not after a submaximal voluntary contraction at 50% maximum. Second, to evoke motoneurone discharge without volitional effort, 10 s tetanic contractions were produced by supramaximal ulnar nerve stimulation at the elbow at physiological frequencies of 25 and 40 Hz. Surprisingly, neither produced depression of F‐waves in ADM to test supramaximal stimulation of the ulnar nerve at the wrist

  1. Unexpected factors affecting the excitability of human motoneurones in voluntary and stimulated contractions.

    PubMed

    Khan, Serajul I; Taylor, Janet L; Gandevia, Simon C

    2016-05-15

    The output of human motoneurone pools decreases with fatiguing exercise, but the mechanisms involved are uncertain. We explored depression of recurrent motoneurone discharges (F-waves) after sustained maximal voluntary contractions (MVCs). MVC depressed the size and frequency of F-waves in a hand muscle but a submaximal contraction (at 50% MVC) did not. Surprisingly, activation of the motoneurones antidromically by stimulation of the ulnar nerve (at 20 or 40 Hz) did not depress F-wave area or persistence. Furthermore, a sustained (3 min) MVC of a hand muscle depressed F-waves in its antagonist but not in a remote hand muscle. Our findings suggest that depression of F-waves after voluntary contractions is not simply due to repetitive activation of the motoneurones but requires descending voluntary drive.  Furthermore, this effect may depress nearby, but not distant, spinal motoneurone pools. There are major spinal changes induced by repetitive activity and fatigue that could contribute to 'central' fatigue but the mechanisms involved are poorly understood in humans. Here we confirmed that the recurrent motoneuronal discharge (F-wave) is reduced during relaxation immediately after a sustained maximal voluntary contraction (MVC) of an intrinsic hand muscle (abductor digiti minimi, ADM) and explored the relationship between motoneurone firing and the depression of F-waves in three ways. First, the depression (in both F-wave area and F-wave persistence) was present after a 10 s MVC (initial decrease 36.4 ± 19.1%; mean ± SD) but not after a submaximal voluntary contraction at 50% maximum. Second, to evoke motoneurone discharge without volitional effort, 10 s tetanic contractions were produced by supramaximal ulnar nerve stimulation at the elbow at physiological frequencies of 25 and 40 Hz. Surprisingly, neither produced depression of F-waves in ADM to test supramaximal stimulation of the ulnar nerve at the wrist. Finally, a sustained MVC (3 min) of the

  2. A novel approach for targeted delivery to motoneurons using cholera toxin-B modified protocells

    PubMed Central

    Gonzalez Porras, Maria A.; Durfee, Paul N.; Gregory, Ashley M.; Sieck, Gary C.; Brinker, C. Jeffrey; Mantilla, Carlos B.

    2017-01-01

    Background Trophic interactions between muscle fibers and motoneurons at the neuromuscular junction (NMJ) play a critical role in determining motor function throughout development, ageing, injury, or disease. Treatment of neuromuscular disorders is hindered by the inability to selectively target motoneurons with pharmacological and genetic interventions. New method We describe a novel delivery system to motoneurons using mesoporous silica nanoparticles encapsulated within a lipid bilayer (protocells) and modified with the atoxic subunit B of the cholera toxin (CTB) that binds to gangliosides present on neuronal membranes. Results CTB modified protocells showed significantly greater motoneuron uptake compared to unmodified protocells after 24 h of treatment (60% vs. 15%, respectively). CTB-protocells showed specific uptake by motoneurons compared to muscle cells and demonstrated cargo release of a surrogate drug. Protocells showed a lack of cytotoxicity and unimpaired cellular proliferation. In isolated diaphragm muscle-phrenic nerve preparations, preferential axon terminal uptake of CTB-modified protocells was observed compared to uptake in surrounding muscle tissue. A larger proportion of axon terminals displayed uptake following treatment with CTB-protocells compared to unmodified protocells (40% vs. 6%, respectively). Comparison with existing method(s) Current motoneuron targeting strategies lack the functionality to load and deliver multiple cargos. CTB-protocells capitalizes on the advantages of liposomes and mesoporous silica nanoparticles allowing a large loading capacity and cargo release. The ability of CTB-protocells to target motoneurons at the NMJ confers a great advantage over existing methods. Conclusions CTB-protocells constitute a viable targeted motoneuron delivery system for drugs and genes facilitating various therapies for neuromuscular diseases. PMID:27641118

  3. A novel approach for targeted delivery to motoneurons using cholera toxin-B modified protocells.

    PubMed

    Gonzalez Porras, Maria A; Durfee, Paul N; Gregory, Ashley M; Sieck, Gary C; Brinker, C Jeffrey; Mantilla, Carlos B

    2016-11-01

    Trophic interactions between muscle fibers and motoneurons at the neuromuscular junction (NMJ) play a critical role in determining motor function throughout development, ageing, injury, or disease. Treatment of neuromuscular disorders is hindered by the inability to selectively target motoneurons with pharmacological and genetic interventions. We describe a novel delivery system to motoneurons using mesoporous silica nanoparticles encapsulated within a lipid bilayer (protocells) and modified with the atoxic subunit B of the cholera toxin (CTB) that binds to gangliosides present on neuronal membranes. CTB modified protocells showed significantly greater motoneuron uptake compared to unmodified protocells after 24h of treatment (60% vs. 15%, respectively). CTB-protocells showed specific uptake by motoneurons compared to muscle cells and demonstrated cargo release of a surrogate drug. Protocells showed a lack of cytotoxicity and unimpaired cellular proliferation. In isolated diaphragm muscle-phrenic nerve preparations, preferential axon terminal uptake of CTB-modified protocells was observed compared to uptake in surrounding muscle tissue. A larger proportion of axon terminals displayed uptake following treatment with CTB-protocells compared to unmodified protocells (40% vs. 6%, respectively). Current motoneuron targeting strategies lack the functionality to load and deliver multiple cargos. CTB-protocells capitalizes on the advantages of liposomes and mesoporous silica nanoparticles allowing a large loading capacity and cargo release. The ability of CTB-protocells to target motoneurons at the NMJ confers a great advantage over existing methods. CTB-protocells constitute a viable targeted motoneuron delivery system for drugs and genes facilitating various therapies for neuromuscular diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Side-alternating vibration training for balance and ankle muscle strength in untrained women.

    PubMed

    Spiliopoulou, Styliani I; Amiridis, Ioannis G; Tsigganos, Georgios; Hatzitaki, Vassilia

    2013-01-01

    Side-alternating vibration (SAV) may help reduce the risk of falling by improving body balance control. Such training has been promoted as a strength-training intervention because it can increase muscle activation through an augmented excitatory input from the muscle spindles. To determine the effect of SAV training on static balance during 3 postural tasks of increasing difficulty and lower limb strength. Randomized controlled clinical trial. Laboratory. A total of 21 healthy women were divided into training (n = 11; age = 43.35 ± 4.12 years, height = 169 ± 6.60 cm, mass = 68.33 ± 11.90 kg) and control (n = 10; age = 42.31 ± 3.73 years, height = 167 ± 4.32 cm, mass = 66.29 ± 10.74 kg) groups. The training group completed a 9-week program during which participants performed 3 sessions per week of ten 15-second isometric contractions with a 30-second active rest of 3 exercises (half-squat, wide-stance squat, 1-legged half-squat) on an SAV plate (acceleration = 0.91-16.3g). The control group did not participate in any form of exercise over the 9-week period. We evaluated isokinetic and isometric strength of the knee extensors and flexors and ankle plantar flexors, dorsiflexors, and evertors. Static balance was assessed using 3 tasks of increasing difficulty (quiet bipedal stance, tandem stance, 1-legged stance). The electromyographic activity of the vastus lateralis, semitendinosus, medial gastrocnemius, tibialis anterior, and peroneus longus was recorded during postural task performance, baseline and pretraining, immediately posttraining, and 15 days posttraining. After training in the training group, ankle muscle strength improved (P = .03), whereas knee muscle strength remained unaltered (P = .13). Improved ankle-evertor strength was observed at all angular velocities (P = .001). Postural sway decreased in both directions but was greater in the mediolateral (P < .001) than anteroposterior (P = .02) direction. The electromyographic activity of the peroneus

  5. The influence of muscle length on the fatigue-related reduction in joint range of motion of the human dorsiflexors.

    PubMed

    Cheng, Arthur J; Davidson, Andrew W; Rice, Charles L

    2010-06-01

    The fatigue-related reduction in joint range of motion (ROM) during dynamic contraction tasks may be related to muscle length-dependent alterations in torque and contractile kinetics, but this has not been systematically explored previously. Twelve young men performed a repetitive voluntary muscle shortening contraction task of the dorsiflexors at a contraction load of 30% of maximum voluntary isometric contraction (MVC) torque, until total 40 degrees ROM had decreased by 50% at task failure (POST) to 20 degrees ROM. At both a short (5 degrees dorsiflexion) and long muscle length (35 degrees plantar flexion joint angle relative to a 0 degrees neutral ankle joint position), voluntary activation, MVC torque, and evoked tibialis anterior contractile properties of a 52.8 Hz high-frequency isometric tetanus [peak evoked torque, maximum rate of torque development (MRTD), maximum rate of relaxation (MRR)] were evaluated at baseline (PRE), at POST, and up to 10 min of recovery. At POST, we measured similar fatigue-related reductions in torque (voluntary and evoked) and slowing of contractile kinetics (MRTD and MRR) at both the short and long muscle lengths. Thus, the fatigue-related reduction in ROM could not be explained by length-dependent fatigue. Although torque (voluntary and evoked) at both muscle lengths was depressed and remained blunted throughout the recovery period, this was not related to the rapid recovery of ROM at 0.5 min after task failure. The reduction in ROM, however, was strongly related to the reduction in joint angular velocity (R(2) = 0.80) during the fatiguing task, although additional factors cannot yet be overlooked.

  6. Discharge properties of motor units during steady isometric contractions performed with the dorsiflexor muscles

    PubMed Central

    Klass, Malgorzata; Duchateau, Jacques; Enoka, Roger M.

    2012-01-01

    The purpose of this study was to record the discharge characteristics of tibialis anterior motor units over a range of target forces and to import these data, along with previously reported observations, into a computational model to compare experimental and simulated measures of torque variability during isometric contractions with the dorsiflexor muscles. The discharge characteristics of 44 motor units were quantified during brief isometric contractions at torques that ranged from recruitment threshold to an average of 22 ± 14.4% maximal voluntary contraction (MVC) torque above recruitment threshold. The minimal [range: 5.8–19.8 pulses per second (pps)] and peak (range: 8.6–37.5 pps) discharge rates of motor units were positively related to the recruitment threshold torque (R2 ≥ 0.266; P < 0.001). The coefficient of variation for interspike interval at recruitment was positively associated with recruitment threshold torque (R2 = 0.443; P < 0.001) and either decreased exponentially or remained constant as target torque increased above recruitment threshold torque. The variability in the simulated torque did not differ from the experimental values once the recruitment range was set to ∼85% MVC torque, and the association between motor twitch contraction times and peak twitch torque was defined as a weak linear association (R2 = 0.096; P < 0.001). These results indicate that the steadiness of isometric contractions performed with the dorsiflexor muscle depended more on the distributions of mechanical properties than discharge properties across the population of motor units in the tibialis anterior. PMID:22442023

  7. Discharge properties of motor units during steady isometric contractions performed with the dorsiflexor muscles.

    PubMed

    Jesunathadas, Mark; Klass, Malgorzata; Duchateau, Jacques; Enoka, Roger M

    2012-06-01

    The purpose of this study was to record the discharge characteristics of tibialis anterior motor units over a range of target forces and to import these data, along with previously reported observations, into a computational model to compare experimental and simulated measures of torque variability during isometric contractions with the dorsiflexor muscles. The discharge characteristics of 44 motor units were quantified during brief isometric contractions at torques that ranged from recruitment threshold to an average of 22 ± 14.4% maximal voluntary contraction (MVC) torque above recruitment threshold. The minimal [range: 5.8-19.8 pulses per second (pps)] and peak (range: 8.6-37.5 pps) discharge rates of motor units were positively related to the recruitment threshold torque (R(2) ≥ 0.266; P < 0.001). The coefficient of variation for interspike interval at recruitment was positively associated with recruitment threshold torque (R(2) = 0.443; P < 0.001) and either decreased exponentially or remained constant as target torque increased above recruitment threshold torque. The variability in the simulated torque did not differ from the experimental values once the recruitment range was set to ∼85% MVC torque, and the association between motor twitch contraction times and peak twitch torque was defined as a weak linear association (R(2) = 0.096; P < 0.001). These results indicate that the steadiness of isometric contractions performed with the dorsiflexor muscle depended more on the distributions of mechanical properties than discharge properties across the population of motor units in the tibialis anterior.

  8. Function of identified motoneurones and co-ordination of primary and secondary motor systems during zebra fish swimming.

    PubMed Central

    Liu, D W; Westerfield, M

    1988-01-01

    1. The activity of the two classes of motoneurones, primary and secondary, which innervate myotomal muscle fibres in the zebra fish, was monitored with electromyographic and intracellular techniques. 2. Simultaneous EMG and intracellular recordings from muscle fibres showed that the activity of the two motor systems and of individual primary motoneurones can be distinguished by recording EMG spikes during swimming. 3. Measurements of EMG spikes demonstrated that primary and secondary motoneurones are co-ordinately activated over a wide range of conditions during normal swimming. 4. During swimming the primary motoneurones within a given segment are usually co-activated although they sometimes fire independently. 5. When different primary motoneurones within a given segment are co-activated, they fire nearly synchronously. 6. We conclude that the primary motoneurones are used principally, although not exclusively, during fast swimming, struggling and the startle response, whereas secondary motoneurones function primarily during slower swimming. PMID:3253426

  9. Mechanism and Design Analysis of Articulated Ankle Foot Orthoses for Drop-Foot

    PubMed Central

    Choudhury, Imtiaz Ahmed; Mamat, Azuddin Bin

    2014-01-01

    Robotic technologies are being employed increasingly in the treatment of lower limb disabilities. Individuals suffering from stroke and other neurological disorders often experience inadequate dorsiflexion during swing phase of the gait cycle due to dorsiflexor muscle weakness. This type of pathological gait, mostly known as drop-foot gait, has two major complications, foot-slap during loading response and toe-drag during swing. Ankle foot orthotic (AFO) devices are mostly prescribed to resolve these complications. Existing AFOs are designed with or without articulated joint with various motion control elements like springs, dampers, four-bar mechanism, series elastic actuator, and so forth. This paper examines various AFO designs for drop-foot, discusses the mechanism, and identifies limitations and remaining design challenges. Along with two commercially available AFOs some designs possess promising prospective to be used as daily-wear device. However, the design and mechanism of AFO must ensure compactness, light weight, low noise, and high efficiency. These entailments present significant engineering challenges to develop a new design with wide consumer adoption. PMID:24892102

  10. A central mesencephalic reticular formation projection to medial rectus motoneurons supplying singly and multiply innervated extraocular muscle fibers.

    PubMed

    Bohlen, Martin O; Warren, Susan; May, Paul J

    2017-06-01

    We recently demonstrated a bilateral projection to the supraoculomotor area from the central mesencephalic reticular formation (cMRF), a region implicated in horizontal gaze changes. C-group motoneurons, which supply multiply innervated fibers in the medial rectus muscle, are located within the primate supraoculomotor area, but their inputs and function are poorly understood. Here, we tested whether C-group motoneurons in Macaca fascicularis monkeys receive a direct cMRF input by injecting this portion of the reticular formation with anterograde tracers in combination with injection of retrograde tracer into the medial rectus muscle. The results indicate that the cMRF provides a dense, bilateral projection to the region of the medial rectus C-group motoneurons. Numerous close associations between labeled terminals and each multiply innervated fiber motoneuron were present. Within the oculomotor nucleus, a much sparser ipsilateral projection onto some of the A- and B- group medial rectus motoneurons that supply singly innervated fibers was observed. Ultrastructural analysis demonstrated a direct synaptic linkage between anterogradely labeled reticular terminals and retrogradely labeled medial rectus motoneurons in all three groups. These findings reinforce the notion that the cMRF is a critical hub for oculomotility by proving that it contains premotor neurons supplying horizontal extraocular muscle motoneurons. The differences between the cMRF input patterns for C-group versus A- and B-group motoneurons suggest the C-group motoneurons serve a different oculomotor role than the others. The similar patterns of cMRF input to C-group motoneurons and preganglionic Edinger-Westphal motoneurons suggest that medial rectus C-group motoneurons may play a role in accommodation-related vergence. © 2017 Wiley Periodicals, Inc.

  11. Phosphatidylinositol 3-kinase activity in murine motoneuron disease: the progressive motor neuropathy mouse.

    PubMed

    Wagey, R; Lurot, S; Perrelet, D; Pelech, S L; Sagot, Y; Krieger, C

    2001-01-01

    A murine model of motoneuron disease, the pmn/pmn mouse, shows a reduction in the retrograde transport of fluorescent probes applied directly onto the cut end of sciatic nerve. Brain-derived neurotrophic factor (BDNF), when co-applied with fluorescent tracers, increases the number of retrograde labelled motoneurons. We demonstrate here that spinal cord tissue from pmn/pmn mice had significantly reduced phosphatidylinositol 3-kinase activity and expression in the particulate fraction compared to controls, without changes in the activities or expression of the downstream kinases, protein kinase B/Akt or Erk1. Systemic administration of BDNF augmented phosphatidylinositol 3-kinase specific activity in spinal cord tissue from pmn/pmn and control mice, with a greater elevation in the particulate fractions of pmn/pmn mice than in controls. We examined the effect of inhibitors of phosphatidylinositol 3-kinase and mitogen-activated protein kinase kinase on the retrograde labelling of motoneurons, 24h following the direct application of inhibitors and Fluorogold to the cut end of sciatic nerve in control and pmn/pmn mice (labelling index). The mitogen-activated protein kinase kinase inhibitor PD 98059 had no effect on the labelling index in control or pmn/pmn mice. In the absence of exogenous BDNF, phosphatidylinositol 3-kinase inhibitors reduced the number of labelled motoneurons in control mice, without changing the labelling index in pmn/pmn. Co-application of phosphatidylinositol 3-kinase inhibitors with BDNF to the cut end of sciatic nerve blocked the action of BDNF on retrograde labelling in pmn/pmn mice. These results indicate that the retrograde labelling of motoneurons is mediated by phosphatidylinositol 3-kinase-dependent and -independent pathways. In pmn/pmn mice, phosphatidylinositol 3-kinase activity in spinal neurons is below the level required for optimal retrograde labelling of motoneurons and labelling can be augmented by the administration of growth

  12. Synaptic sprouting increases the uptake capacities of motoneurons in amyotrophic lateral sclerosis mice

    PubMed Central

    Millecamps, Stéphanie; Nicolle, Delphine; Ceballos-Picot, Irène; Mallet, Jacques; Barkats, Martine

    2001-01-01

    Using adenoviruses encoding reporter genes as retrograde tracers, we assessed the capacity of motoneurons to take up and retrogradely transport adenoviral particles injected into the muscles of transgenic mice expressing the G93A human superoxide dismutase mutation, a model of amyotrophic lateral sclerosis. Surprisingly, transgene expression in the motoneurons was significantly higher in symptomatic mice than in control or presymptomatic mice. Using botulinum toxin to induce nerve sprouting at neuromuscular junctions, we showed that the unexpectedly high level of motoneurons retrograde transduction results, at least in part, from newly acquired uptake properties of the sprouts. These findings demonstrate the remarkable uptake properties of amyotrophic lateral sclerosis motoneurons in response to denervation and the rationale of using intramuscular injections of adenoviruses to overexpress therapeutic proteins in motor neuron diseases. PMID:11404466

  13. F-wave of single firing motor units: correct or misleading criterion of motoneuron excitability in humans?

    PubMed

    Kudina, Lydia P; Andreeva, Regina E

    2017-03-01

    Motoneuron excitability is a critical property for information processing during motor control. F-wave (a motoneuronal recurrent discharge evoked by a motor antidromic volley) is often used as a criterion of motoneuron pool excitability in normal and neuromuscular diseases. However, such using of F-wave calls in question. The present study was designed to explore excitability of single low-threshold motoneurons during their natural firing in healthy humans and to ascertain whether F-wave is a correct measure of motoneuronal excitability. Single motor units (MUs) were activated by gentle voluntary muscle contractions. MU peri-stimulus time histograms and motoneuron excitability changes within a target interspike interval were analysed during testing by motor antidromic and Ia-afferent volleys. It was found that F-waves could be occasionally recorded in some low-threshold MUs. However, during evoking F-wave, in contrast with the H-reflex, peri-stimulus time histograms revealed no statistically significant increase in MU discharge probability. Moreover, surprisingly, motoneurons appeared commonly incapable to fire a recurrent discharge within the most excitable part of a target interval. Thus, the F-wave, unlike the H-reflex, is the incorrect criterion of motoneuron excitability resulting in misleading conclusions. However, it does not exclude the validity of the F-wave as a clinical tool for other aims. It was concluded that the F-wave was first explored in low-threshold MUs during their natural firing. The findings may be useful at interpretations of changes in the motoneuron pool excitability in neuromuscular diseases.

  14. Monosynaptic inputs from the nucleus tractus solitarii to the laryngeal motoneurons in the nucleus ambiguus of the rat.

    PubMed

    Hayakawa, T; Takanaga, A; Maeda, S; Ito, H; Seki, M

    2000-11-01

    The cricothyroid (CT) and the posterior cricoarytenoid (PCA) muscles in the larynx are activated by the laryngeal motoneurons located within the nucleus ambiguus; these motoneurons receive the laryngeal sensory information from the nucleus tractus solitarii (NTS) during respiration and swallowing. We investigated whether the neurons in the NTS projected directly to the laryngeal motoneurons, and what is the synaptic organization of their nerve terminals on the laryngeal motoneurons using the electron microscope. When wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the NTS after cholera toxin subunit B-conjugated HRP (CT-HRP) was injected into the CT muscle or the PCA muscle, the anterogradely WGA-HRP-labeled terminals from the NTS were found to directly contact the retrogradely CT-HRP-labeled dendrites and soma of both the CT and the PCA motoneurons. The labeled NTS terminals comprised about 4% of the axosomatic terminals in a section through the CT motoneurons, and about 9% on both the small (PCA-A) and the large (PCA-B) PCA motoneurons. The number of labeled axosomatic terminals containing round vesicles and making asymmetric synaptic contacts (Gray's type I) was almost equal to that of the labeled terminals containing pleomorphic vesicles and making symmetric synaptic contacts (Gray's type II) on the CT motoneurons. The labeled axosomatic terminals were mostly Gray's type II on the PCA-A motoneurons, while the majority of them were Gray's type I on the PCA-B motoneurons. These results indicate that the laryngeal CT and PCA motoneurons receive a few direct excitatory and inhibitory inputs from the neurons in the NTS.

  15. Synaptic loss and firing alterations in Axotomized Motoneurons are restored by vascular endothelial growth factor (VEGF) and VEGF-B.

    PubMed

    Calvo, Paula M; de la Cruz, Rosa R; Pastor, Angel M

    2018-06-01

    Vascular endothelial growth factor (VEGF), also known as VEGF-A, was discovered due to its vasculogenic and angiogenic activity, but a neuroprotective role for VEGF was later proven for lesions and disorders. In different models of motoneuronal degeneration, VEGF administration leads to a significant reduction of motoneuronal death. However, there is no information about the physiological state of spared motoneurons. We examined the trophic role of VEGF on axotomized motoneurons with recordings in alert animals using the oculomotor system as the experimental model, complemented with a synaptic study at the confocal microscopy level. Axotomy leads to drastic alterations in the discharge characteristics of abducens motoneurons, as well as to a substantial loss of their synaptic inputs. Retrograde delivery of VEGF completely restored the discharge activity and synaptically-driven signals in injured motoneurons, as demonstrated by correlating motoneuronal firing rate with motor performance. Moreover, VEGF-treated motoneurons recovered a normal density of synaptic boutons around motoneuronal somata and in the neuropil, in contrast to the low levels of synaptic terminals found after axotomy. VEGF also reduced the astrogliosis induced by axotomy in the abducens nucleus to control values. The administration of VEGF-B produced results similar to those of VEGF. This is the first work demonstrating that VEGF and VEGF-B restore the normal operating mode and synaptic inputs on injured motoneurons. Altogether these data indicate that these molecules are relevant synaptotrophic factors for motoneurons and support their clinical potential for the treatment of motoneuronal disorders. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Relations among passive electrical properties of lumbar alpha-motoneurones of the cat.

    PubMed Central

    Gustafsson, B; Pinter, M J

    1984-01-01

    The relations among passive membrane properties have been examined in cat motoneurones utilizing exclusively electrophysiological techniques. A significant relation was found to exist between the input resistance and the membrane time constant. The estimated electrotonic length showed no evident tendency to vary with input resistance but did show a tendency to decrease with increasing time constant. Detailed analysis of this trend suggests, however, that a variation in dendritic geometry is likely to exist among cat motoneurones, such that the dendritic trees of motoneurones projecting to fast-twitch muscle units are relatively more expansive than those of motoneurones projecting to slow-twitch units. Utilizing an expression derived from the Rall neurone model, the total capacitance of the equivalent cylinder corresponding to a motoneurone has been estimated. With the assumption of a constant and uniform specific capacitance of 1 mu F/cm2, the resulting values have been used as estimates of cell surface area. These estimates agree well with morphologically obtained measurements from cat motoneurones reported by others. Both membrane time constant (and thus likely specific membrane resistivity) and electrotonic length showed little tendency to vary with surface area. However, after-hyperpolarization (a.h.p.) duration showed some tendency to vary such that cells with brief a.h.p. duration were, on average, larger than those with longer a.h.p. durations. Apart from motoneurones with the lowest values, axonal conduction velocity was only weakly related to variations in estimated surface area. Input resistance and membrane time constant were found to vary systematically with the a.h.p. duration. Analysis suggested that the major part of the increase in input resistance with a.h.p. duration was related to an increase in membrane resistivity and a variation in dendritic geometry rather than to differences in surface area among the motoneurones. The possible effects of

  17. Spike threshold dynamics in spinal motoneurons during scratching and swimming.

    PubMed

    Grigonis, Ramunas; Alaburda, Aidas

    2017-09-01

    Action potential threshold can vary depending on firing history and synaptic inputs. We used an ex vivo carapace-spinal cord preparation from adult turtles to study spike threshold dynamics in motoneurons during two distinct types of functional motor behaviour - fictive scratching and fictive swimming. The threshold potential depolarizes by about 10 mV within each burst of spikes generated during scratch and swim network activity and recovers between bursts to a slightly depolarized level. Slow synaptic integration resulting in a wave of membrane potential depolarization is the factor influencing the threshold potential within firing bursts during motor behaviours. Depolarization of the threshold potential decreases the excitability of motoneurons and may provide a mechanism for stabilization of the response of a motoneuron to intense synaptic inputs to maintain the motor commands within an optimal range for muscle activation. During functional spinal neural network activity motoneurons receive intense synaptic input, and this could modulate the threshold for action potential generation, providing the ability to dynamically adjust the excitability and recruitment order for functional needs. In the present study we investigated the dynamics of action potential threshold during motor network activity. Intracellular recordings from spinal motoneurons in an ex vivo carapace-spinal cord preparation from adult turtles were performed during two distinct types of motor behaviour - fictive scratching and fictive swimming. We found that the threshold of the first spike in episodes of scratching and swimming was the lowest. The threshold potential depolarizes by about 10 mV within each burst of spikes generated during scratch and swim network activity and recovers between bursts to a slightly depolarized level. Depolarization of the threshold potential results in decreased excitability of motoneurons. Synaptic inputs do not modulate the threshold of the first action

  18. Characterization of axon formation in the embryonic stem cell-derived motoneuron.

    PubMed

    Pan, Hung-Chuan; Wu, Ya-Ting; Shen, Shih-Cheng; Wang, Chi-Chung; Tsai, Ming-Shiun; Cheng, Fu-Chou; Lin, Shinn-Zong; Chen, Ching-Wen; Liu, Ching-San; Su, Hong-Lin

    2011-01-01

    The developing neural cell must form a highly organized architecture to properly receive and transmit nerve signals. Neural formation from embryonic stem (ES) cells provides a novel system for studying axonogenesis, which are orchestrated by polarity-regulating molecules. Here the ES-derived motoneurons, identified by HB9 promoter-driven green fluorescent protein (GFP) expression, showed characteristics of motoneuron-specific gene expression. In the majority of motoneurons, one of the bilateral neurites developed into an axon that featured with axonal markers, including Tau1, vesicle acetylcholine transporter, and synaptophysin. Interestingly, one third of the motoneurons developed bi-axonal processes but no multiple axonal GFP cell was found. The neuronal polarity-regulating proteins, including the phosphorylated AKT and ERK, were compartmentalized into both of the bilateral axonal tips. Importantly, this aberrant axon morphology was still present after the engraftment of GFP(+) neurons into the spinal cord, suggesting that even a mature neural environment fails to provide a proper niche to guide normal axon formation. These findings underscore the necessity for evaluating the morphogenesis and functionality of neurons before the clinical trials using ES or somatic stem cells.

  19. Uncoupling nicotine mediated motoneuron axonal pathfinding errors and muscle degeneration in zebrafish

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Welsh, Lillian; Tanguay, Robert L.; Svoboda, Kurt R.

    Zebrafish embryos offer a unique opportunity to investigate the mechanisms by which nicotine exposure impacts early vertebrate development. Embryos exposed to nicotine become functionally paralyzed by 42 hpf suggesting that the neuromuscular system is compromised in exposed embryos. We previously demonstrated that secondary spinal motoneurons in nicotine-exposed embryos were delayed in development and that their axons made pathfinding errors (Svoboda, K.R., Vijayaraghaven, S., Tanguay, R.L., 2002. Nicotinic receptors mediate changes in spinal motoneuron development and axonal pathfinding in embryonic zebrafish exposed to nicotine. J. Neurosci. 22, 10731-10741). In that study, we did not consider the potential role that altered skeletalmore » muscle development caused by nicotine exposure could play in contributing to the errors in spinal motoneuron axon pathfinding. In this study, we show that an alteration in skeletal muscle development occurs in tandem with alterations in spinal motoneuron development upon exposure to nicotine. The alteration in the muscle involves the binding of nicotine to the muscle-specific AChRs. The nicotine-induced alteration in muscle development does not occur in the zebrafish mutant (sofa potato, [sop]), which lacks muscle-specific AChRs. Even though muscle development is unaffected by nicotine exposure in sop mutants, motoneuron axonal pathfinding errors still occur in these mutants, indicating a direct effect of nicotine exposure on nervous system development.« less

  20. Role of motoneuron-derived neurotrophin 3 in survival and axonal projection of sensory neurons during neural circuit formation.

    PubMed

    Usui, Noriyoshi; Watanabe, Keisuke; Ono, Katsuhiko; Tomita, Koichi; Tamamaki, Nobuaki; Ikenaka, Kazuhiro; Takebayashi, Hirohide

    2012-03-01

    Sensory neurons possess the central and peripheral branches and they form unique spinal neural circuits with motoneurons during development. Peripheral branches of sensory axons fasciculate with the motor axons that extend toward the peripheral muscles from the central nervous system (CNS), whereas the central branches of proprioceptive sensory neurons directly innervate motoneurons. Although anatomically well documented, the molecular mechanism underlying sensory-motor interaction during neural circuit formation is not fully understood. To investigate the role of motoneuron on sensory neuron development, we analyzed sensory neuron phenotypes in the dorsal root ganglia (DRG) of Olig2 knockout (KO) mouse embryos, which lack motoneurons. We found an increased number of apoptotic cells in the DRG of Olig2 KO embryos at embryonic day (E) 10.5. Furthermore, abnormal axonal projections of sensory neurons were observed in both the peripheral branches at E10.5 and central branches at E15.5. To understand the motoneuron-derived factor that regulates sensory neuron development, we focused on neurotrophin 3 (Ntf3; NT-3), because Ntf3 and its receptors (Trk) are strongly expressed in motoneurons and sensory neurons, respectively. The significance of motoneuron-derived Ntf3 was analyzed using Ntf3 conditional knockout (cKO) embryos, in which we observed increased apoptosis and abnormal projection of the central branch innervating motoneuron, the phenotypes being apparently comparable with that of Olig2 KO embryos. Taken together, we show that the motoneuron is a functional source of Ntf3 and motoneuron-derived Ntf3 is an essential pre-target neurotrophin for survival and axonal projection of sensory neurons.

  1. Motoneurons regulate the central pattern generator during drug-induced locomotor-like activity in the neonatal mouse

    PubMed Central

    Falgairolle, Melanie; Puhl, Joshua G; Pujala, Avinash; Liu, Wenfang; O’Donovan, Michael J

    2017-01-01

    Motoneurons are traditionally viewed as the output of the spinal cord that do not influence locomotor rhythmogenesis. We assessed the role of motoneuron firing during ongoing locomotor-like activity in neonatal mice expressing archaerhopsin-3 (Arch), halorhodopsin (eNpHR), or channelrhodopsin-2 (ChR2) in Choline acetyltransferase neurons (ChAT+) or Arch in LIM-homeodomain transcription factor Isl1+ neurons. Illumination of the lumbar cord in mice expressing eNpHR or Arch in ChAT+ or Isl1+ neurons, depressed motoneuron discharge, transiently decreased the frequency, and perturbed the phasing of the locomotor-like rhythm. When the light was turned off motoneuron firing and locomotor frequency both transiently increased. These effects were not due to cholinergic neurotransmission, persisted during partial blockade of gap junctions and were mediated, in part, by AMPAergic transmission. In spinal cords expressing ChR2, illumination increased motoneuron discharge and transiently accelerated the rhythm. We conclude that motoneurons provide feedback to the central pattern generator (CPG) during drug-induced locomotor-like activity. DOI: http://dx.doi.org/10.7554/eLife.26622.001 PMID:28671548

  2. Specificity in monosynaptic and disynaptic bulbospinal connections to thoracic motoneurones in the rat

    PubMed Central

    de Almeida, Anoushka T R; Kirkwood, Peter A

    2013-01-01

    The respiratory activity in the intercostal nerves of the rat is unusual, in that motoneurones of both branches of the intercostal nerves, internal and external, are activated during expiration. Here, the pathways involved in that activation were investigated in anaesthetised and in decerebrate rats by cross-correlation and by intracellular spike-triggered averaging from expiratory bulbospinal neurones (EBSNs), with a view to revealing specific connections that could be used in studies of experimental spinal cord injury. Decerebrate preparations, which showed the strongest expiratory activity, were found to be the most suitable for these measurements. Cross-correlations in these preparations showed monosynaptic connections from 16/19 (84%) of EBSNs, but only to internal intercostal nerve motoneurones (24/37, 65% of EBSN/nerve pairs), whereas disynaptic connections were seen for external intercostal nerve motoneurones (4/19, 21% of EBSNs or 7/25, 28% of EBSN/nerve pairs). There was evidence for additional disynaptic connections to internal intercostal nerve motoneurones. Intracellular spike-triggered averaging revealed excitatory postsynaptic potentials, which confirmed these connections. This is believed to be the first report of single descending fibres that participate in two different pathways to two different groups of motoneurones. It is of interest compared with the cat, where only one group of motoneurones is activated during expiration and only one of the pathways has been detected. The specificity of the connections could be valuable in studies of plasticity in pathological situations, but care will be needed in studying connections in such situations, because their strength was found here to be relatively weak. PMID:23774278

  3. Relationship between viscosity of the ankle joint complex and functional ankle instability for inversion ankle sprain patients.

    PubMed

    Lin, Che-Yu; Kang, Jiunn-Horng; Wang, Chung-Li; Shau, Yio-Wha

    2015-03-01

    Measurement of viscosity of the ankle joint complex is a novel method to assess mechanical ankle instability. In order to further investigate the clinical significance of the method, this study intended to investigate the relationship between ankle viscosity and severity of functional ankle instability. Cross-sectional study. 15 participants with unilateral inversion ankle sprain and 15 controls were recruited. Their ankles were further classified into stable and unstable ankles. Ankle viscosity was measured by an instrumental anterior drawer test. Severity of functional ankle instability was measured by the Cumberland Ankle Instability Tool. Unstable ankles were compared with stable ankles. Injured ankles were compared with uninjured ankles of both groups. The spearman's rank correlation coefficient was applied to determine the relationship between ankle viscosity and severity of functional ankle instability in unstable ankles. There was a moderate relationship between ankle viscosity and severity of functional ankle instability (r=-0.64, p<0.0001). Unstable ankles exhibited significantly lower viscosity (p<0.005) and more severe functional ankle instability (p<0.0001) than stable ankles. Injured ankles exhibited significantly lower viscosity and more severe functional ankle instability than uninjured ankles (p<0.0001). There was a moderate relationship between ankle viscosity and severity of functional ankle instability. This finding suggested that, severity of functional ankle instability may be partially attributed to mechanical insufficiencies such as the degenerative changes in ankle viscosity following the inversion ankle sprain. In clinical application, measurement of ankle viscosity could be a useful tool to evaluate severity of chronic ankle instability. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. Neuronal BDNF Signaling Is Necessary for the Effects of Treadmill Exercise on Synaptic Stripping of Axotomized Motoneurons

    PubMed Central

    Krakowiak, Joey; Liu, Caiyue; Papudesu, Chandana; Ward, P. Jillian; Wilhelm, Jennifer C.; English, Arthur W.

    2015-01-01

    The withdrawal of synaptic inputs from the somata and proximal dendrites of spinal motoneurons following peripheral nerve injury could contribute to poor functional recovery. Decreased availability of neurotrophins to afferent terminals on axotomized motoneurons has been implicated as one cause of the withdrawal. No reduction in contacts made by synaptic inputs immunoreactive to the vesicular glutamate transporter 1 and glutamic acid decarboxylase 67 is noted on axotomized motoneurons if modest treadmill exercise, which stimulates the production of neurotrophins by spinal motoneurons, is applied after nerve injury. In conditional, neuron-specific brain-derived neurotrophic factor (BDNF) knockout mice, a reduction in synaptic contacts onto motoneurons was noted in intact animals which was similar in magnitude to that observed after nerve transection in wild-type controls. No further reduction in coverage was found if nerves were cut in knockout mice. Two weeks of moderate daily treadmill exercise following nerve injury in these BDNF knockout mice did not affect synaptic inputs onto motoneurons. Treadmill exercise has a profound effect on synaptic inputs to motoneurons after peripheral nerve injury which requires BDNF production by those postsynaptic cells. PMID:25918648

  5. Mechanisms contributing to the dopamine induction of crawl-like bursting in leech motoneurons.

    PubMed

    Crisp, Kevin M; Gallagher, Brian R; Mesce, Karen A

    2012-09-01

    Dopamine (DA) activates fictive crawling behavior in the medicinal leech. To identify the cellular mechanisms underlying this activation at the level of crawl-specific motoneuronal bursting, we targeted potential cAMP-dependent events that are often activated through DA(1)-like receptor signaling pathways. We found that isolated ganglia produced crawl-like motoneuron bursting after bath application of phosphodiesterase inhibitors (PDIs) that upregulated cAMP. This bursting persisted in salines in which calcium ions were replaced with equimolar cobalt or nickel, but was blocked by riluzole, an inhibitor of a persistent sodium current. PDI-induced bursting contained a number of patterned elements that were statistically similar to those observed during DA-induced fictive crawling, except that one motoneuron (CV) exhibited bursting during the contraction rather than the elongation phase of crawling. Although DA and the PDIs produced similar bursting profiles, intracellular recordings from motoneurons revealed differences in altered membrane properties. For example, DA lowered motoneuron excitability whereas the PDIs increased resting discharge rates. We suggest that PDIs (and DA) activate a sodium-influx-dependent timing mechanism capable of setting the crawl rhythm and that multiple DA receptor subtypes are involved in shaping and modulating the phase relationships and membrane properties of cell-specific members of the crawl network to generate crawling.

  6. Dependence of phrenic motoneurone output on the oscillatory component of arterial blood gas composition.

    PubMed Central

    Cross, B A; Grant, B J; Guz, A; Jones, P W; Semple, S J; Stidwill, R P

    1979-01-01

    1. The hypothesis that respiratory oscillations of arterial blood gas composition influence ventilation has been examined. 2. Phrenic motoneurone output recorded in the C5 root of the left phrenic nerve and the respiratory oscillations of arterial pH in the right common carotid artery were measured in vagotomized anaesthetized dogs which had been paralysed and artificially ventilated. 3. The effect of a change in tidal volume for one or two breaths on phrenic motoneurone output was measured with the inspiratory pump set at a constant frequency similar to, and in phase with, the animal's own respiratory frequency. A reduction of tidal volume to zero or an increase by 30% led to a corresponding change of mean carotid artery pH level. The changes of carotid artery pH resulted in a change of phrenic motoneurone output, predominantly of expiratory time (Te) but to a lesser extent of inspiratory time (T1) and also peak amplitude of 'integrated' phrenic motoneurone output (Phr). Denervation of the carotid bifurcation blocked this response. 4. The onset of movement of the inspiratory pump was triggered by the onset of phrenic motoneurone output. When a time delay was interposed between them, the phase relationship between respiratory oscillations of arterial pH and phrenic motoneurone output altered. The dominant effect was to alter Te; smaller and less consistent changes of Phr and T1 were observed. 5. When the inspiratory pump was maintained at a constant frequency but independent of and slightly different from the animal's own respiratory frequency (as judged by phrenic motoneurone output), the phase relationship between phrenic motoneurone output and the respiratory oscillations of pH changed breath by breath over a sequence of 100-200 breaths, without change of the mean level of arterial blood gas composition. Te varied by up to 30% about its mean value depending on the phase relationship. Ti and Phr were also dependent on the phase relationship but varied to a lesser

  7. Notch Signaling Pathway Is Activated in Motoneurons of Spinal Muscular Atrophy

    PubMed Central

    Caraballo-Miralles, Víctor; Cardona-Rossinyol, Andrea; Garcera, Ana; Torres-Benito, Laura; Soler, Rosa M.; Tabares, Lucía; Lladó, Jerònia; Olmos, Gabriel

    2013-01-01

    Spinal muscular atrophy (SMA) is a neurodegenerative disease produced by low levels of Survival Motor Neuron (SMN) protein that affects alpha motoneurons in the spinal cord. Notch signaling is a cell-cell communication system well known as a master regulator of neural development, but also with important roles in the adult central nervous system. Aberrant Notch function is associated with several developmental neurological disorders; however, the potential implication of the Notch pathway in SMA pathogenesis has not been studied yet. We report here that SMN deficiency, induced in the astroglioma cell line U87MG after lentiviral transduction with a shSMN construct, was associated with an increase in the expression of the main components of Notch signaling pathway, namely its ligands, Jagged1 and Delta1, the Notch receptor and its active intracellular form (NICD). In the SMNΔ7 mouse model of SMA we also found increased astrocyte processes positive for Jagged1 and Delta1 in intimate contact with lumbar spinal cord motoneurons. In these motoneurons an increased Notch signaling was found, as denoted by increased NICD levels and reduced expression of the proneural gene neurogenin 3, whose transcription is negatively regulated by Notch. Together, these findings may be relevant to understand some pathologic attributes of SMA motoneurons. PMID:23759991

  8. The respiratory drive to thoracic motoneurones in the cat and its relation to the connections from expiratory bulbospinal neurones

    PubMed Central

    Saywell, S A; Anissimova, N P; Ford, T W; Meehan, C F; Kirkwood, P A

    2007-01-01

    The descending control of respiratory-related motoneurones in the thoracic spinal cord remains the subject of some debate. In this study, direct connections from expiratory bulbospinal neurones to identified motoneurones were investigated using spike-triggered averaging and the strengths of connection revealed were related to the presence and size of central respiratory drive potentials in the same motoneurones. Intracellular recordings were made from motoneurones in segments T5–T9 of the spinal cord of anaesthetized cats. Spike-triggered averaging from expiratory bulbospinal neurones in the caudal medulla revealed monosynaptic EPSPs in all groups of motoneurones, with the strongest connections to expiratory motoneurones with axons in the internal intercostal nerve. In the latter, connection strength was similar irrespective of the target muscle (e.g. external abdominal oblique or internal intercostal) and the EPSP amplitude was positively correlated with the amplitude of the central respiratory drive potential of the motoneurone. For this group, EPSPs were found in 45/83 bulbospinal neurone/motoneurone pairs, with a mean amplitude of 40.5 μV. The overall strength of the connection supports previous measurements made by cross-correlation, but is about 10 times stronger than that reported in the only previous similar survey to use spike-triggered averaging. Calculations are presented to suggest that this input alone is sufficient to account for all the expiratory depolarization seen in the recorded motoneurones. However, extra sources of input, or amplification of this one, are likely to be necessary to produce a useful motoneurone output. PMID:17204500

  9. Six-Minute Walk Test Performance in Persons With Multiple Sclerosis While Using Passive or Powered Ankle-Foot Orthoses.

    PubMed

    Boes, Morgan K; Bollaert, Rachel E; Kesler, Richard M; Learmonth, Yvonne C; Islam, Mazharul; Petrucci, Matthew N; Motl, Robert W; Hsiao-Wecksler, Elizabeth T

    2018-03-01

    To determine whether a powered ankle-foot orthosis (AFO) that provides dorsiflexor and plantar flexor assistance at the ankle can improve walking endurance of persons with multiple sclerosis (MS). Short-term intervention. University research laboratory. Participants (N=16) with a neurologist-confirmed diagnosis of MS and daily use of a prescribed custom unilateral passive AFO. Three 6-minute walk tests (6MWTs), 1 per footwear condition: shoes (no AFO), prescribed passive AFO, and portable powered AFO (PPAFO). Assistive devices were worn on the impaired limb. Distance walked and metabolic cost of transport were recorded during each 6MWT and compared between footwear conditions. Each participant completed all three 6MWTs within the experimental design. PPAFO use resulted in a shorter 6MWT distance than did a passive AFO or shoe use. No differences were observed in metabolic cost of transport between footwear conditions. The current embodiment of this PPAFO did not improve endurance walking performance during the 6MWT in a sample of participants with gait impairment due to MS. Further research is required to determine whether expanded training or modified design of this powered orthosis can be effective in improving endurance walking performance in persons with gait impairment due to MS. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  10. The membrane properties and firing characteristics of rat jaw-elevator motoneurones.

    PubMed Central

    Moore, J; Appenteng, K

    1990-01-01

    1. We have determined the membrane and firing properties of fifty-six jaw-elevator motoneurones in rats that were anaesthetized with pentobarbitone, paralysed and artificially ventilated. 2. Forty-two neurones were identified as masseter motoneurones and fourteen as masseter synergist motoneurones. The membrane potentials for the sample ranged from -60 to -86 (mean = -68; S.D. = 7.3; n = 56), and spike amplitudes from 50 to 95 mV. The duration of the after-hyperpolarization following antidromic spikes in masseter motoneurones ranged from 15 to 50 ms (mean = 30; S.D. = 12.8) and their amplitudes from 1.0 to 4.5 mV (mean = 2.7; S.D. = 2.2; n = 42). 3. The mean input resistance for the total sample was 2.3 M omega (S.D. = 0.9; n = 56), membrane time constant 3.9 ms (S.D. = 0.9; n = 48) and rheobase 4.2 nA (S.D. = 2.6; n = 56). The distribution of these parameters was independent of membrane potential. We found no significant interrelationships between the membrane properties and one interpretation of this is that our sample may be drawn from a homogenous population of motoneurones. We also suggest that elevator motoneurones may have a lower Rm (specific membrane resistivity) value than cat hindlimb motoneurones because they have a similar range of input resistance values but only half the total surface area. 4. Forty-six out of forty-nine neurones fired repetitively to a depolarizing current pulse at a mean threshold of 1.6 x rheobase. Current-frequency plots were constructed for thirteen neurones and all but one showed a primary and secondary range in the firing of the first interspike interval. The mean slope in the primary range was 31 impulses s-1 nA-1 and 77 impulses s-1 nA-1 for the secondary range. The mean minimal firing frequency for steady firing was 26 impulses s-1 and, in response to an increase of stimulation, the rate increased monotonically with a slope of 11 impulses s-1 nA-1. 5. The dynamic sensitivity of twelve neurones was assessed from their

  11. Immunohistochemical localization of serotonin- and substance P-containing fibers around respiratory muscle motoneurons in the nucleus ambiguus of the cat.

    PubMed

    Holtman, J R

    1988-07-01

    Retrograde tracing with a fluorescent dye (Fast Blue) combined with immunohistochemistry was used to determine if the putative neurotransmitters, serotonin and substance P, are present around posterior cricoarytenoid muscle motoneurons. Fast Blue was injected into the posterior cricoarytenoid muscle of the larynx. Following a 14-21 day survival time to allow for transport of the dye, the animals were perfusion fixed and the brainstem was removed for analysis under the fluorescence microscope. Retrogradely labeled cell bodies containing Fast Blue were found within the nucleus ambiguus from 0.5 to 3.0 mm rostral to obex. These motoneurons ranged in size from 23 to 38 micron. The same tissue sections containing labeled posterior cricoarytenoid muscle motoneurons were then used to determine the distribution of serotonin and substance P around these motoneurons using the indirect immunofluorescence technique. A dense network of serotonin-containing immunoreactive fibers was found around posterior cricoarytenoid muscle motoneurons. The fibers contained varicosities which were in close proximity, actually appearing to surround these motoneurons. Substance P immunoreactive fibers and varicosities were also found around posterior cricoarytenoid muscle motoneurons. The density and pattern of distribution of the substance P immunoreactivity was similar to that of the serotonin immunoreactivity. These results suggest that these putative neurotransmitters may be involved in influencing the activity of posterior cricoarytenoid muscle motoneurons. Serotonin and substance P are also present around other respiratory motoneurons such as phrenic motoneurons. Therefore, these two neurotransmitters may have a more general role in influencing respiratory motor outflow.

  12. Diversification of intrinsic motoneuron electrical properties during normal development and botulinum toxin-induced muscle paralysis in early postnatal mice.

    PubMed

    Nakanishi, S T; Whelan, P J

    2010-05-01

    During early postnatal development, between birth and postnatal days 8-11, mice start to achieve weight-bearing locomotion. In association with the progression of weight-bearing locomotion there are presumed developmental changes in the intrinsic electrical properties of spinal -motoneurons. However, these developmental changes in the properties of -motoneuron properties have not been systematically explored in mice. Here, data are presented documenting the developmental changes of selected intrinsic motoneuron electrical properties, including statistically significant changes in action potential half-width, intrinsic excitability and diversity (quantified as coefficient of variation) of rheobase current, afterhyperpolarization half-decay time, and input resistance. In various adult mammalian preparations, the maintenance of intrinsic motoneuron electrical properties is dependent on activity and/or transmission-sensitive motoneuron-muscle interactions. In this study, we show that botulinum toxin-induced muscle paralysis led to statistically significant changes in the normal development of intrinsic motoneuron electrical properties in the postnatal mouse. This suggests that muscle activity during early neonatal life contributes to the development of normal motoneuron electrical properties.

  13. Mutant SOD1-expressing astrocytes release toxic factors that trigger motoneuron death by inducing hyperexcitability

    PubMed Central

    Fritz, Elsa; Izaurieta, Pamela; Weiss, Alexandra; Mir, Franco R.; Rojas, Patricio; Gonzalez, David; Rojas, Fabiola; Brown, Robert H.; Madrid, Rodolfo

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motoneurons starting in adulthood. Recent studies using cell or animal models document that astrocytes expressing disease-causing mutations of human superoxide dismutase 1 (hSOD1) contribute to the pathogenesis of ALS by releasing a neurotoxic factor(s). Neither the mechanism by which this neurotoxic factor induces motoneuron death nor its cellular site of action has been elucidated. Here we show that acute exposure of primary wild-type spinal cord cultures to conditioned medium derived from astrocytes expressing mutant SOD1 (ACM-hSOD1G93A) increases persistent sodium inward currents (PCNa), repetitive firing, and intracellular calcium transients, leading to specific motoneuron death days later. In contrast to TTX, which paradoxically increased twofold the amplitude of calcium transients and killed motoneurons, reduction of hyperexcitability by other specific (mexiletine) and nonspecific (spermidine and riluzole) blockers of voltage-sensitive sodium (Nav) channels restored basal calcium transients and prevented motoneuron death induced by ACM-hSOD1G93A. These findings suggest that riluzole, the only FDA-approved drug with known benefits for ALS patients, acts by inhibiting hyperexcitability. Together, our data document that a critical element mediating the non-cell-autonomous toxicity of ACM-hSOD1G93A on motoneurons is increased excitability, an observation with direct implications for therapy of ALS. PMID:23486205

  14. Influence of proprioceptive feedback on the firing rate and recruitment of motoneurons

    NASA Astrophysics Data System (ADS)

    De Luca, C. J.; Kline, J. C.

    2012-02-01

    We investigated the relationships of the firing rate and maximal recruitment threshold of motoneurons recorded during isometric contraction with the number of spindles in individual muscles. At force levels above 10% of maximal voluntary contraction, the firing rate was inversely related to the number of spindles in a muscle, with the slope of the relationship increasing with force. The maximal recruitment threshold of motor units increased linearly with the number of spindles in the muscle. Thus, muscles with a greater number of spindles had lower firing rates and a greater maximal recruitment threshold. These findings may be explained by a mechanical interaction between muscle fibres and adjacent spindles. During low-level (0% to 10%) voluntary contractions, muscle fibres of recruited motor units produce force twitches that activate nearby spindles to respond with an immediate excitatory feedback that reaches maximal level. As the force increases further, the twitches overlap and tend towards tetanization, the muscle fibres shorten, the spindles slacken, their excitatory firings decrease, and the net excitation to the homonymous motoneurons decreases. Motoneurons of muscles with greater number of spindles receive a greater decrease in excitation which reduces their firing rates, increases their maximal recruitment threshold, and changes the motoneuron recruitment distribution.

  15. Influence of proprioceptive feedback on the firing rate and recruitment of motoneurons

    PubMed Central

    De Luca, C J; Kline, J C

    2012-01-01

    We investigated the relationships of the firing rate and maximal recruitment threshold of motoneurons recorded during isometric contraction with the number of spindles in individual muscles. At force levels above 10% of maximal voluntary contraction, the firing rate was inversely related to the number of spindles in a muscle, with the slope of the relationship increasing with force. The maximal recruitment threshold of motor units increased linearly with the number of spindles in the muscle. Thus, muscles with a greater number of spindles had lower firing rates and a greater maximal recruitment threshold. These findings may be explained by a mechanical interaction between muscle fibres and adjacent spindles. During low-level (0 to 10%) voluntary contractions, muscle fibres of recruited motor units produce force-twitches that activate nearby spindles to respond with an immediate excitatory feedback that reaches maximal level. As the force increases further, the twitches overlap and tend towards tetanization, the muscle fibres shorten, the spindles slacken, their excitatory firings decrease, and the net excitation to the homonymous motoneurons decreases. Motoneurons of muscles with greater number of spindles receive a greater decrease in excitation which reduces their firing rates, increases their maximal recruitment threshold, and changes the motoneuron recruitment distribution. PMID:22183300

  16. Estimates of the location of L-type Ca2+ channels in motoneurons of different sizes: a computational study.

    PubMed

    Grande, Giovanbattista; Bui, Tuan V; Rose, P Ken

    2007-06-01

    In the presence of monoamines, L-type Ca(2+) channels on the dendrites of motoneurons contribute to persistent inward currents (PICs) that can amplify synaptic inputs two- to sixfold. However, the exact location of the L-type Ca(2+) channels is controversial, and the importance of the location as a means of regulating the input-output properties of motoneurons is unknown. In this study, we used a computational strategy developed previously to estimate the dendritic location of the L-type Ca(2+) channels and test the hypothesis that the location of L-type Ca(2+) channels varies as a function of motoneuron size. Compartmental models were constructed based on dendritic trees of five motoneurons that ranged in size from small to large. These models were constrained by known differences in PIC activation reported for low- and high-conductance motoneurons and the relationship between somatic PIC threshold and the presence or absence of tonic excitatory or inhibitory synaptic activity. Our simulations suggest that L-type Ca(2+) channels are concentrated in hotspots whose distance from the soma increases with the size of the dendritic tree. Moving the hotspots away from these sites (e.g., using the hotspot locations from large motoneurons on intermediate-sized motoneurons) fails to replicate the shifts in PIC threshold that occur experimentally during tonic excitatory or inhibitory synaptic activity. In models equipped with a size-dependent distribution of L-type Ca(2+) channels, the amplification of synaptic current by PICs depends on motoneuron size and the location of the synaptic input on the dendritic tree.

  17. Ankle joint distraction arthroplasty for severe ankle arthritis.

    PubMed

    Xu, Yang; Zhu, Yuan; Xu, Xiang-Yang

    2017-02-28

    Ankle distraction arthroplasty is one option for the treatment of severe ankle arthritis in young patients. The outcomes and factors predicting success in distraction arthroplasty are poorly understood. From January 2011 to May 2015, 16 patients who had undergone ankle distraction arthroplasty for ankle arthritis were operated, including six males and ten females. All patients were available for analysis. The main outcome measurements included joint space on weight bearing radiographs, AOFAS-AH scores (American Orthopaedic Foot & Ankle Society ankle-hindfoot score), VAS scores and SF-36 scores. All 16 patients were followed for a mean follow-up of 40.9 ± 14.7 months (range, 17-67 months). Fourteen of the 16 patients still had their native ankle joints. One patient had undergone ankle arthrodesis 1 year after the operation and one patient had converted to spontaneous ankle fusion at the 3 years follow-up postoperative. The VAS score improved from 5.9 ± 0.8 to 3.7 ± 2.2 (p = 0.0028). The mean AOFAS-AH score improved from 41.9 ± 7.2 preoperatively to 68.1 ± 20.0 postoperatively (p = 0.001). The mean SF-36 score improved from 43.1 ± 7.6 preoperatively to 62.7 ± 18.8 postoperatively (p = 0.002). A weight-bearing ankle space larger than 3 mm at 1 year following distraction is a positive predictive factor. In this study, the treatment of ankle motion distraction for end stage ankle arthritis showed benefit in 9/16 (56.25%) patients at 41 months. It is a promising method for young patients with severe ankle arthritis.

  18. Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menelaou, Evdokia; Paul, Latoya T.; Perera, Surangi N.

    Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMNs). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30 μM). Previous work showed that the paralytic mutant zebrafish known as sofa potato exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at differentmore » developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. - Highlights: • Embryonic nicotine exposure can specifically affect secondary motoneuron axons in a dose

  19. Amyotrophic lateral sclerosis immunoglobulins increase Ca2+ currents in a motoneuron cell line.

    PubMed

    Mosier, D R; Baldelli, P; Delbono, O; Smith, R G; Alexianu, M E; Appel, S H; Stefani, E

    1995-01-01

    The sporadic form of amyotrophic lateral sclerosis (ALS) is an idiopathic and eventually lethal disorder causing progressive degeneration of cortical and spinal motoneurons. Recent studies have shown that the majority of patients with sporadic ALS have serum antibodies that bind to purified L-type voltage-gated calcium channels and that antibody titer correlates with the rate of disease progression. Furthermore, antibodies purified from ALS patient sera have been found to alter the physiologic function of voltage-gated calcium channels in nonmotoneuron cell types. Using whole-cell patch-clamp techniques, immunoglobulins purified from sera of 5 of 6 patients with sporadic ALS are now shown to increase calcium currents in a hybrid motoneuron cell line, VSC4.1. These calcium currents are blocked by the polyamine funnel-web spider toxin FTX, which has previously been shown to block Ca2+ currents and evoked transmitter release at mammalian motoneuron terminals. These data provide additional evidence linking ALS to an autoimmune process and suggest that antibody-induced increases in calcium entry through voltage-gated calcium channels may occur in motoneurons in this disease, with possible deleterious effects in susceptible neurons.

  20. Stretch-sensitive paresis and effort perception in hemiparesis.

    PubMed

    Vinti, Maria; Bayle, Nicolas; Hutin, Emilie; Burke, David; Gracies, Jean-Michel

    2015-08-01

    In spastic paresis, stretch applied to the antagonist increases its inappropriate recruitment during agonist command (spastic co-contraction). It is unknown whether antagonist stretch: (1) also affects agonist recruitment; (2) alters effort perception. We quantified voluntary activation of ankle dorsiflexors, effort perception, and plantar flexor co-contraction during graded dorsiflexion efforts at two gastrocnemius lengths. Eighteen healthy (age 41 ± 13) and 18 hemiparetic (age 54 ± 12) subjects performed light, medium and maximal isometric dorsiflexion efforts with the knee flexed or extended. We determined dorsiflexor torque, Root Mean Square EMG and Agonist Recruitment/Co-contraction Indices (ARI/CCI) from the 500 ms peak voluntary agonist recruitment in a 5-s maximal isometric effort in tibialis anterior, soleus and medial gastrocnemius. Subjects retrospectively reported effort perception on a 10-point visual analog scale. During gastrocnemius stretch in hemiparetic subjects, we observed: (1) a 25 ± 7 % reduction of tibialis anterior voluntary activation (maximum reduction 98 %; knee extended vs knee flexed; p = 0.007, ANOVA); (2) an increase in dorsiflexion effort perception (p = 0.03, ANCOVA). Such changes did not occur in healthy subjects. Effort perception depended on tibialis anterior recruitment only (βARI(TA) = 0.61, p < 0.01) in healthy subjects (not on gastrocnemius medialis co-contraction) while it depended on both tibialis anterior agonist recruitment (βARI(TA) = 0.41, p < 0.001) and gastrocnemius medialis co-contraction (βCCI(MG) = 0.43, p < 0.001) in hemiparetic subjects. In hemiparesis, voluntary ability to recruit agonist motoneurones is impaired--sometimes abolished--by antagonist stretch, a phenomenon defined here as stretch-sensitive paresis. In addition, spastic co-contraction increases effort perception, an additional incentive to evaluate and treat this phenomenon.

  1. GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila

    PubMed Central

    Gowda, Swetha B. M.; Paranjpe, Pushkar D.; Reddy, O. Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich

    2018-01-01

    Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila. Our findings indicate that targeted down-regulation of the GABAA receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila. PMID:29440493

  2. GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila.

    PubMed

    Gowda, Swetha B M; Paranjpe, Pushkar D; Reddy, O Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich; VijayRaghavan, K

    2018-02-27

    Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila Our findings indicate that targeted down-regulation of the GABA A receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila . Copyright © 2018 the Author(s). Published by PNAS.

  3. Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

    PubMed Central

    Jankowska, Elzbieta; Hammar, Ingela; Slawinska, Urszula; Maleszak, Katarzyna; Edgley, Stephen A.

    2007-01-01

    Pathways through which reticulospinal neurons can influence contralateral limb movements were investigated by recording from mo-toneurons innervating hindlimb muscles. Reticulospinal tract fibers were stimulated within the brainstem or in the lateral funiculus of the thoracic spinal cord contralateral to the motoneurons. Effects evoked by ipsilaterally descending reticulospinal tract fibers were eliminated by a spinal hemisection at an upper lumbar level. Stimuli applied in the brainstem evoked EPSPs, IPSPs, or both at latencies of 1.42 ± 0.03 and 1.53 ± 0.04 msec, respectively, from the first components of the descending volleys and with properties indicating a disynaptic linkage, in most contralateral motoneurons: EPSPs in 76% and IPSPs in 26%. EPSPs with characteristics of monosynaptically evoked responses, attributable to direct actions of crossed axon collaterals of reticulospinal fibers, were found in a small proportion of the motoneurons, whether evoked from the brainstem (9%) or from the thoracic cord (12.5%). Commissural neurons, which might mediate the crossed disynaptic actions (i.e., were antidromically activated from contralateral motor nuclei and monosynaptically excited from the ipsilateral reticular formation), were found in Rexed’s lamina VIII in the midlumbar segments (L3–L5). The results reveal that although direct actions of reticulospinal fibers are much more potent on ipsilateral motoneurons, interneuronally mediated actions are as potent contralaterally as ipsilaterally, and midlumbar commissural neurons are likely to contribute to them. They indicate a close coupling between the spinal interneuronal systems used by the reticulospinal neurons to coordinate muscle contractions ipsilaterally and contralaterally. PMID:12629191

  4. The use of dendrograms to describe the electrical activity of motoneurons underlying behaviors in leeches

    PubMed Central

    Juárez-Hernández, León J.; Bisson, Giacomo; Torre, Vincent

    2013-01-01

    The present manuscript aims at identifying patterns of electrical activity recorded from neurons of the leech nervous system, characterizing specific behaviors. When leeches are at rest, the electrical activity of neurons and motoneurons is poorly correlated. When leeches move their head and/or tail, in contrast, action potential (AP) firing becomes highly correlated. When the head or tail suckers detach, specific patterns of electrical activity are detected. During elongation and contraction the electrical activity of motoneurons in the Medial Anterior and Dorsal Posterior nerves increase, respectively, and several motoneurons are activated both during elongation and contraction. During crawling, swimming, and pseudo-swimming patterns of electrical activity are better described by the dendrograms of cross-correlations of motoneurons pairs. Dendrograms obtained from different animals exhibiting the same behavior are similar and by averaging these dendrograms we obtained a template underlying a given behavior. By using this template, the corresponding behavior is reliably identified from the recorded electrical activity. The analysis of dendrograms during different leech behavior reveals the fine orchestration of motoneurons firing specific to each stereotyped behavior. Therefore, dendrograms capture the subtle changes in the correlation pattern of neuronal networks when they become involved in different tasks or functions. PMID:24098274

  5. Ankle instability.

    PubMed

    Ferran, Nicholas A; Oliva, Francesco; Maffulli, Nicola

    2009-06-01

    Acute ankle sprains are common, and if inadequately treated may result in chronic instability. Lateral ankle injuries are most common, with deltoid injuries rare and associated with ankle fractures/dislocation. Medial ankle instability is rare. Functional management of acute lateral ankle sprains is the treatment of choice, with acute ligament repair reserved for athletes. Chronic lateral ankle instability is initially managed conservatively, however, failure of rehabilitation is an indication for surgical management. Nonanatomic tenodesis reconstructions have poor long-term results, sacrifice peroneal tendons, and disrupt normal ankle and hindfoot biomechanics. Anatomic repair of the anterior talofibular and calcaneofibular ligaments is recommended when the quality of the ruptured ligaments permits. Anatomic reconstruction with autograft or allograft should be performed when ligaments are attenuated. The role of arthroscopic reconstruction is evolving. Ankle arthroscopy should be performed at the time of repair or reconstruction and should address any other intra-articular causes of pain.

  6. Effects of robot-guided passive stretching and active movement training of ankle and mobility impairments in stroke.

    PubMed

    Waldman, Genna; Yang, Chung-Yong; Ren, Yupeng; Liu, Lin; Guo, Xin; Harvey, Richard L; Roth, Elliot J; Zhang, Li-Qun

    2013-01-01

    To investigate the effects of controlled passive stretching and active movement training using a portable rehabilitation robot on stroke survivors with ankle and mobility impairment. Twenty-four patients at least 3 months post stroke were assigned to receive 6 week training using the portable robot in a research laboratory (robot group) or an instructed exercise program at home (control group). All patients underwent clinical and biomechanical evaluations in the laboratory at pre-evaluation, post-evaluation, and 6-week follow-up. Subjects in the robot group improved significantly more than that in the control group in reduction in spasticity measured by modified Ashworth scale, mobility by Stroke Rehabilitation Assessment of Movement (STREAM), the balance by Berg balance score, dorsiflexion passive range of motion, dorsiflexion strength, and load bearing on the affected limb during gait after 6-week training. Both groups improved in the STREAM, dorsiflexion active range of motion and dorsiflexor strength after the training, which were retained in the follow-up evaluation. Robot-assisted passive stretching and active movement training is effective in improving motor function and mobility post stroke.

  7. Vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive axon terminals on the rat jaw-closing and jaw-opening motoneurons.

    PubMed

    Park, Sook Kyung; Ko, Sang Jin; Paik, Sang Kyoo; Rah, Jong-Cheol; Lee, Kea Joo; Bae, Yong Chul

    2018-02-23

    To provide information on the glutamatergic synapses on the trigeminal motoneurons, which may be important for understanding the mechanism of control of jaw movements, we investigated the distribution of vesicular glutamate transporter (VGLUT)1-immunopositive (+) and VGLUT2 + axon terminals (boutons) on the rat jaw-closing (JC) and jaw-opening (JO) motoneurons, and their morphological determinants of synaptic strength by retrograde tracing, electron microscopic immunohistochemistry, and quantitative ultrastructural analysis. We found that (1) the large majority of VGLUT + boutons on JC and JO motoneurons were VGLUT2+, (2) the density of VGLUT1 + boutons terminating on JC motoneurons was significantly higher than that on JO motoneurons, (3) the density of VGLUT1 + boutons terminating on non-primary dendrites of JC motoneurons was significantly higher than that on somata or primary dendrites, whereas the density of VGLUT2 + boutons was not significantly different between JC and JO motoneurons and among various compartments of the postsynaptic neurons, and (4) the bouton volume, mitochondrial volume, and active zone area of the VGLUT1 + boutons forming synapses on JC motoneurons were significantly bigger than those of VGLUT2 + boutons. These findings suggest that JC and JO motoneurons receive glutamatergic input primarily from VGLUT2-expressing intrinsic neurons (premotoneurons), and may be controlled differently by neurons in the trigeminal mesencephalic nucleus and by glutamatergic premotoneurons.

  8. SPINAL AND PERIPHERAL DRY NEEDLING VERSUS PERIPHERAL DRY NEEDLING ALONE AMONG INDIVIDUALS WITH A HISTORY OF LATERAL ANKLE SPRAIN: A RANDOMIZED CONTROLLED TRIAL

    PubMed Central

    Rossi, Ainsley; Blaustein, Sara; Brown, Joshua; Dieffenderfer, Kari; Ervin, Elaine; Griffin, Steven; Frierson, Elizabeth; Geist, Kathleen

    2017-01-01

    Background In addition to established interventions, dry needling may reduce impairments leading to greater functional abilities for individuals following ankle sprain. Hypothesis/Purpose The purpose of this study was to compare effects of spinal and peripheral dry needling (DN) with peripheral DN alone on impairments and functional performance among individuals with a history of lateral ankle sprain. Study Design Randomized controlled trial. Methods Twenty individuals with a history of lateral ankle sprain (18 bilateral, 2 unilateral) participated in this study (4 males, 16 females; mean age 28.9 + /- 9.2 years). During the first of two sessions, participants completed the Foot and Ankle Disability Index (FADI) and the Cumberland Ankle Instability Tool (CAIT) and their strength, unilateral balance, and unilateral hop test performance was assessed. Participants were randomly assigned to a spinal and peripheral DN group (SPDN), or a peripheral only DN group (PDN). Participants in the SPDN site group received DN to bilateral L5 multifidi and fibularis longus and brevis muscles on the involved lower extremity. Participants in the PDN group received DN to the fibularis muscles alone. Participants’ strength, balance and hop test performance were reassessed immediately following the intervention, and at follow-up 6-7 days later, all outcome measures were reassessed. Three-way mixed model ANOVAs and Mann-Whitney U tests assessed between group differences for outcome variables with normal distributions and non-normal distributions, respectively. Results ANOVAs showed significant group by time interaction (p<0.05) for invertor strength, significant side by group and time by group interactions (p<0.05) for plantarflexor-evertor strength, no significant findings for dorsiflexor-invertor strength, significant side by time interaction (p<0.05) for unilateral balance, significant main effect of time (p<0.05) for triple hop for distance test, and significant main effect of

  9. ATG5 overexpression is neuroprotective and attenuates cytoskeletal and vesicle-trafficking alterations in axotomized motoneurons.

    PubMed

    Leiva-Rodríguez, Tatiana; Romeo-Guitart, David; Marmolejo-Martínez-Artesero, Sara; Herrando-Grabulosa, Mireia; Bosch, Assumpció; Forés, Joaquim; Casas, Caty

    2018-05-24

    Injured neurons should engage endogenous mechanisms of self-protection to limit neurodegeneration. Enhancing efficacy of these mechanisms or correcting dysfunctional pathways may be a successful strategy for inducing neuroprotection. Spinal motoneurons retrogradely degenerate after proximal axotomy due to mechanical detachment (avulsion) of the nerve roots, and this limits recovery of nervous system function in patients after this type of trauma. In a previously reported proteomic analysis, we demonstrated that autophagy is a key endogenous mechanism that may allow motoneuron survival and regeneration after distal axotomy and suture of the nerve. Herein, we show that autophagy flux is dysfunctional or blocked in degenerated motoneurons after root avulsion. We also found that there were abnormalities in anterograde/retrograde motor proteins, key secretory pathway factors, and lysosome function. Further, LAMP1 protein was missorted and underglycosylated as well as the proton pump v-ATPase. In vitro modeling revealed how sequential disruptions in these systems likely lead to neurodegeneration. In vivo, we observed that cytoskeletal alterations, induced by a single injection of nocodazole, were sufficient to promote neurodegeneration of avulsed motoneurons. Besides, only pre-treatment with rapamycin, but not post-treatment, neuroprotected after nerve root avulsion. In agreement, overexpressing ATG5 in injured motoneurons led to neuroprotection and attenuation of cytoskeletal and trafficking-related abnormalities. These discoveries serve as proof of concept for autophagy-target therapy to halting the progression of neurodegenerative processes.

  10. Syndesmotic ankle sprain.

    PubMed

    Childs, Sharon G

    2012-01-01

    Ankle sprain injuries are the most common type of joint sprain. The prevalence of ankle joint sprains accounts for 21% of joint injuries in the body. Although somewhat rare, high-ankle or syndesmotic ankle sprains occur in up to 15% of ankle trauma. This article will present the pathomechanics of the high-ankle or syndesmotic sprain.

  11. Ankle sprain (image)

    MedlinePlus

    An ankle sprain is a common injury to the ankle. The most common way the ankle is injured is when ... swelling, inflammation, and bruising around the ankle. An ankle sprain injury may take a few weeks to many ...

  12. Selective Requirement for Maintenance of Synaptic Contacts onto Motoneurons by Target-Derived trkB Receptors

    PubMed Central

    2016-01-01

    Synaptic contacts onto motoneurons were studied in mice in which the gene for the trkB neurotrophin receptor was knocked out selectively in a subset of spinal motoneurons. The extent of contacts by structures immunoreactive for either of two different vesicular glutamate transporters (VGLUT1 and VGLUT2), the vesicular GABA transporter, or glutamic acid decarboxylase 67 (GAD67) with the somata of motoneurons, was studied in wild type and trkB knockout cells in tamoxifen treated male and female SLICK-trkB−/− mice. Selective knockout of the trkB gene resulted in a marked reduction in contacts made by VGLUT2- and GAD67-immunoreactive structures in both sexes and a significant reduction in contacts containing only glycine in male mice. No reduction was found for glycinergic contacts in female mice or for VGLUT1 immunoreactive contacts in either sex. Signaling through postsynaptic trkB receptors is considered to be an essential part of a cellular mechanism for maintaining the contacts of some, but not all, synaptic contacts onto motoneurons. PMID:27433358

  13. Ankle sprain - aftercare

    MedlinePlus

    Lateral ankle sprain - aftercare; Medial ankle sprain - aftercare; Medial ankle injury - aftercare; Ankle syndesmosis sprain - aftercare; Syndesmosis injury - aftercare; ATFL injury - aftercare; CFL injury - ...

  14. Muscle length-dependent contribution of motoneuron Cav1.3 channels to force production in model slow motor unit.

    PubMed

    Kim, Hojeong

    2017-07-01

    Persistent inward current (PIC)-generating Ca v 1.3 channels in spinal motoneuron dendrites are thought to be actively recruited during normal behaviors. However, whether and how the activation of PIC channels influences force output of motor unit remains elusive. Here, building a physiologically realistic model of slow motor unit I demonstrated that force production induced by the PIC activation is much smaller for short than lengthened muscles during the regular firing of the motoneuron that transitions from the quiescent state by either a brief current pulse at the soma or a brief synaptic excitation at the dendrites. By contrast, the PIC-induced force potentiation was maximal for short muscles when the motoneuron switched from a stable low-frequency firing state to a stable high-frequency firing state by the current pulse at the soma. Under the synaptic excitation at the dendrites, however, the force could not be potentiated by the transitioning of the motoneuron from a low- to a high-frequency firing state due to the simultaneous onset of PIC at the dendrites and firing at the soma. The strong dependency of the input-output relationship of the motor unit on the neuromodulation and Ia afferent inputs for the PIC channels was further shown under static variations in muscle length. Taken together, these findings suggest that the PIC activation in the motoneuron dendrites may differentially affect the force production of the motor unit, depending not only on the firing state history of the motoneuron and the variation in muscle length but also on the mode of motor activity. NEW & NOTEWORTHY Ca v 1.3 channels in motoneuron dendrites are actively involved during normal motor activities. To investigate the effects of the activation of motoneuron Ca v 1.3 channels on force production, a model motor unit was built based on best-available data. The simulation results suggest that force potentiation induced by Ca v 1.3 channel activation is strongly modulated not only by

  15. Effect of muscle relaxation in the foot on simultaneous muscle contraction in the contralateral hand.

    PubMed

    Kato, Kouki; Kanosue, Kazuyuki

    2016-10-28

    We investigated the effects of foot muscle relaxation and contraction on muscle activities in the hand on both ipsilateral and contralateral sides. The subjects sat in an armchair with hands in the pronated position. They were able to freely move their right/left hand and foot. They performed three tasks for both ipsilateral (right hand and right foot) and contralateral limb coordination (left hand and right foot for a total of six tasks). These tasks involved: (1) wrist extension from a flexed (resting) position, (2) wrist extension with simultaneous ankle dorsiflexion from a plantarflexed (resting) position, and (3) wrist extension with simultaneous ankle relaxation from a dorsiflexed position. The subjects performed each task as fast as possible after hearing the start signal. Reaction time for the wrist extensor contraction (i.e. the degree to which it preceded the motor reaction time), as observed in electromyography (EMG), became longer when it was concurrently done with relaxation of the ankle dorsiflexor. Also, the magnitude of EMG activity became smaller, as compared with activity when wrist extensor contraction was done alone or with contraction of the ankle dorsiflexor. These effects were observed not only for the ipsilateral hand, but also for the contralateral hand. Our findings suggest that muscle relaxation in one limb interferes with muscle contraction in both the ipsilateral and contralateral limbs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Ankle Arthroscopic Reconstruction of Lateral Ligaments (Ankle Anti-ROLL)

    PubMed Central

    Takao, Masato; Glazebrook, Mark; Stone, James; Guillo, Stéphane

    2015-01-01

    Ankle instability is a condition that often requires surgery to stabilize the ankle joint that will improve pain and function if nonoperative treatments fail. Ankle stabilization surgery may be performed as a repair in which the native existing anterior talofibular ligament or calcaneofibular ligament (or both) is imbricated or reattached. Alternatively, when native ankle ligaments are insufficient for repair, a reconstruction of the ligaments may be performed in which an autologous or allograft tendon is used to reconstruct the anterior talofibular ligament or calcaneofibular ligament (or both). Currently, ankle stabilization surgery is most commonly performed through an open incision, but arthroscopic ankle stabilization using repair techniques has been described and is being used more often. We present our technique for anatomic ankle arthroscopic reconstruction of the lateral ligaments (anti-ROLL) performed in an all–inside-out manner that is likely safe for patients and minimally invasive. PMID:26900560

  17. Evaluation of the lambda model for human postural control during ankle strategy.

    PubMed

    Micheau, Philippe; Kron, Aymeric; Bourassa, Paul

    2003-09-01

    An accurate modeling of human stance might be helpful in assessing postural deficit. The objective of this article is to validate a mathematical postural control model for quiet standing posture. The postural dynamics is modeled in the sagittal plane as an inverted pendulum with torque applied at the ankle joint. The torque control system is represented by the physiological lambda model. Two neurophysiological command variables of the central nervous system, designated lambda and micro, establish the dynamic threshold muscle at which motoneuron recruitment begins. Kinematic data and electromyographic signals were collected on four young males in order to measure small voluntary sway and quiet standing posture. Validation of the mathematical model was achieved through comparison of the experimental and simulated results. The mathematical model allows computation of the unmeasurable neurophysiological commands lambda and micro that control the equilibrium position and stability. Furthermore, with the model it is possible to conclude that low-amplitude body sway during quiet stance is commanded by the central nervous system.

  18. Shared Components of Rhythm Generation for Locomotion and Scratching Exist Prior to Motoneurons

    PubMed Central

    Hao, Zhao-Zhe; Berkowitz, Ari

    2017-01-01

    Does the spinal cord use a single network to generate locomotor and scratching rhythms or two separate networks? Previous research showed that simultaneous swim and scratch stimulation (“dual stimulation”) in immobilized, spinal turtles evokes a single rhythm in hindlimb motor nerves with a frequency often greater than during swim stimulation alone or scratch stimulation alone. This suggests that the signals that trigger swimming and scratching converge and are integrated within the spinal cord. However, these results could not determine whether the integration occurs in motoneurons themselves or earlier, in spinal interneurons. Here, we recorded intracellularly from hindlimb motoneurons during dual stimulation. Motoneuron membrane potentials displayed regular oscillations at a higher frequency during dual stimulation than during swim or scratch stimulation alone. In contrast, arithmetic addition of the oscillations during swimming alone and scratching alone with various delays always generated irregular oscillations. Also, the standard deviation of the phase-normalized membrane potential during dual stimulation was similar to those during swimming or scratching alone. In contrast, the standard deviation was greater when pooling cycles of swimming alone and scratching alone for two of the three forms of scratching. This shows that dual stimulation generates a single rhythm prior to motoneurons. Thus, either swimming and scratching largely share a rhythm generator or the two rhythms are integrated into one rhythm by strong interactions among interneurons. PMID:28848402

  19. Static γ-motoneurones couple group Ia and II afferents of single muscle spindles in anaesthetised and decerebrate cats

    PubMed Central

    Gladden, M H; Matsuzaki, H

    2002-01-01

    Ideas about the functions of static γ-motoneurones are based on the responses of primary and secondary endings to electrical stimulation of single static γ-axons, usually at high frequencies. We compared these effects with the actions of spontaneously active γ-motoneurones. In anaesthetised cats, afferents and efferents were recorded in intramuscular nerve branches to single muscle spindles. The occurrence of γ-spikes, identified by a spike shape recognition system, was linked to video-taped contractions of type-identified intrafusal fibres in the dissected muscle spindles. When some static γ-motoneurones were active at low frequency (< 15 Hz) they coupled the firing of group Ia and II afferents. Activity of other static γ-motoneurones which tensed the intrafusal fibres appeared to enhance this effect. Under these conditions the secondary ending responded at shorter latency than the primary ending. In another series of experiments on decerebrate cats, responses of primary and secondary endings of single muscle spindles to activation of γ-motoneurones by natural stimuli were compared with their responses to electrical stimulation of single γ-axons supplying the same spindle. Electrical stimulation mimicked the natural actions of γ-motoneurones on either the primary or the secondary ending, but not on both together. However, γ-activity evoked by natural stimuli coupled the firing of afferents with the muscle at constant length, and also when it was stretched. Analysis showed that the timing and tightness of this coupling determined the degree of summation of excitatory postsynaptic potentials (EPSPs) evoked by each afferent in α-motoneurones and interneurones contacted by terminals of both endings, and thus the degree of facilitation of reflex actions of group II afferents. PMID:12181298

  20. Musculoskeletal modelling of human ankle complex: Estimation of ankle joint moments.

    PubMed

    Jamwal, Prashant K; Hussain, Shahid; Tsoi, Yun Ho; Ghayesh, Mergen H; Xie, Sheng Quan

    2017-05-01

    A musculoskeletal model for the ankle complex is vital in order to enhance the understanding of neuro-mechanical control of ankle motions, diagnose ankle disorders and assess subsequent treatments. Motions at the human ankle and foot, however, are complex due to simultaneous movements at the two joints namely, the ankle joint and the subtalar joint. The musculoskeletal elements at the ankle complex, such as ligaments, muscles and tendons, have intricate arrangements and exhibit transient and nonlinear behaviour. This paper develops a musculoskeletal model of the ankle complex considering the biaxial ankle structure. The model provides estimates of overall mechanical characteristics (motion and moments) of ankle complex through consideration of forces applied along ligaments and muscle-tendon units. The dynamics of the ankle complex and its surrounding ligaments and muscle-tendon units is modelled and formulated into a state space model to facilitate simulations. A graphical user interface is also developed during this research in order to include the visual anatomical information by converting it to quantitative information on coordinates. Validation of the ankle model was carried out by comparing its outputs with those published in literature as well as with experimental data obtained from an existing parallel ankle rehabilitation robot. Qualitative agreement was observed between the model and measured data for both, the passive and active ankle motions during trials in terms of displacements and moments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Expecting ankle tilts and wearing an ankle brace influence joint control in an imitated ankle sprain mechanism during walking.

    PubMed

    Gehring, Dominic; Wissler, Sabrina; Lohrer, Heinz; Nauck, Tanja; Gollhofer, Albert

    2014-03-01

    A thorough understanding of the functional aspects of ankle joint control is essential to developing effective injury prevention. It is of special interest to understand how neuromuscular control mechanisms and mechanical constraints stabilize the ankle joint. Therefore, the aim of the present study was to determine how expecting ankle tilts and the application of an ankle brace influence ankle joint control when imitating the ankle sprain mechanism during walking. Ankle kinematics and muscle activity were assessed in 17 healthy men. During gait rapid perturbations were applied using a trapdoor (tilting with 24° inversion and 15° plantarflexion). The subjects either knew that a perturbation would definitely occur (expected tilts) or there was only the possibility that a perturbation would occur (potential tilts). Both conditions were conducted with and without a semi-rigid ankle brace. Expecting perturbations led to an increased ankle eversion at foot contact, which was mediated by an altered muscle preactivation pattern. Moreover, the maximal inversion angle (-7%) and velocity (-4%), as well as the reactive muscle response were significantly reduced when the perturbation was expected. While wearing an ankle brace did not influence muscle preactivation nor the ankle kinematics before ground contact, it significantly reduced the maximal ankle inversion angle (-14%) and velocity (-11%) as well as reactive neuromuscular responses. The present findings reveal that expecting ankle inversion modifies neuromuscular joint control prior to landing. Although such motor control strategies are weaker in their magnitude compared with braces, they seem to assist ankle joint stabilization in a close-to-injury situation. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Can Chronic Ankle Instability be Prevented? Rethinking Management of Lateral Ankle Sprains.

    ERIC Educational Resources Information Center

    Denegar, Craig R.; Miller, Sayers J., III

    2002-01-01

    Investigates whether chronic ankle instability can be prevented, discussing: the relationship between mechanical and functional instability; normal ankle mechanics, sequelae to lateral ankle sprains, and abnormal ankle mechanics; and tissue healing, joint dysfunction, and acute lateral ankle sprain management. The paper describes a treatment model…

  3. Enrichment of spinal cord cell cultures with motoneurons

    PubMed Central

    1978-01-01

    Spinal cord cell cultures contain several types of neurons. Two methods are described for enriching such cultures with motoneurons (defined here simply as cholinergic cells that are capable of innervating muscle). In the first method, 7-day embryonic chick spinal cord neurons were separated according to size by 1 g velocity sedimentation. It is assumed that cholinergic motoneurons are among the largest cells present at this stage. The spinal cords were dissociated vigorously so that 95-98% of the cells in the initial suspension were isolated from one another. Cells in leading fractions (large cell fractions: LCFs) contain about seven times as much choline acetyltransferase (CAT) activity per unit cytoplasm as do cells in trailing fractions (small cell fractions: SCFs). Muscle cultures seeded with LCFs develop 10-70 times as much CAT as cultures seeded with SCFs and six times as much CAT as cultures seeded with control (unfractionated) spinal cord cells. More than 20% of the large neurons in LCF-muscle cultures innervate nearby myotubes. In the second method, neurons were gently dissociated from 4-day embryonic spinal cords and maintained in vitro. This approach is based on earlier observations that cholinergic neurons are among the first cells to withdraw form the mitotic cycle in the developing chick embryo (Hamburger, V. 1948. J. Comp. Neurol. 88:221- 283; and Levi-Montalcini, R. 1950. J. Morphol. 86:253-283). 4-Day spinal cord-muscle cultures develop three times as much CAT as do 7-day spinal cord-muscle plates, prepared in the same (gentle) manner. More than 50% of the relatively large 4-day neurons innervate nearby myotubes. Thus, both methods are useful first steps toward the complete isolation of motoneurons. Both methods should facilitate study of the development of cholinergic neurons and of nerve-muscle synapse formation. PMID:566275

  4. Mechanisms and functional implications of motoneuron adaptations to increased physical activity.

    PubMed

    MacDonell, Christopher; Gardiner, Phillip

    2018-06-01

    Motoneurons demonstrate adaptations in their physiological properties to alterations in chronic activity levels. The most consistent change that appears to result from endurance-type exercise training is the reduced excitatory current required to initiate and maintain rhythmic firing. While the precise mechanisms through which these neurons adapt to activity are currently unknown, evidence exists that adaptation may involve alterations in the expression of genes that code for membrane receptors which can influence the responses of neurons to transmitters during activation. The influence of these adaptations may also extend to the resting condition, where ambient levels of neuroactive substances may influence ion conductances at rest, and thus result in the activation or inhibition of specific ion conductances that underlie the measurements of increased excitability that have been reported for motoneurons in the anesthetised state. We have applied motoneuron excitability and muscle unit contractile changes with endurance training to a mathematical computerised model of motor unit recruitment (Heckman and Binder, 1991). The results from the modelling exercise demonstrate increased task efficiency at relative levels of effort during a submaximal contraction. The physiological impact that nerve and muscle adaptations have on the neuromuscular system during standardized tasks seem to fit with reported changes in motor unit behaviour in trained human subjects.

  5. Improvement of isometric dorsiflexion protocol for assessment of tibialis anterior muscle strength☆

    PubMed Central

    Siddiqi, Ariba; Arjunan, Sridhar P.; Kumar, Dinesh

    2015-01-01

    It is important to accurately estimate the electromyogram (EMG)/force relationship of triceps surae (TS) muscle for detecting strength deficit of tibalis anterior (TA) muscle. In literature, the protocol for recording EMG and force of dorsiflexion have been described, and the necessity for immobilizing the ankle has been explained. However, there is a significant variability of the results among researchers even though they report the fixation of the ankle. We have determined that toe extension can cause significant variation in the dorsiflexion force and EMG of TS and this can occur despite following the current guidelines which require immobilizing the ankle. The results also show that there was a large increase in the variability of the force and the RMS of EMG of TS when the toes were not strapped compared with when they were strapped. Thus, with the current guidelines, where there are no instructions regarding the necessity of strapping the toes, the EMG/force relationship of TS could be incorrect and give an inaccurate assessment of the dorsiflexor TA strength. In summary, • Current methodology to estimate the dorsiflexor TA strength with respect to the TS activity, emphasizing on ankle immobilization is insufficient to prevent large variability in the measurements. • Toe extension during dorsiflexion was found to be one source of variability in estimating the TA strength. • It is recommended that guidelines for recording force and EMG from TA and TS muscles should require the strapping of the toes along with the need for immobilizing the ankle. PMID:26150978

  6. Improvement of isometric dorsiflexion protocol for assessment of tibialis anterior muscle strength.

    PubMed

    Siddiqi, Ariba; Arjunan, Sridhar P; Kumar, Dinesh

    2015-01-01

    It is important to accurately estimate the electromyogram (EMG)/force relationship of triceps surae (TS) muscle for detecting strength deficit of tibalis anterior (TA) muscle. In literature, the protocol for recording EMG and force of dorsiflexion have been described, and the necessity for immobilizing the ankle has been explained. However, there is a significant variability of the results among researchers even though they report the fixation of the ankle. We have determined that toe extension can cause significant variation in the dorsiflexion force and EMG of TS and this can occur despite following the current guidelines which require immobilizing the ankle. The results also show that there was a large increase in the variability of the force and the RMS of EMG of TS when the toes were not strapped compared with when they were strapped. Thus, with the current guidelines, where there are no instructions regarding the necessity of strapping the toes, the EMG/force relationship of TS could be incorrect and give an inaccurate assessment of the dorsiflexor TA strength. In summary, •Current methodology to estimate the dorsiflexor TA strength with respect to the TS activity, emphasizing on ankle immobilization is insufficient to prevent large variability in the measurements.•Toe extension during dorsiflexion was found to be one source of variability in estimating the TA strength.•It is recommended that guidelines for recording force and EMG from TA and TS muscles should require the strapping of the toes along with the need for immobilizing the ankle.

  7. Control of acceleration during sudden ankle supination in people with unstable ankles.

    PubMed

    Vaes, P; Van Gheluwe, B; Duquet, W

    2001-12-01

    Comparative study of differences in functional control during ankle supination in the standing position in matched stable and unstable ankles (ex post facto design). To document acceleration and deceleration during ankle supination in the standing position and to determine differences in control of supination perturbation between stable and unstable ankles. Repetitive ankle sprain can be explained by mechanical instability only in a minority of cases. Exercise therapy for ankle instability is based on clinical experience. Joint stability has not yet been measured in dynamic situations that are similar to the situations leading to a traumatic sprain. The process of motor control during accelerating ankle supination has not been adequately addressed in the literature. Patients with complaints of ankle instability (16 unstable ankles) and nonimpaired controls (18 stable ankles) were examined (N = 17 subjects, 10 women and 7 men). The average age was 23.7 +/- 5.0 years (range, 20-41 y). Control of supination speed was studied during 50 degrees of ankle supination in the standing position using accelerometry (total supination time and deceleration times) and electromyography (latency time). Timing of motor response was estimated by measuring electromechanical delay. The presence of an early, sudden, and presumably passive slowdown of ankle supination in the standing position was observed. Peroneal muscle motor response was detected before the end of the supination. Unstable ankles showed significantly shorter total supination time (109.3 ms versus 124.1 ms) and significantly longer latency time (58.9 ms versus 47.7 ms). Functional control in unstable ankles is less efficient in decelerating the ankle during the supination test procedures used in our study. Our conclusions are based on significantly faster total supination and significantly slower electromyogram response in unstable ankles. The results support the hypothesis that both decelerating the total supination

  8. Regulation of Survival Motor Neuron Protein by the Nuclear Factor-Kappa B Pathway in Mouse Spinal Cord Motoneurons.

    PubMed

    Arumugam, Saravanan; Mincheva-Tasheva, Stefka; Periyakaruppiah, Ambika; de la Fuente, Sandra; Soler, Rosa M; Garcera, Ana

    2018-06-01

    Survival motor neuron (SMN) protein deficiency causes the genetic neuromuscular disorder spinal muscular atrophy (SMA), characterized by spinal cord motoneuron degeneration. Since SMN protein level is critical to disease onset and severity, analysis of the mechanisms involved in SMN stability is one of the central goals of SMA research. Here, we describe the role of several members of the NF-κB pathway in regulating SMN in motoneurons. NF-κB is one of the main regulators of motoneuron survival and pharmacological inhibition of NF-κB pathway activity also induces mouse survival motor neuron (Smn) protein decrease. Using a lentiviral-based shRNA approach to reduce the expression of several members of NF-κB pathway, we observed that IKK and RelA knockdown caused Smn reduction in mouse-cultured motoneurons whereas IKK or RelB knockdown did not. Moreover, isolated motoneurons obtained from the severe SMA mouse model showed reduced protein levels of several NF-κB members and RelA phosphorylation. We describe the alteration of NF-κB pathway in SMA cells. In the context of recent studies suggesting regulation of altered intracellular pathways as a future pharmacological treatment of SMA, we propose the NF-κB pathway as a candidate in this new therapeutic approach.

  9. Impaired control of weight bearing ankle inversion in subjects with chronic ankle instability.

    PubMed

    Terrier, R; Rose-Dulcina, K; Toschi, B; Forestier, N

    2014-04-01

    Previous studies have proposed that evertor muscle weakness represents an important factor affecting chronic ankle instability. For research purposes, ankle evertor strength is assessed by means of isokinetic evaluations. However, this methodology is constraining for daily clinical use. The present study proposes to assess ankle evertor muscle weakness using a new procedure, one that is easily accessible for rehabilitation specialists. To do so, we compared weight bearing ankle inversion control between patients suffering from chronic ankle instability and healthy subjects. 12 healthy subjects and 11 patients suffering from chronic ankle instability conducted repetitions of one leg weight bearing ankle inversion on a specific ankle destabilization device equipped with a gyroscope. Ankle inversion control was performed by means of an eccentric recruitment of evertor muscles. Instructions were to perform, as slow as possible, the ankle inversion while resisting against full body weight applied on the tested ankle. Data clearly showed higher angular inversion velocity peaks in patients suffering from chronic ankle instability. This illustrates an impaired control of weight bearing ankle inversion and, by extension, an eccentric weakness of evertor muscles. The present study supports the hypothesis of a link between the decrease of ankle joint stability and evertor muscle weakness. Moreover, it appears that the new parameter is of use in a clinical setting. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. MHC class I, beta2 microglobulin, and the INF-gamma receptor are upregulated in aged motoneurons.

    PubMed

    Edström, Erik; Kullberg, Susanna; Ming, Yu; Zheng, Huaiyu; Ulfhake, Brun

    2004-12-15

    During aging, spinal cord motoneurons show characteristic changes including the loss of afferent boutons, a selective process that associates with gliosis and behavioral motor impairment. Evidence suggests that the major histocompatibility complex Class I (MHC I) system may be involved in synaptic plasticity of neurons during development and regeneration. In search of a mechanism governing senescent changes in synaptic connectivity, we report evidence for increased expression of MHC I and beta2 microglobulin (beta2M) in motoneurons and glial-like profiles of 30-month-old rats. The regulatory signal(s) for MHC I expression in normal neurons remains unresolved but among tentative molecules are cytokines such as interferon-gamma (INF-gamma) and tumor necrosis factor alpha (TNF-alpha). Interestingly, aged motoneurons, overlapping with those showing increased levels of MHC I, contained increased levels of INF-gamma receptor message. INF-gamma mRNA was detected at low levels in most (8/9) of the aged spinal cords but only infrequently (2/9) in young adult spinal cords; however, the cellular localization of INF-gamma mRNA could not be determined. Our data also indicates that TNF-alpha is upregulated in the senescent spinal cord but that TNF-alpha immunoreactive protein does not associate with motoneurons. We report evidence for an increased expression of MHC I and beta2M in senescent spinal motoneurons and discuss the possibility that this regulation associates with INF-gamma or changes in neurotrophin signaling and neuron activity in senescence. (c) 2004 Wiley-Liss, Inc.

  11. Marked and variable inhibition by chemical fixation of cytochrome oxidase and succinate dehydrogenase in single motoneurons

    NASA Technical Reports Server (NTRS)

    Chalmers, G. R.; Edgerton, V. R.

    1989-01-01

    The effect of tissue fixation on succinate dehydrogenase and cytochrome oxidase activity in single motoneurons of the rat was demonstrated using a computer image processing system. Inhibition of enzyme activity by chemical fixation was variable, with some motoneurons being affected more than others. It was concluded that quantification of enzymatic activity in chemically fixed tissue provides an imprecise estimate of enzyme activities found in fresh-frozen tissues.

  12. Monosynaptic EPSPs elicited by single interneurones and spindle afferents in trigeminal motoneurones of anaesthetized rats.

    PubMed Central

    Grimwood, P D; Appenteng, K; Curtis, J C

    1992-01-01

    1. Our aim has been to quantify the monosynaptic connections of trigeminal interneurones and spindle afferents onto jaw-elevator motoneurones as a step towards identifying common features in organization of monosynaptic inputs onto motoneurones. We have used the intracellular variant of the spike-triggered averaging method to examine the connections of single identified trigeminal interneurones and jaw-elevator muscle spindle afferents onto single jaw-elevator motoneurones. The interneurones examined lay in the region immediately caudal to the trigeminal motor nucleus. The experiments were performed on rats anaesthetized with pentobarbitone, paralysed and artificially ventilated. 2. Ten EPSPs and eight IPSPs were obtained from examining the connections of seventeen interneurones to thirty-six motoneurones, suggesting a functional connectivity of 50% for individual interneurones onto elevator motoneurones. Fourteen EPSPs were obtained from examining the connections of thirteen spindle afferents onto twenty-seven motoneurones, giving a functional connectivity of 52% for individual spindle afferents onto elevator motoneurones. The amplitudes of the EPSPs elicited by interneurones ranged from 7-48 microV (mean = 17, S.D. = 12.5, n = 10) and from 7 to 289 microV (mean = 64, S.D. = 76.0, n = 14) for the spindle-mediated EPSPs; the difference in the two means was not significant (P = 0.07). 3. However, the amplitude of averaged responses obtained by signal averaging methods are dependent on the assumption that the postsynaptic response occurs following every impulse in the presynaptic neurone. We therefore estimated the percentage of sweeps which contained EPSPs triggered by the presynaptic neurone under study. In essence the method used consisted of visual inspection of the individual sweeps comprising an average in order to assess the occurrence of EPSPs within six separate time windows, each of duration +/- 0.3 ms. Five windows were placed at randomly selected times on

  13. Targeted Delivery of TrkB Receptor to Phrenic Motoneurons Enhances Functional Recovery of Rhythmic Phrenic Activity after Cervical Spinal Hemisection

    PubMed Central

    Gransee, Heather M.; Zhan, Wen-Zhi; Sieck, Gary C.; Mantilla, Carlos B.

    2013-01-01

    Progressive recovery of rhythmic phrenic activity occurs over time after a spinal cord hemisection involving unilateral transection of anterolateral funiculi at C2 (SH). Brain-derived neurotrophic factor (BDNF) acting through its full-length tropomyosin related kinase receptor subtype B (TrkB.FL) contributes to neuroplasticity after spinal cord injury, but the specific cellular substrates remain unclear. We hypothesized that selectively targeting increased TrkB.FL expression to phrenic motoneurons would be sufficient to enhance recovery of rhythmic phrenic activity after SH. Several adeno-associated virus (AAV) serotypes expressing GFP were screened to determine specificity for phrenic motoneuron transduction via intrapleural injection in adult rats. GFP expression was present in the cervical spinal cord 3 weeks after treatment with AAV serotypes 7, 8, and 9, but not with AAV2, 6, or rhesus-10. Overall, AAV7 produced the most consistent GFP expression in phrenic motoneurons. SH was performed 3 weeks after intrapleural injection of AAV7 expressing human TrkB.FL-FLAG or saline. Delivery of TrkB.FL-FLAG to phrenic motoneurons was confirmed by FLAG protein expression in the phrenic motor nucleus and human TrkB.FL mRNA expression in microdissected phrenic motoneurons. In all SH rats, absence of ipsilateral diaphragm EMG activity was confirmed at 3 days post-SH, verifying complete interruption of ipsilateral descending drive to phrenic motoneurons. At 14 days post-SH, all AAV7-TrkB.FL treated rats (n = 11) displayed recovery of ipsilateral diaphragm EMG activity compared to 3 out of 8 untreated SH rats (p<0.01). During eupnea, AAV7-TrkB.FL treated rats exhibited 73±7% of pre-SH root mean squared EMG vs. only 31±11% in untreated SH rats displaying recovery (p<0.01). This study provides direct evidence that increased TrkB.FL expression in phrenic motoneurons is sufficient to enhance recovery of ipsilateral rhythmic phrenic activity after SH, indicating that

  14. Increases in human motoneuron excitability after cervical spinal cord injury depend on the level of injury.

    PubMed

    Thomas, Christine K; Häger, Charlotte K; Klein, Cliff S

    2017-02-01

    After human spinal cord injury (SCI), motoneuron recruitment and firing rate during voluntary and involuntary contractions may be altered by changes in motoneuron excitability. Our aim was to compare F waves in single thenar motor units paralyzed by cervical SCI to those in uninjured controls because at the single-unit level F waves primarily reflect the intrinsic properties of the motoneuron and its initial segment. With intraneural motor axon stimulation, F waves were evident in all 4 participants with C 4 -level SCI, absent in 8 with C 5 or C 6 injury, and present in 6 of 12 Uninjured participants (P < 0.001). The percentage of units that generated F waves differed across groups (C 4 : 30%, C 5 or C 6 : 0%, Uninjured: 16%; P < 0.001). Mean (±SD) proximal axon conduction velocity was slower after C 4 SCI [64 ± 4 m/s (n = 6 units), Uninjured: 73 ± 8 m/s (n = 7 units); P = 0.037]. Mean distal axon conduction velocity differed by group [C 4 : 40 ± 8 m/s (n = 20 units), C 5 or C 6 : 49 ± 9 m/s (n = 28), Uninjured: 60 ± 7 m/s (n = 45); P < 0.001]. Motor unit properties (EMG amplitude, twitch force) only differed after SCI (P ≤ 0.004), not by injury level. Motor units with F waves had distal conduction velocities, M-wave amplitudes, and twitch forces that spanned the respective group range, indicating that units with heterogeneous properties produced F waves. Recording unitary F waves has shown that thenar motoneurons closer to the SCI (C 5 or C 6 ) have reduced excitability whereas those further away (C 4 ) have increased excitability, which may exacerbate muscle spasms. This difference in motoneuron excitability may be related to the extent of membrane depolarization following SCI. Unitary F waves were common in paralyzed thenar muscles of people who had a chronic spinal cord injury (SCI) at the C 4 level compared with uninjured people, but F waves did not occur in people that had SCI at the C 5 or C 6 level. These results highlight that intrinsic motoneuron

  15. Isolated syndesmosis ankle injury.

    PubMed

    Valkering, Kars P; Vergroesen, Diederik A; Nolte, Peter A

    2012-12-01

    Isolated syndesmosis injuries often go unrecognized and are diagnosed as lateral ankle sprains; however, they are more disabling than lateral ankle sprains. The reported incidence of isolated syndesmosis injuries in acute ankle sprains ranges between 1% and 16%. When ankle disability lasts for more than 2 months after an ankle sprain, the incidence increases to 23.6%. Diagnostic workup may include stress radiographs, magnetic resonance imaging, or diagnostic arthroscopy. A simple stress test radiograph may reveal an unstable grade III syndesmosis sprain that may go unrecognized on plain anteroposterior and mortise or lateral radiographs of the ankle. The duration of symptoms in isolated syndesmosis injury is longer and more severe, often leading to chronic symptoms or ankle instability requiring operative stabilization.This article describes the clinical presentation, injury classification, and operative stabilization techniques of isolated syndesmosis injuries. The authors performed their preferred operative stabilization technique for isolated syndesmosis injury-arthroscopic debridement of the ankle with syndesmotic stabilization with a syndesmotic screw-in 4 patients. All patients were evaluated 1 year postoperatively with subjective and objective assessment scales. Three of 4 patients showed good improvement of general subjective ankle symptoms and subjective ankle instability rating and a high Sports Ankle Rating System score after 1 year. Copyright 2012, SLACK Incorporated.

  16. Influence of ankle joint plantarflexion and dorsiflexion on lateral ankle sprain: A computational study.

    PubMed

    Purevsuren, Tserenchimed; Kim, Kyungsoo; Batbaatar, Myagmarbayar; Lee, SuKyoung; Kim, Yoon Hyuk

    2018-05-01

    Understanding the mechanism of injury involved in lateral ankle sprain is essential to prevent injury, to establish surgical repair and reconstruction, and to plan reliable rehabilitation protocols. Most studies for lateral ankle sprain posit that ankle inversion, internal rotation, and plantarflexion are involved in the mechanism of injury. However, recent studies indicated that ankle dorsiflexion also plays an important role in the lateral ankle sprain mechanism. In this study, the contributions of ankle plantarflexion and dorsiflexion on the ankle joint were evaluated under complex combinations of internal and inversion moments. A multibody ankle joint model including 24 ligaments was developed and validated against two experimental cadaveric studies. The effects of ankle plantarflexion (up to 60°) and dorsiflexion (up to 30°) on the lateral ankle sprain mechanism under ankle inversion moment coupled with internal rotational moment were investigated using the validated model. Lateral ankle sprain injuries can occur during ankle dorsiflexion, in which the calcaneofibular ligament and anterior talofibular ligament tears may occur associated with excessive inversion and internal rotational moment, respectively. Various combinations of inversion and internal moment may lead to anterior talofibular ligament injuries at early ankle plantarflexion, while the inversion moment acts as a primary factor to tear the anterior talofibular ligament in early plantarflexion. It is better to consider inversion and internal rotation as primary factors of the lateral ankle sprain mechanism, while plantarflexion or dorsiflexion can be secondary factor. This information will help to clarify the lateral ankle sprain mechanism of injury.

  17. Preparatory co-activation of the ankle muscles may prevent ankle inversion injuries

    PubMed Central

    DeMers, Matthew S.; Hicks, Jennifer L.; Delp, Scott L.

    2018-01-01

    Ankle inversion sprains are the most frequent acute musculoskeletal injuries occurring in physical activity. Interventions that retrain muscle coordination have helped rehabilitate injured ankles, but it is unclear which muscle coordination strategies, if any, can prevent ankle sprains. The purpose of this study was to determine whether coordinated activity of the ankle muscles could prevent excessive ankle inversion during a simulated landing on a 30-degree incline. We used a set of musculoskeletal simulations to evaluate the efficacy of two strategies for coordinating the ankle evertor and invertor muscles during simulated landing scenarios: planned co-activation and stretch reflex activation with physiologic latency (60-millisecond delay). A full-body musculoskeletal model of landing was used to generate simulations of a subject dropping onto an inclined surface with each coordination condition. Within each condition, the intensity of evertor and invertor co-activity or stretch reflexes were varied systematically. The simulations revealed that strong preparatory co-activation of the ankle evertors and invertors prior to ground contact prevented ankle inversion from exceeding injury thresholds by rapidly generating eversion moments after initial contact. Conversely, stretch reflexes were too slow to generate eversion moments before the simulations reached the threshold for inversion injury. These results suggest that training interventions to protect the ankle should focus on stiffening the ankle with muscle co-activation prior to landing. The musculoskeletal models, controllers, software, and simulation results are freely available online at http://simtk.org/home/ankle-sprains, enabling others to reproduce the results and explore new injury scenarios and interventions. PMID:28057351

  18. Chronic ankle instability: Current perspectives

    PubMed Central

    Al-Mohrej, Omar A.; Al-Kenani, Nader S.

    2016-01-01

    Ankle sprain is reported to be among the most common recurrent injuries. About 20% of acute ankle sprain patients develop chronic ankle instability. The failure of functional rehabilitation after acute ankle sprain leads to the development of chronic ankle instability. Differentiation between functional and anatomical ankle instability is very essential to guide the proper treatment. Stability testing by varus stress test and anterior drawer test should be carried out. Subtalar instability is an important pathology that is commonly by passed during the assessment of chronic ankle instability. Unlike acute ankle sprain, chronic ankle instability might require surgical intervention. The surgical and conservative management options can be very much developed by in-depth knowledge of the ankle anatomy, biomechanics, and pathology. Anatomical repair, augmentation by tendon, or both are the basic methods of surgical intervention. Arthroscopy is becoming more popular in the management of chronic ankle instability. PMID:27843798

  19. Clinical tests of ankle plantarflexor strength do not predict ankle power generation during walking.

    PubMed

    Kahn, Michelle; Williams, Gavin

    2015-02-01

    The aim of this study was to investigate the relationship between a clinical test of ankle plantarflexor strength and ankle power generation (APG) at push-off during walking. This is a prospective cross-sectional study of 102 patients with traumatic brain injury. Handheld dynamometry was used to measure ankle plantarflexor strength. Three-dimensional gait analysis was performed to quantify ankle power generation at push-off during walking. Ankle plantarflexor strength was only moderately correlated with ankle power generation at push-off (r = 0.43, P < 0.001; 95% confidence interval, 0.26-0.58). There was also a moderate correlation between ankle plantarflexor strength and self-selected walking velocity (r = 0.32, P = 0.002; 95% confidence interval, 0.13-0.48). Handheld dynamometry measures of ankle plantarflexor strength are only moderately correlated with ankle power generation during walking. This clinical test of ankle plantarflexor strength is a poor predictor of calf muscle function during gait in people with traumatic brain injury.

  20. REM Sleep–like Atonia of Hypoglossal (XII) Motoneurons Is Caused by Loss of Noradrenergic and Serotonergic Inputs

    PubMed Central

    Fenik, Victor B.; Davies, Richard O.; Kubin, Leszek

    2017-01-01

    Rationale Studies of hypoglossal (XII) motoneurons that innervate the genioglossus muscle, an upper airway dilator, suggested that the suppression of upper airway motor tone during REM sleep is caused by withdrawal of excitation mediated by norepinephrine and serotonin. Objectives Our objectives were to determine whether antagonism of aminergic receptors located in the XII nucleus region can abolish the REM sleep–like atonia of XII motoneurons, and whether both serotonergic and noradrenergic antagonists are required to achieve this effect. Methods REM sleep–like episodes were elicited in anesthetized rats by pontine carbachol injections before and at various times after microinjection of prazosin and methysergide combined, or of only one of the drugs, into the XII nucleus. Measurements and Main Results Spontaneous XII nerve activity was significantly reduced, by 35 to 81%, by each antagonist alone and in combination, indicating that XII motoneurons were under both noradrenergic and serotonergic endogenous excitatory drives. During the 32 to 81 min after microinjections of both antagonists, pontine carbachol caused no depression of XII nerve activity, whereas other characteristic effects (activation of the hippocampal and cortical EEG, and slowing of the respiratory rate) remained intact. A partial recovery of the depressant effect of carbachol then occurred parallel to the recovery of spontaneous XII nerve activity from the depressant effect of the antagonists. Microinjections of either antagonist alone did not eliminate the depressant effect of carbachol. Conclusions The REM sleep–like depression of XII motoneuronal activity induced by pontine carbachol can be fully accounted for by the combined withdrawal of noradrenergic and serotonergic effects on XII motoneurons. PMID:16100007

  1. Ankle-Dorsiflexion Range of Motion After Ankle Self-Stretching Using a Strap

    PubMed Central

    Jeon, In-cheol; Kwon, Oh-yun; Yi, Chung-Hwi; Cynn, Heon-Seock; Hwang, Ui-jae

    2015-01-01

    Context  A variety of ankle self-stretching exercises have been recommended to improve ankle-dorsiflexion range of motion (DFROM) in individuals with limited ankle dorsiflexion. A strap can be applied to stabilize the talus and facilitate anterior glide of the distal tibia at the talocrural joint during ankle self-stretching exercises. Novel ankle self-stretching using a strap (SSS) may be a useful method of improving ankle DFROM. Objective  To compare the effects of 2 ankle-stretching techniques (static stretching versus SSS) on ankle DFROM. Design  Randomized controlled clinical trial. Setting  University research laboratory. Patients or Other Participants  Thirty-two participants with limited active dorsiflexion (<20°) while sitting (14 women and 18 men) were recruited. Main Outcome Measure(s)  The participants performed 2 ankle self-stretching techniques (static stretching and SSS) for 3 weeks. Active DFROM (ADFROM), passive DFROM (PDFROM), and the lunge angle were measured. An independent t test was used to compare the improvements in these values before and after the 2 stretching interventions. The level of statistical significance was set at α = .05. Results  Active DFROM and PDFROM were greater in both stretching groups after the 3-week interventions. However, ADFROM, PDFROM, and the lunge angle were greater in the SSS group than in the static-stretching group (P < .05). Conclusions  Ankle SSS is recommended to improve ADFROM, PDFROM, and the lunge angle in individuals with limited DFROM. PMID:26633750

  2. Comparison of custom-moulded ankle orthosis with hinged joints and off-the-shelf ankle braces in preventing ankle sprain in lateral cutting movements.

    PubMed

    Lee, Winson C C; Kobayashi, Toshiki; Choy, Barton T S; Leung, Aaron K L

    2012-06-01

    A custom moulded ankle orthosis with hinged joints potentially offers a better control over the subtalar joint and the ankle joint during lateral cutting movements, due to total contact design and increase in material strength. To test the above hypothesis by comparing it to three other available orthoses. Repeated measures. Eight subjects with a history of ankle sprains (Grade 2), and 11 subjects without such history performed lateral cutting movements in four test conditions: 1) non-orthotic, 2) custom-moulded ankle orthosis with hinges, 3) Sport-Stirrup, and 4) elastic ankle sleeve with plastic support. A VICON motion analysis system was used to study the motions at the ankle and subtalar joints. The custom-moulded ankle orthosis significantly lowered the inversion angle at initial contact (p = 0.006) and the peak inversion angle (p = 0.000) during lateral cutting movements in comparison to non-orthotic condition, while the other two orthoses did not. The three orthoses did not affect the plantarflexion motions, which had been suggested by previous studies to be important in shock wave attenuation. The custom-moulded ankle orthosis with hinges could better control inversion and thus expected to better prevent ankle sprain in lateral cutting movements. Custom-moulded ankle orthoses are not commonly used in preventing ankle sprains. This study raises the awareness of the use of custom-moulded ankle orthoses which are expected to better prevent ankle sprains.

  3. Contribution of intrinsic properties and synaptic inputs to motoneuron discharge patterns: a simulation study

    PubMed Central

    ElBasiouny, Sherif M.; Rymer, W. Zev; Heckman, C. J.

    2012-01-01

    Motoneuron discharge patterns reflect the interaction of synaptic inputs with intrinsic conductances. Recent work has focused on the contribution of conductances mediating persistent inward currents (PICs), which amplify and prolong the effects of synaptic inputs on motoneuron discharge. Certain features of human motor unit discharge are thought to reflect a relatively stereotyped activation of PICs by excitatory synaptic inputs; these features include rate saturation and de-recruitment at a lower level of net excitation than that required for recruitment. However, PIC activation is also influenced by the pattern and spatial distribution of inhibitory inputs that are activated concurrently with excitatory inputs. To estimate the potential contributions of PIC activation and synaptic input patterns to motor unit discharge patterns, we examined the responses of a set of cable motoneuron models to different patterns of excitatory and inhibitory inputs. The models were first tuned to approximate the current- and voltage-clamp responses of low- and medium-threshold spinal motoneurons studied in decerebrate cats and then driven with different patterns of excitatory and inhibitory inputs. The responses of the models to excitatory inputs reproduced a number of features of human motor unit discharge. However, the pattern of rate modulation was strongly influenced by the temporal and spatial pattern of concurrent inhibitory inputs. Thus, even though PIC activation is likely to exert a strong influence on firing rate modulation, PIC activation in combination with different patterns of excitatory and inhibitory synaptic inputs can produce a wide variety of motor unit discharge patterns. PMID:22031773

  4. Primary ankle arthrodesis for neglected open Weber B ankle fracture dislocation.

    PubMed

    Thomason, Katherine; Ramesh, Ashwanth; McGoldrick, Niall; Cove, Richard; Walsh, James C; Stephens, Michael M

    2014-01-01

    Primary ankle arthrodesis used to treat a neglected open ankle fracture dislocation is a unique decision. A 63-year-old man presented to the emergency department with a 5-day-old open fracture dislocation of his right ankle. After thorough soft tissue debridement, primary arthrodesis of the tibiotalar joint was performed using initial Kirschner wire fixation and an external fixator. Definitive soft tissue coverage was later achieved using a latissimus dorsi free flap. The fusion was consolidated to salvage the limb from amputation. The use of primary arthrodesis to treat a compound ankle fracture dislocation has not been previously described. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Transformation of synaptic vesicle phenotype in the intramedullary axonal arbors of cat spinal motoneurons following peripheral nerve injury.

    PubMed

    Havton, L A; Kellerth, J O

    2001-08-01

    Permanent transection of a peripheral motor nerve induces a gradual elimination of whole axon collateral systems in the axotomized spinal motoneurons. There is also an initial concurrent decrease in the amount of recurrent inhibition exerted by these arbors in the spinal cord for up to 6 weeks after the injury, whereas the same reflex action returns to normal by the 12-week postoperative state. The aim of the present investigation was to study the fine structure of the intramedullary axonal arbors of axotomized alpha-motoneurons in the adult cat spinal cord following a permanent peripheral motor nerve lesion. For this purpose, single axotomized alpha-motoneurons were labeled intracellularly with horseradish peroxidase at 12 weeks after permanent transection of their peripheral motor nerve. The intramedullary portions of their motor axon and axon collateral arbors were first reconstructed at the light microscopic level and subsequently studied ultrastructurally. This study shows that the synaptic contacts made by the intramedullary axon collateral arbors of axotomized motoneurons have undergone a change in synaptic vesicle ultrastructure from spherical and clear vesicles to spherical and dense-cored vesicles at 12 weeks after the transection of their peripheral axons. We suggest that the present transformation in synaptic vesicle fine structure may also correspond to a change in the contents of these boutons. This may, in turn, be responsible for the strengthening and recovery of the recurrent inhibitory reflex action exerted by the axotomized spinal motoneurons following a prolonged permanent motor nerve injury.

  6. miR-7-1 POTENTIATED ESTROGEN RECEPTOR AGONISTS FOR FUNCTIONAL NEUROPROTECTION IN VSC4.1 MOTONEURONS

    PubMed Central

    CHAKRABARTI, M.; BANIK, N. L.; RAY, S. K.

    2013-01-01

    Protection of motoneurons is an important goal in the treatment of spinal cord injury (SCI). We tested whether neuroprotective microRNAs (miRs) like miR-206, miR-17, miR-21, miR-7-1, and miR-106a could enhance efficacy of estrogen receptor (ER) agonists such as 1,3,5-tris (4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT, ERα agonist), Way200070 (WAY, ERβ agonist), and estrogen (EST, ERα and ERβ agonist) in preventing apoptosis in the calcium ionophore (CI) insulted VSC4.1 motoneurons. We determined that 200 nM CI induced 70% cell death. Treatment with 50 nM PPT, 100 nM WAY, and 150 nM EST induced overexpression of ERα, ERβ, and both receptors, respectively, at mRNA and protein levels. Treatment with ER agonists significantly upregulated miR-206, miR-17, and miR-7-1 in the CI insulted VSC4.1 motoneurons. Transfection with miR-206, miR-17, or miR-7-1 mimic potentiated WAY or EST to inhibit apoptosis in the CI insulted VSC4.1 motoneurons. Overexpression of miR-7-1 maximally increased efficacy of WAY and EST for down regulation of pro-apoptotic Bax and upregulation of anti-apoptotic Bcl-2. A search using miRDB indicated that miR-7-1 could inhibit expression of L-type Ca2+ channel protein alpha 1C (CPα1C). miR-7-1 overexpression and WAY or EST treatment down regulated CPα1C but upregulated p-Akt to trigger cell survival signaling. The same therapeutic strategy increased expression of the Ca2+/calmodulin-dependent protein kinase II beta (CaMKIIβ) and the phosphorylated cAMP response element binding protein (p-CREB) so as to promote Bcl-2 transcription. Whole cell membrane potential and mitochondrial membrane potential studies indicated that miR-7-1 highly potentiated EST to preserve functionality in the CI insulted VSC4.1 motoneurons. In conclusion, our data indicated that miR-7-1 most significantly potentiated efficacy of EST for functional neuroprotection and this therapeutic strategy could be used in the future to attenuate apoptosis of motoneurons in SCI. PMID

  7. Properties of human motoneurones and their synaptic noise deduced from motor unit recordings with the aid of computer modelling.

    PubMed

    Matthews, P B

    1999-01-01

    This paper reviews two new facets of the behaviour of human motoneurones; these were demonstrated by modelling combined with analysis of long periods of low-frequency tonic motor unit firing (sub-primary range). 1) A novel transformation of the interval histogram has shown that the effective part of the membrane's post-spike voltage trajectory is a segment of an exponential (rather than linear), with most spikes being triggered by synaptic noise before the mean potential reaches threshold. The curvature of the motoneurone's trajectory affects virtually all measures of its behaviour and response to stimulation. The 'trajectory' is measured from threshold, and so includes any changes in threshold during the interspike interval. 2) A novel rhythmic stimulus (amplitude-modulated pulsed vibration) has been used to show that the motoneurone produces appreciable phase-advance during sinusoidal excitation. At low frequencies, the advance increases with rising stimulus frequency but then, slightly below the motoneurones mean firing rate, it suddenly becomes smaller. The gain has a maximum for stimuli at the mean firing rate (the 'carrier'). Such behaviour is functionally important since it affects the motoneurone's response to any rhythmic input, whether generated peripherally by the receptors (as in tremor) or by the CNS (as with cortical oscillations). Low mean firing rates favour tremor, since the high gain and reduced phase advance at the 'carrier' reduce the stability of the stretch reflex.

  8. Rapid activity-dependent modulation of the intrinsic excitability through up-regulation of KCNQ/Kv7 channel function in neonatal spinal motoneurons.

    PubMed

    Lombardo, Joseph; Sun, Jianli; Harrington, Melissa A

    2018-01-01

    Activity-dependent changes in the properties of the motor system underlie the necessary adjustments in its responsiveness on the basis of the environmental and developmental demands of the organism. Although plastic changes in the properties of the spinal cord have historically been neglected because of the archaic belief that the spinal cord is constituted by a hardwired network that simply relays information to muscles, plenty of evidence has been accumulated showing that synapses impinging on spinal motoneurons undergo short- and long-term plasticity. In the brain, brief changes in the activity level of the network have been shown to be paralleled by changes in the intrinsic excitability of the neurons and are suggested to either reinforce or stabilize the changes at the synaptic level. However, rapid activity-dependent changes in the intrinsic properties of spinal motoneurons have never been reported. In this study, we show that in neonatal mice the intrinsic excitability of spinal motoneurons is depressed after relatively brief but sustained changes in the spinal cord network activity. Using electrophysiological techniques together with specific pharmacological blockers of KCNQ/Kv7 channels, we demonstrate their involvement in the reduction of the intrinsic excitability of spinal motoneurons. This action results from an increased M-current, the product of the activation of KCNQ/Kv7 channels, which leads to a hyperpolarization of the resting membrane potential and a decrease in the input resistance of spinal motoneurons. Computer simulations showed that specific up-regulations in KCNQ/Kv7 channels functions lead to a modulation of the intrinsic excitability of spinal motoneurons as observed experimentally. These results indicate that KCNQ/Kv7 channels play a fundamental role in the activity-dependent modulation of the excitability of spinal motoneurons.

  9. Effects of long term Tai Chi practice and jogging exercise on muscle strength and endurance in older people.

    PubMed

    Xu, D Q; Li, J X; Hong, Y

    2006-01-01

    To investigate the influence of regular Tai Chi (TC) practice and jogging on muscle strength and endurance in the lower extremities of older people. Twenty one long term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30 degrees/s and 120 degrees/s. Ankle dorsiflexors and plantar flexors were tested at 30 degrees/s and the dynamic endurance of the knee flexors and extensors was assessed at a speed of 180 degrees/s. The differences in the muscle strength of the knee joint amongst the three experimental groups were significant at the higher velocity. The strengths of knee extensors and flexors in the control group were significantly lower than those in the jogging group and marginally lower than those in the TC group. For the ankle joint, the subjects in both the TC and jogging groups generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than in controls. Regular older TC practitioners and joggers showed better scores than the sedentary controls on most muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.

  10. Descending pathways to the cutaneus trunci muscle motoneuronal cell group in the cat

    NASA Technical Reports Server (NTRS)

    Holstege, Gert; Blok, Bertil F.

    1989-01-01

    The descending pathways to the motoneuronal cell group of the cutaneous trunci muscle (CTM) of the cat were investigated by injecting H-3-labeled lucine into the brain stem, the diencephalon, or the C1, C2, C6, and C8 segments of the spinal cord, and examining fixed autoradiographic sections of the spinal cord and brain regions. Results demonstrate presence of specific supraspinal projectons to the CTM motor nucleus originating in the contralateral nucleus retroambiguous and the ipsilateral dorsolateral pontine tegmentum. Results also suggest that propriospinal pathways to the CTM motor nucleus originating in the cervical cord do not exist, although these propriospinal projections to all other motoneuronal cell groups surrounding the CTM nucleus are very strong.

  11. α-Motoneurons maintain biophysical heterogeneity in obesity and diabetes in Zucker rats.

    PubMed

    MacDonell, Christopher W; Chopek, Jeremy W; Gardiner, Kalan R; Gardiner, Phillip F

    2017-10-01

    Small-diameter sensory dysfunction resulting from diabetes has received much attention in the literature, whereas the impact of diabetes on α-motoneurons (MN) has not. In addition, the chance of developing insulin resistance and diabetes is increased in obesity. No study has examined the impact of obesity or diabetes on the biophysical properties of MN. Lean Zucker rats and Zucker diabetic fatty (ZDF) rats were separated into lean, obese (ZDF fed standard chow), and diabetic (ZDF fed high-fat diet that led to diabetes) groups. Glass micropipettes recorded hindlimb MN properties from identified flexor and extensor MN. MN were separated within their groups on the basis of input conductance, which created high- and low-input conductance subpopulations for each. A significant shorter (20%) afterhyperpolarization half-decay (AHP 1/2 ) was found in low-conductance MN for the diabetic group only, whereas AHP½ tended to be shorter in the obese group (19%). Significant positive correlations were found among rheobase and input conductance for both lean and obese animals. No differences were found between the groups for afterhyperpolarization amplitude (AHP amp ), input conductance, rheobase, or any of the rhythmic firing properties (frequency-current slope and spike-frequency adaptation index). MN properties continue to be heterogeneous in obese and diabetic animals. Obesity does not seem to influence lumbar MN. Despite the resistance of MN to the impact of diabetes, the reduced AHP 1/2 decay and the tendency for a reduction in AHP amp may be the first sign of change to MN function. NEW & NOTEWORTHY Knowledge about the impact of obesity and diabetes on the biophysical properties of motoneurons is lacking. We found that diabetes reduces the duration of the afterhyperpolarization and that motoneuron function is unchanged by obesity. A reduced afterhyperpolarization may impact discharge characteristics and may be the first sign of change to motoneuron function. Copyright

  12. Effects of the application of ankle functional rehabilitation exercise on the ankle joint functional movement screen and isokinetic muscular function in patients with chronic ankle sprain.

    PubMed

    Ju, Sung-Bum; Park, Gi Duck

    2017-02-01

    [Purpose] This study was conducted to investigate the effects of ankle functional rehabilitation exercise on ankle joint functional movement screen results and isokinetic muscular function in patients with chronic ankle sprain patients. [Subjects and Methods] In this study, 16 patients with chronic ankle sprain were randomized to an ankle functional rehabilitation exercise group (n=8) and a control group (n=8). The ankle functional rehabilitation exercise centered on a proprioceptive sense exercise program, which was applied 12 times for 2 weeks. To verify changes after the application, ankle joint functional movement screen scores and isokinetic muscular function were measured and analyzed. [Results] The ankle functional rehabilitation exercise group showed significant improvements in all items of the ankle joint functional movement screen and in isokinetic muscular function after the exercise, whereas the control group showed no difference after the application. [Conclusion] The ankle functional rehabilitation exercise program can be effectively applied in patients with chronic ankle sprain for the improvement of ankle joint functional movement screen score and isokinetic muscular function.

  13. Effects of the application of ankle functional rehabilitation exercise on the ankle joint functional movement screen and isokinetic muscular function in patients with chronic ankle sprain

    PubMed Central

    Ju, Sung-Bum; Park, Gi Duck

    2017-01-01

    [Purpose] This study was conducted to investigate the effects of ankle functional rehabilitation exercise on ankle joint functional movement screen results and isokinetic muscular function in patients with chronic ankle sprain patients. [Subjects and Methods] In this study, 16 patients with chronic ankle sprain were randomized to an ankle functional rehabilitation exercise group (n=8) and a control group (n=8). The ankle functional rehabilitation exercise centered on a proprioceptive sense exercise program, which was applied 12 times for 2 weeks. To verify changes after the application, ankle joint functional movement screen scores and isokinetic muscular function were measured and analyzed. [Results] The ankle functional rehabilitation exercise group showed significant improvements in all items of the ankle joint functional movement screen and in isokinetic muscular function after the exercise, whereas the control group showed no difference after the application. [Conclusion] The ankle functional rehabilitation exercise program can be effectively applied in patients with chronic ankle sprain for the improvement of ankle joint functional movement screen score and isokinetic muscular function. PMID:28265157

  14. Ankle taping can reduce external ankle joint moments during drop landings on a tilted surface.

    PubMed

    Sato, Nahoko; Nunome, Hiroyuki; Hopper, Luke S; Ikegami, Yasuo

    2017-09-20

    Ankle taping is commonly used to prevent ankle sprains. However, kinematic assessments investigating the biomechanical effects of ankle taping have provided inconclusive results. This study aimed to determine the effect of ankle taping on the external ankle joint moments during a drop landing on a tilted surface at 25°. Twenty-five participants performed landings on a tilted force platform that caused ankle inversion with and without ankle taping. Landing kinematics were captured using a motion capture system. External ankle inversion moment, the angular impulse due to the medio-lateral and vertical components of ground reaction force (GRF) and their moment arm lengths about the ankle joint were analysed. The foot plantar inclination relative to the ground was assessed. In the taping condition, the foot plantar inclination and ankle inversion angular impulse were reduced significantly compared to that of the control. The only component of the external inversion moment to change significantly in the taped condition was a shortened medio-lateral GRF moment arm length. It can be assumed that the ankle taping altered the foot plantar inclination relative to the ground, thereby shortening the moment arm of medio-lateral GRF that resulted in the reduced ankle inversion angular impulse.

  15. Reliability and smallest real difference of the ankle lunge test post ankle fracture.

    PubMed

    Simondson, David; Brock, Kim; Cotton, Susan

    2012-02-01

    This study aimed to determine the reliability and the smallest real difference of the Ankle Lunge test in an ankle fracture patient population. In the post immobilisation stage of ankle fracture, ankle dorsiflexion is an important measure of progress and outcome. The Ankle Lunge test measures weight bearing dorsiflexion, resulting in negative scores (knee to wall distance) and positive scores (toe to wall distance), for which the latter has proven reliability in normal subjects only. A consecutive sample of ankle fracture patients with permission to commence weight bearing, were recruited to the study. Three measurements of the Ankle Lunge Test were performed each by two raters, one senior and one junior physiotherapist. These occurred prior to therapy sessions in the second week after plaster removal. A standardised testing station was utilised and allowed for both knee to wall distance and toe to wall distance measurement. Data was collected from 10 individuals with ankle fracture, with an average age of 36 years (SD 14.8). Seventy seven percent of observations were negative. Intra and inter-rater reliability yielded intra class correlations at or above 0.97, p < .001. There was a significant systematic bias towards improved scores during repeated measurement for one rater (p = .01). The smallest real difference was calculated as 13.8mm. The Ankle Lunge test is a practical and reliable tool for measuring weightbearing dorsiflexion post ankle fracture. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Immunohistochemical study of motoneurons in lumbar spinal cord of c57black/6 mice after 30-days space flight

    NASA Astrophysics Data System (ADS)

    Tyapkina, Oksana; Islamov, Rustem; Nurullin, Leniz; Petrov, Konstantin.; Rezvyakov, Pavel; Nikolsky, Evgeny

    To investigate mechanisms of hypogravity motor syndrome development the immunoexpression of heat shock proteins (Hsp27 and Hsp70), proteins of synaptic transmission (Synaptophysin and PSD95) and neuroprotective proteins (VEGF and Flt-1) in motoneurons of lumbar spinal cord in c57black/6 control mice (n=2) and after 30-days space flight (n=2) was studied. For a quantitative assessment of target proteins level in motoneurons frozen cross sections of lumbar spinal cord were underwent to immunohistochemical staining. Primary antibodies against VEGF, Flt-1, Hsp27 and Hsp70 (SantaCruz Biotechnology, inc. USA), against Synaptophysin and PSD95 (Abcam plc, UK) were visualized by streptavidin-biotin method. Images of spinal cords were received using OlympusBX51WI microscope with AxioCamMRm camera (CarlZeiss, Germany) and the AxioVisionRel. 4.6.3 software (CarlZeiss, Germany). The digitized data were analyzed using ImageJ 1.43 software (NIH, the USA). Quantitively, protein level in motoneurons was estimated by the density of immunoprecipitation. Results of research have not revealed any reliable changes in the immunnoexpression of vascular endothelial growth factor (VEGF) and its Flt-1 receptor in motoneurons of lumbar spinal cord in control and in mice after 30-day space flight. Studying of heat shock proteins, such as Hsp27 and Hsp70, revealed the decrease in level of these proteins immunoexpression in motoneurons of mice from flight group by 15% and 10%, respectively. Some decrease in level of immunnoexpression of presynaptic membrane proteins (synaptophysin, by 21%) and proteins of postsynaptic area (PSD95, by 55%) was observed after space flight. The data obtained testify to possible changes in a functional state (synaptic activity and stress resistance) of motoneurons of lumbar spinal cord in mice after space flight. Thus, we obtained new data on involvement of motoneurons innervating skeletal muscles in development of hypogravity motor syndrome. Research was supported

  17. Differences in kinematic control of ankle joint motions in people with chronic ankle instability.

    PubMed

    Kipp, Kristof; Palmieri-Smith, Riann M

    2013-06-01

    People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls. Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by simultaneously examining the three-dimensional co-variation of plantarflexion/dorsiflexion, toe-in/toe-out rotation, and inversion/eversion motions with principal component analysis. Group differences in the variance proportions of the first two principal components indicated that the angular co-variation between ankle joint motions was more linear in the control group, but more planar in the chronic ankle instability group. Frontal and transverse plane motions, in particular, contributed to the group differences in the linearity and planarity of angular co-variation. People with chronic ankle instability use a different kinematic control strategy to coordinate ankle joint motions during a single-leg landing task. Compared to the healthy group, the chronic ankle instability group's control strategy appeared to be more complex and involved joint-specific contributions that would tend to predispose this group to recurring episodes of instability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Therapeutic interventions for increasing ankle dorsiflexion after ankle sprain: a systematic review.

    PubMed

    Terada, Masafumi; Pietrosimone, Brian G; Gribble, Phillip A

    2013-01-01

    Clinicians perform therapeutic interventions, such as stretching, manual therapy, electrotherapy, ultrasound, and exercises, to increase ankle dorsiflexion. However, authors of previous studies have not determined which intervention or combination of interventions is most effective. To determine the magnitude of therapeutic intervention effects on and the most effective therapeutic interventions for restoring normal ankle dorsiflexion after ankle sprain. We performed a comprehensive literature search in Web of Science and EBSCO HOST from 1965 to May 29, 2011, with 19 search terms related to ankle sprain, dorsiflexion, and intervention and by cross-referencing pertinent articles. Eligible studies had to be written in English and include the means and standard deviations of both pretreatment and posttreatment in patients with acute, subacute, or chronic ankle sprains. Outcomes of interest included various joint mobilizations, stretching, local vibration, hyperbaric oxygen therapy, electrical stimulation, and mental-relaxation interventions. We extracted data on dorsiflexion improvements among various therapeutic applications by calculating Cohen d effect sizes with associated 95% confidence intervals (CIs) and evaluated the methodologic quality using the Physiotherapy Evidence Database (PEDro) scale. In total, 9 studies (PEDro score = 5.22 ± 1.92) met the inclusion criteria. Static-stretching interventions with a home exercise program had the strongest effects on increasing dorsiflexion in patients 2 weeks after acute ankle sprains (Cohen d = 1.06; 95% CI = 0.12, 2.42). The range of effect sizes for movement with mobilization on ankle dorsiflexion among individuals with recurrent ankle sprains was small (Cohen d range = 0.14 to 0.39). Static-stretching intervention as a part of standardized care yielded the strongest effects on dorsiflexion after acute ankle sprains. The existing evidence suggests that clinicians need to consider what may be the limiting factor of

  19. The effect of combined mechanism ankle support on postural control of patients with chronic ankle instability.

    PubMed

    Hadadi, Mohammad; Ebrahimi, Ismaeil; Mousavi, Mohammad Ebrahim; Aminian, Gholamreza; Esteki, Ali; Rahgozar, Mehdi

    2017-02-01

    Chronic ankle instability is associated with neuromechanical changes and poor postural stability. Despite variety of mechanisms of foot and ankle orthoses, almost none apply comprehensive mechanisms to improve postural control in all subgroups of chronic ankle instability patients. The purpose of this study was to investigate the effect of an ankle support implementing combined mechanisms to improve postural control in chronic ankle instability patients. Cross-sectional study. An ankle support with combined mechanism was designed based on most effective action mechanisms of foot and ankle orthoses. The effect of this orthosis on postural control was evaluated in 20 participants with chronic ankle instability and 20 matched healthy participants. The single-limb stance balance test was measured in both groups with and without the new orthosis using a force platform. The results showed that application of combined mechanism ankle support significantly improved all postural sway parameters in chronic ankle instability patients. There were no differences in means of investigated parameters with and without the orthosis in the healthy group. No statistically significant differences were found in postural sway between chronic ankle instability patients and healthy participants after applying the combined mechanism ankle support. The combined mechanism ankle support is effective in improving static postural control of chronic ankle instability patients to close to the postural sway of healthy individual. the orthosis had no adverse effects on balance performance of healthy individuals. Clinical relevance Application of the combined mechanism ankle support for patients with chronic ankle instability is effective in improving static balance. This may be helpful in reduction of recurrence of ankle sprain although further research about dynamic conditions is needed.

  20. Ankle fracture spur sign is pathognomonic for a variant ankle fracture.

    PubMed

    Hinds, Richard M; Garner, Matthew R; Lazaro, Lionel E; Warner, Stephen J; Loftus, Michael L; Birnbaum, Jacqueline F; Burket, Jayme C; Lorich, Dean G

    2015-02-01

    The hyperplantarflexion variant ankle fracture is composed of a posterior tibial lip fracture with posterolateral and posteromedial fracture fragments separated by a vertical fracture line. This infrequently reported injury pattern often includes an associated "spur sign" or double cortical density at the inferomedial tibial metaphysis. The objective of this study was to quantitatively establish the association of the ankle fracture spur sign with the hyperplantarflexion variant ankle fracture. Our clinical database of operative ankle fractures was retrospectively reviewed for the incidence of hyperplantarflexion variant and nonvariant ankle fractures as determined by assessment of injury radiographs, preoperative advanced imaging, and intraoperative observation. Injury radiographs were then evaluated for the presence of the spur sign, and association between the spur sign and variant fractures was analyzed. The incidence of the hyperplantarflexion variant fracture among all ankle fractures was 6.7% (43/640). The spur sign was present in 79% (34/43) of variant fractures and absent in all nonvariant fractures, conferring a specificity of 100% in identifying variant fractures. Positive predictive value and negative predictive value were 100% and 99%, respectively. The ankle fracture spur sign was pathognomonic for the hyperplantarflexion variant ankle fracture. It is important to identify variant fractures preoperatively as patient positioning, operative approach, and fixation construct of variant fractures often differ from those employed for osteosynthesis of nonvariant fractures. Identification of the spur sign should prompt acquisition of advanced imaging to formulate an appropriate operative plan to address the variant fracture pattern. Level III, retrospective comparative study. © The Author(s) 2014.

  1. The leather ankle lacer.

    PubMed Central

    Saltzman, C. L.; Shurr, D.; Kamp, J.; Cook, T. A.

    1995-01-01

    The purpose of this study was to evaluate the efficacy of a leather ankle lacer for treating painful problems of the ankle and hindfoot. The evaluation involved patient self assessment, clinical examination and radiographic determination of the effectiveness of the ankle lacer. Overall, patients had moderate pain relief with significant but not complete restriction of motion. Based on this study and our clinical experience, we find the leather ankle lacer to be a compliant and comfortable treatment strategy for patients with painful ankle and hindfoot problems who desire some retained motion. Images Figure 1A & B Figure 2 Figure 3 PMID:7634034

  2. Analysis of the Effects of Normal Walking on Ankle Joint Contact Characteristics After Acute Inversion Ankle Sprain.

    PubMed

    Bae, Ji Yong; Park, Kyung Soon; Seon, Jong Keun; Jeon, Insu

    2015-12-01

    To show the causal relationship between normal walking after various lateral ankle ligament (LAL) injuries caused by acute inversion ankle sprains and alterations in ankle joint contact characteristics, finite element simulations of normal walking were carried out using an intact ankle joint model and LAL injury models. A walking experiment using a volunteer with a normal ankle joint was performed to obtain the boundary conditions for the simulations and to support the appropriateness of the simulation results. Contact pressure and strain on the talus articular cartilage and anteroposterior and mediolateral translations of the talus were calculated. Ankles with ruptured anterior talofibular ligaments (ATFLs) had a higher likelihood of experiencing increased ankle joint contact pressures, strains and translations than ATFL-deficient ankles. In particular, ankles with ruptured ATFL + calcaneofibular ligaments and all ruptured ankles had a similar likelihood as the ATFL-ruptured ankles. The push off stance phase was the most likely situation for increased ankle joint contact pressures, strains and translations in LAL-injured ankles.

  3. Neuromodulation impact on nonlinear firing behavior of a reduced model motoneuron with the active dendrite

    PubMed Central

    Kim, Hojeong; Heckman, C. J.

    2014-01-01

    Neuromodulatory inputs from brainstem systems modulate the normal function of spinal motoneurons by altering the activation properties of persistent inward currents (PICs) in their dendrites. However, the effect of the PIC on firing outputs also depends on its location in the dendritic tree. To investigate the interaction between PIC neuromodulation and PIC location dependence, we used a two-compartment model that was biologically realistic in that it retains directional and frequency-dependent electrical coupling between the soma and the dendrites, as seen in multi-compartment models based on full anatomical reconstructions of motoneurons. Our two-compartment approach allowed us to systematically vary the coupling parameters between the soma and the dendrite to accurately reproduce the effect of location of the dendritic PIC on the generation of nonlinear (hysteretic) motoneuron firing patterns. Our results show that as a single parameter value for PIC activation was either increased or decreased by 20% from its default value, the solution space of the coupling parameter values for nonlinear firing outputs was drastically reduced by approximately 80%. As a result, the model tended to fire only in a linear mode at the majority of dendritic PIC sites. The same results were obtained when all parameters for the PIC activation simultaneously changed only by approximately ±10%. Our results suggest the democratization effect of neuromodulation: the neuromodulation by the brainstem systems may play a role in switching the motoneurons with PICs at different dendritic locations to a similar mode of firing by reducing the effect of the dendritic location of PICs on the firing behavior. PMID:25309410

  4. Divergence between motoneurons: gene expression profiling provides a molecular characterization of functionally discrete somatic and autonomic motoneurons

    PubMed Central

    Cui, Dapeng; Dougherty, Kimberly J.; Machacek, David W.; Sawchuk, Michael; Hochman, Shawn; Baro, Deborah J.

    2009-01-01

    Studies in the developing spinal cord suggest that different motoneuron (MN) cell types express very different genetic programs, but the degree to which adult programs differ is unknown. To compare genetic programs between adult MN columnar cell types, we used laser capture micro-dissection (LCM) and Affymetrix microarrays to create expression profiles for three columnar cell types: lateral and medial MNs from lumbar segments and sympathetic preganglionic motoneurons located in the thoracic intermediolateral nucleus. A comparison of the three expression profiles indicated that ~7% (813/11,552) of the genes showed significant differences in their expression levels. The largest differences were observed between sympathetic preganglionic MNs and the lateral motor column, with 6% (706/11,552) of the genes being differentially expressed. Significant differences in expression were observed for 1.8% (207/11,552) of the genes when comparing sympathetic preganglionic MNs with the medial motor column. Lateral and medial MNs showed the least divergence, with 1.3% (150/11,552) of the genes being differentially expressed. These data indicate that the amount of divergence in expression profiles between identified columnar MNs does not strictly correlate with divergence of function as defined by innervation patterns (somatic/muscle vs. autonomic/viscera). Classification of the differentially expressed genes with regard to function showed that they underpin all fundamental cell systems and processes, although most differentially expressed genes encode proteins involved in signal transduction. Mining the expression profiles to examine transcription factors essential for MN development suggested that many of the same transcription factors participatein combinatorial codes in embryonic and adult neurons, but patterns of expression change significantly. PMID:16317082

  5. Ankle and knee biomechanics during normal walking following ankle plantarflexor fatigue.

    PubMed

    Hunt, Michael A; Hatfield, Gillian L

    2017-08-01

    The purpose of this study was to investigate the immediate effects of unilateral ankle plantarflexor fatigue on bilateral knee and ankle biomechanics during gait. Lower leg kinematics, kinetics, and muscle activation were assessed before and after an ankle plantarflexor fatiguing protocol in 31 healthy individuals. Fatigue (defined as >10% reduction in maximal isometric ankle plantarflexor torque production and a downward shift in the median power frequency of both heads of the gastrocnemius muscle of the fatigued limb) was achieved in 18 individuals, and only their data were used for analysis purposes. Compared to pre-fatigue walking trials, medial gastrocnemius activity was significantly reduced in the study (fatigued) limb. Other main changes following fatigue included significantly more knee flexion during loading, and an associated larger external knee flexion moment in the study limb. At the ankle joint, participants exhibited significantly less peak plantarflexion (occurring at toe-off) with fatigue. No significant differences were observed in the contralateral (non-fatigued) limb. Findings from this study indicate that fatigue of the ankle plantarflexor muscle does not produce widespread changes in gait biomechanics, suggesting that small to moderate changes in maximal ankle plantarflexor force production capacity (either an increase or decrease) will not have a substantial impact on normal lower limb functioning during gait. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Clinical examination results in individuals with functional ankle instability and ankle-sprain copers.

    PubMed

    Wright, Cynthia J; Arnold, Brent L; Ross, Scott E; Ketchum, Jessica; Ericksen, Jeffrey; Pidcoe, Peter

    2013-01-01

    Why some individuals with ankle sprains develop functional ankle instability and others do not (ie, copers) is unknown. Current understanding of the clinical profile of copers is limited. To contrast individuals with functional ankle instability (FAI), copers, and uninjured individuals on both self-reported variables and clinical examination findings. Cross-sectional study. Sports medicine research laboratory. Participants consisted of 23 individuals with a history of 1 or more ankle sprains and at least 2 episodes of giving way in the past year (FAI: Cumberland Ankle Instability Tool [CAIT] score = 20.52 ± 2.94, episodes of giving way = 5.8 ± 8.4 per month), 23 individuals with a history of a single ankle sprain and no subsequent episodes of instability (copers: CAIT score = 27.74 ± 1.69), and 23 individuals with no history of ankle sprain and no instability (uninjured: CAIT score = 28.78 ± 1.78). Self-reported disability was recorded using the CAIT and Foot and Ankle Ability Measure for Activities of Daily Living and for Sports. On clinical examination, ligamentous laxity and tenderness, range of motion (ROM), and pain at end ROM were recorded. Questionnaire scores for the CAIT, Foot and Ankle Ability Measure for Activities of Daily Living and for Sports, ankle inversion and anterior drawer laxity scores, pain with palpation of the lateral ligaments, ankle ROM, and pain at end ROM. Individuals with FAI had greater self-reported disability for all measures (P < .05). On clinical examination, individuals with FAI were more likely to have greater talar tilt laxity, pain with inversion, and limited sagittal-plane ROM than copers (P < .05). Differences in both self-reported disability and clinical examination variables distinguished individuals with FAI from copers at least 1 year after injury. Whether the deficits could be detected immediately postinjury to prospectively identify potential copers is unknown.

  7. MiR-7-1 potentiated estrogen receptor agonists for functional neuroprotection in VSC4.1 motoneurons.

    PubMed

    Chakrabarti, M; Banik, N L; Ray, S K

    2014-01-03

    Protection of motoneurons is an important goal in the treatment of spinal cord injury (SCI). We tested whether neuroprotective microRNAs (miRs) like miR-206, miR-17, miR-21, miR-7-1, and miR-106a could enhance efficacy of estrogen receptor (ER) agonists such as 1,3,5-tris (4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT, ERα agonist), Way200070 (WAY, ERβ agonist), and estrogen (EST, ERα and ERβ agonist) in preventing apoptosis in the calcium ionophore (CI)-insulted ventral spinal cord 4.1 (VSC4.1) motoneurons. We determined that 200 nM CI induced 70% cell death. Treatment with 50 nM PPT, 100 nM WAY, and 150 nM EST induced overexpression of ERα, ERβ, and both receptors, respectively, at mRNA and protein levels. Treatment with ER agonists significantly upregulated miR-206, miR-17, and miR-7-1 in the CI-insulted VSC4.1 motoneurons. Transfection with miR-206, miR-17, or miR-7-1 mimic potentiated WAY or EST to inhibit apoptosis in the CI-insulted VSC4.1 motoneurons. Overexpression of miR-7-1 maximally increased efficacy of WAY and EST for down regulation of pro-apoptotic Bax and upregulation of anti-apoptotic Bcl-2. A search using microRNA database (miRDB) indicated that miR-7-1 could inhibit the expression of L-type Ca(2+) channel protein alpha 1C (CPα1C). miR-7-1 overexpression and WAY or EST treatment down regulated CPα1C but upregulated p-Akt to trigger cell survival signaling. The same therapeutic strategy increased expression of the Ca(2+)/calmodulin-dependent protein kinase II beta (CaMKIIβ) and the phosphorylated cAMP response element binding protein (p-CREB) so as to promote Bcl-2 transcription. Whole cell membrane potential and mitochondrial membrane potential studies indicated that miR-7-1 highly potentiated EST to preserve functionality in the CI-insulted VSC4.1 motoneurons. In conclusion, our data indicated that miR-7-1 most significantly potentiated efficacy of EST for functional neuroprotection and this therapeutic strategy could be used in the future

  8. Doublecortin is expressed in trigeminal motoneurons that innervate the velar musculature of lampreys: considerations on the evolution and development of the trigeminal system.

    PubMed

    Barreiro-Iglesias, Antón; Romaus-Sanjurjo, Daniel; Senra-Martínez, Pablo; Anadón, Ramón; Rodicio, María Celina

    2011-01-01

    Studies in lampreys have revealed interesting aspects of the evolution of the trigeminal system and the jaw. In the present study, we found a marker that distinguishes subpopulations of trigeminal motoneurons innervating two different kinds of oropharyngeal muscles. Immunofluorescence with an antibody against doublecortin (DCX; a neuron-specific phosphoprotein) enabled identification of the trigeminal motoneurons that innervate the velar musculature of larval and recently transformed sea lampreys. DCX-immunoreactive (-ir) motoneurons were observed in the rostro-lateral part of the trigeminal motor nucleus of these animals, but not in lampreys 1 month or more after metamorphosis. Combined double DCX/tubulin and serotonin/tubulin immunofluorescence and tract-tracing experiments with neurobiotin (NB) were also performed in larvae for further characterization of this system. Rich innervation by DCX-ir fibers was observed on the muscle fibers of the velum but not on the upper lip or lower lip muscles, which were innervated by tubulin-ir/DCX-negative fibers. No double-labelled DCX-ir motoneurons were observed in experiments in which the tracer NB was applied to the upper lip. Innervation of velar muscles by serotonergic fibers is also reported. The present results indicate that development of the trigeminal motoneurons innervating the velum differs from that of the trigeminal motoneurons innervating the lips, which is probably related to the dramatic regression of the velum during metamorphosis. The absence of data on a similar subsystem in the trigeminal motor nucleus of gnathostomes suggests that they may be lamprey-specific motoneurons. These results provide support for the "heterotopic theory" of jaw evolution and are inconsistent with the theories of a velar origin for the gnathostome jaw. © 2011 Wiley Periodicals, Inc.

  9. Mechanical instability destabilises the ankle joint directly in the ankle-sprain mechanism.

    PubMed

    Gehring, Dominic; Faschian, Katrin; Lauber, Benedikt; Lohrer, Heinz; Nauck, Tanja; Gollhofer, Albert

    2014-03-01

    Despite massive research efforts, it remains unclear how mechanical ankle instability (MAI) and functional ankle instability (FAI) affect joint control in the situation of ankle sprain. Thus, the purpose of this study was to evaluate whether individuals with MAI have deficits in stabilising their ankle joint in a close-to-injury situation compared with those with FAI and healthy controls. Ankle-joint control was assessed by means of three-dimensional motion analysis and electromyography in participants with FAI and MAI (n=19), in participants with pure FAI (n=9) and in healthy controls (n=18). Close-to-injury situations were simulated during standing, walking and jumping by means of a custom-made tilt platform. Individuals with FAI and MAI displayed significantly greater maximum ankle inversion angles (+5°) and inversion velocities (+50°/s) in the walking and jumping conditions compared to those with pure FAI and controls. Furthermore, individuals in the FAI and MAI group showed a significantly decreased pre-activation of the peroneus longus muscle during jumping compared to those with FAI. No differences between groups were found for plantar flexion and internal rotation, or for muscle activities following tilting of the platform. The present study demonstrates that MAI is characterised by impairments of ankle-joint control in close-to-injury situations. This could make these individuals more prone to recurrent ankle sprains, and suggests the need for additional mechanical support such as braces or even surgery. In addition, the study highlights the fact that dynamic experimental test conditions in the acting participant are needed to further unravel the mystery of chronic ankle instability.

  10. Ankle syndesmotic injury.

    PubMed

    Zalavras, Charalampos; Thordarson, David

    2007-06-01

    Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome.

  11. Therapeutic Interventions for Increasing Ankle Dorsiflexion After Ankle Sprain: A Systematic Review

    PubMed Central

    Terada, Masafumi; Pietrosimone, Brian G.; Gribble, Phillip A.

    2013-01-01

    Context: Clinicians perform therapeutic interventions, such as stretching, manual therapy, electrotherapy, ultrasound, and exercises, to increase ankle dorsiflexion. However, authors of previous studies have not determined which intervention or combination of interventions is most effective. Objective: To determine the magnitude of therapeutic intervention effects on and the most effective therapeutic interventions for restoring normal ankle dorsiflexion after ankle sprain. Data Sources: We performed a comprehensive literature search in Web of Science and EBSCO HOST from 1965 to May 29, 2011, with 19 search terms related to ankle sprain, dorsiflexion, and intervention and by cross-referencing pertinent articles. Study Selection: Eligible studies had to be written in English and include the means and standard deviations of both pretreatment and posttreatment in patients with acute, subacute, or chronic ankle sprains. Outcomes of interest included various joint mobilizations, stretching, local vibration, hyperbaric oxygen therapy, electrical stimulation, and mental-relaxation interventions. Data Extraction: We extracted data on dorsiflexion improvements among various therapeutic applications by calculating Cohen d effect sizes with associated 95% confidence intervals (CIs) and evaluated the methodologic quality using the Physiotherapy Evidence Database (PEDro) scale. Data Synthesis: In total, 9 studies (PEDro score = 5.22 ± 1.92) met the inclusion criteria. Static-stretching interventions with a home exercise program had the strongest effects on increasing dorsiflexion in patients 2 weeks after acute ankle sprains (Cohen d = 1.06; 95% CI = 0.12, 2.42). The range of effect sizes for movement with mobilization on ankle dorsiflexion among individuals with recurrent ankle sprains was small (Cohen d range = 0.14 to 0.39). Conclusions: Static-stretching intervention as a part of standardized care yielded the strongest effects on dorsiflexion after acute ankle sprains. The

  12. hnRNP R and its main interactor, the noncoding RNA 7SK, coregulate the axonal transcriptome of motoneurons.

    PubMed

    Briese, Michael; Saal-Bauernschubert, Lena; Ji, Changhe; Moradi, Mehri; Ghanawi, Hanaa; Uhl, Michael; Appenzeller, Silke; Backofen, Rolf; Sendtner, Michael

    2018-03-20

    Disturbed RNA processing and subcellular transport contribute to the pathomechanisms of motoneuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. RNA-binding proteins are involved in these processes, but the mechanisms by which they regulate the subcellular diversity of transcriptomes, particularly in axons, are not understood. Heterogeneous nuclear ribonucleoprotein R (hnRNP R) interacts with several proteins involved in motoneuron diseases. It is located in axons of developing motoneurons, and its depletion causes defects in axon growth. Here, we used individual nucleotide-resolution cross-linking and immunoprecipitation (iCLIP) to determine the RNA interactome of hnRNP R in motoneurons. We identified ∼3,500 RNA targets, predominantly with functions in synaptic transmission and axon guidance. Among the RNA targets identified by iCLIP, the noncoding RNA 7SK was the top interactor of hnRNP R. We detected 7SK in the nucleus and also in the cytosol of motoneurons. In axons, 7SK localized in close proximity to hnRNP R, and depletion of hnRNP R reduced axonal 7SK. Furthermore, suppression of 7SK led to defective axon growth that was accompanied by axonal transcriptome alterations similar to those caused by hnRNP R depletion. Using a series of 7SK-deletion mutants, we show that the function of 7SK in axon elongation depends on its interaction with hnRNP R but not with the PTEF-B complex involved in transcriptional regulation. These results propose a role for 7SK as an essential interactor of hnRNP R to regulate its function in axon maintenance. Copyright © 2018 the Author(s). Published by PNAS.

  13. The canonical nuclear factor-κB pathway regulates cell survival in a developmental model of spinal cord motoneurons.

    PubMed

    Mincheva, Stefka; Garcera, Ana; Gou-Fabregas, Myriam; Encinas, Mario; Dolcet, Xavier; Soler, Rosa M

    2011-04-27

    In vivo and in vitro motoneuron survival depends on the support of neurotrophic factors. These factors activate signaling pathways related to cell survival or inactivate proteins involved in neuronal death. In the present work, we analyzed the involvement of the nuclear factor-κB (NF-κB) pathway in mediating mouse spinal cord motoneuron survival promoted by neurotrophic factors. This pathway comprises ubiquitously expressed transcription factors that could be activated by two different routes: the canonical pathway, associated with IKKα/IKKβ kinase phosphorylation and nuclear translocation RelA (p65)/p50 transcription factors; and the noncanonical pathway, related to IKKα kinase homodimer phosphorylation and RelB/p52 transcription factor activation. In our system, we show that neurotrophic factors treatment induced IKKα and IKKβ phosphorylation and RelA nuclear translocation, suggesting NF-κB pathway activation. Protein levels of different members of the canonical or noncanonical pathways were reduced in a primary culture of isolated embryonic motoneurons using an interference RNA approach. Even in the presence of neurotrophic factors, selective reduction of IKKα, IKKβ, or RelA proteins induced cell death. In contrast, RelB protein reduction did not have a negative effect on motoneuron survival. Together these results demonstrated that the canonical NF-κB pathway mediates motoneuron survival induced by neurotrophic factors, and the noncanonical pathway is not related to this survival effect. Canonical NF-κB blockade induced an increase of Bim protein level and apoptotic cell death. Bcl-x(L) overexpression or Bax reduction counteracted this apoptotic effect. Finally, RelA knockdown causes changes of CREB and Smn protein levels.

  14. Sprained Ankles

    MedlinePlus

    ... away before the ligament is injured. Types of Sprains In young children, the ankle is the most commonly sprained joint, followed by ... A walking cast may be necessary if the ankle or foot injury has been severe. Most grade 1 sprains will heal within two weeks without subsequent complications. ...

  15. Does the subtalar joint compensate for ankle malalignment in end-stage ankle arthritis?

    PubMed

    Wang, Bibo; Saltzman, Charles L; Chalayon, Ornusa; Barg, Alexej

    2015-01-01

    Patients with ankle arthritis often present with concomitant hindfoot deformity, which may involve the tibiotalar and subtalar joints. However, the possible compensatory mechanisms of these two mechanically linked joints are not well known. In this study we sought to (1) compare ankle and hindfoot alignment of our study cohort with end-stage ankle arthritis with that of a control group; (2) explore the frequency of compensated malalignment between the tibiotalar and subtalar joints in our study cohort; and (3) assess the intraobserver and interobserver reliability of classification methods of hindfoot alignment used in this study. Between March 2006 and September 2013, we performed 419 ankle arthrodesis and ankle replacements (380 patients). In this study, we evaluated radiographs for 233 (56%) ankles (226 patients) which met the following inclusion criteria: (1) no prior subtalar arthrodesis; (2) no previously failed total ankle replacement or ankle arthrodesis; (3) with complete conventional radiographs (all three ankle views were required: mortise, lateral, and hindfoot alignment view). Ankle and hindfoot alignment was assessed by measurement of the medial distal tibial angle, tibial talar surface angle, talar tilting angle, tibiocalcaneal axis angle, and moment arm of calcaneus. The obtained values were compared with those observed in the control group of 60 ankles from 60 people. Only those without obvious degenerative changes of the tibiotalar and subtalar joints and without previous surgeries of the ankle or hindfoot were included in the control group. Demographic data for the patients with arthritis and the control group were comparable (sex, p=0.321; age, p=0.087). The frequency of compensated malalignment between the tibiotalar and subtalar joints, defined as tibiocalcaneal angle or moment arm of the calcaneus being greater or smaller than the same 95% CI statistical cutoffs from the control group, was tallied. All ankle radiographs were independently

  16. Test-retest reliability of sudden ankle inversion measurements in subjects with healthy ankle joints.

    PubMed

    Eechaute, Christophe; Vaes, Peter; Duquet, William; Van Gheluwe, Bart

    2007-01-01

    Sudden ankle inversion tests have been used to investigate whether the onset of peroneal muscle activity is delayed in patients with chronically unstable ankle joints. Before interpreting test results of latency times in patients with chronic ankle instability and healthy subjects, the reliability of these measures must be first demonstrated. To investigate the test-retest reliability of variables measured during a sudden ankle inversion movement in standing subjects with healthy ankle joints. Validation study. Research laboratory. 15 subjects with healthy ankle joints (30 ankles). Subjects stood on an ankle inversion platform with both feet tightly fixed to independently moveable trapdoors. An unexpected sudden ankle inversion of 50 degrees was imposed. We measured latency and motor response times and electromechanical delay of the peroneus longus muscle, along with the time and angular position of the first and second decelerating moments, the mean and maximum inversion speed, and the total inversion time. Correlation coefficients and standard error of measurements were calculated. Intraclass correlation coefficients ranged from 0.17 for the electromechanical delay of the peroneus longus muscle (standard error of measurement = 2.7 milliseconds) to 0.89 for the maximum inversion speed (standard error of measurement = 34.8 milliseconds). The reliability of the latency and motor response times of the peroneus longus muscle, the time of the first and second decelerating moments, and the mean and maximum inversion speed was acceptable in subjects with healthy ankle joints and supports the investigation of the reliability of these measures in subjects with chronic ankle instability. The lower reliability of the electromechanical delay of the peroneus longus muscle and the angular positions of both decelerating moments calls the use of these variables into question.

  17. X-Ray Exam: Ankle

    MedlinePlus

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Ankle KidsHealth / For Parents / X-Ray Exam: Ankle What's in this article? What ... Have Questions Print What It Is An ankle X-ray is a safe and painless test that ...

  18. Synaptology of the direct projections from the nucleus of the solitary tract to pharyngeal motoneurons in the nucleus ambiguus of the rat.

    PubMed

    Hayakawa, T; Zheng, J Q; Seki, M; Yajima, Y

    1998-04-13

    During the pharyngeal phase of the swallowing reflex, the nucleus of the solitary tract (NTS) receives peripheral inputs from the pharynx by means of the glossopharyngeal ganglion and is the location of premotor neurons for the pharyngeal (PH) motoneurons. The semicompact formation of the nucleus ambiguus (AmS) is composed of small and medium-sized neurons that do not project to the pharynx, and large PH motoneurons. We investigated whether the neurons in the NTS projected directly to the PH motoneurons or to the other kinds of neurons in the AmS by using the electron microscope. When wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the NTS after cholera toxin subunit B-conjugated HRP (CT-HRP) injections into the pharyngeal muscles of male Sprague-Dawley rats, many nerve terminals anterogradely labeled with WGA-HRP were found to contact PH motoneurons retrogradely labeled with CT-HRP. Most of the labeled axodendritic terminals (63%) contained pleomorphic vesicles with symmetric synaptic contacts (Gray's type II), and the remaining ones contained round vesicles with asymmetric synaptic contacts (Gray's type I). About 14% of the axosomatic terminals on PH motoneuron in a sectional plane were anterogradely labeled, and about 70% of the labeled axosomatic terminals were Gray's type II. Observations of serial ultrathin sections revealed that both the small and the medium-sized neurons received only a few labeled axosomatic terminals that were exclusively Gray's type I. These results indicate that the NTS neurons may send mainly inhibitory as well as a few excitatory inputs directly to the PH motoneurons in the AmS.

  19. Clinical Examination Results in Individuals With Functional Ankle Instability and Ankle-Sprain Copers

    PubMed Central

    Wright, Cynthia J.; Arnold, Brent L.; Ross, Scott E.; Ketchum, Jessica; Ericksen, Jeffrey; Pidcoe, Peter

    2013-01-01

    Context: Why some individuals with ankle sprains develop functional ankle instability and others do not (ie, copers) is unknown. Current understanding of the clinical profile of copers is limited. Objective: To contrast individuals with functional ankle instability (FAI), copers, and uninjured individuals on both self-reported variables and clinical examination findings. Design: Cross-sectional study. Setting: Sports medicine research laboratory. Patients or Other Participants: Participants consisted of 23 individuals with a history of 1 or more ankle sprains and at least 2 episodes of giving way in the past year (FAI: Cumberland Ankle Instability Tool [CAIT] score = 20.52 ± 2.94, episodes of giving way = 5.8 ± 8.4 per month), 23 individuals with a history of a single ankle sprain and no subsequent episodes of instability (copers: CAIT score = 27.74 ± 1.69), and 23 individuals with no history of ankle sprain and no instability (uninjured: CAIT score = 28.78 ± 1.78). Intervention(s): Self-reported disability was recorded using the CAIT and Foot and Ankle Ability Measure for Activities of Daily Living and for Sports. On clinical examination, ligamentous laxity and tenderness, range of motion (ROM), and pain at end ROM were recorded. Main Outcome Measure(s): Questionnaire scores for the CAIT, Foot and Ankle Ability Measure for Activities of Daily Living and for Sports, ankle inversion and anterior drawer laxity scores, pain with palpation of the lateral ligaments, ankle ROM, and pain at end ROM. Results: Individuals with FAI had greater self-reported disability for all measures (P < .05). On clinical examination, individuals with FAI were more likely to have greater talar tilt laxity, pain with inversion, and limited sagittal-plane ROM than copers (P < .05). Conclusions: Differences in both self-reported disability and clinical examination variables distinguished individuals with FAI from copers at least 1 year after injury. Whether the deficits could be detected

  20. Robotic cadaver testing of a new total ankle prosthesis model (German Ankle System).

    PubMed

    Richter, Martinus; Zech, Stefan; Westphal, Ralf; Klimesch, Yvone; Gosling, Thomas

    2007-12-01

    An investigation was carried out into possible increased forces, torques, and altered motions during load-bearing ankle motion after implantation of two different total ankle prostheses. We hypothesized that the parameters investigated would not differ in relation to the two implants compared. We included two different ankle prostheses (Hintegra, Newdeal, Vienne, France; German Ankle System, R-Innovation, Coburg, Germany). The prostheses were implanted in seven paired cadaver specimens. The specimens were mounted on an industrial robot that enables complex motion under predefined conditions (RX 90, Stäubli, Bayreuth, Germany). The robot detected the load-bearing (30 kg) motion of the 100(th) cycle of the specimens without prostheses as the baseline for the later testing, and mimicked that exact motion during 100 cycles after the prostheses were implanted. The resulting forces, torques, and bone motions were recorded and the differences between the prostheses compared. The Hintegra and German Ankle System, significantly increased the forces and torques in relation to the specimen without a prosthesis with one exception (one-sample-t-test, each p < or = 0.01; exception, parameter lateral force measured with the German Ankle System, p = 0.34). The force, torque, and motion differences between the specimens before and after implantation of the prostheses were lower with the German Ankle System than with the Hintegra (unpaired t-test, each p < or = 0.05). The German Ankle System prosthesis had less of an effect on resulting forces and torques during partial weightbearing passive ankle motion than the Hintegra prosthesis. This might improve function and minimize loosening during the clinical use.

  1. Wildtype motoneurons, ALS-Linked SOD1 mutation and glutamate profoundly modify astrocyte metabolism and lactate shuttling.

    PubMed

    Madji Hounoum, Blandine; Mavel, Sylvie; Coque, Emmanuelle; Patin, Franck; Vourc'h, Patrick; Marouillat, Sylviane; Nadal-Desbarats, Lydie; Emond, Patrick; Corcia, Philippe; Andres, Christian R; Raoul, Cédric; Blasco, Hélène

    2017-04-01

    The selective degeneration of motoneuron that typifies amyotrophic lateral sclerosis (ALS) implicates non-cell-autonomous effects of astrocytes. However, mechanisms underlying astrocyte-mediated neurotoxicity remain largely unknown. According to the determinant role of astrocyte metabolism in supporting neuronal function, we propose to explore the metabolic status of astrocytes exposed to ALS-associated conditions. We found a significant metabolic dysregulation including purine, pyrimidine, lysine, and glycerophospholipid metabolism pathways in astrocytes expressing an ALS-causing mutated superoxide dismutase-1 (SOD1) when co-cultured with motoneurons. SOD1 astrocytes exposed to glutamate revealed a significant modification of the astrocyte metabolic fingerprint. More importantly, we observed that SOD1 mutation and glutamate impact the cellular shuttling of lactate between astrocytes and motoneurons with a decreased in extra- and intra-cellular lactate levels in astrocytes. Based on the emergent strategy of metabolomics, this work provides novel insight for understanding metabolic dysfunction of astrocytes in ALS conditions and opens the perspective of therapeutics targets through focusing on these metabolic pathways. GLIA 2017 GLIA 2017;65:592-605. © 2017 Wiley Periodicals, Inc.

  2. Soma size and Cav1.3 channel expression in vulnerable and resistant motoneuron populations of the SOD1G93A mouse model of ALS

    PubMed Central

    Shoenfeld, Liza; Westenbroek, Ruth E.; Fisher, Erika; Quinlan, Katharina A.; Tysseling, Vicki M.; Powers, Randall K.; Heckman, Charles J.; Binder, Marc D.

    2014-01-01

    Abstract Although the loss of motoneurons is an undisputed feature of amyotrophic lateral sclerosis (ALS) in man and in its animal models (SOD1 mutant mice), how the disease affects the size and excitability of motoneurons prior to their degeneration is not well understood. This study was designed to test the hypothesis that motoneurons in mutant SOD1G93A mice exhibit an enlargement of soma size (i.e., cross‐sectional area) and an increase in Cav1.3 channel expression at postnatal day 30, well before the manifestation of physiological symptoms that typically occur at p90 (Chiu et al. 1995). We made measurements of spinal and hypoglossal motoneurons vulnerable to degeneration, as well as motoneurons in the oculomotor nucleus that are resistant to degeneration. Overall, we found that the somata of motoneurons in male SOD1G93A mutants were larger than those in wild‐type transgenic males. When females were included in the two groups, significance was lost. Expression levels of the Cav1.3 channels were not differentiated by genotype, sex, or any interaction of the two. These results raise the intriguing possibility of an interaction between male sex steroid hormones and the SOD1 mutation in the etiopathogenesis of ALS. PMID:25107988

  3. Ankle Plantarflexor Spasticity Does Not Restrict the Recovery of Ankle Plantarflexor Strength or Ankle Power Generation for Push-Off During Walking Following Traumatic Brain Injury.

    PubMed

    Williams, Gavin; Banky, Megan; Olver, John

    2016-01-01

    The main aim of this project was to determine the impact of plantarflexor spasticity on muscle performance for ambulant people with traumatic brain injury (TBI). A large metropolitan rehabilitation hospital. Seventy-two ambulant people with TBI who were attending physiotherapy for mobility limitations. Twenty-four participants returned for a 6-month follow-up reassessment. Cross-sectional cohort study. Self-selected walking speed, Tardieu scale, ankle plantarflexor strength, and ankle power generation (APG). Participants with ankle plantarflexor spasticity had significantly lower self-selected walking speed; however, there was no significant difference in ankle plantarflexor strength or APG. Participants with ankle plantarflexor spasticity were not restricted in the recovery of self-selected walking speed, ankle plantarflexor strength, or APG, indicating equivalent ability to improve their mobility over time despite the presence of spasticity. Following TBI, people with ankle plantarflexor spasticity have significantly greater mobility limitations than those without spasticity, yet retain the capacity for recovery of self-selected walking speed, ankle plantarflexor strength, and APG.

  4. Accumulation of glycogen in axotomized adult rat facial motoneurons.

    PubMed

    Takezawa, Yosuke; Baba, Otto; Kohsaka, Shinichi; Nakajima, Kazuyuki

    2015-06-01

    This study biochemically determined glycogen content in the axotomized facial nucleus of adult rats up to 35 days postinsult. The amounts of glycogen in the transected facial nucleus were significantly increased at 5 days postinsult, peaked at 7 days postinsult, and declined to the control levels at 21-35 days postinsult. Immunohistochemical analysis with antiglycogen antibody revealed that the quantity of glycogen granules in the axotomized facial nucleus was greater than that in the control nucleus at 7 days postinjury. Dual staining methods with antiglycogen antibody and a motoneuron marker clarified that the glycogen was localized mainly in motoneurons. Immunoblotting and quantification analysis revealed that the ratio of inactive glycogen synthase (GS) to total GS was significantly decreased in the injured nucleus at about 1-3 days postinsult and significantly increased from 7 to 14 days postinsult, suggesting that glycogen is actively synthesized in the early period postinjury but suppressed after 7 days postinsult. The enhanced glycogen at about 5-7 days postinsult is suggested to be responsible for the decrease in inactive GS levels, and the decrease of glycogen after 7 days postinsult is considered to be caused by increased inactive GS levels and possibly the increase in active glycogen phosphorylase. © 2015 Wiley Periodicals, Inc.

  5. Dynamic balance deficits in individuals with chronic ankle instability compared to ankle sprain copers 1 year after a first-time lateral ankle sprain injury.

    PubMed

    Doherty, Cailbhe; Bleakley, Chris; Hertel, Jay; Caulfield, Brian; Ryan, John; Delahunt, Eamonn

    2016-04-01

    To quantify the dynamic balance deficits that characterise a group with chronic ankle instability compared to lateral ankle sprain copers and non-injured controls using kinematic and kinetic outcomes. Forty-two participants with chronic ankle instability and twenty-eight lateral ankle sprain copers were initially recruited within 2 weeks of sustaining a first-time, acute lateral ankle sprain and required to attend our laboratory 1 year later to complete the current study protocol. An additional group of non-injured individuals were also recruited to act as a control group. All participants completed the anterior, posterior-lateral and posterior-medial reach directions of the star excursion balance test. Sagittal plane kinematics of the lower extremity and associated fractal dimension of the centre of pressure path were also acquired. Participants with chronic ankle instability displayed poorer performance in the anterior, posterior-medial and posterior-lateral reach directions compared with controls bilaterally, and in the posterior-lateral direction compared with lateral ankle sprain copers on their 'involved' limb only. These performance deficits in the posterior-lateral and posterior-medial directions were associated with reduced flexion and dorsiflexion displacements at the hip, knee and ankle at the point of maximum reach, and coincided with reduced complexity of the centre of pressure path. In comparison with lateral ankle sprain copers and controls, participants with chronic ankle instability were characterised by dynamic balance deficits as measured using the SEBT. This was attested to reduced sagittal plane motions at the hip, knee and ankle joints, and reduced capacity of the stance limb to avail of its supporting base. III.

  6. Contribution of ankle-foot orthosis moment in regulating ankle and knee motions during gait in individuals post-stroke.

    PubMed

    Kobayashi, Toshiki; Orendurff, Michael S; Singer, Madeline L; Gao, Fan; Foreman, K Bo

    2017-06-01

    Ankle-foot orthosis moment resisting plantarflexion has systematic effects on ankle and knee joint motion in individuals post-stroke. However, it is not known how much ankle-foot orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated ankle-foot orthosis moment to regulate ankle and knee joint motion during gait in individuals post-stroke. Gait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated ankle-foot orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-foot orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the ankle-foot orthosis around the ankle joint measured by bench testing. The ankle-foot orthosis moment and the joint angular position (ankle and knee) relationship in a gait cycle was plotted to quantify the ankle-foot orthosis moment needed to regulate the joint motion. Ankle and knee joint motion were regulated according to the amount of ankle-foot orthosis moment during gait. The ankle-foot orthosis maintained the ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from -0.029 (0.011) to -0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative). Quantifying the contribution of ankle-foot orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an ankle-foot orthosis for individuals post-stroke. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. An uncommon ankle sprain.

    PubMed

    van Zoest, Wart J F; Janssen, Rob P A; Tseng, Carroll M E S

    2007-11-01

    Ankle sprain is the most frequently occurring acute injury in tennis, accounting for 20-25% of all injuries. In the current paper, we assess the cause of ankle sprain and suggest possibilities to be considered during diagnosis. We assessed a professional tennis player with a partial tear of the long peroneal tendon after an ankle sprain by physical exam, X-ray and MRI. Conservative treatment by means of soft cast and propriocepsis training led to full recovery. Peroneal tendon disorders must be part of the differential diagnosis after ankle sprain in the professional athlete.

  8. A Simulation Based Analysis of Motor Unit Number Index (MUNIX) Technique Using Motoneuron Pool and Surface Electromyogram Models

    PubMed Central

    Li, Xiaoyan; Rymer, William Zev; Zhou, Ping

    2013-01-01

    Motor unit number index (MUNIX) measurement has recently achieved increasing attention as a tool to evaluate the progression of motoneuron diseases. In our current study, the sensitivity of the MUNIX technique to changes in motoneuron and muscle properties was explored by a simulation approach utilizing variations on published motoneuron pool and surface electromyogram (EMG) models. Our simulation results indicate that, when keeping motoneuron pool and muscle parameters unchanged and varying the input motor unit numbers to the model, then MUNIX estimates can appropriately characterize changes in motor unit numbers. Such MUNIX estimates are not sensitive to different motor unit recruitment and rate coding strategies used in the model. Furthermore, alterations in motor unit control properties do not have a significant effect on the MUNIX estimates. Neither adjustment of the motor unit recruitment range nor reduction of the motor unit firing rates jeopardizes the MUNIX estimates. The MUNIX estimates closely correlate with the maximum M wave amplitude. However, if we reduce the amplitude of each motor unit action potential rather than simply reduce motor unit number, then MUNIX estimates substantially underestimate the motor unit numbers in the muscle. These findings suggest that the current MUNIX definition is most suitable for motoneuron diseases that demonstrate secondary evidence of muscle fiber reinnervation. In this regard, when MUNIX is applied, it is of much importance to examine a parallel measurement of motor unit size index (MUSIX), defined as the ratio of the maximum M wave amplitude to the MUNIX. However, there are potential limitations in the application of the MUNIX methods in atrophied muscle, where it is unclear whether the atrophy is accompanied by loss of motor units or loss of muscle fiber size. PMID:22514208

  9. Assessment of Ankle Injuries

    ERIC Educational Resources Information Center

    Mai, Nicholas; Cooper, Leslie

    2009-01-01

    School nurses are faced with the challenge of identifying and treating ankle injuries in the school setting. There is little information guiding the assessment and treatment of these children when an injury occurs. It is essential for school nurses to understand ankle anatomy, pathophysiology of the acute ankle injury, general and orthopedic…

  10. Chronic Ankle Instability

    MedlinePlus

    ... top of the talus is dome-shaped and... Softball Injuries to the Foot and Ankle Your feet ... ankles take a beating when you are playing softball. Softball players should be aware of the following ...

  11. Ankle-Brachial Index

    MedlinePlus

    ... in which the arteries in your legs or arms are narrowed or blocked. People with peripheral artery ... ankle with your blood pressure measured at your arm. A low ankle-brachial index number can indicate ...

  12. Does electrical stimulation reduce spasticity after stroke? A randomized controlled study.

    PubMed

    Bakhtiary, Amir H; Fatemy, Elham

    2008-05-01

    To investigate the therapeutic effect of electrical stimulation on plantarflexor spasticity in stroke patients. A randomized controlled clinical trial study. Rehabilitation clinic of Semnan University of Medical Sciences. Forty stroke patients (aged from 42 to 65 years) with ankle plantarflexor spasticity. Fifteen minutes of inhibitory Bobath techniques were applied to one experimental group and a combination of 9 minutes of electrical stimulation on the dorsiflexor muscles and inhibitory Bobath techniques was applied to another group for 20 sessions daily. Passive ankle joint dorsiflexion range of motion, dorsiflexion strength test, plantarflexor muscle tone by Modified Ashworth Scale and soleus muscle H-reflex. The mean change of passive ankle joint dorsiflexion in the combination therapy group was 11.4 (SD 4.79) degrees versus 6.1 (SD 3.09) degrees, which was significantly higher (P = 0.001). The mean change of plantarflexor muscle tonicity measured by the Modified Ashworth Scale in the combination therapy group was -1.6 (SD 0.5) versus -1.1 (SD 0.31) in the Bobath group (P = 0.001). Dorsiflexor muscle strength was also increased significantly (P = 0.04) in the combination therapy group (0.7 +/- 0.37) compared with the Bobath group (0.4 +/- 0.23). However, no significant change in the amplitude of H-reflex was found between combination therapy (-0.41 +/- 0.29) and Bobath (-0.3 +/- 0.28) groups. Therapy combining Bobath inhibitory technique and electrical stimulation may help to reduce spasticity effectively in stroke patients.

  13. Physical performance measures that predict faller status in community-dwelling older adults.

    PubMed

    Macrae, P G; Lacourse, M; Moldavon, R

    1992-01-01

    Falls are a leading cause of fatal and nonfatal injuries among the elderly. Accurate determination of risk factors associated with falls in older adults is necessary, not only for individual patient management, but also for the development of fall prevention programs. The purpose of this study was to evaluate the effectiveness of clinical measures, such as the one-legged stance test (OLST), sit-to-stand test (STST), manual muscle tests (MMT), and response speed in predicting faller status in community-dwelling older adults (N = 94, age 60-89 years). The variables assessed were single-leg standing (as measured by OLST), STST, and MMT of 12 different muscle groups (hip flexors, hip abductors, hip adductors, knee flexors, knee extensors, ankle dorsiflexors, ankle plantarflexors, shoulder flexors, shoulder abductors, elbow flexors, elbow extensors, and finger flexors), and speed of response (as measured by a visual hand reaction and movement time task). Of the 94 older adults assessed, 28 (29.7%) reported at least one fall within the previous year. The discriminant analysis revealed that there were six variables that significantly discriminated between fallers and nonfallers. These variables included MMT of the ankle dorsiflexors, knee flexors, hip abductors, and knee extensors, as well as time on the OLST and the STST. The results indicate that simple clinical measures of musculoskeletal function can discriminate fallers from nonfallers in community-dwelling older adults. J Orthop Sports Phys Ther 1992;16(3):123-128.

  14. Effect of External Ankle Support on Ankle and Knee Biomechanics During the Cutting Maneuver in Basketball Players.

    PubMed

    Klem, Nardia-Rose; Wild, Catherine Y; Williams, Sian A; Ng, Leo

    2017-03-01

    Despite the high prevalence of lower extremity injuries in female basketball players as well as a high proportion of athletes who wear ankle braces, there is a paucity of research pertaining to the effects of ankle bracing on ankle and knee biomechanics during basketball-specific tasks. To compare the effects of a lace-up brace (ASO), a hinged brace (Active T2), and no ankle bracing (control) on ankle and knee joint kinematics and joint reaction forces in female basketball athletes during a cutting maneuver. Controlled laboratory study. Twenty healthy, semi-elite female basketball players performed a cutting task under both ankle brace conditions (lace-up ankle brace and hinged ankle brace) and a no-brace condition. The 3-dimensional kinematics of the ankle and knee during the cutting maneuver were measured with an 18-camera motion analysis system (250 Hz), and ground-reaction force data were collected by use of a multichannel force plate (2000 Hz) to quantify ankle and knee joint reaction forces. Conditions were randomized using a block randomization method. Compared with the control condition, the hinged ankle brace significantly restricted peak ankle inversion (mean difference, 1.7°; P = .023). No significant difference was found between the lace-up brace and the control condition ( P = .865). Compared with the lace-up brace, the hinged brace significantly reduced ankle and knee joint compressive forces at the time of peak ankle dorsiflexion (mean difference, 1.5 N/kg [ P = .018] and 1.4 N/kg [ P = .013], respectively). Additionally, the hinged ankle brace significantly reduced knee anterior shear forces compared with the lace-up brace both during the deceleration phase and at peak ankle dorsiflexion (mean difference, 0.8 N/kg [ P = .018] and 0.9 N/kg [ P = .011], respectively). The hinged ankle brace significantly reduced ankle inversion compared with the no-brace condition and reduced ankle and knee joint forces compared with the lace-up brace in a female

  15. Anterior ankle arthroscopy, distraction or dorsiflexion?

    PubMed

    de Leeuw, Peter A J; Golanó, Pau; Clavero, Joan A; van Dijk, C Niek

    2010-05-01

    Anterior ankle arthroscopy can basically be performed by two different methods; the dorsiflexion- or distraction method. The objective of this study was to determine the size of the anterior working area for both the dorsiflexion and distraction method. The anterior working area is anteriorly limited by the overlying anatomy which includes the neurovascular bundle. We hypothesize that in ankle dorsiflexion the anterior neurovascular bundle will move away anteriorly from the ankle joint, whereas in ankle distraction the anterior neurovascular bundle is pulled tight towards the joint, thereby decreasing the safe anterior working area. Six fresh frozen ankle specimens, amputated above the knee, were scanned with computed tomography. Prior to scanning the anterior tibial artery was injected with contrast fluid and subsequently each ankle was scanned both in ankle dorsiflexion and in distraction. A special device was developed to reproducibly obtain ankle dorsiflexion and distraction in the computed tomography scanner. The distance between the anterior border of the inferior tibial articular facet and the posterior border of the anterior tibial artery was measured. The median distance from the anterior border of the inferior tibial articular facet to the posterior border of the anterior tibial artery in ankle dorsiflexion and distraction was 0.9 cm (range 0.7-1.5) and 0.7 cm (range 0.5-0.8), respectively. The distance in ankle dorsiflexion significantly exceeded the distance in ankle distraction (P = 0.03). The current study shows a significantly increased distance between the anterior distal tibia and the overlying anterior neurovascular bundle with the ankle in a slightly dorsiflexed position as compared to the distracted ankle position. We thereby conclude that the distracted ankle position puts the neurovascular structures more at risk for iatrogenic damage when performing anterior ankle arthroscopy.

  16. Anterior ankle arthroscopy, distraction or dorsiflexion?

    PubMed Central

    Golanó, Pau; Clavero, Joan A.; van Dijk, C. Niek

    2010-01-01

    Anterior ankle arthroscopy can basically be performed by two different methods; the dorsiflexion- or distraction method. The objective of this study was to determine the size of the anterior working area for both the dorsiflexion and distraction method. The anterior working area is anteriorly limited by the overlying anatomy which includes the neurovascular bundle. We hypothesize that in ankle dorsiflexion the anterior neurovascular bundle will move away anteriorly from the ankle joint, whereas in ankle distraction the anterior neurovascular bundle is pulled tight towards the joint, thereby decreasing the safe anterior working area. Six fresh frozen ankle specimens, amputated above the knee, were scanned with computed tomography. Prior to scanning the anterior tibial artery was injected with contrast fluid and subsequently each ankle was scanned both in ankle dorsiflexion and in distraction. A special device was developed to reproducibly obtain ankle dorsiflexion and distraction in the computed tomography scanner. The distance between the anterior border of the inferior tibial articular facet and the posterior border of the anterior tibial artery was measured. The median distance from the anterior border of the inferior tibial articular facet to the posterior border of the anterior tibial artery in ankle dorsiflexion and distraction was 0.9 cm (range 0.7–1.5) and 0.7 cm (range 0.5–0.8), respectively. The distance in ankle dorsiflexion significantly exceeded the distance in ankle distraction (P = 0.03). The current study shows a significantly increased distance between the anterior distal tibia and the overlying anterior neurovascular bundle with the ankle in a slightly dorsiflexed position as compared to the distracted ankle position. We thereby conclude that the distracted ankle position puts the neurovascular structures more at risk for iatrogenic damage when performing anterior ankle arthroscopy. PMID:20217392

  17. Active ankle motion may result in changes to the talofibular interval in individuals with chronic ankle instability and ankle sprain copers: a preliminary study.

    PubMed

    Croy, Theodore; Cosby, Nicole L; Hertel, Jay

    2013-08-01

    Alterations in talocrural joint arthrokinematics related to repositioning of the talus or fibula following ankle sprain have been reported in radiological and clinical studies. It is unclear if these changes can result from normal active ankle motion. The study objective was to determine if active movement created changes in the sagittal plane talofibular interval in ankles with a history of lateral ankle sprain and instability. Three subject groups [control (n = 17), ankle sprain copers (n = 20), and chronic ankle instability (n = 20)] underwent ultrasound imaging of the anterolateral ankle gutter to identify the lateral malleolus and talus over three trials. Between trials, subjects actively plantar and dorsiflexed the ankle three times. The sagittal plane talofibular interval was assessed by measuring the anteroposterior distance (mm) between the lateral malleolus and talus from an ultrasound image. Between group and trial differences were analyzed with repeated measures analysis of variance and post-hoc t-tests. Fifty-seven subjects participated. A significant group-by-trial interaction was observed (F4,108 = 3.5; P = 0.009). The talofibular interval was increased in both copers [2.4±3.6 mm; 95% confidence interval (CI): 0.73-4.1; P = 0.007] and chronic ankle instability (4.1±4.6 mm; 95% CI: 1.9-6.2; P = 0.001) at trial 3 while no changes were observed in control ankle talar position (0.06±2.8mm; 95% CI: -1.5-1.4; P = 0.93). The talofibular interval increased only in subjects with a history of lateral ankle sprain with large clinical effect sizes observed. These findings suggest that an alteration in the position of the talus or fibula occurred with non-weight bearing sagittal plane motion. These findings may have diagnostic and therapeutic implications for manual therapists.

  18. Design and development of a novel viscoelastic ankle-foot prosthesis based on the human ankle biomechanics.

    PubMed

    Safaeepour, Zahra; Esteki, Ali; Tabatabai Ghomshe, Farhad; Mousavai, Mohammad E

    2014-10-01

    In the present study, a new approach was applied to design and develop a viscoelastic ankle-foot prosthesis. The aim was to replicate the intact ankle moment-angle loop in the normal walking speed. The moment-angle loop of intact ankle was divided into four parts, and the appropriate models including two viscoelastic units of spring-damper mechanism were considered to replicate the passive ankle dynamics. The developed prototype was then tested on a healthy subject with the amputee gait simulator. The result showed that prosthetic ankle moment-angle loop was similar to that of intact ankle with the distinct four periods. The findings suggest that the prototype successfully provided the human ankle passive dynamics. Therefore, the viscoelastic units could imitate the four periods of a normal gait. The novel viscoelastic foot prosthesis could provide natural ankle dynamics in a gait cycle. Applying simple but biomechanical approach is suggested in conception of new designs for prosthetic ankle-foot mechanisms. © The International Society for Prosthetics and Orthotics 2014.

  19. Effects of circumferential ankle pressure on ankle proprioception, stiffness, and postural stability: a preliminary investigation.

    PubMed

    You, Sung H; Granata, Kevin P; Bunker, Linda K

    2004-08-01

    Cross-sectional repeated-measures design. Determine the effects of circumferential ankle pressure (CAP) intervention on proprioceptive acuity, ankle stiffness, and postural stability. The application of CAP using braces, taping, and adaptive shoes or military boots is widely used to address chronic ankle instability (CAI). An underlying assumption is that the CAP intervention might improve ankle stability through increased proprioceptive acuity and stiffness in the ankle. METHOD AND MEASURES: A convenience sample of 10 subjects was recruited from the local university community and categorized according to proprioceptive acuity (high, low) and ankle stability (normal, CAI). Proprioceptive acuity was measured when blindfolded subjects were asked to accurately reproduce a self-selected target ankle position before and after the application of CAP. Proprioceptive acuity was determined in 5 different ankle joint position sense tests: neutral, inversion, eversion, plantar flexion, and dorsiflexion. Joint position angles were recorded electromechanically using a potentiometer. Passive ankle stiffness was computed from the ratio of applied static moment versus angular displacement. Active ankle stiffness was determined from biomechanical analyses of ankle motion following a mediolateral perturbation. Postural stability was quantified from the center of pressure displacement in the mediolateral and the anteroposterior directions in unipedal stance. All measurements were recorded with and without CAP applied by a pediatric blood pressure cuff. Data were analyzed using a separate mixed-model analysis of variance (ANOVA) for each dependent variable. Post hoc comparison using Tukey's honestly significant difference (HSD) test was performed if significant interactions were obtained. Significance level was set at P<.05 for all analyses. Significant group (high versus low proprioceptive acuity) x CAP interactions were identified for postural stability. Passive ankle stiffness was

  20. All-inside, anatomical lateral ankle stabilization for revision and complex primary lateral ankle stabilization: a technique guide.

    PubMed

    Prissel, Mark A; Roukis, Thomas S

    2014-12-01

    Lateral ankle instability is a common mechanical problem that often requires surgical management when conservative efforts fail. Historically, myriad open surgical approaches have been proposed. Recently, consideration for arthroscopic management of lateral ankle instability has become popular, with promising results. Unfortunately, recurrent inversion ankle injury following lateral ankle stabilization can occur and require revision surgery. To date, arthroscopic management for revision lateral ankle stabilization has not been described. We present a novel arthroscopic technique combining an arthroscopic lateral ankle stabilization kit with a suture anchor ligament augmentation system for revision as well as complex primary lateral ankle stabilization. © 2014 The Author(s).

  1. Transcutaneous electrical nerve stimulation combined with task-related training improves lower limb functions in subjects with chronic stroke.

    PubMed

    Ng, Shamay S M; Hui-Chan, Christina W Y

    2007-11-01

    Previous studies have shown that repeated sensory inputs could enhance brain plasticity and cortical motor output. The purpose of this study was to investigate whether combining electrically induced sensory inputs through transcutaneous electrical nerve stimulation (TENS) with task-related training (TRT) in a home-based program would augment voluntary motor output in chronic stroke survivors better than either treatment alone or no treatment. Eighty-eight patients with stroke were assigned randomly to receive a home-based program of (1) TENS, (2) TENS+TRT, (3) placebo TENS+TRT, or (4) no treatment (control) 5 days a week for 4 weeks. Outcome measurements included Composite Spasticity Scale, peak torques generated during maximum isometric voluntary contraction of ankle dorsiflexors and plantarflexors, and gait velocity recorded at baseline, after 2 and 4 weeks of treatment, and 4 weeks after treatment ended. When compared with TENS, the combined TENS+TRT group showed significantly greater improvement in ankle dorsiflexion torque at follow-up and in ankle plantarflexion torque at week 2 and follow-up (P<0.01). When compared with placebo+TRT, the TENS+TRT group produced earlier and greater reduction of plantarflexor spasticity and improvement in ankle dorsiflexion torque at week 2 (P<0.01). When compared with all 3 groups, the TENS+TRT group showed significantly greater improvement in gait velocity (P<0.01). In patients with chronic stroke, 20 sessions of a combined TENS+TRT home-based program decreased plantarflexor spasticity, improved dorsiflexor and plantarflexor strength, and increased gait velocity significantly more than TENS alone, placebo+TRT, or no treatment. Such improvements can even be maintained 4 weeks after treatment ended.

  2. Anterior ankle impingement syndromes.

    PubMed

    Umans, Hilary R; Cerezal, Luiz

    2008-06-01

    Ankle impingement syndromes are painful conditions that may complicate ankle trauma and are characterized by chronic, progressive pain, swelling, and limitation of movement. These disorders are subclassified according to anatomical location about the tibiotalar joint. This article reviews the various forms of anterior ankle impingement, detailing the unique clinical features, anatomical considerations, pathoetiology, and imaging findings for each.

  3. Cross-talk between IGF-1 and estrogen receptors attenuates intracellular changes in ventral spinal cord 4.1 motoneuron cells due to interferon-gamma exposure

    PubMed Central

    Park, Sookyoung; Nozaki, Kenkichi; Smith, Joshua A.; Krause, James S.; Banik, Naren L.

    2014-01-01

    Insulin-like growth factor-1 (IGF-1) is a neuroprotective growth factor that promotes neuronal survival by inhibition of apoptosis. In order to examine whether IGF-1 exerts cytoprotective effects against extracellular inflammatory stimulation, ventral spinal cord 4.1 (VSC4.1) motoneuron cells were treated with interferon-gamma (IFN-γ). Our data demonstrated apoptotic changes, increased calpain:calpastatin and Bax:Bcl-2 ratios, and expression of apoptosis related proteases (caspase-3 and −12) in motoneurons rendered by IFN-γ in a dose-dependent manner. Post-treatment with IGF-1 attenuated these changes. In addition, IGF-1 treatment of motoneurons exposed to IFN-γ decreased expression of inflammatory markers (cyclooxygenase-2 and nuclear factor-kappa B:inhibitor of kappa B ratio). Furthermore, IGF-1 attenuated the loss of expression of IGF-1 receptors (IGF-1Rα and IGF-1Rβ) and estrogen receptors (ERα and ERβ) induced by IFN-γ. To determine whether the protective effects of IGF-1 are associated with ERs, ERs antagonist ICI and selective siRNA targeted against ERα and ERβ were used in VSC4.1 motoneurons. Distinctive morphological changes were observed following siRNA knockdown of ERα and ERβ. In particular, apoptotic cell death assessed by TUNEL assay was enhanced in both ERα and ERβ-silenced VSC4.1 motoneurons following IFN-γ and IGF-1 exposure. These results suggest that IGF-1 protects motoneurons from inflammatory insult by a mechanism involving pivotal interactions with ERα and ERβ. PMID:24188094

  4. An uncommon ankle sprain

    PubMed Central

    van Zoest, Wart J F; Janssen, Rob P A; Tseng, Carroll M E S

    2007-01-01

    Objective Ankle sprain is the most frequently occurring acute injury in tennis, accounting for 20–25% of all injuries. In the current paper, we assess the cause of ankle sprain and suggest possibilities to be considered during diagnosis. Methods We assessed a professional tennis player with a partial tear of the long peroneal tendon after an ankle sprain by physical exam, X‐ray and MRI. Results Conservative treatment by means of soft cast and propriocepsis training led to full recovery. Conclusion Peroneal tendon disorders must be part of the differential diagnosis after ankle sprain in the professional athlete. PMID:17957026

  5. Astrocytes expressing mutant SOD1 and TDP43 trigger motoneuron death that is mediated via sodium channels and nitroxidative stress

    PubMed Central

    Rojas, Fabiola; Cortes, Nicole; Abarzua, Sebastian; Dyrda, Agnieszka; van Zundert, Brigitte

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disorder caused by dysfunction and degeneration of motor neurons. Multiple disease-causing mutations, including in the genes for SOD1 and TDP-43, have been identified in ALS. Astrocytes expressing mutant SOD1 are strongly implicated in the pathogenesis of ALS: we have shown that media conditioned by astrocytes carrying mutant SOD1G93A contains toxic factor(s) that kill motoneurons by activating voltage-sensitive sodium (Nav) channels. In contrast, a recent study suggests that astrocytes expressing mutated TDP43 contribute to ALS pathology, but do so via cell-autonomous processes and lack non-cell-autonomous toxicity. Here we investigate whether astrocytes that express diverse ALS-causing mutations release toxic factor(s) that induce motoneuron death, and if so, whether they do so via a common pathogenic pathway. We exposed primary cultures of wild-type spinal cord cells to conditioned medium derived from astrocytes (ACM) that express SOD1 (ACM-SOD1G93A and ACM-SOD1G86R) or TDP43 (ACM-TDP43A315T) mutants; we show that such exposure rapidly (within 30–60 min) increases dichlorofluorescein (DCF) fluorescence (indicative of nitroxidative stress) and leads to extensive motoneuron-specific death within a few days. Co-application of the diverse ACMs with anti-oxidants Trolox or esculetin (but not with resveratrol) strongly improves motoneuron survival. We also find that co-incubation of the cultures in the ACMs with Nav channel blockers (including mexiletine, spermidine, or riluzole) prevents both intracellular nitroxidative stress and motoneuron death. Together, our data document that two completely unrelated ALS models lead to the death of motoneuron via non-cell-autonomous processes, and show that astrocytes expressing mutations in SOD1 and TDP43 trigger such cell death through a common pathogenic pathway that involves nitroxidative stress, induced at least in part by Nav channel activity. PMID:24570655

  6. Ankle ligament healing after an acute ankle sprain: an evidence-based approach.

    PubMed

    Hubbard, Tricia J; Hicks-Little, Charlie A

    2008-01-01

    To perform a systematic review to determine the healing time of the lateral ankle ligaments after an acute ankle sprain. We identified English-language research studies from 1964 to 2007 by searching MEDLINE, Physiotherapy Evidence Database (PEDro), SportDiscus, and CINAHL using the terms ankle sprain, ankle rehabilitation, ankle injury, ligament healing, and immobilization. We selected studies that described randomized, controlled clinical trials measuring ligament laxity either objectively or subjectively immediately after injury and at least 1 more time after injury. Two reviewers independently scored the 7 studies that met the inclusion criteria. Because of differences in study designs, a meta-analysis could not be performed. Effect sizes and confidence intervals could be calculated only for 1 study. The percentages of subjective and objective instability were calculated for the remaining studies. Ankle laxity improved over a period of 6 weeks to 1 year. One author showed stress talar tilt values of 16.10 +/- 8.8 degrees immediately after injury and 3.4 +/- 3.6 degrees at 3 months after injury. In 2 articles, the authors reported that positive anterior drawer tests were still present in 3% to 31% of participants at 6 months after injury. Additionally, feelings of instability affected 7% to 42% of participants up to 1 year after injury. In the studies that we examined, it took at least 6 weeks to 3 months before ligament healing occurred. However, at 6 weeks to 1 year after injury, a large percentage of participants still had objective mechanical laxity and subjective ankle instability. Direct comparison among articles is difficult because of differences in methods. More research focusing on more reliable methods of measuring ankle laxity is needed so that clinicians can know how long ligament healing takes after injury. This knowledge will help clinicians to make better decisions during rehabilitation and for return to play.

  7. Chronic musculoskeletal ankle disorders in Sri Lanka.

    PubMed

    Weerasekara, Ishanka; Hiller, Claire E

    2017-05-25

    Musculoskeletal disorders of the lower extremities are commonly affected by chronicity and disability. One of the most commonly affected areas is the ankle. Epidemiological information is limited for chronic musculoskeletal ankle disorders in the general community, particularly in the developing world. This study aimed to determine the prevalence and impact of chronic musculoskeletal ankle disorders in the Sri Lankan community. A cross-sectional stratified random sample of people (n = 1000) aged 18 to 85 years in Sri Lanka was undertaken by questionnaire in the general community setting. Of those questionnaires, 827 participants provided data. Point prevalence for no history of ankle injury or ankle disorders, history of ankle injuries without chronic ankle disorders, and chronic ankle disorders were obtained. Point prevalence of chronic musculoskeletal disorders and causes for chronicity was evaluated. There were 448 (54.2%) participants with no ankle disorders, 164 (19.8%) with a history of ankle injury but no chronic disorders, and 215 (26.0%) with chronic ankle disorders. The major component of chronic ankle disorders was musculoskeletal disorders (n = 113, 13.7% of the total sample), most of which were due to ankle injury (n = 80, 9.7% of the total). Sprains were responsible for 17.7% of the total ankle injuries. Arthritis was the other main cause for chronicity of ankle disorders with 4% of total participants (n = 33). Almost 14% of the Sri Lankan community was affected by chronic musculoskeletal ankle disorders. The majority were due to a previous ankle injury, and arthritis. Most people had to limit or change their physical activity because of the chronic ankle disorder. A very low utility of physiotherapy services was observed.

  8. Total ankle arthroplasty versus ankle arthrodesis. Comparison of sports, recreational activities and functional outcome.

    PubMed

    Schuh, Reinhard; Hofstaetter, Jochen; Krismer, Martin; Bevoni, Roberto; Windhager, Reinhard; Trnka, Hans-Joerg

    2012-06-01

    Ankle arthrodesis (AAD) and total ankle replacement (TAR) are the major surgical treatment options for severe ankle arthritis. There is an ongoing discussion in the orthopaedic community whether ankle arthrodesis or ankle fusion should be the treatment of choice for end stage osteoarthritis. The purpose of this study was to compare the participation in sports and recreational activities in patients who underwent either AAD or TAR for end-stage osteoarthritis of the ankle. A total of 41 patients (21 ankle arthrodesis /20 TAR) were examined at 34.5 (SD18.0) months after surgery. At follow-up, pre- and postoperative participation in sports and recreational activities has been assessed. Activity levels were determined using the ankle activity score according to Halasi et al. and the University of California at Los Angeles (UCLA) activity scale. Clinical and functional outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. The percentage of patients participating in sports and recreational activities, UCLA score and AOFAS score were compared between both treatment groups. In the AAD group 86% were active in sports preoperatively and in the TAR group this number was 76%. Postoperatively in both groups 76% were active in sports (AAD, p = 0.08). The UCLA score was 7.0 (± 1.9) in the AAD group and 6.8 (± 1.8) in the TAR group (p = 0.78). The AOFAS score reached 75.6 (± 14) in the AAD group and 75.6 (± 16) in the TAR group (p = 0.97). The ankle activity score decrease was statistically significant for both groups (p = 0.047). Our study revealed no significant difference between the groups concerning activity levels, participation in sports activities, UCLA and AOFAS score. After AAD the number of patients participating in sports decreased. However, this change was not statistically significant.

  9. Anterior ankle arthrodesis

    PubMed Central

    Slater, Gordon L; Sayres, Stephanie C; O’Malley, Martin J

    2014-01-01

    Ankle arthrodesis is a common procedure that resolves many conditions of the foot and ankle; however, complications following this procedure are often reported and vary depending on the fixation technique. Various techniques have been described in the attempt to achieve ankle arthrodesis and there is much debate as to the efficiency of each one. This study aims to evaluate the efficiency of anterior plating in ankle arthrodesis using customised and Synthes TomoFix plates. We present the outcomes of 28 ankle arthrodeses between 2005 and 2012, specifically examining rate of union, patient-reported outcomes scores, and complications. All 28 patients achieved radiographic union at an average of 36 wk; the majority of patients (92.86%) at or before 16 wk, the exceptions being two patients with Charcot joints who were noted to have bony union at a three year review. Patient-reported outcomes scores significantly increased (P < 0.05). Complications included two delayed unions as previously mentioned, infection, and extended postoperative pain. With multiple points for fixation and coaxial screw entry points, the contoured customised plate offers added compression and provides a rigid fixation for arthrodesis stabilization. PMID:24649408

  10. The morphology and electrical geometry of rat jaw-elevator motoneurones.

    PubMed Central

    Moore, J A; Appenteng, K

    1991-01-01

    1. The aim of this work was to quantify both the morphology and electrical geometry of the dendritic trees of jaw-elevator motoneurones. To do this we have made intracellular recordings from identified motoneurones in anaesthetized rats, determined their membrane properties and then filled them with horseradish peroxidase by ionophoretic ejection. Four neurones were subsequently fully reconstructed and the lengths and diameters of all the dendritic segments measured. 2. The mean soma diameter was 25 microns and values of mean dendritic length for individual cells ranged from 514 to 773 microns. Dendrites branched on average 9.1 times to produce 10.2 end-terminations. Dendritic segments could be represented as constant diameter cylinders between branch points. Values of dendritic surface area ranged from 1.08 to 2.52 x 10(5) microns 2 and values of dendritic to total surface area from 98 to 99%. 3. At branch points the ratio of the summed diameters of the daughter dendrites to the 3/2 power against the parent dendrite to the 3/2 power was exactly 1.0. Therefore the individual branch points could be collapsed into a single cylinder. Furthermore for an individual dendrite the diameter of this cylinder remained constant with increasing electrical distance from the soma. Thus individual dendrites can be represented electrically as cylinders of constant diameter. 4. However dendrites of a given neurone terminated at different electrical distances from the soma. The equivalent-cylinder diameter of the combined dendritic tree remained constant over the proximal half and then showed a pronounced reduction over the distal half. The reduction in equivalent diameter could be ascribed to the termination of dendrites at differing electrical distances from the soma. Therefore the complete dendritic tree of these motoneurones is best represented as a cylinder over the proximal half of their electrical length but as a cone over the distal half. PMID:1804966

  11. Ankle Sprains. A Round Table.

    ERIC Educational Resources Information Center

    Physician and Sportsmedicine, 1986

    1986-01-01

    Types of ankle sprains, surgical versus nonsurgical treatment, tape versus brace for support, rehabilitation, exercise, and prevention of ankle sprains are discussed by a panel of experts. An acute ankle taping technique is illustrated. (MT)

  12. Role of Ankle Arthroscopy in Management of Acute Ankle Fracture.

    PubMed

    Chan, Kwok Bill; Lui, Tun Hing

    2016-11-01

    To report the operative findings of ankle arthroscopy during open reduction and internal fixation of acute ankle fractures. This was a retrospective review of 254 consecutive patients with acute ankle fractures who were treated with open reduction and internal fixation of the fractures, and ankle arthroscopy was performed at the same time. The accuracy of fracture reduction, the presence of syndesmosis disruption and its reduction, and the presence of ligamentous injuries and osteochondral lesions were documented. Second-look ankle arthroscopy was performed during syndesmosis screw removal 6 weeks after the key operation. There were 6 patients with Weber A, 177 patients with Weber B, 51 patients with Weber C, and 20 patients with isolated medial malleolar fractures. Syndesmosis disruption was present in 0% of patients with Weber A fracture, 52% of patients with Weber B fracture, 92% of patients with Weber C fracture, and 20% of the patients with isolated medial malleolar fracture. Three patients with Weber B and one patient with Weber C fracture have occult syndesmosis instability after screw removal. Osteochondral lesion was present in no patient with Weber A fracture, 26% of the Weber B cases, 24% of the Weber C cases, and 20% of isolated medial malleolar fracture cases. The association between the presence of deep deltoid ligament tear and syndesmosis disruption (warranting syndesmosis screw fixation) in Weber B cases was statistically significant but not in Weber C cases. There was no statistically significant association between the presence of posterior malleolar fracture and syndesmosis instability that warrant screw fixation. Ankle arthroscopy is a useful adjuvant tool to understand the severity and complexity of acute ankle fracture. Direct arthroscopic visualization ensures detection and evaluation of intra-articular fractures, syndesmosis disruption, and associated osteochondral lesions and ligamentous injuries. Level IV, case series

  13. Active ankle motion may result in changes to the talofibular interval in individuals with chronic ankle instability and ankle sprain copers: a preliminary study

    PubMed Central

    Croy, Theodore; Cosby, Nicole L; Hertel, Jay

    2013-01-01

    Introduction: Alterations in talocrural joint arthrokinematics related to repositioning of the talus or fibula following ankle sprain have been reported in radiological and clinical studies. It is unclear if these changes can result from normal active ankle motion. The study objective was to determine if active movement created changes in the sagittal plane talofibular interval in ankles with a history of lateral ankle sprain and instability. Methods: Three subject groups [control (n = 17), ankle sprain copers (n = 20), and chronic ankle instability (n = 20)] underwent ultrasound imaging of the anterolateral ankle gutter to identify the lateral malleolus and talus over three trials. Between trials, subjects actively plantar and dorsiflexed the ankle three times. The sagittal plane talofibular interval was assessed by measuring the anteroposterior distance (mm) between the lateral malleolus and talus from an ultrasound image. Between group and trial differences were analyzed with repeated measures analysis of variance and post-hoc t-tests. Results: Fifty-seven subjects participated. A significant group-by-trial interaction was observed (F4,108 = 3.5; P = 0.009). The talofibular interval was increased in both copers [2.4±3.6 mm; 95% confidence interval (CI): 0.73–4.1; P = 0.007] and chronic ankle instability (4.1±4.6 mm; 95% CI: 1.9–6.2; P = 0.001) at trial 3 while no changes were observed in control ankle talar position (0.06±2.8mm; 95% CI: −1.5–1.4; P = 0.93). Discussion: The talofibular interval increased only in subjects with a history of lateral ankle sprain with large clinical effect sizes observed. These findings suggest that an alteration in the position of the talus or fibula occurred with non-weight bearing sagittal plane motion. These findings may have diagnostic and therapeutic implications for manual therapists. PMID:24421623

  14. Robust and accurate decoding of motoneuron behavior and prediction of the resulting force output.

    PubMed

    Thompson, Christopher K; Negro, Francesco; Johnson, Michael D; Holmes, Matthew R; McPherson, Laura Miller; Powers, Randall K; Farina, Dario; Heckman, Charles J

    2018-05-03

    The spinal alpha motoneuron is the only cell in the human CNS whose discharge can be routinely recorded in humans. We have reengineered motor unit collection and decomposition approaches, originally developed in humans, to measure the neural drive to muscle and estimate muscle force generation in the decerebrate cat model. Experimental, computational, and predictive approaches are used to demonstrate the validity of this approach across a wide range of modes to activate the motor pool. The utility of this approach is shown through the ability to track individual motor units across trials, allowing for better predictions of muscle force than the electromyography signal, and providing insights in to the stereotypical discharge characteristics in response to synaptic activation of the motor pool. This approach now allows for a direct link between the intracellular data of single motoneurons, the discharge properties of motoneuron populations, and muscle force generation in the same preparation. The discharge of a spinal alpha motoneuron and the resulting contraction of its muscle fibers represents the functional quantum of the motor system. Recent advances in the recording and decomposition of the electromyographic signal allows for the identification of several tens of concurrently active motor units. These detailed population data provide the potential to achieve deep insights into the synaptic organization of motor commands. Yet most of our understanding of the synaptic input to motoneurons is derived from intracellular recordings in animal preparations. Thus, it is necessary to extend the new electrode and decomposition methods to recording of motor unit populations in these same preparations. To achieve this goal, we use high-density electrode arrays and decomposition techniques, analogous to those developed for humans, to record and decompose the activity of tens of concurrently active motor units in a hindlimb muscle in the decerebrate cat. Our results showed

  15. Transfibular ankle arthrodesis: A novel method for ankle fusion – A short term retrospective study

    PubMed Central

    Balaji, S Muthukumar; Selvaraj, V; Devadoss, Sathish; Devadoss, Annamalai

    2017-01-01

    Background: Ankle arthrodesis has long been the traditional operative treatment for posttraumatic arthritis, rheumatoid arthritis, infection, neuromuscular conditions, and salvage of failed ankle arthroplasty. It remains the treatment of choice for patients in whom heavy and prolonged activity is anticipated. We present our short term followup study of functional outcome of patients who underwent transfibular ankle arthrodesis for arthritis of ankle due to various indications. Materials and Methods: 29 transfibular ankle arthrodesis in 29 patients performed between April 2009 and April 2014 were included in this study. The mean age was 50 years (range 22-75 years). The outcome analysis with a minimum of 1-year postoperative followup were included. All the patients were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) Hindfoot scale. Results: All cases of ankle fusions (100%) progressed to solid union in a mean postoperative duration of 3.8 months (range 3–6 months). All patients had sound arthrodesis. The mean followup period was 32.52 months (standard deviation ± 10.34). The mean AOFAS score was 74 (pain score = 32, functional score = 42). We found that twenty patients (68.96%) out of 29, had excellent results, 7 (24.13%) had good, and 2 (6.89%) showed fair results. Conclusion: Transfibular ankle arthrodesis is a simple and effective procedure for ankle arthritis. It achieves a high rate of union and good functional outcome on midterm followup. PMID:28216754

  16. Cross-talk between IGF-1 and estrogen receptors attenuates intracellular changes in ventral spinal cord 4.1 motoneuron cells because of interferon-gamma exposure.

    PubMed

    Park, Sookyoung; Nozaki, Kenkichi; Smith, Joshua A; Krause, James S; Banik, Naren L

    2014-03-01

    Insulin-like growth factor-1 (IGF-1) is a neuroprotective growth factor that promotes neuronal survival by inhibition of apoptosis. To examine whether IGF-1 exerts cytoprotective effects against extracellular inflammatory stimulation, ventral spinal cord 4.1 (VSC4.1) motoneuron cells were treated with interferon-gamma (IFN-γ). Our data demonstrated apoptotic changes, increased calpain:calpastatin and Bax:Bcl-2 ratios, and expression of apoptosis-related proteases (caspase-3 and -12) in motoneurons rendered by IFN-γ in a dose-dependent manner. Post-treatment with IGF-1 attenuated these changes. In addition, IGF-1 treatment of motoneurons exposed to IFN-γ decreased expression of inflammatory markers (cyclooxygenase-2 and nuclear factor-kappa B:inhibitor of kappa B ratio). Furthermore, IGF-1 attenuated the loss of expression of IGF-1 receptors (IGF-1Rα and IGF-1Rβ) and estrogen receptors (ERα and ERβ) induced by IFN-γ. To determine whether the protective effects of IGF-1 are associated with ERs, ERs antagonist ICI and selective siRNA targeted against ERα and ERβ were used in VSC4.1 motoneurons. Distinctive morphological changes were observed following siRNA knockdown of ERα and ERβ. In particular, apoptotic cell death assessed by TUNEL assay was enhanced in both ERα and ERβ-silenced VSC4.1 motoneurons following IFN-γ and IGF-1 exposure. These results suggest that IGF-1 protects motoneurons from inflammatory insult by a mechanism involving pivotal interactions with ERα and ERβ. © 2013 International Society for Neurochemistry.

  17. Spring-like Ankle Foot Orthoses reduce the energy cost of walking by taking over ankle work.

    PubMed

    Bregman, D J J; Harlaar, J; Meskers, C G M; de Groot, V

    2012-01-01

    In patients with central neurological disorders, gait is often limited by a reduced ability to push off with the ankle. To overcome this reduced ankle push-off, energy-storing, spring-like carbon-composite Ankle Foot Orthoses (AFO) can be prescribed. It is expected that the energy returned by the AFO in late stance will support ankle push-off, and reduce the energy cost of walking. In 10 patients with multiple sclerosis and stroke the energy cost of walking, 3D kinematics, joint power, and joint work were measured during gait, with and without the AFO. The mechanical characteristics of the AFO were measured separately, and used to calculate the contribution of the AFO to the ankle kinetics. We found a significant decrease of 9.8% in energy cost of walking when walking with the AFO. With the AFO, the range of motion of the ankle was reduced by 12.3°, and the net work around the ankle was reduced by 29%. The total net work in the affected leg remained unchanged. The AFO accounted for 60% of the positive ankle work, which reduced the total amount of work performed by the leg by 11.1% when walking with the AFO. The decrease in energy cost when walking with a spring-like energy-storing AFO in central neurological patients is not induced by an augmented net ankle push-off, but by the AFO partially taking over ankle work. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. The improvement of postural control in patients with mechanical ankle instability after lateral ankle ligaments reconstruction.

    PubMed

    Li, Hong-Yun; Zheng, Jie-Jiao; Zhang, Jian; Cai, Ye-Hua; Hua, Ying-Hui; Chen, Shi-Yi

    2016-04-01

    Lateral ankle sprain is the most common injury. A previous study demonstrated that patients with mechanical ankle instability suffered deficits in postural control, indicating that structural damage of the lateral ankle ligaments may produce a balance deficit. The purpose of this study was to confirm that lateral ligaments reconstruction could improve postural control in patients with mechanical ankle instability. A total of 15 patients were included in the study. Each patient had a history of an ankle sprain with persistent symptoms of ankle instability and a positive anterior drawer test and had been treated nonoperatively for at least 3 months. All patients were diagnosed with lateral ankle ligaments tear by ultrasonography and magnetic resonance imaging. They underwent arthroscopic debridement and open lateral ankle ligaments reconstruction with a modified Broström procedure. One day before and 6 months after the operation, all of the participants underwent single-limb postural sway tests. The anterior drawer test and the American Orthopedic Foot and Ankle Society scale score were used to evaluate the clinical results in these patients. At 6 months after the operation, with the patients' eyes closed, there was significantly decreased postural sway in the anteroposterior direction, the circumferential area, and the total path length on the operated ankles compared with those measurements before the operation. With eyes open, however, no difference was found in postural sway before and after the operation. Postural control was improved by reconstructing the lateral ligaments. IV.

  19. Reorganization of laryngeal motoneurons after crush injury in the recurrent laryngeal nerve of the rat

    PubMed Central

    Hernández-Morato, Ignacio; Valderrama-Canales, Francisco J; Berdugo, Gabriel; Arias, Gonzalo; McHanwell, Stephen; Sañudo, José; Vázquez, Teresa; Pascual-Font, Arán

    2013-01-01

    Motoneurons innervating laryngeal muscles are located in the nucleus ambiguus (Amb), but there is no general agreement on the somatotopic representation and even less is known on how an injury in the recurrent laryngeal nerve (RLN) affects this pattern. This study analyzes the normal somatotopy of those motoneurons and describes its changes over time after a crush injury to the RLN. In the control group (control group 1, n = 9 rats), the posterior cricoarytenoid (PCA) and thyroarytenoid (TA) muscles were injected with cholera toxin-B. In the experimental groups the left RLN of each animal was crushed with a fine tip forceps and, after several survival periods (1, 2, 4, 8, 12 weeks; minimum six rats per time), the PCA and TA muscles were injected as described above. After each surgery, the motility of the vocal folds was evaluated. Additional control experiments were performed; the second control experiment (control group 2, n = 6 rats) was performed labeling the TA and PCA immediately prior to the section of the superior laryngeal nerve (SLN), in order to eliminate the possibility of accidental labeling of the cricothyroid (CT) muscle by spread from the injection site. The third control group (control group 3, n = 5 rats) was included to determine if there is some sprouting from the SLN into the territories of the RLN after a crush of this last nerve. One week after the crush injury of the RLN, the PCA and TA muscles were injected immediately before the section of the SLN. The results show that a single population of neurons represents each muscle with the PCA in the most rostral position followed caudalwards by the TA. One week post-RLN injury, both the somatotopy and the number of labeled motoneurons changed, where the labeled neurons were distributed randomly; in addition, an area of topographical overlap of the two populations was observed and vocal fold mobility was lost. In the rest of the survival periods, the overlapping area is larger, but the movement of

  20. Properties of synaptic transmission from the reticular formation dorsal to the facial nucleus to trigeminal motoneurons during early postnatal development in rats.

    PubMed

    Gemba-Nishimura, A; Inoue, T; Nakamura, S; Nakayama, K; Mochizuki, A; Shintani, S; Yoshimura, S

    2010-03-31

    We previously reported that electrical stimulation of the reticular formation dorsal to the facial nucleus (RdVII) elicited excitatory masseter responses at short latencies and that RdVII neurons were antidromically activated by stimulation of the trigeminal motor nucleus (MoV), suggesting that excitatory premotor neurons targeting the MoV are likely located in the RdVII. We thus examined the properties of synaptic transmission from the RdVII to jaw-closing and jaw-opening motoneurons in horizontal brainstem preparations from developing rats using voltage-sensitive dye, patch-clamp recordings and laser photostimulation. Electrical stimulation of the RdVII evoked optical responses in the MoV. Combined bath application of the non-N-methyl-d-aspartate (non-NMDA) receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and the NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (APV) reduced these optical responses, and addition of the glycine receptor antagonist strychnine and the GABA(A) receptor antagonist bicuculline further reduced the remaining responses. Electrical stimulation of the RdVII evoked postsynaptic currents (PSCs) in all 19 masseter motoneurons tested in postnatal day (P)1-4 rats, and application of CNQX and the NMDA receptor antagonist (+/-)-3(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) reduced the PSC amplitudes by more than 50%. In the presence of CNQX and CPP, the GABA(A) receptor antagonist SR95531 further reduced PSC amplitude, and addition of strychnine abolished the remaining PSCs. Photostimulation of the RdVII with caged glutamate also evoked PSCs in masseter motoneurons of P3-4 rats. In P8-11 rats, electrical stimulation of the RdVII also evoked PSCs in all 14 masseter motoneurons tested, and the effects of the antagonists on the PSCs were similar to those in P1-4 rats. On the other hand, RdVII stimulation evoked PSCs in only three of 16 digastric motoneurons tested. These results suggest that both neonatal and

  1. Acute ankle sprain in dancers.

    PubMed

    Russell, Jeffrey A

    2010-01-01

    Ankle sprain is a common injury in dancers. Because of the relative frequency of this injury and its wide acceptance as a likely part of an active lifestyle, in many individuals it may not receive the careful attention it deserves. An extreme ankle range of motion and excellent ankle stability are fundamental to success in dance. Hence, following a proper treatment protocol is crucial for allowing a dancer who suffers an ankle sprain to return to dance as soon as possible without impaired function. This article reviews the basic principles of the etiology and management of ankle sprain in dancers. Key concepts are on-site examination and treatment, early restoration, dance-specific rehabilitation, and a carefully administered safe return to dance. Additionally, injuries that may occur in conjunction with ankle sprain are highlighted, and practical, clinically relevant summary concepts for dance healthcare professionals, dance scientists, dance teachers, and dancers are provided.

  2. Comparison of Multisegmental Foot and Ankle Motion Between Total Ankle Replacement and Ankle Arthrodesis in Adults.

    PubMed

    Seo, Sang Gyo; Kim, Eo Jin; Lee, Doo Jae; Bae, Kee Jeong; Lee, Kyoung Min; Lee, Dong Yeon

    2017-09-01

    Total ankle replacement (TAR) and ankle arthrodesis (AA) are usually performed for severe ankle arthritis. We compared postoperative foot segmental motion during gait in patients treated with TAR and AA. Gait analysis was performed in 17 and 7 patients undergoing TAR and AA, respectively. Subjects were evaluated using a 3-dimensional multisegmental foot model with 15 markers. Temporal gait parameters were calculated. The maximum and minimum values and the differences in hallux, forefoot, hindfoot, and arch in 3 planes (sagittal, coronal, transverse) were compared between the 2 groups. One hundred healthy adults were evaluated as a control. Gait speed was faster in the TAR ( P = .028). On analysis of foot and ankle segmental motion, the range of hindfoot sagittal motion was significantly greater in the TAR (15.1 vs 10.2 degrees in AA; P = .004). The main component of motion increase was hindfoot dorsiflexion (12.3 and 8.6 degrees). The range of forefoot sagittal motion was greater in the TAR (9.3 vs 5.8 degrees in AA; P = .004). Maximum ankle power in the TAR (1.16) was significantly higher than 0.32 in AA; P = .008). However, the range of hindfoot and forefoot sagittal motion was decreased in both TAR and AA compared with the control group ( P = .000). Although biomechanical results of TAR and AA were not similar to those in the normal controls, joint motions in the TAR more closely matched normal values. Treatment decision making should involve considerations of the effect of surgery on the adjacent joints. Level III, case-control study.

  3. [Ankle arthrodesis with interposition graft as a salvage procedure after failed total ankle replacement].

    PubMed

    Schill, Stephan

    2007-12-01

    Restoration of painless function to the lower limb by ankle fusion after failure of total ankle arthroplasty. Loose total ankle replacement. Severe ankle destruction and axial deviation in rheumatoid patients. Severe osteoarthritis in the subtalar and ankle joints. Infected total ankle replacement. Severe arterial occlusive disease of the affected extremity. Transfibular approach to the subtalar and ankle joints. Osteotomy and resection of the distal fibula 7-8 cm proximal to the tip of the lateral malleolus. Removal of the prosthetic components, synovectomy, and revitalization of the remaining bone surface. Removal of any residual articular cartilage from the subtalar joint surfaces. Determination of the extent of bone loss and defect filling with horizontally or vertically placed tricortical and cancellous bone graft from the resected fibula and, if necessary, from the ipsilateral anterior iliac crest. Tibiotalocalcaneal arthrodesis by retrograde insertion of a retrograde locking nail. Wound closure in layers. Split below-knee cast. Mobilization with below-knee cast without weight bearing for 6 weeks. Dynamic locking of the intramedullary nail. Partial weight bearing with a walker up to 20 kg for an additional 6 weeks. Gradual increase in weight bearing in accordance with radiologic evidence of consolidation. Fitted orthopedic shoe with rocker-bottom sole, and made to measure insoles. From January 2003 to September 2006, 15 patients with infected ankle prosthesis loosening (six Thompson-Richards prostheses, eight S.T.A.R. prostheses, and one Salto prosthesis) were treated. All patients underwent tibiotalocalcaneal interposition arthrodesis with femoral nailing in retrograde technique. The average AOFAS (American Orthopaedic Foot and Ankle Society) Score was 57.9 points (35-81 points) postoperatively. One patient developed a nonunion and revision surgery will have to be performed. Another patient with delayed wound healing and skin necrosis needed plastic surgery.

  4. Altered knee and ankle kinematics during squatting in those with limited weight-bearing-lunge ankle-dorsiflexion range of motion.

    PubMed

    Dill, Karli E; Begalle, Rebecca L; Frank, Barnett S; Zinder, Steven M; Padua, Darin A

    2014-01-01

    Ankle-dorsiflexion (DF) range of motion (ROM) may influence movement variables that are known to affect anterior cruciate ligament loading, such as knee valgus and knee flexion. To our knowledge, researchers have not studied individuals with limited or normal ankle DF-ROM to investigate the relationship between those factors and the lower extremity movement patterns associated with anterior cruciate ligament injury. To determine, using 2 different measurement techniques, whether knee- and ankle-joint kinematics differ between participants with limited and normal ankle DF-ROM. Cross-sectional study. Sports medicine research laboratory. Forty physically active adults (20 with limited ankle DF-ROM, 20 with normal ankle DF-ROM). Ankle DF-ROM was assessed using 2 techniques: (1) nonweight-bearing ankle DF-ROM with the knee straight, and (2) weight-bearing lunge (WBL). Knee flexion, knee valgus-varus, knee internal-external rotation, and ankle DF displacements were assessed during the overhead-squat, single-legged squat, and jump-landing tasks. Separate 1-way analyses of variance were performed to determine whether differences in knee- and ankle-joint kinematics existed between the normal and limited groups for each assessment. We observed no differences between the normal and limited groups when classifying groups based on nonweight-bearing passive-ankle DF-ROM. However, individuals with greater ankle DF-ROM during the WBL displayed greater knee-flexion and ankle-DF displacement and peak knee flexion during the overhead-squat and single-legged squat tasks. In addition, those individuals also demonstrated greater knee-varus displacement during the single-legged squat. Greater ankle DF-ROM assessed during the WBL was associated with greater knee-flexion and ankle-DF displacement during both squatting tasks as well as greater knee-varus displacement during the single-legged squat. Assessment of ankle DF-ROM using the WBL provided important insight into compensatory

  5. Prospective Computed Tomographic Analysis of Osteochondral Lesions of the Ankle Joint Associated With Ankle Fractures.

    PubMed

    Nosewicz, Tomasz L; Beerekamp, M Suzan H; De Muinck Keizer, Robert-Jan O; Schepers, Tim; Maas, Mario; Niek van Dijk, C; Goslings, J Carel

    2016-08-01

    Osteochondral lesions (OCLs) associated with ankle fracture correlate with unfavorable outcome. The goals of this study were to detect OCLs following ankle fracture, to associate fracture type to OCLs and to investigate whether OCLs affect clinical outcome. 100 ankle fractures requiring operative treatment were prospectively included (46 men, 54 women; mean age 44 ± 14 years, range 20-77). All ankle fractures (conventional radiography; 71 Weber B, 22 Weber C, 1 Weber A, 4 isolated medial malleolus and 2 isolated posterior malleolus fractures) were treated by open reduction and internal fixation. Multidetector computed tomography (CT) was performed postoperatively. For each OCL, the location, size, and Loomer OCL classification (CT modified Berndt and Harty classification) were determined. The subjective Foot and Ankle Outcome Scoring (FAOS) was used for clinical outcome at 1 year. OCLs were found in 10/100 ankle fractures (10.0%). All OCLs were solitary talar lesions. Four OCLs were located posteromedial, 4 posterolateral, 1 anterolateral, and 1 anteromedial. There were 2 type I OCLs (subchondral compression), 6 type II OCLs (partial, nondisplaced fracture) and 2 type IV OCLs (displaced fracture). Mean OCL size (largest diameter) was 4.4 ± 1.7 mm (range, 1.7 mm to 6.2 mm). Chi-square analysis showed no significant association between ankle fracture type and occurrence of OCLs. OCLs did occur only in Lauge-Hansen stage III/IV ankle fractures. There were no significant differences in FAOS outcome between patients with or without OCLs. Ten percent of investigated ankle fractures had associated OCLs on CT. Although no significant association between fracture type and OCL was found, OCLs only occurred in Lauge-Hansen stage III/IV ankle fractures. With the numbers available, OCLs did not significantly affect clinical outcome at 1 year according to FAOS. Level IV, observational study. © The Author(s) 2016.

  6. Retrospective comparison of the Low Risk Ankle Rules and the Ottawa Ankle Rules in a pediatric population.

    PubMed

    Ellenbogen, Amy L; Rice, Amy L; Vyas, Pranav

    2017-09-01

    A recent multicenter prospective Canadian study presented prospective evidence supporting the Low Risk Ankle Rules (LRAR) as a means of reducing the number of ankle radiographs ordered for children presenting with an ankle injury while maintaining nearly 100% sensitivity. This is in contrast to a previous prospective study which showed that this rule yielded only 87% sensitivity. It is important to further investigate the LRAR and compare them with the already validated Ottawa Ankle Rules (OAR) to potentially curb healthcare costs and decrease unnecessary radiation exposure without compromising diagnostic accuracy. We conducted a retrospective chart review of 980 qualifying patients ages 12months to 18years presenting with ankle injury to a commonly staffed 310 bed children's hospital and auxiliary site pediatric emergency department. There were 28 high-risk fractures identified. The Ottawa Ankle Rules had a sensitivity of 100% (95% CI 87.7-100), specificity of 33.1% (95% CI 30.1-36.2), and would have reduced the number of ankle radiographs ordered by 32.1%. The Low Risk Ankle Rules had a sensitivity of 85.7% (95% CI 85.7-96), specificity of 64.9% (95% CI 61.8-68), and would have reduced the number of ankle radiographs ordered by 63.1%. The latter rule missed 4 high-risk fractures. The Low Risk Ankle Rules may not be sensitive enough for use in Pediatric Emergency Departments, while the Ottawa Ankle Rules again demonstrated 100% sensitivity. Further research on ways to implement the Ottawa Ankle Rules and maximize its ability to decrease wait times, healthcare costs, and improve patient satisfaction are needed. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. A three-dimensional model to assess the effect of ankle joint axis misalignments in ankle-foot orthoses.

    PubMed

    Fatone, Stefania; Johnson, William Brett; Tucker, Kerice

    2016-04-01

    Misalignment of an articulated ankle-foot orthosis joint axis with the anatomic joint axis may lead to discomfort, alterations in gait, and tissue damage. Theoretical, two-dimensional models describe the consequences of misalignments, but cannot capture the three-dimensional behavior of ankle-foot orthosis use. The purpose of this project was to develop a model to describe the effects of ankle-foot orthosis ankle joint misalignment in three dimensions. Computational simulation. Three-dimensional scans of a leg and ankle-foot orthosis were incorporated into a link segment model where the ankle-foot orthosis joint axis could be misaligned with the anatomic ankle joint axis. The leg/ankle-foot orthosis interface was modeled as a network of nodes connected by springs to estimate interface pressure. Motion between the leg and ankle-foot orthosis was calculated as the ankle joint moved through a gait cycle. While the three-dimensional model corroborated predictions of the previously published two-dimensional model that misalignments in the anterior -posterior direction would result in greater relative motion compared to misalignments in the proximal -distal direction, it provided greater insight showing that misalignments have asymmetrical effects. The three-dimensional model has been incorporated into a freely available computer program to assist others in understanding the consequences of joint misalignments. Models and simulations can be used to gain insight into functioning of systems of interest. We have developed a three-dimensional model to assess the effect of ankle joint axis misalignments in ankle-foot orthoses. The model has been incorporated into a freely available computer program to assist understanding of trainees and others interested in orthotics. © The International Society for Prosthetics and Orthotics 2014.

  8. Ottawa Ankle Rules and Subjective Surgeon Perception to Evaluate Radiograph Necessity Following Foot and Ankle Sprain

    PubMed Central

    Pires, RES; Pereira, AA; Abreu-e-Silva, GM; Labronici, PJ; Figueiredo, LB; Godoy-Santos, AL; Kfuri, M

    2014-01-01

    Background: Foot and ankle injuries are frequent in emergency departments. Although only a few patients with foot and ankle sprain present fractures and the fracture patterns are almost always simple, lack of fracture diagnosis can lead to poor functional outcomes. Aim: The present study aims to evaluate the reliability of the Ottawa ankle rules and the orthopedic surgeon subjective perception to assess foot and ankle fractures after sprains. Subjects and Methods: A cross-sectional study was conducted from July 2012 to December 2012. Ethical approval was granted. Two hundred seventy-four adult patients admitted to the emergency department with foot and/or ankle sprain were evaluated by an orthopedic surgeon who completed a questionnaire prior to radiographic assessment. The Ottawa ankle rules and subjective perception of foot and/or ankle fractures were evaluated on the questionnaire. Results: Thirteen percent (36/274) patients presented fracture. Orthopedic surgeon subjective analysis showed 55.6% sensitivity, 90.1% specificity, 46.5% positive predictive value and 92.9% negative predictive value. The general orthopedic surgeon opinion accuracy was 85.4%. The Ottawa ankle rules presented 97.2% sensitivity, 7.8% specificity, 13.9% positive predictive value, 95% negative predictive value and 19.9% accuracy respectively. Weight-bearing inability was the Ottawa ankle rule item that presented the highest reliability, 69.4% sensitivity, 61.6% specificity, 63.1% accuracy, 21.9% positive predictive value and 93% negative predictive value respectively. Conclusion: The Ottawa ankle rules showed high reliability for deciding when to take radiographs in foot and/or ankle sprains. Weight-bearing inability was the most important isolated item to predict fracture presence. Orthopedic surgeon subjective analysis to predict fracture possibility showed a high specificity rate, representing a confident method to exclude unnecessary radiographic exams. PMID:24971221

  9. Presynaptic control of transmission along the pathway mediating disynaptic reciprocal inhibition in the cat

    PubMed Central

    Enríquez-Denton, M; Nielsen, J; Perreault, M-C; Morita, H; Petersen, N; Hultborn, H

    2000-01-01

    In cat lumbar motoneurones, disynaptic inhibitory postsynaptic potentials (IPSPs) evoked by stimulation of antagonist motor nerves were depressed for at least 150 ms following conditioning stimulation of flexor (1.7-2 times threshold (T)) and ankle extensor (5T) nerves. The aim of the present study was to investigate the possibility that this depression is caused by presynaptic inhibitory mechanisms acting at the terminals of group I afferent fibres projecting to the Ia inhibitory interneurones and/or the terminals of these interneurones to the target motoneurones. Conditioning stimulation of flexor, but not ankle extensor, nerves evoked a depression of the monosynaptic Ia excitatory postsynaptic potentials (EPSPs) recorded intracellularly in Ia inhibitory interneurones. This depression lasted between 200 and 700 ms and was not accompanied by a depression of the monosynaptic EPSPs evoked by stimulation of descending pathways. These results suggest that flexor, but not ankle extensor, group I afferent fibres can modulate sensory transmission at the synapse between Ia afferent fibres and Ia inhibitory interneurones. Conditioning stimulation of flexor muscle nerves, extensor muscle nerves and cutaneous nerves produced a long-lasting increase in excitability of the terminals of the Ia inhibitory interneurones. The increase in the excitability of the terminals was not secondary to an electrotonic spread of synaptic excitation at the soma. Indeed, concomitant with the excitability increase of the terminals there were signs of synaptic inhibition in the soma. The unitary IPSPs induced in target motoneurones following the spike activity of single Ia inhibitory interneurones were depressed by conditioning stimulation of muscle and cutaneous nerves. Since the conditioning stimulation also evoked compound IPSPs in those motoneurones, a firm conclusion as to whether unitary IPSP depression involved presynaptic inhibitory mechanism of the terminals of the interneurones could

  10. The ANKLE TRIAL (ANKLE treatment after injuries of the ankle ligaments): what is the benefit of external support devices in the functional treatment of acute ankle sprain? : a randomised controlled trial

    PubMed Central

    2012-01-01

    Background Acute lateral ankle ligament injuries are very common problems in present health care. Still there is no hard evidence about which treatment strategy is superior. Current evidence supports the view that a functional treatment strategy is preferable, but insufficient data are present to prove the benefit of external support devices in these types of treatment. The hypothesis of our study is that external ankle support devices will not result in better outcome in the treatment of acute ankle sprains, compared to a purely functional treatment strategy. Overall objective is to compare the results of three different strategies of functional treatment for acute ankle sprain, especially to determine the advantages of external support devices in addition to functional treatment strategy, based on balance and coordination exercises. Methods/design This study is designed as a randomised controlled multi-centre trial with one-year follow-up. Adult and healthy patients (N = 180) with acute, single sided and first inversion trauma of the lateral ankle ligaments will be included. They will all follow the same schedule of balancing exercises and will be divided into 3 treatment groups, 1. pressure bandage and tape, 2. pressure bandage and brace and 3. no external support. Primary outcome measure is the Karlsson scoring scale; secondary outcomes are FAOS (subscales), number of recurrent ankle injuries, Visual Analogue Scales of pain and satisfaction and adverse events. They will be measured after one week, 6 weeks, 6 months and 1 year. Discussion The ANKLE TRIAL is a randomized controlled trial in which a purely functional treated control group, without any external support is investigated. Results of this study could lead to other opinions about usefulness of external support devices in the treatment of acute ankle sprain. Trial registration Netherlands Trial Register (NTR): NTR2151 PMID:22340371

  11. Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

    PubMed Central

    Roy, Anindo; Bever, Christopher T.; Forrester, Larry W.; Macko, Richard F.; Hogan, Neville

    2011-01-01

    Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults. PMID:21346215

  12. Mobile ankle and knee perturbator.

    PubMed

    Andersen, Jacob Buus; Sinkjaer, Thomas

    2003-10-01

    A mobile ankle and knee perturbator has been developed. It consists of a functional joint with an integrated clutch. Four Bowden wires connect the joint to a powerful motor and a double pneumatic cylinder. When needed during any time of the gait cycle, it is possible to impose an ankle rotation by engaging the clutch and rotating the ankle or knee joint with a predefined displacement. The system is designed to investigate electrophysiological and biomechanical features of the human ankle or knee joint during gait.

  13. Position versus force control: using the 2-DOF robotic ankle trainer to assess ankle's motor control.

    PubMed

    Farjadian, Amir B; Nabian, Mohsen; Hartman, Amber; Corsino, Johnathan; Mavroidis, Constantinos; Holden, Maureen K

    2014-01-01

    An estimated of 2,000,000 acute ankle sprains occur annually in the United States. Furthermore, ankle disabilities are caused by neurological impairments such as traumatic brain injury, cerebral palsy and stroke. The virtually interfaced robotic ankle and balance trainer (vi-RABT) was introduced as a cost-effective platform-based rehabilitation robot to improve overall ankle/balance strength, mobility and control. The system is equipped with 2 degrees of freedom (2-DOF) controlled actuation along with complete means of angle and torque measurement mechanisms. Vi-RABT was used to assess ankle strength, flexibility and motor control in healthy human subjects, while playing interactive virtual reality games on the screen. The results suggest that in the task with 2-DOF, subjects have better control over ankle's position vs. force.

  14. RMI study and clinical correlations of ankle retinacula damage and outcomes of ankle sprain.

    PubMed

    Stecco, Antonio; Stecco, Carla; Macchi, Veronica; Porzionato, Andrea; Ferraro, Claudio; Masiero, Stefano; De Caro, Raffaele

    2011-12-01

    Recent studies reveal the role of the ankle retinacula in proprioception and functional stability of the ankle, but there is no clear evidence of their role in the outcomes of ankle sprain. 25 patients with outcomes of ankle sprain were evaluated by MRI to analyze possible damage to the ankle retinacula. Patients with damage were subdivided into two groups: group A comprised cases with ankle retinacula damage only, and group B those also with anterior talofibular ligament rupture or bone marrow edema. Both groups were examined by VAS, CRTA and static posturography and underwent three treatments of deep connective tissue massage (Fascial Manipulation technique). All evaluations were repeated after the end of treatment and at 1, 3 and 6 months. At MRI, alteration of at least one of the ankle retinacula was evident in 21 subjects, and a further lesion was also identified in 7 subjects. After treatment, VAS and CRTA evaluations showed a statistically significant decrease in values with respect to those before treatment (p < 0.0001). There were also significant improvements (p < 0.05) in stabilometric platform results. No significant difference was found between groups A and B. The initial benefit was generally maintained at follow-up. The alteration of retinacula at MRI clearly corresponds to the proprioceptive damage revealed by static posturography and clinical examination. Treatment focused on the retinacula may improve clinical outcomes and stabilometric data.

  15. Ankle injuries in athletes.

    PubMed

    Wilkerson, L A

    1992-06-01

    Ankle injuries are the most frequent cause of physician evaluation in a sports-oriented environment. The lateral ligaments are most commonly injured. With a detailed history, physical and radiographic examination to avoid missing underlying pathology, the primary care physician can diagnose and treat the majority of ankle injuries. Occasionally, stress radiographs, arthograms, or magnetic resonance imaging (MRI) is needed. The vast majority of ankle sprains can be treated with adhesive tape strapping or semirigid orthotics and nonsteroidal anti-inflammatory medication followed by rehabilitation. Key points of rehabilitation are control of pain and swelling acutely with nonsteroidal anti-inflammatories and RICE (rest, ice, compression, and elevation), then restoring normal range of motion, strengthening muscle groups, and retraining proprioception of the ankle joint.

  16. Motoneuron firing and isomyosin type of muscle fibres in prior polio.

    PubMed Central

    Borg, K; Borg, J; Dhoot, G; Edström, L; Grimby, L; Thornell, L E

    1989-01-01

    In patients with prior polio there was an excessive use of remaining motor units and an absence of type II muscle fibres in the tibialis anterior (TA). In the present study, eight subjects with prior polio with more than 90% type I fibres in the TA were examined. The aim was to elucidate whether the lack of type II muscle fibres was due to a selective loss of motoneurons with high threshold and high axonal conduction velocity or due to a muscle fibre transition from type II to type I. There was no decrease of the proportion of motoneurons with high threshold and high axonal conduction velocity. Monoclonal antibodies against fast and slow myosin heavy chains (MHC) were used as histochemical markers and many muscle fibres of type I according to ATPase stainability showed a binding of both anti-fast and anti-slow MHC. It is suggested that the type I muscle fibre dominance in prior polio subjects with excessive use of TA during walking is due to a muscle fibre transition from type II to type I and not to a loss of one class of motor units. Images PMID:2529353

  17. The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale; translation and validation of the Dutch language version for ankle fractures.

    PubMed

    de Boer, A Siebe; Tjioe, Roderik J C; Van der Sijde, Fleur; Meuffels, Duncan E; den Hoed, Pieter T; Van der Vlies, Cornelis H; Tuinebreijer, Wim E; Verhofstad, Michael H J; Van Lieshout, Esther M M

    2017-08-03

    The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale is among the most commonly used instruments for measuring outcome of treatment in patients who sustained a complex ankle or hindfoot injury. It consists of a patient-reported and a physician-reported part. A validated, Dutch version of this instrument is currently not available. The aim of this study was to translate the instrument into Dutch and to determine the measurement properties of the AOFAS Ankle-Hindfoot Scale Dutch language version (DLV) in patients with a unilateral ankle fracture. Multicentre (two Dutch hospitals), prospective observational study. In total, 142 patients with a unilateral ankle fracture were included. Ten patients were lost to follow-up. Patients completed the subjective (patient-reported) part of the AOFAS Ankle-Hindfoot Scale-DLV. A physician or trained physician-assistant completed the physician-reported part. For comparison and evaluation of the measuring characteristics, the Foot Function Index and the Short Form-36 were completed by the patient. Descriptive statistics (including floor and ceiling effects), reliability (ie, internal consistency), construct validity, reproducibility (ie, test-retest reliability, agreement and smallest detectable change) and responsiveness were determined. The AOFAS-DLV and its subscales showed good internal consistency (Cronbach's α >0.90). Construct validity and longitudinal validity were proven to be adequate (76.5% of predefined hypotheses were confirmed). Floor effects were not present. Ceiling effects were present from 6 months onwards, as expected. Responsiveness was adequate, with a smallest detectable change of 12.0 points. The AOFAS-DLV is a reliable, valid and responsive measurement instrument for evaluating functional outcome in patients with a unilateral ankle fracture. This implies that the questionnaire is suitable to compare different treatment modalities within this population or to compare outcome across

  18. Talofibular interval changes after acute ankle sprain: a stress ultrasonography study of ankle laxity.

    PubMed

    Croy, Theodore; Saliba, Susan; Saliba, Ethan; Anderson, Mark W; Hertel, Jay

    2013-11-01

    Quantifying talocrural joint laxity after ankle sprain is problematic. Stress ultrasonography (US) can image the lateral talocrural joint and allow the measurement of the talofibular interval, which may suggest injury to the anterior talofibular ligament (ATFL). The acute talofibular interval changes after lateral ankle sprain are unknown. Twenty-five participants (9 male, 16 female; age 21.8 ± 3.2 y, height 167.8 ± 34.1 cm, mass 72.7 ± 13.8 kg) with 27 acute, lateral ankle injuries underwent bilateral stress US imaging at baseline (<7 d) and on the affected ankle at 3 wk and 6 wk from injury in 3 ankle conditions: neutral, anterior drawer, and inversion. Talofibular interval (mm) was measured using imaging software and self-reported function (activities of daily living [ADL] and sports) by the Foot and Ankle Ability Measure (FAAM). The talofibular interval increased with anterior-drawer stress in the involved ankle (22.65 ± 3.75 mm; P = .017) over the uninvolved ankle (19.45 ± 2.35 mm; limb × position F1,26 = 4.9, P = .035) at baseline. Inversion stress also resulted in greater interval changes (23.41 ± 2.81 mm) than in the uninvolved ankles (21.13 ± 2.08 mm). A main effect for time was observed for inversion (F2,52 = 4.3, P = .019, 21.93 ± 2.24 mm) but not for anterior drawer (F2,52 = 3.1, P = .055, 21.18 ± 2.34 mm). A significant reduction in the talofibular interval took place between baseline and week 3 inversion measurements only (F1,26 = 5.6, P = .026). FAAM-ADL and sports results increased significantly from baseline to wk 3 (21.9 ± 16.2, P < .0001 and 23.8 ± 16.9, P < .0001) and from wk 3 to wk 6 (2.5 ± 4.4, P = .009 and 10.5 ± 13.2, P = .001). Stress US methods identified increased talofibular interval changes suggestive of talocrural laxity and ATFL injury using anterior drawer and inversion stress that, despite significant improvements in self-reported function, only marginally improved during the 6 wk after ankle sprain. Stress US

  19. [Arthroscopic therapy of ankle joint impingement syndrome after operation of ankle joint fracture dislocation].

    PubMed

    Feng, Zhibin; Mi, Kun; Wei, Renzhi; Liu, Wu; Wang, Bin

    2011-07-01

    To study the operative procedure and the effectiveness of arthroscopic therapy for ankle joint impingement syndrome after operation of ankle joint fracture dislocation. Between March 2008 and April 2010, 38 patients with ankle joint impingement syndrome after operation of ankle joint fracture dislocation were treated. Among them, there were 28 males and 10 females with an average age of 28 years (range, 18 to 42 years). The time from internal fixation to admission was 12-16 months (mean, 13.8 months). There were pressing pain in anterolateral and anterior ankle. The dorsal extension ranged from -20 to -5 degrees (mean, -10.6 degrees), and the palmar flexion was 30-40 degrees (mean, 35.5 degrees). The total score was 48.32 +/- 9.24 and the pain score was 7.26 +/- 1.22 before operation according to American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score system. The X-ray films showed osteophyte formation in anterior tibia and talus; MRI showed cartilage injury in 22 cases. Arthroscopic intervention included removing osteophytes, debriding fabric scars and synovial membrane tissues, and removing osteochondral fragments. Arthroscopic microfracture technique was used in 22 patients with cartilage injury. All incisions healed primarily. Thirty-eight cases were followed up 10-26 months (mean, 16 months). At last follow-up, 26 patients had normal range of motion (ROM); the dorsal extension was 15-25 degrees (mean, 19.6 degrees) and the palmar flexion was 35-45 degrees (mean, 40.7 degrees). Eight patients had mild limited ROM; the dorsal extension was 5-15 degrees (mean, 7.2 degrees) and the palmar flexion was 35-45 degrees (mean, 39.5 degrees). Four patients had mild limited ROM and pain in posterior portion of the ankle after a long walking (3-4 hours); the dorsal extension was 0-5 degrees (mean, 2.6 degrees) and the palmar flexion was 35-40 degrees (mean, 37.5 degrees). The total score was 89.45 +/- 9.55 and the pain score was 1.42 +/- 1.26 after

  20. On a method to detect long-latency excitations and inhibitions of single hand muscle motoneurons in man.

    PubMed

    Awiszus, F; Feistner, H; Schäfer, S S

    1991-01-01

    The peri-stimulus-time histogram (PSTH) analysis of stimulus-related neuronal spike train data is usually regarded as a method to detect stimulus-induced excitations or inhibitions. However, for a fairly regularly discharging neuron such as the human alpha-motoneuron, long-latency modulations of a PSTH are difficult to interpret as PSTH modulations can also occur as a consequence of a modulated neuronal autocorrelation. The experiments reported here were made (i) to investigate the extent to which a PSTH of a human hand-muscle motoneuron may be contaminated by features of the autocorrelation and (ii) to develop methods that display the motoneuronal excitations and inhibitions without such contamination. Responses of 29 single motor units to electrical ulnar nerve stimulation below motor threshold were investigated in the first dorsal interosseous muscle of three healthy volunteers using an experimental protocol capable of demonstrating the presence of autocorrelative modulations in the neuronal response. It was found for all units that the PSTH as well as the cumulative sum (CUSUM) derived from these responses were severely affected by the presence of autocorrelative features. On the other hand, calculating the CUSUM in a slightly modified form yielded--for all units investigated--a neuronal output feature sensitive only to motoneuronal excitations and inhibitions induced by the afferent volley. The price that has to be paid to arrive at such a modified CUSUM (mCUSUM) was a high computational effort prohibiting the on-line availability of this output feature during the experiment. It was found, however, that an interspike interval superposition plot (IISP)--easily obtainable during the experiment--is also free of autocorrelative features.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Differences in lateral ankle laxity measured via stress ultrasonography in individuals with chronic ankle instability, ankle sprain copers, and healthy individuals.

    PubMed

    Croy, Theodore; Saliba, Susan A; Saliba, Ethan; Anderson, Mark W; Hertel, Jay

    2012-07-01

    Cross-sectional. To use stress ultrasonography to measure the change in anterior talofibular ligament length during the simulated anterior drawer and ankle inversion stress tests. In approximately 30% of individuals, ankle sprains may eventually develop into chronic ankle instability (CAI) with recurrent symptoms. Individuals with CAI and those who have a history of ankle sprain (greater than 1 year prior) without chronic instability (copers) may or may not have mechanical laxity. Sixty subjects (n=60 ankles) were divided into 3 groups: 1) Control subjects without ankle injury history (n=20; mean ± SD age; 24.8 ± 4.8 years; height, 173.7 ± 9.4 cm; weight, 77.2 ± 19.5 kg), ankle sprain copers (n=20; 22.3 ± 2.9 years; 172.8 ± 11.3 cm; 72.4 ± 14.3 kg), and subjects with CAI (n=20; 23.5 ± 4.2 years; 174.6 ± 9.6 cm; 74.8 ± 17.3 kg). Ligament length change with the anterior drawer and end range ankle inversion was calculated from ultrasound images. The Foot and Ankle Ability Measure (FAAM) was used to quantify self-reported function on activities-of-daily living (ADL) and sports. The anterior drawer test resulted in length changes that were greater (F₂,₅₇=6.2, P=.004) in the CAI (mean ± SD length change, 15.6 ± 15.1%, P=.006) and the coper groups (14.0 ± 15.9%, P=.016) compared to the control group (1.3 ± 10.7%); however the length change for the CAI and coper groups were not different (P=.93). Ankle inversion similarly resulted in greater ligament length change (F₂,₅₇=6.5, P=.003) in the CAI (25.3 ± 15.5%, P=.003) and coper groups (20.2 ± 19.6%, P=.039) compared to the control group (7.4 ± 12.9%); with no difference in length change between the copers and CAI groups (P=.59). The CAI group had a lower score on the FAAM-ADL (87.4 ± 13.4%) and FAAM-Sports (74.2 ± 17.8%) when compared to the control (98.8 ± 2.9% and 98.9 ± 3.1%, P<.0001) and coper groups (99.4 ± 1.8% and 94.6 ± 8.8%, P<.0001). Stress ultrasonography identified greater

  2. Gene targeting of Gemin2 in mice reveals a correlation between defects in the biogenesis of U snRNPs and motoneuron cell death

    PubMed Central

    Jablonka, Sibylle; Holtmann, Bettina; Meister, Gunter; Bandilla, Michael; Rossoll, Wilfried; Fischer, Utz; Sendtner, Michael

    2002-01-01

    Neuronal degeneration in spinal muscular atrophy is caused by reduced expression of the survival motor neuron (SMN) protein. SMN and the tightly interacting Gemin2 form part of a macromolecular complex (SMN complex) that mediates assembly of spliceosomal small nuclear ribonucleoproteins (U snRNPs). We used mouse genetics to investigate the function of this complex in motoneuron maintenance. Reduced Smn/Gemin2 protein levels lead to disturbed U snRNP assembly as indicated by reduced nuclear accumulation of Sm proteins. This finding correlates with enhanced motoneuron degeneration in Gemin2+/−/Smn+/− mice. Our data provide in vivo evidence that impaired production of U snRNPs contributes to motoneuron degeneration. PMID:12091709

  3. Ankle Fusion Combined With Calcaneal Sliding Osteotomy for Severe Arthritic Ball and Socket Ankle Deformity.

    PubMed

    Cho, Byung-Ki; Park, Kyoung-Jin; Choi, Seung-Myung; Kang, Sang-Woo; Lee, Hyung-Ki

    2016-12-01

    Although a ball and socket ankle deformity is usually congenital and asymptomatic, abnormal inversion and eversion mobility can result in recurrent ankle sprain and osteoarthritis. This retrospective study was performed to evaluate the clinical and radiologic outcomes of ankle fusion combined with calcaneal sliding osteotomy for severe arthritic ball and socket ankle deformity. Fourteen patients with severe arthritic ball and socket ankle deformity were followed for more than 3 years after operation. The clinical evaluation consisted of American Orthopaedic Foot & Ankle Society (AOFAS) score, Foot and Ankle Ability Measure (FAAM), visual analog scale (VAS) for pain, and subjective satisfaction score. The period to fusion and union of osteotomy, the change of hindfoot alignment angle, and complications were evaluated radiologically. AOFAS and FAAM scores were significantly improved from an average of 37.4 and 34.5 points to 74.6 and 78.5 points, respectively. VAS for pain with walking over 20 minutes was significantly improved from an average of 8.4 points to 1.9 points. The average satisfaction score of patients was 88.9 points. The difference in heel alignment angle (compared to contralateral side) was significantly improved from an average of 34.8 to 5.4 degrees. There were 2 cases of progressive arthritis in an adjacent joint and 1 case of failed fusion. Ankle fusion combined with calcaneal sliding osteotomy can be an effective operative option for ball and socket ankle deformity with advanced arthritis. In spite of increased complication rate, reliable pain relief, and restoration of gait ability through correcting hindfoot malalignment could improve the quality of life. Level IV, retrospective case series. © The Author(s) 2016.

  4. Altered Knee and Ankle Kinematics During Squatting in Those With Limited Weight-Bearing–Lunge Ankle-Dorsiflexion Range of Motion

    PubMed Central

    Dill, Karli E.; Begalle, Rebecca L.; Frank, Barnett S.; Zinder, Steven M.; Padua, Darin A.

    2014-01-01

    Context: Ankle-dorsiflexion (DF) range of motion (ROM) may influence movement variables that are known to affect anterior cruciate ligament loading, such as knee valgus and knee flexion. To our knowledge, researchers have not studied individuals with limited or normal ankle DF-ROM to investigate the relationship between those factors and the lower extremity movement patterns associated with anterior cruciate ligament injury. Objective: To determine, using 2 different measurement techniques, whether knee- and ankle-joint kinematics differ between participants with limited and normal ankle DF-ROM. Design: Cross-sectional study. Setting: Sports medicine research laboratory. Patients or Other Participants: Forty physically active adults (20 with limited ankle DF-ROM, 20 with normal ankle DF-ROM). Main Outcome Measure(s): Ankle DF-ROM was assessed using 2 techniques: (1) nonweight-bearing ankle DF-ROM with the knee straight, and (2) weight-bearing lunge (WBL). Knee flexion, knee valgus-varus, knee internal-external rotation, and ankle DF displacements were assessed during the overhead-squat, single-legged squat, and jump-landing tasks. Separate 1-way analyses of variance were performed to determine whether differences in knee- and ankle-joint kinematics existed between the normal and limited groups for each assessment. Results: We observed no differences between the normal and limited groups when classifying groups based on nonweight-bearing passive-ankle DF-ROM. However, individuals with greater ankle DF-ROM during the WBL displayed greater knee-flexion and ankle-DF displacement and peak knee flexion during the overhead-squat and single-legged squat tasks. In addition, those individuals also demonstrated greater knee-varus displacement during the single-legged squat. Conclusions: Greater ankle DF-ROM assessed during the WBL was associated with greater knee-flexion and ankle-DF displacement during both squatting tasks as well as greater knee-varus displacement during

  5. Neuromuscular plasticity in the locust after permanent removal of an excitatory motoneuron of the extensor tibiae muscle.

    PubMed

    Büschges, A; Djokaj, S; Bässler, D; Bässler, U; Rathmayer, W

    2000-01-01

    The capacity of the larval insect nervous system to compensate for the permanent loss of one of the two excitatory motoneurons innervating a leg muscle was investigated in the locust (Locusta migratoria). In the fourth instar, the fast extensor tibiae (FETi) motoneuron in the mesothoracic ganglion was permanently removed by photoinactivation with a helium-cadmium laser. Subsequently, the animals were allowed to develop into adulthood. When experimental animals were tested as adults after final ecdysis, fast-contracting fibers in the most proximal region of the corresponding extensor muscle, which are normally predominantly innervated by FETi only, uniformly responded to activity of the slow extensor tibiae (SETi) neuron. In adult operated animals, single pulses to SETi elicited large junctional responses in the fibers which resulted in twitch contractions of these fibers similar to the responses to FETi activity in control animals. The total number of muscle fibers, their properties as histochemically determined contractional types (fast and slow), and their distribution were not affected by photoinactivation of FETi. Possible mechanisms enabling the larval neuromuscular system to compensate for the loss of FETi through functionally similar innervation by a different motoneuron, i.e. SETi, are discussed. Copyright 2000 John Wiley & Sons, Inc.

  6. Anatomy of the ankle ligaments: a pictorial essay.

    PubMed

    Golanó, Pau; Vega, Jordi; de Leeuw, Peter A J; Malagelada, Francesc; Manzanares, M Cristina; Götzens, Víctor; van Dijk, C Niek

    2016-04-01

    Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail.

  7. What Is a Foot and Ankle Surgeon?

    MedlinePlus

    ... Foot & Ankle Surgeon? A A A | Print | Share What is a Foot & Ankle Surgeon? Foot and ankle ... of conditions that affect people of every age. What education has a foot and ankle surgeon received? ...

  8. Acute ankle sprain: conservative or surgical approach?

    PubMed Central

    Al-Mohrej, Omar A.; Al-Kenani, Nader S.

    2016-01-01

    Ankle sprains fall into two main categories: acute ankle sprains and chronic ankle instability, which are among the most common recurrent injuries during occupational activities, athletic events, training and army service. Acute ankle sprain is usually managed conservatively and functional rehabilitation failure by conservative treatment leads to development of chronic ankle instability, which most often requires surgical intervention. Enhancing the in-depth knowledge of the ankle anatomy, biomechanics and pathology helps greatly in deciding the management options. Cite this article: Al-Mohrej OA, Al-Kenani NS. Acute ankle sprain: conservative or surgical approach? EFORT Open Rev 2016;1:34-44. DOI: 10.1302/2058-5241.1.000010. PMID:28461926

  9. Do ankle orthoses improve ankle proprioceptive thresholds or unipedal balance in older persons with peripheral neuropathy?

    PubMed

    Son, Jaebum; Ashton-Miller, James A; Richardson, James K

    2010-05-01

    To determine whether ankle orthoses that provide medial and lateral support, and have been found to decrease gait variability in older persons with peripheral neuropathy, decrease (improve) frontal plane ankle proprioceptive thresholds or increase unipedal stance time in that same population. Observational study in which unipedal stance time was determined with a stopwatch, and frontal plane ankle (inversion and eversion) proprioceptive thresholds were quantified during bipedal stance using a foot cradle system and a series of 100 rotational stimuli, in 11 older neuropathic subjects (8 men; age 72 +/- 7.1 yr) with and without ankle orthoses. The subjects demonstrated no change in combined frontal plane (inversion + eversion) proprioceptive thresholds or unipedal stance time with vs. without the orthoses (1.06 +/- 0.56 vs. 1.13 +/- 0.39 degrees, respectively; P = 0.955 and 6.1 +/- 6.5 vs. 6.2 +/- 5.4 secs, respectively; P = 0.922). Ankle orthoses that provide medial-lateral support do not seem to change ankle inversion/eversion proprioceptive thresholds or unipedal stance time in older persons with diabetic peripheral neuropathy. Previously identified improvements in gait variability using orthoses in this population are therefore likely related to an orthotically induced stiffening of the ankle rather than a change in ankle afferent function.

  10. Clinical assessment of acute lateral ankle sprain injuries (ROAST): 2019 consensus statement and recommendations of the International Ankle Consortium.

    PubMed

    Delahunt, Eamonn; Bleakley, Chris M; Bossard, Daniela S; Caulfield, Brian M; Docherty, Carrie L; Doherty, Cailbhe; Fourchet, François; Fong, Daniel T; Hertel, Jay; Hiller, Claire E; Kaminski, Thomas W; McKeon, Patrick O; Refshauge, Kathryn M; Remus, Alexandria; Verhagen, Evert; Vicenzino, Bill T; Wikstrom, Erik A; Gribble, Phillip A

    2018-06-09

    Lateral ankle sprain injury is the most common musculoskeletal injury incurred by individuals who participate in sports and recreational physical activities. Following initial injury, a high proportion of individuals develop long-term injury-associated symptoms and chronic ankle instability. The development of chronic ankle instability is consequent on the interaction of mechanical and sensorimotor insufficiencies/impairments that manifest following acute lateral ankle sprain injury. To reduce the propensity for developing chronic ankle instability, clinical assessments should evaluate whether patients in the acute phase following lateral ankle sprain injury exhibit any mechanical and/or sensorimotor impairments. This modified Delphi study was undertaken under the auspices of the executive committee of the International Ankle Consortium. The primary aim was to develop recommendations, based on expert (n=14) consensus, for structured clinical assessment of acute lateral ankle sprain injuries. After two modified Delphi rounds, consensus was achieved on the clinical assessment of acute lateral ankle sprain injuries. Consensus was reached on a minimum standard clinical diagnostic assessment. Key components of this clinical diagnostic assessment include: establishing the mechanism of injury, as well as the assessment of ankle joint bones and ligaments. Through consensus, the expert panel also developed the International Ankle Consortium Rehabilitation-Oriented ASsessmenT (ROAST). The International Ankle Consortium ROAST will help clinicians identify mechanical and/or sensorimotor impairments that are associated with chronic ankle instability. This consensus statement from the International Ankle Consortium aims to be a key resource for clinicians who regularly assess individuals with acute lateral ankle sprain injuries. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted

  11. Anatomy of the ankle ligaments: a pictorial essay

    PubMed Central

    Vega, Jordi; de Leeuw, Peter A. J.; Malagelada, Francesc; Manzanares, M. Cristina; Götzens, Víctor; van Dijk, C. Niek

    2010-01-01

    Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail. PMID:20309522

  12. Activation properties of trigeminal motoneurons in participants with and without bruxism

    PubMed Central

    D'Amico, Jessica M.; Yavuz, Ş. Utku; Saraçoğlu, Ahmet; Atiş, Elif Sibel; Türker, Kemal S.

    2013-01-01

    In animals, sodium- and calcium-mediated persistent inward currents (PICs), which produce long-lasting periods of depolarization under conditions of low synaptic drive, can be activated in trigeminal motoneurons following the application of the monoamine serotonin. Here we examined if PICs are activated in human trigeminal motoneurons during voluntary contractions and under physiological levels of monoaminergic drive (e.g., serotonin and norepinephrine) using a paired motor unit analysis technique. We also examined if PICs activated during voluntary contractions are larger in participants who demonstrate involuntary chewing during sleep (bruxism), which is accompanied by periods of high monoaminergic drive. In control participants, during a slowly increasing and then decreasing isometric contraction, the firing rate of an earlier-recruited masseter motor unit, which served as a measure of synaptic input to a later-recruited test unit, was consistently lower during derecruitment of the test unit compared with at recruitment (ΔF = 4.6 ± 1.5 imp/s). The ΔF, therefore, is a measure of the reduction in synaptic input needed to counteract the depolarization from the PIC to provide an indirect estimate of PIC amplitude. The range of ΔF values measured in the bruxer participants during similar voluntary contractions was the same as in controls, suggesting that abnormally high levels of monoaminergic drive are not continually present in the absence of involuntary motor activity. We also observed a consistent “onion skin effect” during the moderately sized contractions (<20% of maximal), whereby the firing rate of higher threshold motor units discharged at slower rates (by 4–7 imp/s) compared with motor units with relatively lower thresholds. The presence of lower firing rates in the more fatigue-prone, higher threshold trigeminal motoneurons, in addition to the activation of PICs, likely facilitates the activation of the masseter muscle during motor activities

  13. Modulation of leak K(+) channel in hypoglossal motoneurons of rats by serotonin and/or variation of pH value.

    PubMed

    Xu, Xue-Feng; Tsai, Hao-Jan; Li, Lin; Chen, Yi-Fan; Zhang, Cheng; Wang, Guang-Fa

    2009-08-25

    The cloned TWIK-related acid-sensitive K(+) channel (TASK-1) is sensitive to the pH changes within physiological pH range (pK~7.4). Recently, the native TASK-1-like channel was suggested to be the main contributor to the background (or leak) K(+) conductance in the motoneurons of the brain stem. Serotonin (5-HT) and variation of pH value in perfused solution could modulate these currents. Here we aimed to examine the properties and modulation of the currents by serotonin or variation of pH value in hypoglossal motoneurons of rats. Transverse slices were prepared from the brainstem of neonatal Sprague-Dawley rats (postnatal days 7-8). Hypoglossal motoneurons were used for the study. The leak K(+) current (TASK-1-like current) and hyperpolarization-activated cationic current (I(h)) were recorded with the whole-cell patch-clamp technique. The results showed that these currents were inhibited by acidified artificial cerebrospinal fluid (ACSF, pH 6.0) and activated by alkalized ACSF (pH 8.5). 5-HT (10 mumol/L) significantly inhibited both leak K(+) current and I(h) with depolarization of membrane potential and the occurrence of oscillation and/or spikes. Bath application of Ketanserine, an antagonist of 5-HT₂ receptor, reversed or reduced the inhibitory effect of acidified solution on leak K(+) current and I(h). The results suggest that 5-HT₂ receptors mediate the effects of acidified media on leak K(+) current and I(h) in hypoglossal motoneurons.

  14. Gene expression changes in spinal motoneurons of the SOD1(G93A) transgenic model for ALS after treatment with G-CSF.

    PubMed

    Henriques, Alexandre; Kastner, Stefan; Chatzikonstantinou, Eva; Pitzer, Claudia; Plaas, Christian; Kirsch, Friederike; Wafzig, Oliver; Krüger, Carola; Spoelgen, Robert; Gonzalez De Aguilar, Jose-Luis; Gretz, Norbert; Schneider, Armin

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is an incurable fatal motoneuron disease with a lifetime risk of approximately 1:400. It is characterized by progressive weakness, muscle wasting, and death ensuing 3-5 years after diagnosis. Granulocyte-colony stimulating factor (G-CSF) is a drug candidate for ALS, with evidence for efficacy from animal studies and interesting data from pilot clinical trials. To gain insight into the disease mechanisms and mode of action of G-CSF, we performed gene expression profiling on isolated lumbar motoneurons from SOD1(G93A) mice, the most frequently studied animal model for ALS, with and without G-CSF treatment. Motoneurons from SOD1(G93A) mice present a distinct gene expression profile in comparison to controls already at an early disease stage (11 weeks of age), when treatment was initiated. The degree of deregulation increases at a time where motor symptoms are obvious (15 weeks of age). Upon G-CSF treatment, transcriptomic deregulations of SOD1(G93A) motoneurons were notably restored. Discriminant analysis revealed that SOD1 mice treated with G-CSF has a transcriptom close to presymptomatic SOD1 mice or wild type mice. Some interesting genes modulated by G-CSF treatment relate to neuromuscular function such as CCR4-NOT or Prss12. Our data suggest that G-CSF is able to re-adjust gene expression in symptomatic SOD1(G93A) motoneurons. This provides further arguments for G-CSF as a promising drug candidate for ALS.

  15. Gene expression changes in spinal motoneurons of the SOD1G93A transgenic model for ALS after treatment with G-CSF

    PubMed Central

    Henriques, Alexandre; Kastner, Stefan; Chatzikonstantinou, Eva; Pitzer, Claudia; Plaas, Christian; Kirsch, Friederike; Wafzig, Oliver; Krüger, Carola; Spoelgen, Robert; Gonzalez De Aguilar, Jose-Luis; Gretz, Norbert; Schneider, Armin

    2015-01-01

    Background: Amyotrophic lateral sclerosis (ALS) is an incurable fatal motoneuron disease with a lifetime risk of approximately 1:400. It is characterized by progressive weakness, muscle wasting, and death ensuing 3–5 years after diagnosis. Granulocyte-colony stimulating factor (G-CSF) is a drug candidate for ALS, with evidence for efficacy from animal studies and interesting data from pilot clinical trials. To gain insight into the disease mechanisms and mode of action of G-CSF, we performed gene expression profiling on isolated lumbar motoneurons from SOD1G93A mice, the most frequently studied animal model for ALS, with and without G-CSF treatment. Results: Motoneurons from SOD1G93A mice present a distinct gene expression profile in comparison to controls already at an early disease stage (11 weeks of age), when treatment was initiated. The degree of deregulation increases at a time where motor symptoms are obvious (15 weeks of age). Upon G-CSF treatment, transcriptomic deregulations of SOD1G93A motoneurons were notably restored. Discriminant analysis revealed that SOD1 mice treated with G-CSF has a transcriptom close to presymptomatic SOD1 mice or wild type mice. Some interesting genes modulated by G-CSF treatment relate to neuromuscular function such as CCR4-NOT or Prss12. Conclusions: Our data suggest that G-CSF is able to re-adjust gene expression in symptomatic SOD1G93A motoneurons. This provides further arguments for G-CSF as a promising drug candidate for ALS. PMID:25653590

  16. [Influence of Ankle Braces on the Prevalence of Ankle Inversion Injuries in the Swiss Volleyball National League A].

    PubMed

    Jaggi, J; Kneubühler, S; Rogan, S

    2016-06-01

    Ankle inversion is a common injury among volleyball players. The injury rate during a game is 2.1 times higher than during training. As a result, the preventive use of ankle braces is frequently observed in Swiss volleyball leagues. Studies have shown that ankle braces have a preventive effect on the prevalence of ankle inversion. In Switzerland there has been no investigation into the preventive use of braces and their influence on prevalence. For this reason, the goals of this study are 1) to determine when, why and by whom ankle braces are worn and 2) to evaluate the injury rate of users and non-users of ankle braces. A modified questionnaire was sent to 18 men's and women's teams of the Swiss National League A. The questionnaire included questions about injury rates and the circumstances of ankle inversion injuries. The data were statistically analysed with Microsoft Excel 2012 and SPSS Version 20. The overall response rate was 61 %, allowing data from 181 players to be analysed. 33 % (59 of 181) of the players used an ankle brace. There was a statistically significant difference in the prevalence of ankle inversion between users (12 injured) and non-users (8 injured) (p = 0.006). Wearing an ankle brace during training or during a game made no difference in the prevention of injuries (p = 0.356). More athletes were injured during training (n = 13) than during a game (n = 7). The results of the present study indicate that volleyball players preferably wear ankle braces to prevent injury. More than one third of the players in the study wore an ankle brace, 60 % for primary prevention and 40 % for secondary prevention due to a previous injury. The study shows that significantly more users than non-users of ankle braces were injured. This is contrary to literature. Furthermore it was shown that more injuries occur during training than during a game. This finding results from the fact that ankle braces were rarely worn during training. It is

  17. Cost-effectiveness analysis of total ankle arthroplasty.

    PubMed

    SooHoo, Nelson F; Kominski, Gerald

    2004-11-01

    There is renewed interest in total ankle arthroplasty as an alternative to ankle fusion in the treatment of end-stage ankle arthritis. Despite a lack of long-term data on the clinical outcomes associated with these implants, the use of ankle arthroplasty is expanding. The purpose of this cost-effectiveness analysis was to evaluate whether the currently available literature justifies the emerging use of total ankle arthroplasty. This study also identifies thresholds for the durability and function of ankle prostheses that, if met, would support more widespread dissemination of this new technology. A decision model was created for the treatment of ankle arthritis. The literature was reviewed to identify possible outcomes and their probabilities following ankle fusion and ankle arthroplasty. Each outcome was weighted for quality of life with use of a utility factor, and effectiveness was expressed in units of quality-adjusted life years. Gross costs were estimated from Medicare charge and reimbursement data for the relevant codes. The effect of the uncertainty of estimates of costs and effectiveness was assessed with sensitivity analysis. The reference case of our model assumed a ten-year duration of survival of the prosthesis, resulting in an incremental cost-effectiveness ratio for ankle arthroplasty of $18,419 per quality-adjusted life year gained. This reflects a gain of 0.52 quality-adjusted life years at a cost of $9578 when ankle arthroplasty is chosen over fusion. This ratio compares favorably with the cost-effectiveness of other medical and surgical interventions. Sensitivity analysis determined that the cost per quality-adjusted life year gained with ankle arthroplasty rises above $50,000 if the prosthesis is assumed to fail before seven years. Treatment options with ratios above $50,000 per quality-adjusted life year are commonly considered to have limited cost-effectiveness. This threshold is also crossed when the theoretical functional advantages of ankle

  18. Do Ankle Orthoses Improve Ankle Proprioceptive Thresholds or Unipedal Balance in Older Persons with Peripheral Neuropathy?

    PubMed Central

    Son, Jaebum; Ashton-Miller, James A.; Richardson, James K.

    2010-01-01

    Objective To determine whether ankle orthoses that provide medial and lateral support, and have been found to decrease gait variability in older persons with peripheral neuropathy, decrease (improve) frontal plane ankle proprioceptive thresholds or increase unipedal stance time in that same population. Design Observational study in which unipedal stance time was determined with a stopwatch, and frontal plane ankle (inversion and eversion) proprioceptive thresholds were quantified during bipedal stance with and without the ankle orthoses, in 11 older diabetic subjects with peripheral neuropathy (8 men; age 72 ± 7.1 years) using a foot cradle system which presented a series of 100 rotational stimuli. Results The subjects demonstrated no change in combined frontal plane (inversion + eversion) proprioceptive thresholds or unipedal stance time with versus without the orthoses (1.06 ± 0.56 versus 1.13 ± 0.39 degrees, respectively; p = 0.955 and 6.1 ± 6.5 versus 6.2 ± 5.4 seconds, respectively; p = 0.922). Conclusion Ankle orthoses which provide medial-lateral support do not appear to change ankle inversion/eversion proprioceptive thresholds or unipedal stance time in older persons with diabetic peripheral neuropathy. Previously identified improvements in gait variability using orthoses in this population are therefore likely related to an orthotically-induced stiffening of the ankle rather than a change in ankle afferent function. PMID:20407302

  19. Reactive oxygen species trigger motoneuron death in non-cell-autonomous models of ALS through activation of c-Abl signaling.

    PubMed

    Rojas, Fabiola; Gonzalez, David; Cortes, Nicole; Ampuero, Estibaliz; Hernández, Diego E; Fritz, Elsa; Abarzua, Sebastián; Martinez, Alexis; Elorza, Alvaro A; Alvarez, Alejandra; Court, Felipe; van Zundert, Brigitte

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease in which pathogenesis and death of motor neurons are triggered by non-cell-autonomous mechanisms. We showed earlier that exposing primary rat spinal cord cultures to conditioned media derived from primary mouse astrocyte conditioned media (ACM) that express human SOD1(G93A) (ACM-hSOD1(G93A)) quickly enhances Nav channel-mediated excitability and calcium influx, generates intracellular reactive oxygen species (ROS), and leads to death of motoneurons within days. Here we examined the role of mitochondrial structure and physiology and of the activation of c-Abl, a tyrosine kinase that induces apoptosis. We show that ACM-hSOD1(G93A), but not ACM-hSOD1(WT), increases c-Abl activity in motoneurons, interneurons and glial cells, starting at 60 min; the c-Abl inhibitor STI571 (imatinib) prevents this ACM-hSOD1(G93A)-mediated motoneuron death. Interestingly, similar results were obtained with ACM derived from astrocytes expressing SOD1(G86R) or TDP43(A315T). We further find that co-application of ACM-SOD1(G93A) with blockers of Nav channels (spermidine, mexiletine, or riluzole) or anti-oxidants (Trolox, esculetin, or tiron) effectively prevent c-Abl activation and motoneuron death. In addition, ACM-SOD1(G93A) induces alterations in the morphology of neuronal mitochondria that are related with their membrane depolarization. Finally, we find that blocking the opening of the mitochondrial permeability transition pore with cyclosporine A, or inhibiting mitochondrial calcium uptake with Ru360, reduces ROS production and c-Abl activation. Together, our data point to a sequence of events in which a toxic factor(s) released by ALS-expressing astrocytes rapidly induces hyper-excitability, which in turn increases calcium influx and affects mitochondrial structure and physiology. ROS production, mediated at least in part through mitochondrial alterations, trigger c-Abl signaling and lead to motoneuron death.

  20. Reactive oxygen species trigger motoneuron death in non-cell-autonomous models of ALS through activation of c-Abl signaling

    PubMed Central

    Rojas, Fabiola; Gonzalez, David; Cortes, Nicole; Ampuero, Estibaliz; Hernández, Diego E.; Fritz, Elsa; Abarzua, Sebastián; Martinez, Alexis; Elorza, Alvaro A.; Alvarez, Alejandra; Court, Felipe; van Zundert, Brigitte

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease in which pathogenesis and death of motor neurons are triggered by non-cell-autonomous mechanisms. We showed earlier that exposing primary rat spinal cord cultures to conditioned media derived from primary mouse astrocyte conditioned media (ACM) that express human SOD1G93A (ACM-hSOD1G93A) quickly enhances Nav channel-mediated excitability and calcium influx, generates intracellular reactive oxygen species (ROS), and leads to death of motoneurons within days. Here we examined the role of mitochondrial structure and physiology and of the activation of c-Abl, a tyrosine kinase that induces apoptosis. We show that ACM-hSOD1G93A, but not ACM-hSOD1WT, increases c-Abl activity in motoneurons, interneurons and glial cells, starting at 60 min; the c-Abl inhibitor STI571 (imatinib) prevents this ACM-hSOD1G93A-mediated motoneuron death. Interestingly, similar results were obtained with ACM derived from astrocytes expressing SOD1G86R or TDP43A315T. We further find that co-application of ACM-SOD1G93A with blockers of Nav channels (spermidine, mexiletine, or riluzole) or anti-oxidants (Trolox, esculetin, or tiron) effectively prevent c-Abl activation and motoneuron death. In addition, ACM-SOD1G93A induces alterations in the morphology of neuronal mitochondria that are related with their membrane depolarization. Finally, we find that blocking the opening of the mitochondrial permeability transition pore with cyclosporine A, or inhibiting mitochondrial calcium uptake with Ru360, reduces ROS production and c-Abl activation. Together, our data point to a sequence of events in which a toxic factor(s) released by ALS-expressing astrocytes rapidly induces hyper-excitability, which in turn increases calcium influx and affects mitochondrial structure and physiology. ROS production, mediated at least in part through mitochondrial alterations, trigger c-Abl signaling and lead to motoneuron death. PMID:26106294

  1. Management of Osseous and Soft-Tissue Ankle Equinus During Total Ankle Replacement.

    PubMed

    Roukis, Thomas S; Simonson, Devin C

    2015-10-01

    Obtaining functional alignment of a total ankle replacement, including physiologic sagittal plane range of motion, is paramount for a successful outcome. This article reviews the literature on techniques available for correction of osseous and soft-tissue equinus at the time of index total ankle replacement. These techniques include anterior tibiotalar joint cheilectomy, posterior superficial muscle compartment lengthening, posterior ankle capsule release, and release of the posterior portions of the medial and lateral collateral ligament complexes. The rationale for these procedures and the operative sequence of events for these procedures are presented. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Uptake and intracellular fate of cholera toxin subunit b-modified mesoporous silica nanoparticle-supported lipid bilayers (aka protocells) in motoneurons.

    PubMed

    Gonzalez Porras, Maria A; Durfee, Paul; Giambini, Sebastian; Sieck, Gary C; Brinker, C Jeffrey; Mantilla, Carlos B

    2018-04-01

    Cholera toxin B (CTB) modified mesoporous silica nanoparticle supported lipid bilayers (CTB-protocells) are a promising, customizable approach for targeting therapeutic cargo to motoneurons. In the present study, the endocytic mechanism and intracellular fate of CTB-protocells in motoneurons were examined to provide information for the development of therapeutic application and cargo delivery. Pharmacological inhibitors elucidated CTB-protocells endocytosis to be dependent on the integrity of lipid rafts and macropinocytosis. Using immunofluorescence techniques, live confocal and transmission electron microscopy, CTB-protocells were primarily found in the cytosol, membrane lipid domains and Golgi. There was no difference in the amount of motoneuron activity dependent uptake of CTB-protocells in neuromuscular junctions, consistent with clathrin activation at the axon terminals during low frequency activity. In conclusion, CTB-protocells uptake is mediated principally by lipid rafts and macropinocytosis. Once internalized, CTB-protocells escape lysosomal degradation, and engage biological pathways that are not readily accessible by untargeted delivery methods. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. [REACTIVE CHANGES IN SPINAL CORD MOTONEURONS AFTER SCIATIC NERVE INJURY AFTER HIGH-FREQUENCY ELECTROSURGICAL INSTRUMENT APPLICATION].

    PubMed

    Korsak, A; Chaikovsky, Yu; Sokurenko, L; Likhodiievskyi, V; Neverovskyi, A

    2016-02-01

    A new experimental model for tissues connection at peripheral nerve injury site in form of tissues welding was designed. In current study we investigated motoneuron state 1, 3, 6 and 12 weeks after peripheral nerve injury and surgical repair with high-frequency electrosurgical technology. Spinal cord sections was stained by Nissl method and observed with light microscopy. We found that postoperative period in animals from experimental groups characterized by qualitative changes in neurons from spinal motor centers that can be interpreted as compensatory processes as response to alteration. In animals from group with high-frequency electrosurgical technology usage stabilization processes passes more quickly comparatively to animals with epineural sutures. High-frequency electrosurgical technology usage provides less harmful effects on motoneurons than epineural suturing.

  4. Joint stability characteristics of the ankle complex in female athletes with histories of lateral ankle sprain, part II: clinical experience using arthrometric measurement.

    PubMed

    Kovaleski, John E; Heitman, Robert J; Gurchiek, Larry R; Hollis, J M; Liu, Wei; Pearsall, Albert W

    2014-01-01

    This is part II of a 2-part series discussing stability characteristics of the ankle complex. In part I, we used a cadaver model to examine the effects of sectioning the lateral ankle ligaments on anterior and inversion motion and stiffness of the ankle complex. In part II, we wanted to build on and apply these findings to the clinical assessment of ankle-complex motion and stiffness in a group of athletes with a history of unilateral ankle sprain. To examine ankle-complex motion and stiffness in a group of athletes with reported history of lateral ankle sprain. Cross-sectional study. University research laboratory. Twenty-five female college athletes (age = 19.4 ± 1.4 years, height = 170.2 ± 7.4 cm, mass = 67.3 ± 10.0 kg) with histories of unilateral ankle sprain. All ankles underwent loading with an ankle arthrometer. Ankles were tested bilaterally. The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness. Anterior displacement of the ankle complex did not differ between the uninjured and sprained ankles (P = .37), whereas ankle-complex rotation was greater for the sprained ankles (P = .03). The sprained ankles had less anterior and inversion end-range stiffness than the uninjured ankles (P < .01). Changes in ankle-complex laxity and end-range stiffness were detected in ankles with histories of sprain. These results indicate the presence of altered mechanical characteristics in the soft tissues of the sprained ankles.

  5. Osteoligamentous injuries of the medial ankle joint.

    PubMed

    Lötscher, P; Lang, T H; Zwicky, L; Hintermann, B; Knupp, M

    2015-12-01

    Injuries of the ankle joint have a high incidence in daily life and sports, thus, playing an important socioeconomic role. Therefore, proper diagnosis and adequate treatment are mandatory. While most of the ligament injuries around the ankle joint are treated conservatively, great controversy exists on how to treat deltoid ligament injuries in ankle fractures. Missed injuries and inadequate treatment of the medial ankle lead to inferior outcome with instability, progressive deformity, and ankle joint osteoarthritis.

  6. Ankle muscle coactivation and its relationship with ankle joint kinematics and kinetics during gait in hemiplegic patients after stroke.

    PubMed

    Kitatani, Ryosuke; Ohata, Koji; Sato, Shuhei; Watanabe, Aki; Hashiguchi, Yu; Yamakami, Natsuki; Sakuma, Kaoru; Yamada, Shigehito

    2016-06-01

    Increased ankle muscle coactivation during gait is a compensation strategy for enhancing postural stability in patients after stroke. However, no previous studies have demonstrated that increased ankle muscle coactivation influenced ankle joint movements during gait in patients after stroke. To investigate the relationship between ankle muscle coactivation and ankle joint movements in hemiplegic patients after stroke. Seventeen patients after stroke participated. The coactivation index (CoI) at the ankle joint was calculated separately for the first and second double support (DS1 and DS2, respectively) and single support (SS) phases on the paretic and non-paretic sides during gait using surface electromyography. Simultaneously, three-dimensional motion analysis was performed to measure the peak values of the ankle joint angle, moment, and power in the sagittal plane. Ground reaction forces (GRFs) of the anterior and posterior components and centers of pressure (COPs) trajectory ranges and velocities were also measured. The CoI during the SS phase on the paretic side was negatively related to ankle dorsiflexion angle, ankle plantarflexion moment, ankle joint power generation, and COP velocity on the paretic side. Furthermore, the CoI during the DS2 phase on both sides was negatively related to anterior GRF amplitude on each side. Increased ankle muscle coactivation is related to decreased ankle joint movement during the SS phase on the paretic side to enhance joint stiffness and compensate for stance limb instability, which may be useful for patients who have paretic instability during the stance phase after stroke.

  7. Drosophila female-specific Ilp7 motoneurons are generated by Fruitless-dependent cell death in males and by a double-assurance survival role for Transformer in females.

    PubMed

    Garner, Sarah Rose C; Castellanos, Monica C; Baillie, Katherine E; Lian, Tianshun; Allan, Douglas W

    2018-01-08

    Female-specific Ilp7 neuropeptide-expressing motoneurons (FS-Ilp7 motoneurons) are required in Drosophila for oviduct function in egg laying. Here, we uncover cellular and genetic mechanisms underlying their female-specific generation. We demonstrate that programmed cell death (PCD) eliminates FS-Ilp7 motoneurons in males, and that this requires male-specific splicing of the sex-determination gene fruitless ( fru ) into the Fru MC isoform. However, in females, fru alleles that only generate Fru M isoforms failed to kill FS-Ilp7 motoneurons. This blockade of Fru M -dependent PCD was not attributable to doublesex gene function but to a non-canonical role for transformer ( tra ), a gene encoding the RNA splicing activator that regulates female-specific splicing of fru and dsx transcripts. In both sexes, we show that Tra prevents PCD even when the Fru M isoform is expressed. In addition, we found that Fru MC eliminated FS-Ilp7 motoneurons in both sexes, but only when Tra was absent. Thus, Fru MC -dependent PCD eliminates female-specific neurons in males, and Tra plays a double-assurance function in females to establish and reinforce the decision to generate female-specific neurons. © 2018. Published by The Company of Biologists Ltd.

  8. Minor or occult ankle instability as a cause of anterolateral pain after ankle sprain.

    PubMed

    Vega, Jordi; Peña, Fernando; Golanó, Pau

    2016-04-01

    The aim of this study was to determine which intra-articular injuries are associated with chronic anterolateral pain and functional instability after an ankle sprain. From 2008 to 2010, records of all patients who underwent ankle joint arthroscopy with anterolateral pain and functional instability after an ankle sprain were reviewed. A systematic arthroscopic examination of the intra-articular structures of the ankle joint was performed. Location and characteristics of the injuries were identified and recorded. A total of 36 ankle arthroscopic procedures were reviewed. A soft-tissue occupying mass over the lateral recess was present in 18 patients (50%). A partial injury of the anterior talofibular ligament (ATFL) was observed in 24 patients (66.6%). Cartilage abrasion due to the distal fascicle of the anteroinferior tibiofibular ligament coming into contact with the talus was seen in 21 patients (58.3%), but no thickening of the ligament was observed. Injury to the intra-articular posterior structures, including the transverse ligament in 19 patients (52.7%) and the posterior surface of the distal tibia in 21 patients (58.3%), was observed. Intra-articular pathological findings have been observed in patients affected by anterolateral pain after an ankle sprain. Despite no demonstrable abnormal lateral laxity, morphologic ATFL abnormality has been observed on arthroscopic evaluation. An injury of the ATFL is present in patients with chronic anterolateral pain and functional instability after an ankle sprain. A degree of microinstability due to a deficiency of the ATFL could explain the intra-articular pathological findings and the patients' complaints. IV.

  9. Effect of muscle tone on ankle kinetics during gait with ankle-foot orthoses in persons with stroke.

    PubMed

    Mizuno, Shiho; Sonoda, Shigeru; Takeda, Kotaro; Maeshima, Shinichiro

    2017-12-01

    Background Individuals exhibiting hemiplegia and increased ankle plantar flexors muscle tone following stroke are frequently prescribed an ankle-foot orthosis (AFO) to regain functional ambulation. The effect of muscle tone on ankle kinetics when walking with an AFO remains unknown. Objectives To investigate the effect of plantar flexion (PF) muscle tone on ankle plantar flexion torque during walking with an ankle-foot orthosis Methods The study included 80 participants with first-ever stroke whose manual muscle testing (MMT) of ankle DF 0-4, and 10 healthy subjects. Participants were instructed to walk on a treadmill, at a comfortable speed, wearing an instrumented AFO. Minimum PF torque during the last half of swing was extracted as an outcome measure. Resistive PF torques during passive slow and fast stretches were measured with a custom-built device, with torques at 10° DF (T10°-slow and T10°-fast) extracted as defining parameters for stiffness and muscle tone, respectively. Results Correlations between both T10°-slow and T10°-fast variables with minimum PF torque were fair among ankle DF MMT 0-3 groups (r = 0.71 -0.74, p < 0.01), with no correlation observed among the MMT 4 group and healthy subjects. Conclusions Effects of muscle tone on ankle kinetics during swing phase, with an AFO, were observed in persons with severe ankle DF paresis. Quantitative evaluation of ankle kinetics during gait with an AFO in addition to evaluation of muscle tone at rest is contributory to objective assessment of a muscle tone, not subjective rating scale at rest, or visual inspection of walking.

  10. Chronic ankle instability and common fibular nerve injury.

    PubMed

    Benchortane, Michaël; Collado, Hervé; Coudreuse, Jean-Marie; Desnuelle, Claude; Viton, Jean-Michel; Delarque, Alain

    2011-03-01

    The lateral collateral ligaments of the ankle are often damaged in ankle inversion injuries. Ankle inversion may also cause injury to other structures located around the ankle or further away, such as the common fibular nerve. Few descriptions exist of common fibular nerve injury associated with ankle sprains and chronic ankle instability. We describe the case of a patient who sustained common fibular nerve injury during each of two ankle sprain recurrences involving the lateral collateral ligaments. Our objectives are to illustrate the links between common fibular nerve and lateral collateral ligament injuries and to emphasize the importance of the neurological evaluation in patients seen for ankle sprains or chronic ankle instability. Copyright © 2010 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

  11. Design of a simple, lightweight, passive-elastic ankle exoskeleton supporting ankle joint stiffness

    NASA Astrophysics Data System (ADS)

    Kim, Seyoung; Son, Youngsu; Choi, Sangkyu; Ham, Sangyong; Park, Cheolhoon

    2015-09-01

    In this study, a passive-elastic ankle exoskeleton (PEAX) with a one-way clutch mechanism was developed and then pilot-tested with vertical jumping to determine whether the PEAX is sufficiently lightweight and comfortable to be used in further biomechanical studies. The PEAX was designed to supplement the function of the Achilles tendon and ligaments as they passively support the ankle torque with their inherent stiffness. The main frame of the PEAX consists of upper and lower parts connected to each other by tension springs (N = 3) and lubricated hinge joints. The upper part has an offset angle of 5° with respect to the vertical line when the springs are in their resting state. Each spring has a slack length of 8 cm and connects the upper part to the tailrod of the lower part in the neutral position. The tailrod freely rotates with low friction but has a limited range of motion due to the stop pin working as a one-way clutch. Because of the one-way clutch system, the tension springs store the elastic energy only due to an ankle dorsiflexion when triggered by the stop pin. This clutch mechanism also has the advantage of preventing any inconvenience during ankle plantarflexion because it does not limit the ankle joint motion during the plantarflexion phase. In pilot jumping tests, all of the subjects reported that the PEAX was comfortable for jumping due to its lightweight (approximately 1 kg) and compact (firmly integrated with shoes) design, and subjects were able to nearly reach their maximum vertical jump heights while wearing the PEAX. During the countermovement jump, elastic energy was stored during dorsiflexion by spring extension and released during plantarflexion by spring restoration, indicating that the passive spring torque (i.e., supportive torque) generated by the ankle exoskeleton partially supported the ankle joint torque throughout the process.

  12. Design of a simple, lightweight, passive-elastic ankle exoskeleton supporting ankle joint stiffness.

    PubMed

    Kim, Seyoung; Son, Youngsu; Choi, Sangkyu; Ham, Sangyong; Park, Cheolhoon

    2015-09-01

    In this study, a passive-elastic ankle exoskeleton (PEAX) with a one-way clutch mechanism was developed and then pilot-tested with vertical jumping to determine whether the PEAX is sufficiently lightweight and comfortable to be used in further biomechanical studies. The PEAX was designed to supplement the function of the Achilles tendon and ligaments as they passively support the ankle torque with their inherent stiffness. The main frame of the PEAX consists of upper and lower parts connected to each other by tension springs (N = 3) and lubricated hinge joints. The upper part has an offset angle of 5° with respect to the vertical line when the springs are in their resting state. Each spring has a slack length of 8 cm and connects the upper part to the tailrod of the lower part in the neutral position. The tailrod freely rotates with low friction but has a limited range of motion due to the stop pin working as a one-way clutch. Because of the one-way clutch system, the tension springs store the elastic energy only due to an ankle dorsiflexion when triggered by the stop pin. This clutch mechanism also has the advantage of preventing any inconvenience during ankle plantarflexion because it does not limit the ankle joint motion during the plantarflexion phase. In pilot jumping tests, all of the subjects reported that the PEAX was comfortable for jumping due to its lightweight (approximately 1 kg) and compact (firmly integrated with shoes) design, and subjects were able to nearly reach their maximum vertical jump heights while wearing the PEAX. During the countermovement jump, elastic energy was stored during dorsiflexion by spring extension and released during plantarflexion by spring restoration, indicating that the passive spring torque (i.e., supportive torque) generated by the ankle exoskeleton partially supported the ankle joint torque throughout the process.

  13. Invariant ankle moment patterns when walking with and without a robotic ankle exoskeleton.

    PubMed

    Kao, Pei-Chun; Lewis, Cara L; Ferris, Daniel P

    2010-01-19

    To guide development of robotic lower limb exoskeletons, it is necessary to understand how humans adapt to powered assistance. The purposes of this study were to quantify joint moments while healthy subjects adapted to a robotic ankle exoskeleton and to determine if the period of motor adaptation is dependent on the magnitude of robotic assistance. The pneumatically powered ankle exoskeleton provided plantar flexor torque controlled by the wearer's soleus electromyography (EMG). Eleven naïve individuals completed two 30-min sessions walking on a split-belt instrumented treadmill at 1.25m/s while wearing the ankle exoskeleton. After two sessions of practice, subjects reduced their soleus EMG activation by approximately 36% and walked with total ankle moment patterns similar to their unassisted gait (r(2)=0.98+/-0.02, THSD, p>0.05). They had substantially different ankle kinematic patterns compared to their unassisted gait (r(2)=0.79+/-0.12, THSD, p<0.05). Not all of the subjects reached a steady-state gait pattern within the two sessions, in contrast to a previous study using a weaker robotic ankle exoskeleton (Gordon and Ferris, 2007). Our results strongly suggest that humans aim for similar joint moment patterns when walking with robotic assistance rather than similar kinematic patterns. In addition, greater robotic assistance provided during initial use results in a longer adaptation process than lesser robotic assistance. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. The feasibility of point-of-care ankle ultrasound examination in patients with recurrent ankle sprain and chronic ankle instability: Comparison with magnetic resonance imaging.

    PubMed

    Lee, Sun Hwa; Yun, Seong Jong

    2017-10-01

    To evaluate the feasibility of point-of-care ankle ultrasound compared with magnetic resonance imaging (MRI) for diagnosing major ligaments and Achilles tendon injuries in patients with recurrent ankle sprain and chronic instability, and to evaluate inter-observer reliability between an emergency physician and a musculoskeletal radiology fellow. A prospective cross-sectional study was conducted in an emergency department. Patients with recurrent ankle sprain and chronic instability were recruited. An emergency physician and a musculoskeletal radiology fellow independently evaluated the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), distal anterior tibiofibular ligament (ATiFL), deltoid ligament, and Achilles tendon using point-of-care ankle ultrasound. Findings were classified normal, partial tear, and complete tear. MRI was used as the reference standard. We calculated diagnostic values for point-of-care ankle ultrasound for both reviewers and compared them using DeLong's test. Intra-class correlation coefficients (ICCs) were calculated for agreement between each reviewer and the reference standard, and between the two reviewers. Eighty-five patients were enrolled. Point-of-care ankle ultrasound showed acceptable sensitivity (96.4-100%), specificity (95.0-100%), and accuracy (96.5-100%); these performance markers did not differ significantly between reviewers. Agreement between each reviewer and the reference standard was excellent (emergency physician, ICC=0.846-1.000; musculoskeletal radiology fellow, ICC=0.930-1.000), as was inter-observer agreement (ICC=0.873-1.000). Point-of-care ankle ultrasound is as precise as MRI for detecting major ankle ligament and Achilles tendon injuries; it could be used for immediate diagnosis and further pre-operative imaging. Moreover, it may reduce the interval from emergency department admission to admission for surgical intervention, and may save costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Eye movements and abducens motoneuron behavior after cholinergic activation of the nucleus reticularis pontis caudalis.

    PubMed

    Márquez-Ruiz, Javier; Escudero, Miguel

    2010-11-01

    the aim of this work was to characterize eye movements and abducens (ABD) motoneuron behavior after cholinergic activation of the nucleus reticularis pontis caudalis (NRPC). six female adult cats were prepared for chronic recording of eye movements (using the scleral search-coil technique), electroencephalography, electromyography, ponto-geniculo-occipital (PGO) waves in the lateral geniculate nucleus, and ABD motoneuron activities after microinjections of the cholinergic agonist carbachol into the NRPC. unilateral microinjections of carbachol in the NRPC induced tonic and phasic phenomena in the oculomotor system. Tonic effects consisted of ipsiversive rotation to the injected side, convergence, and downward rotation of the eyes. Phasic effects consisted of bursts of rhythmic rapid eye movements directed contralaterally to the injected side along with PGO-like waves in the lateral geniculate and ABD nuclei. Although tonic effects were dependent on the level of drowsiness, phasic effects were always present and appeared along with normal saccades when the animal was vigilant. ABD motoneurons showed phasic activities associated with ABD PGO-like waves during bursts of rapid eye movements, and tonic and phasic activities related to eye position and velocity during alertness. the cholinergic activation of the NRPC induces oculomotor phenomena that are somewhat similar to those described during REM sleep. A precise comparison of the dynamics and timing of the eye movements further suggests that a temporal organization of both NRPCs is needed to reproduce the complexity of the oculomotor behavior during REM sleep.

  16. Joint Stability Characteristics of the Ankle Complex in Female Athletes With Histories of Lateral Ankle Sprain, Part II: Clinical Experience Using Arthrometric Measurement

    PubMed Central

    Kovaleski, John E.; Heitman, Robert J.; Gurchiek, Larry R.; Hollis, J. M.; Liu, Wei; IV, Albert W. Pearsall

    2014-01-01

    Context: This is part II of a 2-part series discussing stability characteristics of the ankle complex. In part I, we used a cadaver model to examine the effects of sectioning the lateral ankle ligaments on anterior and inversion motion and stiffness of the ankle complex. In part II, we wanted to build on and apply these findings to the clinical assessment of ankle-complex motion and stiffness in a group of athletes with a history of unilateral ankle sprain. Objective: To examine ankle-complex motion and stiffness in a group of athletes with reported history of lateral ankle sprain. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: Twenty-five female college athletes (age = 19.4 ± 1.4 years, height = 170.2 ± 7.4 cm, mass = 67.3 ± 10.0 kg) with histories of unilateral ankle sprain. Intervention(s): All ankles underwent loading with an ankle arthrometer. Ankles were tested bilaterally. Main Outcome Measure(s): The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness. Results: Anterior displacement of the ankle complex did not differ between the uninjured and sprained ankles (P = .37), whereas ankle-complex rotation was greater for the sprained ankles (P = .03). The sprained ankles had less anterior and inversion end-range stiffness than the uninjured ankles (P < .01). Conclusions: Changes in ankle-complex laxity and end-range stiffness were detected in ankles with histories of sprain. These results indicate the presence of altered mechanical characteristics in the soft tissues of the sprained ankles. PMID:24568223

  17. Directing clinical care using lower extremity biomechanics in patients with ankle osteoarthritis and ankle arthroplasty.

    PubMed

    Queen, Robin

    2017-11-01

    Ankle osteoarthritis is a debilitating disease with approximately 50,000 new cases per year leading to skeletal deformity, severe and recurrent pain, cartilage breakdown, and gait dysfunction limiting patient mobility and well-being. Although many treatments (total ankle arthroplasty [TAA], ankle fusion [arthrodesis], and ankle distraction arthroplasty) relieve pain, it is not clear that these procedures significantly improve patient mobility. The goal of the research presented here is to summarize what is presently known about lower extremity gait mechanics and outcomes and to quantify the impact of ankle osteoarthritis and TAA have on these measures using an explicitly holistic and mechanistic approach. Our recent studies have explored physical performance and energy recovery and revealed unexpected patterns and sequelae to treatment including incomplete restoration of gait function. These studies demonstrated for the first time the extreme levels and range of gait and balance dysfunction present in ankle osteoarthritis patients as well as quantifying the ways in which the affected joint alters movement and loading patterns not just in the painful joint, but throughout both the ipsilateral and contralateral lower extremity. Through this work, we determined that relieving pain alone through TAA is not enough to restore normal walking mechanics and balance due to underlying causes including limited ankle range of motion and balance deficits leading to long-term disability despite treatment. The results indicate the need to consider additional therapeutic interventions aimed at restoring balance, ankle range of motion, and movement symmetry in order to improve long-term health and function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2345-2355, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Neuromuscular Junction Formation between Human Stem cell-derived Motoneurons and Human Skeletal Muscle in a Defined System

    PubMed Central

    Guo, Xiufang; Gonzalez, Mercedes; Stancescu, Maria; Vandenburgh, Herman; Hickman, James

    2011-01-01

    Functional in vitro models composed of human cells will constitute an important platform in the next generation of system biology and drug discovery. This study reports a novel human-based in vitro Neuromuscular Junction (NMJ) system developed in a defined serum-free medium and on a patternable non-biological surface. The motoneurons and skeletal muscles were derived from fetal spinal stem cells and skeletal muscle stem cells. The motoneurons and skeletal myotubes were completely differentiated in the co-culture based on morphological analysis and electrophysiology. NMJ formation was demonstrated by phase contrast microscopy, immunocytochemistry and the observation of motoneuron-induced muscle contractions utilizing time lapse recordings and their subsequent quenching by D-Tubocurarine. Generally, functional human based systems would eliminate the issue of species variability during the drug development process and its derivation from stem cells bypasses the restrictions inherent with utilization of primary human tissue. This defined human-based NMJ system is one of the first steps in creating functional in vitro systems and will play an important role in understanding NMJ development, in developing high information content drug screens and as test beds in preclinical studies for spinal or muscular diseases/injuries such as muscular dystrophy, Amyotrophic lateral sclerosis and spinal cord repair. PMID:21944471

  19. Neuromuscular junction formation between human stem cell-derived motoneurons and human skeletal muscle in a defined system.

    PubMed

    Guo, Xiufang; Gonzalez, Mercedes; Stancescu, Maria; Vandenburgh, Herman H; Hickman, James J

    2011-12-01

    Functional in vitro models composed of human cells will constitute an important platform in the next generation of system biology and drug discovery. This study reports a novel human-based in vitro Neuromuscular Junction (NMJ) system developed in a defined serum-free medium and on a patternable non-biological surface. The motoneurons and skeletal muscles were derived from fetal spinal stem cells and skeletal muscle stem cells. The motoneurons and skeletal myotubes were completely differentiated in the co-culture based on morphological analysis and electrophysiology. NMJ formation was demonstrated by phase contrast microscopy, immunocytochemistry and the observation of motoneuron-induced muscle contractions utilizing time-lapse recordings and their subsequent quenching by d-Tubocurarine. Generally, functional human based systems would eliminate the issue of species variability during the drug development process and its derivation from stem cells bypasses the restrictions inherent with utilization of primary human tissue. This defined human-based NMJ system is one of the first steps in creating functional in vitro systems and will play an important role in understanding NMJ development, in developing high information content drug screens and as test beds in preclinical studies for spinal or muscular diseases/injuries such as muscular dystrophy, Amyotrophic lateral sclerosis and spinal cord repair. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Development and validation of the Sports Athlete Foot and Ankle Score: an instrument for sports-related ankle injuries.

    PubMed

    Morssinkhof, M L A; Wang, O; James, L; van der Heide, H J L; Winson, I G

    2013-09-01

    Many existing scoring systems assess ankle function, but there is no evidence that any of them has been validated in a group of patients with a higher demand on their ankle function. Problems include ceiling effects, not being able to detect change or they do not contain a sports-subscale. The aim of this study was to create a validated self-administered scoring system for ankle injuries in the higher performing athlete. First, 26 patients were interviewed to solicit opinions needed to create the final score, which is modified from the Foot and Ankle Outcome Score (FAOS). Second, SAFAS was validated in a group of 25 athletes with and 14 athletes without ankle injury. It is a self-administered region specific sports foot and ankle score that contains four subscales assessing the levels of symptoms, pain, daily living and sports. The Spearman correlation coefficients between SAFAS and the Foot and Ankle Ability Measure (FAAM) ranged from 0.78 to 0.88. Content validity is established by key informant interviews, expert opinions and a high satisfaction rate of 75%. Cronbach's alpha indicated good internal consistency of each subscale ranging from 0.77 to 0.92. SAFAS has shown good evidence for being a valid instrudent for assessing sports-related ankle injuries in high-performing athletes. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  1. Four Weeks of Balance Training does not Affect Ankle Joint Stiffness in Subjects with Unilateral Chronic Ankle Instability

    PubMed Central

    Jain, Tarang Kumar; Wauneka, Clayton N.; Liu, Wen

    2016-01-01

    Background Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with chronic ankle instability (CAI) but the biomechanical pathways underlying the clinical outcomes are still unknown. This study was conducted to determine if a 4-week balance training intervention can alter the mechanical characteristics in ankles with CAI. Methods Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n = 11, 35.1 ± 9.3 years) or intervention (n = 11, 33.5 ± 6.6 years) group. Subjects in the intervention group were trained on the affected limb with static and dynamic components using a Biodex balance stability system for 4-weeks. The ankle joint stiffness and neutral zone in inversion and eversion directions on the involved and uninvolved limbs was measured at baseline and post-intervention using a dynamometer. Results At baseline, the mean values of the inversion stiffness (0.69 ± 0.37 Nm/degree) in the involved ankle was significantly lower (p < 0.011, 95% CI [0.563, 0.544]) than that of uninvolved contralateral ankle (0.99 ± 0.41 Nm/degree). With the available sample size, the eversion stiffness, inversion neutral zone, and eversion neutral zone were not found to be significantly different between the involved and uninvolved contralateral ankles. The 4-week balance training intervention failed to show any significant effect on the passive ankle stiffness and neutral zones in inversion and eversion. Conclusion Decreased inversion stiffness in the involved chronic unstable ankle was found that of uninvolved contralateral ankle. The 4-week balance training program intervention was ineffective in altering the mechanical characteristics of ankles with CAI. Level of evidence Randomized controlled clinical trial; Level of evidence, 1. PMID:27642647

  2. Posterior impingement syndromes of the ankle.

    PubMed

    Lee, Justin C; Calder, James D F; Healy, Jeremiah C

    2008-06-01

    Acute, or repetitive, compression of the posterior structures of the ankle may lead to posterior ankle impingement (PAI) syndrome, posteromedial ankle impingement (PoMI) syndrome, or Haglund's syndrome. The etiology of each of these conditions is quite different. Variations in posterior ankle osseous and soft tissue anatomy contribute to the etiology of PAI and Haglund's syndromes. The presence of an os trigonum or Stieda process is classically associated with PAI syndrome, whereas a prominent posterosuperior tubercle of the os calcis or Haglund's deformity is the osseous predisposing factor in Haglund's syndrome. PoMI has no defined predisposing anatomical variants but typically follows an inversion-supination injury of the ankle joint. This article discusses the biomechanics, clinical features, imaging, and management of each of these conditions. Magnetic resonance imaging (MRI) provides the optimal tool in posterior ankle assessment, and this review focuses on the MRI findings of each of the conditions just listed.

  3. Adaptations of motoneuron properties to chronic compensatory muscle overload

    PubMed Central

    Hałuszka, A.; Mrówczyński, W.; Gardiner, P. F.; Celichowski, J.

    2015-01-01

    The aim of the study was to determine whether chronic muscle overload has measurable effect on electrophysiological properties of motoneurons (MNs), and whether duration of this overload influences intensity of adaptations. The compensatory overload was induced in the rat medial gastrocnemius (MG) by bilateral tenotomy of its synergists (lateral gastrocnemius, soleus, and plantaris); as a result, only the MG was able to evoke the foot plantar flexion. To assure regular activation of the MG muscle, rats were placed in wheel-equipped cages and subjected to a low-level treadmill exercise. The intracellular recordings from MG motoneurons were made after 5 or 12 wk of the overload, and in a control group of intact rats. Some of the passive and threshold membrane properties as well as rhythmic firing properties were considerably modified in fast-type MNs, while remaining unaltered in slow-type MNs. The significant changes included a shortening of the spike duration and the spike rise time, an increase of the afterhyperpolarization amplitude, an increase of the input resistance, a decrease of the rheobase, and a decrease of the minimum current necessary to evoke steady-state firing. The data suggest higher excitability of fast-type MNs innervating the overloaded muscle, and a shift towards electrophysiological properties of slow-type MNs. All of the adaptations could be observed after 5 wk of the compensatory overload with no further changes occurring after 12 wk. This indicates that the response to an increased level of chronic activation of MNs is relatively quick and stable. PMID:25695651

  4. Depletion of TDP-43 affects Drosophila motoneurons terminal synapsis and locomotive behavior.

    PubMed

    Feiguin, Fabian; Godena, Vinay K; Romano, Giulia; D'Ambrogio, Andrea; Klima, Raffaella; Baralle, Francisco E

    2009-05-19

    Pathological modifications in the highly conserved and ubiquitously expressed heterogeneous ribonucleoprotein TDP-43 were recently associated to neurodegenerative diseases including amyotrophic lateral sclerosis (ALS), a late-onset disorder that affects predominantly motoneurons [Neumann, M. et al. (2006) Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science 314, 130-133, Sreedharan, J. et al. (2008) TDP-43 mutations in familial and sporadic amyotrophic lateral sclerosis. Science 319, 1668-1672, Kabashi, E. et al. (2008) TARDBP mutations in individuals with sporadic and familial amyotrophic lateral sclerosis. Nat. Genet. 40, 572-574]. However, the function of TDP-43 in vivo is unknown and a possible direct role in neurodegeneration remains speculative. Here, we report that flies lacking Drosophila TDP-43 appeared externally normal but presented deficient locomotive behaviors, reduced life span and anatomical defects at the neuromuscular junctions. These phenotypes were rescued by expression of the human protein in a restricted group of neurons including motoneurons. Our results demonstrate the role of this protein in vivo and suggest an alternative explanation to ALS pathogenesis that may be more due to the lack of TDP 43 function than to the toxicity of the aggregates.

  5. Method to Reduce Muscle Fatigue During Transcutaneous Neuromuscular Electrical Stimulation in Major Knee and Ankle Muscle Groups.

    PubMed

    Sayenko, Dimitry G; Nguyen, Robert; Hirabayashi, Tomoyo; Popovic, Milos R; Masani, Kei

    2015-09-01

    A critical limitation with transcutaneous neuromuscular electrical stimulation as a rehabilitative approach is the rapid onset of muscle fatigue during repeated contractions. We have developed a method called spatially distributed sequential stimulation (SDSS) to reduce muscle fatigue by distributing the center of electrical field over a wide area within a single stimulation site, using an array of surface electrodes. To extend the previous findings and to prove feasibility of the method by exploring the fatigue-reducing ability of SDSS for lower limb muscle groups in the able-bodied population, as well as in individuals with spinal cord injury (SCI). SDSS was delivered through 4 active electrodes applied to the knee extensors and flexors, plantarflexors, and dorsiflexors, sending a stimulation pulse to each electrode one after another with 90° phase shift between successive electrodes. Isometric ankle torque was measured during fatiguing stimulations using SDSS and conventional single active electrode stimulation lasting 2 minutes. We demonstrated greater fatigue-reducing ability of SDSS compared with the conventional protocol, as revealed by larger values of fatigue index and/or torque peak mean in all muscles except knee flexors of able-bodied individuals, and in all muscles tested in individuals with SCI. Our study has revealed improvements in fatigue tolerance during transcutaneous neuromuscular electrical stimulation using SDSS, a stimulation strategy that alternates activation of subcompartments of muscles. The SDSS protocol can provide greater stimulation times with less decrement in mechanical output compared with the conventional protocol. © The Author(s) 2014.

  6. Ankle Distraction Arthroplasty: Indications, Technique, and Outcomes.

    PubMed

    Bernstein, Mitchell; Reidler, Jay; Fragomen, Austin; Rozbruch, S Robert

    2017-02-01

    Ankle distraction is an alternative to ankle arthrodesis or total ankle arthroplasty in younger patients with arthritis. Ankle distraction involves the use of external fixation to mechanically unload the ankle joint, which allows for stable, congruent range of motion in the setting of decreased mechanical loading, potentially promoting cartilage repair. Adjunct surgical procedures are frequently done to address lower-extremity malalignment, ankle equinus contractures, and impinging tibiotalar osteophytes. Patients can bear full weight during the treatment course. The distraction frame frequently uses a hinge, and patients are encouraged to do daily range-of-motion exercises. Although the initial goal of the procedure is to delay arthrodesis, many patients achieve lasting clinical benefits, obviating the need for total ankle arthroplasty or fusion. Complications associated with external fixation are common, and patients should be counseled that clinical improvements occur slowly and often are not achieved until at least 1 year after frame removal.

  7. The cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains.

    PubMed

    Fatoye, Francis; Haigh, Carol

    2016-05-01

    To examine the cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains. Economic evaluation based on cost-utility analysis. Ankle sprains are a source of morbidity and absenteeism from work, accounting for 15-20% of all sports injuries. Semi-rigid ankle brace and taping are functional treatment interventions used by Musculoskeletal Physiotherapists and Nurses to facilitate return to work following acute ankle sprains. A decision model analysis, based on cost-utility analysis from the perspective of National Health Service was used. The primary outcomes measure was incremental cost-effectiveness ratio, based on quality-adjusted life years. Costs and quality of life data were derived from published literature, while model clinical probabilities were sourced from Musculoskeletal Physiotherapists. The cost and quality adjusted life years gained using semi-rigid ankle brace was £184 and 0.72 respectively. However, the cost and quality adjusted life years gained following taping was £155 and 0.61 respectively. The incremental cost-effectiveness ratio for the semi-rigid brace was £263 per quality adjusted life year. Probabilistic sensitivity analysis showed that ankle brace provided the highest net-benefit, hence the preferred option. Taping is a cheaper intervention compared with ankle brace to facilitate return to work following first-time ankle sprains. However, the incremental cost-effectiveness ratio observed for ankle brace was less than the National Institute for Health and Care Excellence threshold and the intervention had a higher net-benefit, suggesting that it is a cost-effective intervention. Decision-makers may be willing to pay £263 for an additional gain in quality adjusted life year. The findings of this economic evaluation provide justification for the use of semi-rigid ankle brace by Musculoskeletal Physiotherapists and Nurses to facilitate return to work in individuals with first-time ankle

  8. Effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability.

    PubMed

    Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn

    2018-01-01

    [Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.

  9. Musculoskeletal ultrasonography delineates ankle symptoms in rheumatoid arthritis.

    PubMed

    Toyota, Yukihiro; Tamura, Maasa; Kirino, Yohei; Sugiyama, Yumiko; Tsuchida, Naomi; Kunishita, Yosuke; Kishimoto, Daiga; Kamiyama, Reikou; Miura, Yasushi; Minegishi, Kaoru; Yoshimi, Ryusuke; Ueda, Atsuhisa; Nakajima, Hideaki

    2017-05-01

    To clarify the use of musculoskeletal ultrasonography (US) of ankle joints in rheumatoid arthritis (RA). Consecutive RA patients with or without ankle symptoms participated in the study. The US, clinical examination (CE), and patients' visual analog scale for pain (pVAS) for ankles were assessed. Prevalence of tibiotalar joint synovitis and tenosynovitis were assessed by grayscale (GS) and power Doppler (PD) US using a semi-quantitative grading (0-3). The positive US and CE findings were defined as GS score ≥2 and/or PD score ≥1, and joint swelling and/or tenderness, respectively. Multivariate analysis with the generalized linear mixed model was performed by assigning ankle pVAS as a dependent variable. Among a total of 120 ankles from 60 RA patients, positive ankle US findings were found in 21 (35.0%) patients. The concordance rate of CE and US was moderate (kappa 0.57). Of the 88 CE negative ankles, US detected positive findings in 9 (10.2%) joints. Multivariate analysis revealed that ankle US, clinical disease activity index, and foot Health Assessment Questionnaire, but not CE, was independently associated with ankle pVAS. US examination is useful to illustrate RA ankle involvement, especially for patients who complain ankle pain but lack CE findings.

  10. Glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners.

    PubMed

    Tai, Suh-Jun; Liu, Ren-Shyan; Kuo, Ya-Chen; Hsu, Chi-Yang; Chen, Chi-Hsien

    2010-04-30

    The aim of this study was to determine glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners. Positron emission tomography (PET) using 18F-fluoro-2-deoxyglucose (FDG) was performed to determine the patterns of glucose uptake in lower limbs of short-distance (SD group, n=8) and long-distance (LD group, n=8) male runners after a modified 20 min Bruce treadmill test. Magnetic resonance imaging (MRI) was used to delineate the muscle groups in lower limbs. Muscle groups from hip, knee, and ankle movers were measured. The total FDG uptake and the standard uptake value (SUV) for each muscle group were compared between the 2 groups. For the SD and LD runners, the 2 major muscle groups utilizing glucose during running were knee extensors and ankle plantarflexors, which accounted for 49.3 +/- 8.1% (25.1 +/- 4.7% and 24.2 +/- 6.0%) of overall lower extremity glucose uptake for SD group, and 51.3 +/- 8.0% (27.2 +/- 2.7% and 24.0 +/- 8.1%) for LD group. No difference in muscle glucose uptake was noted for other muscle groups. For SD runners, the SUVs for the muscle groups varied from 0.49 +/- 0.27 for the ankle plantarflexors, to 0.20 +/- 0.08 for the hip flexor. For the LD runners, the highest and lowest SUVs were 0.43 +/- 0.15 for the ankle dorsiflexors and 0.21 +/- 0.19 for the hip. For SD and LD groups, no difference in muscle SUV was noted for the muscle groups. However, the SUV ratio between the ankle dorsiflexors and plantarflexors in the LD group was significantly greater than that in the SD group. We thus conclude that the major propelling muscle groups account for approximately 50% of lower limb glucose utilization during running. Thus, the other muscle groups involving maintenance of balance, limb deceleration, and shock absorption utilize an equal amount. This result provides a new insight into glucose distribution in skeletal muscle, suggesting that propellers and supporters are both energetically important

  11. Quantitative evaluation of the viscoelastic properties of the ankle joint complex in patients suffering from ankle sprain by the anterior drawer test.

    PubMed

    Lin, Che-Yu; Shau, Yio-Wha; Wang, Chung-Li; Chai, Huei-Ming; Kang, Jiunn-Horng

    2013-06-01

    Biological tissues such as ligaments exhibit viscoelastic behaviours. Injury to the ligament may induce changes of these viscoelastic properties, and these changes could serve as biomarkers to detect the injury. In the present study, a novel instrument was developed to non-invasive quantify the viscoelastic properties of the ankle in vivo by the anterior drawer test. The purpose of the study was to investigate the reliability of the instrument and to compare the viscoelastic properties of the ankle between patients suffering from ankle sprain and controls. Eight patients and eight controls participated in the present study. The reliability test was performed on three randomly chosen subjects. In patient and control test, both ankles of each subject were tested to evaluate the viscoelastic properties of the ankle. The viscosity index was defined for quantitatively evaluating the viscosity of the ankle. Greater viscosity index was associated with lower viscosity. Injured and uninjured ankles of patient and both ankles of controls were compared. The instrument exhibited excellent test-retest reliability (r > 0.9). Injured ankles exhibited significantly less viscosity than uninjured ankles, since injured ankles of patients had significantly higher viscosity index (8,148 ± 5,266) compared with uninjured ankles of patients (948 ± 617; p = 0.008) and controls (1,326 ± 613; p < 0.001). The study revealed that the viscoelastic properties of the ankle can serve as sensitive and useful clinical biomarkers to differentiate between injured and uninjured ankles. The method may provide a clinical examination for objectively evaluating lateral ankle ligament injuries.

  12. Functional Motor Recovery from Motoneuron Axotomy Is Compromised in Mice with Defective Corticospinal Projections

    PubMed Central

    Ding, Yuetong; Qu, Yibo; Feng, Jia; Wang, Meizhi; Han, Qi; So, Kwok-Fai; Wu, Wutian; Zhou, Libing

    2014-01-01

    Brachial plexus injury (BPI) and experimental spinal root avulsion result in loss of motor function in the affected segments. After root avulsion, significant motoneuron function is restored by re-implantation of the avulsed root. How much this functional recovery depends on corticospinal inputs is not known. Here, we studied that question using Celsr3|Emx1 mice, in which the corticospinal tract (CST) is genetically absent. In adult mice, we tore off right C5–C7 motor and sensory roots and re-implanted the right C6 roots. Behavioral studies showed impaired recovery of elbow flexion in Celsr3|Emx1 mice compared to controls. Five months after surgery, a reduced number of small axons, and higher G-ratio of inner to outer diameter of myelin sheaths were observed in mutant versus control mice. At early stages post-surgery, mutant mice displayed lower expression of GAP-43 in spinal cord and of myelin basic protein (MBP) in peripheral nerves than control animals. After five months, mutant animals had atrophy of the right biceps brachii, with less newly formed neuromuscular junctions (NMJs) and reduced peak-to-peak amplitudes in electromyogram (EMG), than controls. However, quite unexpectedly, a higher motoneuron survival rate was found in mutant than in control mice. Thus, following root avulsion/re-implantation, the absence of the CST is probably an important reason to hamper axonal regeneration and remyelination, as well as target re-innervation and formation of new NMJ, resulting in lower functional recovery, while fostering motoneuron survival. These results indicate that manipulation of corticospinal transmission may help improve functional recovery following BPI. PMID:25003601

  13. The effect of external ankle support on knee and ankle joint movement and loading in netball players.

    PubMed

    Vanwanseele, Benedicte; Stuelcken, Max; Greene, Andrew; Smith, Richard

    2014-09-01

    External ankle support has been successfully used to prevent ankle sprains. However, some recent studies have indicated that reducing ankle range of motion can place larger loads on the knee. The aim of this study was to investigate the effect of external ankle support (braces and high-top shoes) on the ankle and knee joint loading during a netball specific landing task. A repeated measure design. High performance netball players with no previously diagnosed severe ankle or knee injury (n=11) were recruited from NSW Institute of Sport netball programme. The kinematic and kinetic data were collected simultaneously using a 3-D Motion Analysis System and one Kistler force plate to measure ground reaction forces. Players performed a single leg landing whilst receiving a pass while wearing a standard netball shoe, the same shoe with a lace-up brace and a high-top shoe. Only the brace condition significantly reduced the ankle range of motion in the frontal plane (in/eversion) by 3.95 ± 3.74 degrees compared to the standard condition. No changes were found for the knee joint loading in the brace condition. The high-top shoes acted to increase the peak knee internal rotation moment by 15%. Both the brace and high-top conditions brought about increases in the peak ankle plantar flexion moment during the landing phase. Lace-up braces can be used by netball players to restrict ankle range of motion during a single leg landing while receiving a pass without increasing the load on the knee joint. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  14. Clinical evaluation of a new noninvasive ankle arthrometer.

    PubMed

    Nauck, Tanja; Lohrer, Heinz; Gollhofer, Albert

    2010-06-01

    A nonradiographic arthrometer was developed to objectively quantify anterior talar drawer instability in stable and unstable ankles. Diagnostic validity of this device was previously demonstrated in a cadaver study. The aim of the present study was to validate the ankle arthrometer in an in vivo setting. Twenty-three subjects participated in the study. An orthopedic surgeon first performed a manual anterior talar drawer test to classify the subjects' ankles as stable or unstable. The subjects were then evaluated using the ankle arthrometer, and filled out a validated self-reported questionnaire (German version of the Foot and Ankle Ability Measure [FAAM-G]). Ankle stiffness was calculated from the low linear region (40-60 N) of the load deformation curves obtained from the ankle arthrometer. Reliability testing of these stiffness values was done based on load deformation curves, with 150 and 200 N maximum anterior drawer loads applied in the ankle arthrometer. Using the manual anterior drawer test, 16 ankles were classified as stable and 7 were classified as unstable. Arthrometer stiffness analysis differentiated stable from unstable ankles (P = 0.00 and P = 0.01, respectively). Test-retest demonstrated an accurate reliability (intraclass correlation coefficient = 0.80). A significant correlation was found between both FAAM-G subscales and the arthrometer stiffness values (r = 0.43 and 0.54; P = 0.04 and 0.01). Discussion Subjects with and without mechanical ankle instability could be differentiated by ankle arthrometer stiffness analysis and the FAAM-G questionnaire results. This nonradiographic device may be relevant for screening athletes at risk for ankle injuries, for clinical follow-up studies, and implementing preventive strategies. Validity and reliability of the new ankle arthrometer is demonstrated in a small cohort in an in vivo setting.

  15. RNA content in spinal cord motoneurons during hypokinesia

    NASA Technical Reports Server (NTRS)

    Gorbunova, A. V.

    1980-01-01

    The effect of a diminished motor activity of rats upon the ribonucleic and (RNA) content in a single isolated motoneuron of frontal of their spinal cord was studied. Within a 1 to 30 day exposure of rats to the hypokinetic conditions, RNA content was found to decrease on the 1st, 3rd, and 5th day and to return to the initial level by the 7th day. No changes in RNA content were observed during the subsequent stages of the xperiments. The volume of the nerve cells declined on the 3rd and 5th day, whereas RNA concentration reduced on the 1st, 3rd, 5th, and 30th day.

  16. Loss of Ranbp2 in motoneurons causes disruption of nucleocytoplasmic and chemokine signaling, proteostasis of hnRNPH3 and Mmp28, and development of amyotrophic lateral sclerosis-like syndromes.

    PubMed

    Cho, Kyoung-In; Yoon, Dosuk; Qiu, Sunny; Danziger, Zachary; Grill, Warren M; Wetsel, William C; Ferreira, Paulo A

    2017-05-01

    The pathogenic drivers of sporadic and familial motor neuron disease (MND), such amyotrophic lateral sclerosis (ALS), are unknown. MND impairs the Ran GTPase cycle, which controls nucleocytoplasmic transport, ribostasis and proteostasis; however, cause-effect mechanisms of Ran GTPase modulators in motoneuron pathobiology have remained elusive. The cytosolic and peripheral nucleoporin Ranbp2 is a crucial regulator of the Ran GTPase cycle and of the proteostasis of neurological disease-prone substrates, but the roles of Ranbp2 in motoneuron biology and disease remain unknown. This study shows that conditional ablation of Ranbp2 in mouse Thy1 motoneurons causes ALS syndromes with hypoactivity followed by hindlimb paralysis, respiratory distress and, ultimately, death. These phenotypes are accompanied by: a decline in the nerve conduction velocity, free fatty acids and phophatidylcholine of the sciatic nerve; a reduction in the g-ratios of sciatic and phrenic nerves; and hypertrophy of motoneurons. Furthermore, Ranbp2 loss disrupts the nucleocytoplasmic partitioning of the import and export nuclear receptors importin β and exportin 1, respectively, Ran GTPase and histone deacetylase 4. Whole-transcriptome, proteomic and cellular analyses uncovered that the chemokine receptor Cxcr4, its antagonizing ligands Cxcl12 and Cxcl14, and effector, latent and activated Stat3 all undergo early autocrine and proteostatic deregulation, and intracellular sequestration and aggregation as a result of Ranbp2 loss in motoneurons. These effects were accompanied by paracrine and autocrine neuroglial deregulation of hnRNPH3 proteostasis in sciatic nerve and motoneurons, respectively, and post-transcriptional downregulation of metalloproteinase 28 in the sciatic nerve. Mechanistically, our results demonstrate that Ranbp2 controls nucleocytoplasmic, chemokine and metalloproteinase 28 signaling, and proteostasis of substrates that are crucial to motoneuronal homeostasis and whose impairments

  17. Footwear and ankle stability in the basketball player.

    PubMed

    Petrov, O; Blocher, K; Bradbury, R L; Saxena, A; Toy, M L

    1988-04-01

    Ankle stability in basketball players is affected by footwear. Athletic shoe manufacturers have introduced specialized lacing systems and high-top performance shoes to improve ankle stability. These performance shoes not only aid in preventing ankle injuries, but also protect injured ankles.

  18. Ankle mechanics during sidestep cutting implicates need for 2-degrees of freedom powered ankle-foot prostheses.

    PubMed

    Ficanha, Evandro M; Rastgaar, Mohammad; Kaufman, Kenton R

    2015-01-01

    The ankle joint of currently available powered prostheses is capable of controlling one degree of freedom (DOF), focusing on improved mobility in the sagittal plane. To increase agility, the requirements of turning in prosthesis design need to be considered. Ankle kinematics and kinetics were studied during sidestep cutting and straight walking. There were no significant differences between the ankle sagittal plane mechanics when comparing sidestep cutting and straight walking; however, significant differences were observed in ankle frontal plane mechanics. During straight walking, the inversion-eversion (IE) angles were smaller than with sidestep cutting. The ankle that initiated the sidestep cutting showed progressively increasing inversion from 2 to 13 degrees while the following contralateral step showed progressively decreasing inversion from 8 to -4 degrees during normal walking speed. The changes in IE kinematics were the most significant during sidestep cutting compared with straight walking. The IE moments of the step that initiated the sidestep cutting were always in eversion, acting as a braking moment opposing the inverting motion. This suggests that an ankle-foot prosthesis with active DOFs in the sagittal and frontal planes will increase the agility of gait for patients with limb loss.

  19. Modeling and stress analyses of a normal foot-ankle and a prosthetic foot-ankle complex.

    PubMed

    Ozen, Mustafa; Sayman, Onur; Havitcioglu, Hasan

    2013-01-01

    Total ankle replacement (TAR) is a relatively new concept and is becoming more popular for treatment of ankle arthritis and fractures. Because of the high costs and difficulties of experimental studies, the developments of TAR prostheses are progressing very slowly. For this reason, the medical imaging techniques such as CT, and MR have become more and more useful. The finite element method (FEM) is a widely used technique to estimate the mechanical behaviors of materials and structures in engineering applications. FEM has also been increasingly applied to biomechanical analyses of human bones, tissues and organs, thanks to the development of both the computing capabilities and the medical imaging techniques. 3-D finite element models of the human foot and ankle from reconstruction of MR and CT images have been investigated by some authors. In this study, data of geometries (used in modeling) of a normal and a prosthetic foot and ankle were obtained from a 3D reconstruction of CT images. The segmentation software, MIMICS was used to generate the 3D images of the bony structures, soft tissues and components of prosthesis of normal and prosthetic ankle-foot complex. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones, soft tissues and components of prosthesis were independently developed to form foot and ankle complex. SOLIDWORKS program was used to form the boundary surfaces of all model components and then the solid models were obtained from these boundary surfaces. Finite element analyses software, ABAQUS was used to perform the numerical stress analyses of these models for balanced standing position. Plantar pressure and von Mises stress distributions of the normal and prosthetic ankles were compared with each other. There was a peak pressure increase at the 4th metatarsal, first metatarsal and talus bones and a decrease at the intermediate cuneiform and calcaneus bones, in

  20. Static Postural Stability in Chronic Ankle Instability, An Ankle Sprain and Healthy Ankles.

    PubMed

    Kwon, Yong Ung

    2018-05-18

    To identify the single leg balance (SLB) test that discriminates among healthy, coper, and chronic ankle instability (CAI) groups and to determine effects of ankle muscles on the balance error scoring system (BESS) among the three populations. 60 subjects (20 per group) performed the SLB test with eyes open (EO) and eyes closed (EC). Normalized mean amplitude (NMA) of the tibia anterior (TA), fibularis longus (FL), and medial gastrocnemius (MG) muscles and BESS were measured while performing the SLB test. The coper group had a lower error score than the CAI group in the EC. NMA was greater in the CAI group compared to in the healthy and coper groups regardless of muscle type. NMA of the TA was less than the PL and MG regardless of the group in the EO. The CAI group demonstrated greater NMAs of the PL and MG than the healthy and coper groups in the EC. The CAI group demonstrated greater NMA of the PL and MG by compensating their ankle muscles in the EO and EC. BESS suggests that the coper group may have coping mechanisms to stabilize static postural control compared to the CAI group. The EC may be better to detect static postural instability in the CAI or coper group. © Georg Thieme Verlag KG Stuttgart · New York.

  1. The Cumberland Ankle Instability Tool (CAIT) in the Dutch population with and without complaints of ankle instability.

    PubMed

    Vuurberg, Gwendolyn; Kluit, Lana; van Dijk, C Niek

    2018-03-01

    To develop a translated Dutch version of the Cumberland Ankle Instability Tool (CAIT) and test its psychometric properties in a Dutch population with foot and ankle complaints. The CAIT was translated into the Dutch language using a forward-backward translation design. Of the 130 subsequent patients visiting the outpatient clinic for foot and ankle complaints who were asked to fill out a questionnaire containing the CAIT, the Foot and Ankle Outcome Score (FAOS), and the numeric rating scale (NRS) pain, 98 completed the questionnaire. After a 1-week period, patients were asked to fill out a second questionnaire online containing the CAIT and NRS pain. This second questionnaire was completed by 70 patients. With these data, the construct validity, test-retest reliability, internal consistency, measurement error, and ceiling and floor effects were assessed. Additionally, a cut-off value to discriminate between stable and unstable ankles, in patients with ankle complaints, was calculated. Construct validity showed moderate correlations between the CAIT and FAOS subscales (Spearman's correlation coefficient (SCC) = 0.36-0.43), and the NRS pain (SCC = -0.55). The cut-off value was found at 11.5 points of the total CAIT score (range 0-30). Test-retest reliability showed to be excellent with an intraclass correlation coefficient of 0.94. Internal consistency was high (Cronbach's α = 0.86). No ceiling or floor effects were detected. Based on the results, the Dutch version of the CAIT is a valid and reliable questionnaire to assess ankle instability in the Dutch population and is able to differentiate between a functionally unstable and stable ankle. The tool is the first suitable tool to objectify the severity of ankle instability specific complaints and assess change in the Dutch population. Level of evidence II.

  2. Ankle Fractures Often Not Diagnosed

    MedlinePlus

    ... top of the talus is dome-shaped and... Softball Injuries to the Foot and Ankle Your feet ... ankles take a beating when you are playing softball. Softball players should be aware of the following ...

  3. Total ankle arthroplasty versus ankle arthrodesis for the treatment of end-stage ankle arthritis: a meta-analysis of comparative studies.

    PubMed

    Kim, Hyun Jung; Suh, Dong Hun; Yang, Jae Hyuk; Lee, Jin Woo; Kim, Hak Jun; Ahn, Hyeong Sik; Han, Seung Woo; Choi, Gi Won

    2017-01-01

    Total ankle arthroplasty (TAA) and ankle arthrodesis (AA) are the main surgical treatment options for end-stage ankle arthritis. Although the superiority of each modality remains debated, there remains a lack of high-quality evidence-based studies, such as randomized controlled clinical trials, and meta-analyses of comparative studies. We performed a meta-analysis of comparative studies to determine whether there is a significant difference between these two procedures in terms of (i) clinical scores and patient satisfaction, (ii) re-operations, and (iii) complications. We conducted a comprehensive search in the MEDLINE, EMBASE, and Cochrane library databases. Only retrospective or prospective comparative studies were included in this meta-analysis. The literature search, data extraction, and quality assessment were conducted by two independent reviewers. The primary outcomes were clinical scores and patient satisfaction. We also investigated the prevalence of complications and the re-operation rate. Ten comparative studies were included (four prospective and six retrospective studies). There were no significant differences between the two procedures in the American Orthopaedic Foot and Ankle Society ankle-hindfoot score, Short Form-36 physical component summary and mental component summary scores, visual analogue scale for pain, and patient satisfaction rate. The risk of re-operation and major surgical complications were significantly increased in the TAA group. The meta-analysis revealed that TAA and AA could achieve similar clinical outcomes, whereas the incidence of re-operation and major surgical complication was significantly increased in TAA. Further studies of high methodological quality with long-term follow-up are required to confirm our conclusions.

  4. Predicted percentage dissatisfied with ankle draft.

    PubMed

    Liu, S; Schiavon, S; Kabanshi, A; Nazaroff, W W

    2017-07-01

    Draft is unwanted local convective cooling. The draft risk model of Fanger et al. (Energy and Buildings 12, 21-39, 1988) estimates the percentage of people dissatisfied with air movement due to overcooling at the neck. There is no model for predicting draft at ankles, which is more relevant to stratified air distribution systems such as underfloor air distribution (UFAD) and displacement ventilation (DV). We developed a model for predicted percentage dissatisfied with ankle draft (PPD AD ) based on laboratory experiments with 110 college students. We assessed the effect on ankle draft of various combinations of air speed (nominal range: 0.1-0.6 m/s), temperature (nominal range: 16.5-22.5°C), turbulence intensity (at ankles), sex, and clothing insulation (<0.7 clo; lower legs uncovered and covered). The results show that whole-body thermal sensation and air speed at ankles are the dominant parameters affecting draft. The seated subjects accepted a vertical temperature difference of up to 8°C between ankles (0.1 m) and head (1.1 m) at neutral whole-body thermal sensation, 5°C more than the maximum difference recommended in existing standards. The developed ankle draft model can be implemented in thermal comfort and air diffuser testing standards. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Overuse ankle injuries in professional Irish dancers.

    PubMed

    Walls, R J; Brennan, S A; Hodnett, P; O'Byrne, J M; Eustace, S J; Stephens, M M

    2010-03-01

    Overuse ankle injuries have been described in elite athletes and professional ballet dancers however the spectrum of injuries experienced by professional Irish dancers has not been defined. A troupe of actively performing dancers from an Irish-dance show were recruited (eight male, ten female; mean age, 26 years). The prevalence of overuse injuries in the right ankle was determined from magnetic resonance imaging. Foot and ankle self-report questionnaires were also completed (AOFAS and FAOS). Only three ankles were considered radiologically normal. Achilles tendinopathy, usually insertional, was the most frequent observation (n=14) followed by plantar fasciitis (n=7), bone oedema (n=2) and calcaneocuboid joint degeneration (n=2). There were limited correlations between MRI patterns and clinical scores indicating that many conditions are sub-clinical. Dancers with ankle pain had poor low (p=0.004) and high (p=0.013) level function. Overuse ankle injuries are common in Irish dancers. Incorporating eccentric exercises and plantar fascia stretching into a regular training program may benefit this population. Copyright 2009 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  6. Acute and chronic lateral ankle instability in the athlete.

    PubMed

    Chan, Keith W; Ding, Bryan C; Mroczek, Kenneth J

    2011-01-01

    Ankle sprain injuries are the most common injury sustained during sporting activities. Three-quarters of ankle injuries involve the lateral ligamentous complex, comprised of the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL). The most common mechanism of injury in lateral ankle sprains occurs with forced plantar flexion and inversion of the ankle as the body's center of gravity rolls over the ankle. The ATFL followed by the CFL are the most commonly injured ligaments. Eighty percent of acute ankle sprains make a full recovery with conservative management, while 20% of acute ankle sprains develop mechanical or functional instability, resulting in chronic ankle instability. Treatment of acute ankle sprains generally can be successfully managed with a short period of immobilization that is followed by functional rehabilitation. Patients with chronic ankle instability who fail functional rehabilitation are best treated with a Brostrom-Gould anatomic repair or, in those patients with poor tissue quality or undergoing revision surgery, an anatomic reconstruction.

  7. Total ankle replacement systems available in the United States.

    PubMed

    Coetzee, J Chris; Deorio, James K

    2010-01-01

    Ankle replacement continues to be a viable option for treating patients with ankle arthritis. Over the past 10 years, there has been a significant increase in the number of ankle replacement systems available for use. Current controversy centers on whether fixed- or mobile-bearing devices are most advantageous. Most total ankle systems used outside the United States are mobile-bearing devices, whereas ankle replacement systems used in the United States are all essentially fixed-bearing devices. Not all ankles with degenerative changes are amenable to replacement surgery, and several exclusion criteria are well documented. Ankle replacement is especially complicated because of the ankle's proximity to the foot and the important role that the balance and alignment of the foot play in the success of the ankle replacement. Foot deformities should be treated before or at the time of ankle replacement surgery. Ignoring foot deformities can lead to failure of the ankle replacement. It is also of paramount importance to consider the stability of the ankle ligaments. An unstable ankle with a varus or valgus deformity of more than 20 degrees is probably not amenable to ankle replacement. There are currently no reliable options to predictably reconstruct the lateral or medial ligaments in these severe deformities. It is important to be aware of the ankle replacement systems currently available in the United States and understand the key features of each design. Devices approved by the US Food and Drug Administration, a device that is awaiting approval, and a device that is being evaluated by the Food and Drug Administration in a prospective randomized clinical trial are discussed, along with an objective comparison of fixed- and mobile-bearing devices.

  8. Effects of Nintendo Wii Fit Plus training on ankle strength with functional ankle instability.

    PubMed

    Kim, Ki-Jong; Jun, Hyun-Ju; Heo, Myoung

    2015-11-01

    [Purpose] The objective of this study was to examine the effects of a training program using the Nintendo Wii Fit Plus on the ankle muscle strengths of subjects with functional ankle instability. [Subjects and Methods] This study was conducted using subjects in their 20s who had functional ankle instability. They were randomized to a strengthening training group and a balance training group with 10 subjects in each, and they performed an exercise using Nintendo Wii Fit Plus for 20 minutes. In addition, every participant completed preparation and finishing exercises for 5 minutes, respectively. [Results] The muscle strengths after conducting plantar flexion and dorsiflexion significantly increased at the angular velocities of 60° and 120° in the strengthening training group. Furthermore, the muscle strengths after conducting plantar flexion, dorsiflexion, eversion, and inversion significantly increased at the angular velocities of 60° and 120° in the balance training group. [Conclusion] The balance training group using Nintendo Wii Fit Plus showed better results than the strengthening training group. Consequently, it is recommended to add the balance training program of the Nintendo Wii Fit Plus to conventional exercise programs to improve ankle muscle strength in functional ankle instability at a low cost.

  9. Effects of Nintendo Wii Fit Plus training on ankle strength with functional ankle instability

    PubMed Central

    Kim, Ki-Jong; Jun, Hyun-Ju; Heo, Myoung

    2015-01-01

    [Purpose] The objective of this study was to examine the effects of a training program using the Nintendo Wii Fit Plus on the ankle muscle strengths of subjects with functional ankle instability. [Subjects and Methods] This study was conducted using subjects in their 20s who had functional ankle instability. They were randomized to a strengthening training group and a balance training group with 10 subjects in each, and they performed an exercise using Nintendo Wii Fit Plus for 20 minutes. In addition, every participant completed preparation and finishing exercises for 5 minutes, respectively. [Results] The muscle strengths after conducting plantar flexion and dorsiflexion significantly increased at the angular velocities of 60° and 120° in the strengthening training group. Furthermore, the muscle strengths after conducting plantar flexion, dorsiflexion, eversion, and inversion significantly increased at the angular velocities of 60° and 120° in the balance training group. [Conclusion] The balance training group using Nintendo Wii Fit Plus showed better results than the strengthening training group. Consequently, it is recommended to add the balance training program of the Nintendo Wii Fit Plus to conventional exercise programs to improve ankle muscle strength in functional ankle instability at a low cost. PMID:26696703

  10. Adenosine A1-Dopamine D1 Receptor Heteromers Control the Excitability of the Spinal Motoneuron.

    PubMed

    Rivera-Oliver, Marla; Moreno, Estefanía; Álvarez-Bagnarol, Yocasta; Ayala-Santiago, Christian; Cruz-Reyes, Nicole; Molina-Castro, Gian Carlo; Clemens, Stefan; Canela, Enric I; Ferré, Sergi; Casadó, Vicent; Díaz-Ríos, Manuel

    2018-05-24

    While the role of the ascending dopaminergic system in brain function and dysfunction has been a subject of extensive research, the role of the descending dopaminergic system in spinal cord function and dysfunction is just beginning to be understood. Adenosine plays a key role in the inhibitory control of the ascending dopaminergic system, largely dependent on functional complexes of specific subtypes of adenosine and dopamine receptors. Combining a selective destabilizing peptide strategy with a proximity ligation assay and patch-clamp electrophysiology in slices from male mouse lumbar spinal cord, the present study demonstrates the existence of adenosine A 1 -dopamine D 1 receptor heteromers in the spinal motoneuron by which adenosine tonically inhibits D 1 receptor-mediated signaling. A 1 -D 1 receptor heteromers play a significant control of the motoneuron excitability, represent main targets for the excitatory effects of caffeine in the spinal cord and can constitute new targets for the pharmacological therapy after spinal cord injury, motor aging-associated disorders and restless legs syndrome.

  11. Peculiarities in Ankle Cartilage.

    PubMed

    Kraeutler, Matthew J; Kaenkumchorn, Tanyaporn; Pascual-Garrido, Cecilia; Wimmer, Markus A; Chubinskaya, Susanna

    2017-01-01

    Posttraumatic osteoarthritis (PTOA) is the most common form of osteoarthritis (OA) of the ankle joint. PTOA occurs as a result of several factors, including the poor regenerative capacity of hyaline articular cartilage as well as increased contact stresses following trauma. The purpose of this article is to review the epidemiology, pathogenesis, and potential targets for treatment of PTOA in the ankle joint. Previous reviews primarily addressed clinical approaches to ankle PTOA, while the focus of the current article will be specifically on the newly acquired knowledge of the cellular mechanisms that drive PTOA in the ankle joint and means for potential targeted therapeutics that might halt the progression of cartilage degeneration and/or improve the outcome of surgical interventions. Three experimental treatment strategies are discussed in this review: (1) increasing the anabolic potential of chondrocytes through treatment with growth factors such as bone morphogenetic protein-7; (2) limiting chondrocyte cell death either through the protection of cell membrane with poloxamer 188 or inhibiting activity of intracellular proteases, caspases, which are responsible for cell death by apoptosis; and (3) inhibiting catabolic/inflammatory responses of chondrocytes by treating them with anti-inflammatory agents such as tumor necrosis factor-α antagonists. Future studies should focus on identifying the appropriate timing for treatment and an appropriate combination of anti-inflammatory, chondro- and matrix-protective biologics to limit the progression of trauma-induced cartilage degeneration and prevent the development of PTOA in the ankle joint.

  12. Functional ankle control of rock climbers

    PubMed Central

    Schweizer, A; Bircher, H; Kaelin, X; Ochsner, P

    2005-01-01

    Objective: To evaluate whether rock climbing type exercise would be of value in rehabilitating ankle injuries to improve ankle stability and coordination. Results: The rock climbers showed significantly better results in the stabilometry and greater absolute and relative maximum strength of flexion in the ankle. The soccer players showed greater absolute but not relative strength in extension. Conclusion: Rock climbing, because of its slow and controlled near static movements, may be of value in the treatment of functional ankle instability. However, it has still to be confirmed whether it is superior to the usual rehabilitation exercises such as use of the wobble board. PMID:15976164

  13. A Survey of Parachute Ankle Brace Breakages

    DTIC Science & Technology

    2008-01-10

    experience an ankle fracture , and 1.75 times more likely to experience an ankle injury of any type. Injuries to other parts of the lower body...A SURVEY OF PARACHUTE ANKLE BRACE BREAKAGES USACHPPM REPORT NO. 12-MA01Q2A-08 REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704...CONTRACT NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE A Survey of Parachute Ankle Brace Breakages 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER

  14. Effects of repeated ankle stretching on calf muscle-tendon and ankle biomechanical properties in stroke survivors

    PubMed Central

    Gao, Fan; Ren, Yupeng; Roth, Elliot J.; Harvey, Richard; Zhang, Li-Qun

    2011-01-01

    Background The objective of this study was to investigate changes in active and passive biomechanical properties of the calf muscle-tendon unit induced by controlled ankle stretching in stroke survivors. Methods Ten stroke survivors with ankle spasticity/contracture and ten healthy control subjects received intervention of 60-min ankle stretching. Joint biomechanical properties including resistance torque, stiffness and index of hysteresis were evaluated pre- and post-intervention. Achilles tendon length was measured using ultrasonography. The force output of the triceps surae muscles was characterized via the torque-angle relationship, by stimulating the calf muscles at a controlled intensity across different ankle positions. Findings Compared to healthy controls, the ankle position corresponding to the peak torque of the stroke survivors was shifted towards plantar flexion (P<0.001). Stroke survivors showed significantly higher resistance torques and joint stiffness (P<0.05), and these higher resistances were reduced significantly after the stretching intervention, especially in dorsiflexion (P = 0.013). Stretching significantly improved the force output of the impaired calf muscles in stroke survivors under matched stimulations (P<0.05). Ankle range of motion was also increased by stretching (P<0.001). Interpretation At the joint level, repeated stretching loosened the ankle joint with increased passive joint range of motion and decreased joint stiffness. At the muscle-tendon level, repeated stretching improved calf muscle force output, which might be associated with decreased muscle fascicle stiffness, increased fascicle length and shortening of the Achilles tendon. The study provided evidence of improvement in muscle tendon properties through stretching intervention. PMID:21211873

  15. Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

    PubMed Central

    Young, Ki Won; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

    2015-01-01

    Background We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Methods Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. Results The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Conclusions Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were

  16. Paratrooper's ankle fracture: posterior malleolar fracture.

    PubMed

    Young, Ki Won; Kim, Jin-su; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

    2015-03-01

    We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to

  17. The Effect of Lateral Ankle Ligament Repair in Muscle Reaction Time in Patients with Mechanical Ankle Instability.

    PubMed

    Li, H-Y; Zheng, J-J; Zhang, J; Hua, Y-H; Chen, S-Y

    2015-11-01

    Studies have shown that functional ankle instability can result in prolonged muscle reaction time. However, the deficit in muscle reaction time in patients with mechanical ankle instability (MAI) and the effect of lateral ankle ligament repair on muscle reaction time are unclear. The purpose of this study was to identify the deficit in muscle reaction time, and to evaluate the role of lateral ligament repair in improving muscle reaction time in MAI patients. Sixteen MAI patients diagnosed with lateral ankle ligament tears by ultrasonography and magnetic resonance imaging underwent arthroscopic debridement and open lateral ankle ligament repair with a modified Broström procedure. One day before the operation, reaction times of the tibialis anterior and peroneus longus muscles were recorded following sudden inversion perturbation while walking on a custom walkway, and anterior drawer test (ADT) and American Orthopaedic Foot and Ankle Society (AOFAS) scale score were evaluated. Six months postoperatively, muscle reaction time, ADT and AOFAS scale score were reevaluated, and muscle reaction times in 15 healthy controls were also recorded. Preoperatively, the affected ankles in the MAI group had significantly delayed tibialis anterior and peroneus longus muscles reaction times compared with controls. Six months after the operation, median AOFAS scale scores were significantly greater than preoperatively, and ADT was negative in the MAI group. However, the affected ankles in the MAI group showed no difference in muscle reaction time compared with preoperative values. MAI patients had prolonged muscle reaction time. The modified Broström procedure produced satisfactory clinical outcomes in MAI patients, but did not shorten reaction times of the tibialis anterior and peroneus longus muscles. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Force and displacement measurements of the distal fibula during simulated ankle loading tests for high ankle sprains.

    PubMed

    Markolf, Keith L; Jackson, Steven; McAllister, David R

    2012-09-01

    Syndesmosis (high ankle) sprains produce disruption of the distal tibiofibular ligaments. Forces on the distal fibula that produce these injuries are unknown. Twenty-seven fresh-frozen lower extremities were used for this study. A load cell recorded forces acting on the distal fibula from forced ankle dorsiflexion and applied external foot torque; medial-lateral and anterior-posterior displacements of the distal fibula were recorded. Fibular forces and axial displacements were also recorded with applied axial force. During forced ankle dorsiflexion and external foot torque tests, the distal fibula always displaced posteriorly with respect to the tibia with no measurable medial-lateral displacement. With 10 Nm dorsiflexion moment, cutting the tibiofibular ligaments approximately doubled fibular force and displacement values. Cutting the tibiofibular ligaments significantly increased fibular displacement from applied external foot torque. Fibular forces and axial displacements from applied axial weight-bearing force were highest with the foot dorsiflexed. The highest mean fibular force in the study (271.9 N) occurred with 10 Nm external foot torque applied to a dorsiflexed foot under 1000 N axial force. Two important modes of loading that could produce high ankle sprains were identified: forced ankle dorsiflexion and external foot torque applied to a dorsiflexed ankle loaded with axial force. The distal tibiofibular ligaments restrained fibular displacement during these tests. Residual mortise widening observed at surgery may be the result of tibiofibular ligament injuries caused by posterior displacement of the fibula. Therefore, a syndesmosis screw used to fix the fibula would be subjected to posterior bending forces from these loading modes. Ankle bracing to prevent extreme ankle dorsiflexion during rehabilitation may be advisable to prevent excessive fibular motions that could affect syndesmosis healing.

  19. Two genetic loci associated with ankle injury.

    PubMed

    Kim, Stuart K; Kleimeyer, John P; Ahmed, Marwa A; Avins, Andrew L; Fredericson, Michael; Dragoo, Jason L; Ioannidis, John P A

    2017-01-01

    Ankle injuries, including sprains, strains and other joint derangements and instability, are common, especially for athletes involved in indoor court or jumping sports. Identifying genetic loci associated with these ankle injuries could shed light on their etiologies. A genome-wide association screen was performed using publicly available data from the Research Program in Genes, Environment and Health (RPGEH) including 1,694 cases of ankle injury and 97,646 controls. An indel (chr21:47156779:D) that lies close to a collagen gene, COL18A1, showed an association with ankle injury at genome-wide significance (p = 3.8x10-8; OR = 1.99; 95% CI = 1.75-2.23). A second DNA variant (rs13286037 on chromosome 9) that lies within an intron of the transcription factor gene NFIB showed an association that was nearly genome-wide significant (p = 5.1x10-8; OR = 1.63; 95% CI = 1.46-1.80). The ACTN3 R577X mutation was previously reported to show an association with acute ankle sprains, but did not show an association in this cohort. This study is the first genome-wide screen for ankle injury that yields insights regarding the genetic etiology of ankle injuries and provides DNA markers with the potential to inform athletes about their genetic risk for ankle injury.

  20. Two genetic loci associated with ankle injury

    PubMed Central

    Kleimeyer, John P.; Ahmed, Marwa A.; Avins, Andrew L.; Fredericson, Michael; Dragoo, Jason L.; Ioannidis, John P. A.

    2017-01-01

    Ankle injuries, including sprains, strains and other joint derangements and instability, are common, especially for athletes involved in indoor court or jumping sports. Identifying genetic loci associated with these ankle injuries could shed light on their etiologies. A genome-wide association screen was performed using publicly available data from the Research Program in Genes, Environment and Health (RPGEH) including 1,694 cases of ankle injury and 97,646 controls. An indel (chr21:47156779:D) that lies close to a collagen gene, COL18A1, showed an association with ankle injury at genome-wide significance (p = 3.8x10-8; OR = 1.99; 95% CI = 1.75–2.23). A second DNA variant (rs13286037 on chromosome 9) that lies within an intron of the transcription factor gene NFIB showed an association that was nearly genome-wide significant (p = 5.1x10-8; OR = 1.63; 95% CI = 1.46–1.80). The ACTN3 R577X mutation was previously reported to show an association with acute ankle sprains, but did not show an association in this cohort. This study is the first genome-wide screen for ankle injury that yields insights regarding the genetic etiology of ankle injuries and provides DNA markers with the potential to inform athletes about their genetic risk for ankle injury. PMID:28957384

  1. Biomechanics of the ankle-foot system during stair ambulation: implications for design of advanced ankle-foot prostheses.

    PubMed

    Sinitski, Emily H; Hansen, Andrew H; Wilken, Jason M

    2012-02-02

    Unilateral lower limb prosthesis users display temporal, kinematic, and kinetic asymmetries between limbs while ascending and descending stairs. These asymmetries are due, in part, to the inability of current prosthetic devices to effectively mimic normal ankle function. The purpose of this study was to provide a comprehensive set of biomechanical data for able-bodied and unilateral transtibial amputee (TTA) ankle-foot systems for level-ground (LG), stair ascent (SA), and stair descent (SD), and to characterize deviations from normal performance associated with prosthesis use. Ankle joint kinematics, kinetics, torque-angle curves, and effective shapes were calculated for twelve able-bodied individuals and twelve individuals with TTA. The data from this study demonstrated the prosthetic limb can more effectively mimic the range of motion and power output of a normal ankle-foot during LG compared to SA and SD. There were larger differences between the prosthetic and able-bodied limbs during SA and SD, most evident in the torque-angle curves and effective shapes. These data can be used by persons designing ankle-foot prostheses and provide comparative data for assessment of future ankle-foot prosthesis designs. Published by Elsevier Ltd.

  2. Effects of 2 ankle destabilization devices on electromyography measures during functional exercises in individuals with chronic ankle instability.

    PubMed

    Donovan, Luke; Hart, Joseph M; Hertel, Jay

    2015-03-01

    Randomized crossover laboratory study. To determine the effects of ankle destabilization devices on surface electromyography (sEMG) measures of selected lower extremity muscles during functional exercises in participants with chronic ankle instability. Ankle destabilization devices are rehabilitation tools that can be worn as a boot or sandal to increase lower extremity muscle activation during walking in healthy individuals. However, they have not been tested in a population with pathology. Fifteen adults with chronic ankle instability participated. Surface electromyography electrodes were located over the anterior tibialis, fibularis longus, lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius. The activity level of these muscles was recorded in a single testing session during unipedal stance with eyes closed, the Star Excursion Balance Test, lateral hops, and treadmill walking. Each task was performed under 3 conditions: shod, ankle destabilization boot, and ankle destabilization sandal. Surface electromyography signal amplitudes were measured for each muscle during each exercise for all 3 conditions. Participants demonstrated a significant increase, with moderate to large effect sizes, in sEMG signal amplitude of the fibularis longus in the ankle destabilization boot and ankle destabilization sandal conditions during the unipedal eyes-closed balance test, the Star Excursion Balance Test in the anterior and posteromedial directions, lateral hops, and walking, when compared to the shod condition. Both devices also resulted in an increase in sEMG signal amplitudes, with large effect sizes of the lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius during the unipedal-stance-with-eyes-closed test, compared to the shod condition. Wearing ankle destabilization devices caused greater muscle activation during functional exercises in individuals with chronic ankle instability. Based on the magnitude of the effect, there were

  3. The course of the superficial peroneal nerve in relation to the ankle position: anatomical study with ankle arthroscopic implications

    PubMed Central

    Golanó, Pau; Sierevelt, Inger N.; van Dijk, C. Niek

    2010-01-01

    Despite the fact that the superficial peroneal nerve is the only nerve in the human body that can be made visible; iatrogenic damage to this nerve is the most frequently reported complication in anterior ankle arthroscopy. One of the methods to visualize the nerve is combined ankle plantar flexion and inversion. In the majority of cases, the superficial peroneal nerve can be made visible. The portals for anterior ankle arthroscopy are however created with the ankle in the neutral or slightly dorsiflexed position and not in combined plantar flexion and inversion. The purpose of this study was to undertake an anatomical study to the course of the superficial peroneal nerve in different positions of the foot and ankle. We hypothesize that the anatomical localization of the superficial peroneal nerve changes with different foot and ankle positions. In ten fresh frozen ankle specimens, a window, only affecting the skin, was made at the level of the anterolateral portal for anterior ankle arthroscopy in order to directly visualize the superficial peroneal nerve, or if divided, its terminal branches. Nerve movement was assessed from combined 10° plantar flexion and inversion to 5° dorsiflexion, standardized by the Telos stress device. Also for the 4th toe flexion, flexion of all the toes and for skin tensioning possible nerve movement was determined. The mean superficial peroneal nerve movement was 2.4 mm to the lateral side when the ankle was moved from 10° plantar flexion and inversion to the neutral ankle position and 3.6 mm to the lateral side from 10° plantar flexion and inversion to 5° dorsiflexion. Both displacements were significant (P < 0.01). The nerve consistently moves lateral when the ankle is manoeuvred from combined plantar flexion and inversion to the neutral or dorsiflexed position. If visible, it is therefore advised to create the anterolateral portal medial from the preoperative marking, in order to prevent iatrogenic damage to the superficial

  4. Validity of an ankle joint motion and position sense measurement system and its application in healthy subjects and patients with ankle sprain.

    PubMed

    Lin, Chueh-Ho; Chiang, Shang-Lin; Lu, Liang-Hsuan; Wei, Shun-Hwa; Sung, Wen-Hsu

    2016-07-01

    Ankle motion and proprioception in multiple axis movements are crucial for daily activities. However, few studies have developed and used a multiple axis system for measuring ankle motion and proprioception. This study was designed to validate a novel ankle haptic interface system that measures the ankle range of motion (ROM) and joint position sense in multiple plane movements, investigating the proprioception deficits during joint position sense tasks for patients with ankle instability. Eleven healthy adults (mean ± standard deviation; age, 24.7 ± 1.9 years) and thirteen patients with ankle instability were recruited in this study. All subjects were asked to perform tests to evaluate the validity of the ankle ROM measurements and underwent tests for validating the joint position sense measurements conducted during multiple axis movements of the ankle joint. Pearson correlation was used for validating the angular position measurements obtained using the developed system; the independent t test was used to investigate the differences in joint position sense task performance for people with or without ankle instability. The ROM measurements of the device were linearly correlated with the criterion standards (r = 0.99). The ankle instability and healthy groups were significantly different in direction, absolute, and variable errors of plantar flexion, dorsiflexion, inversion, and eversion (p < 0.05). The results demonstrate that the novel ankle joint motion and position sense measurement system is valid and can be used for measuring the ankle ROM and joint position sense in multiple planes and indicate proprioception deficits for people with ankle instability. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. [Eleven-Year Experience with Total Ankle Arthroplasty].

    PubMed

    Popelka, S; Sosna, A; Vavřík, P; Jahoda, D; Barták, V; Landor, I

    2016-01-01

    PURPOSE OF THE STUDY Total joint replacement is one of the options in surgical treatment of advanced ankle arthritis. It allows the ankle to remain mobile but, unfortunately, it does not provide the same longevity as total knee or hip replacements. Therefore, decisions concerning the kind of treatment are very individual and depend on the clinical status and opinion of each patient. MATERIAL AND METHODS A total of 132 total ankle replacements were carried out in the period from 2004 to 2015. The prostheses used included the Ankle Evolutive System (AES) in 52 patients, Mobility Total Ankle System (DePuy) in 24 patients and, recently, Rebalance Total Ankle Replacement implant in 53 patients. Three patients allergic to metal received the Taric prosthesis. Revision arthroplasty using the Hintegra prosthesis was carried out in four patients. The outcome of arthroplasty was evaluated on the American Orthopaedic Foot and Ankle Society (AOFAS) scoring scale. Indications for total ankle arthroplasty included post-traumatic arthritis in 83 patients, rheumatoid arthritis in 37 and primary arthritis in 12 patients. There were 78 women and 54 men, with an average age of 55.6 years at the time of surgery. RESULTS The average follow-up was 6.1 years (1-11 years). The average AOFAS score of the whole group increased from 33.2 before surgery to 82.5 after it. The primary indication had an important role. Arthroplasty outcomes were poorer in patients with post-traumatic arthritis than in those with rheumatoid arthritis or primary arthritis. In patients with post-traumatic arthritis, the average AOFAS score rose to 78.6 due to restricted motion of the ankle, and some patients continued to have pain when walking. The average AOFAS score in a total of 49 patients who had rheumatoid arthritis or primary arthritis reached a value of 86.4. Post-operative complications were recorded in ten patients (7.6%) in whom part of the wound was healing by second intention. Ossification was also a

  6. Transplantation of motoneurons derived from MASH1-transfected mouse ES cells reconstitutes neural networks and improves motor function in hemiplegic mice.

    PubMed

    Ikeda, Ritsuko; Kurokawa, Manae S; Chiba, Shunmei; Yoshikawa, Hideshi; Hashimoto, Takuo; Tadokoro, Mamoru; Suzuki, Noboru

    2004-10-01

    Mouse embryonic stem (ES) cells were transfected with a MASH1 expression vector and G418-resistant cells were selected. The MASH1-transfected cells became neuron-like appearance and expressed betaIIItubulin and panNCAM. Glial fibrillary acidic protein (GFAP) and galactocerebroside (GalC)-expressing cells were rarely detected. Half of the neural cells differentiated into the Islet1+ motoneuron lineage. Thus, we obtained motoneuron lineage-enriched neuronal cells by transfection of ES cells with MASH1. A hemiplegic model of mice was developed by cryogenic injury of the motor cortex, and motoneuron lineage-enriched neuronal cells were transplanted underneath the injured motor cortex neighboring the periventricular region. The motor function of the recipients was assessed by a beam walking and rotarod tests, whereby the results gradually improved, but little improvement was observed in vehicle injected control mice. We found that the grafted cells not only remained close to the implantation site, but also exhibited substantial migration, penetrating into the damaged lesion in a directed manner up to the cortical region. Grafted neuronal cells that had migrated into the cortex were elongated axon-positive for neurofilament middle chain (NFM). Synaptophysin immunostaining showed a positive staining pattern around the graft, suggesting that the transplanted neurons interacted with the recipient neurons to form a neural network. Our study suggests that the motoneuron lineage can be induced from ES cells, and grafted cells adapt to the host environment and can reconstitute a neural network to improve motor function of a paralyzed limb.

  7. [Posterior ankle impingement syndrome].

    PubMed

    Bojanić, Ivan; Janjić, Tamara; Dimnjaković, Damjan; Križan, Sanja; Smoljanović, Tomislav

    2015-01-01

    Posterior ankle impingement syndrome (PAIS) is a clinical syndrome characterized by posterior ankle pain which occurs in maximal forced plantar flexion of the foot. PAIS can be the result of an acute injury of the ankle, which is more often in general population, or it can be the result of the overuse syndrome, which is more often in athletes and ballet dancers. The etiology of PAIS may involve bony structures or soft tissue structures, or, more often, the combination of both. The diagnosis of PAIS is based on patient's clinical history and physical examination with the hyperplantarflexion test as a very important part of it. Physical examination should be completed with imaging techniques, which most often include magnetic resonance imaging (MRI) or computed tomography (CT) to confirm the diagnosis of PAIS. Conservative treatment is recommended as the primary treatment strategy. In those cases where 3 to 6 months of conservative treatment fails, open or, more often, arthroscopic/endoscopic surgery may be recommended. Nowadays, a 2-portal endoscopic approach introduced by van Dijk et al. in 2000 is the method of choice for the treatment of posterior ankle impingement syndrome.

  8. [Lateral instability of the upper ankle joint].

    PubMed

    Harrasser, N; Eichelberg, K; Pohlig, F; Waizy, H; Toepfer, A; von Eisenhart-Rothe, R

    2016-11-01

    Because of their frequency, ankle sprains are of major clinical and economic importance. The simple sprain with uneventful healing has to be distinguished from the potentially complicated sprain which is at risk of transition to chronic ankle instability. Conservative treatment is indicated for the acute, simple ankle sprain without accompanying injuries and also in cases of chronic instability. If conservative treatment fails, good results can be achieved by anatomic ligament reconstruction of the lateral ankle ligaments. Arthroscopic techniques offer the advantage of joint inspection and addressing intra-articular pathologies in combination with ligament repair. Accompanying pathologies must be adequately addressed during ligament repair to avoid persistent ankle discomfort. If syndesmotic insufficiency and tibiofibular instability are suspected, the objective should be early diagnosis with MRI and surgical repair.

  9. The management of failed ankle replacement.

    PubMed

    Kotnis, R; Pasapula, C; Anwar, F; Cooke, P H; Sharp, R J

    2006-08-01

    Advances in the design of the components for total ankle replacement have led to a resurgence of interest in this procedure. Between January 1999 and December 2004, 16 patients with a failed total ankle replacement were referred to our unit. In the presence of infection, a two-stage salvage procedure was planned. The first involved the removal of the components and the insertion of a cement spacer. Definitive treatment options included hindfoot fusion with a circular frame or amputation. When there was no infection, a one-stage salvage procedure was planned. Options included hindfoot fusion with an intramedullary nail or revision total ankle replacement. When there was suspicion of infection, a percutaneous biopsy was performed. The patients were followed up for a minimum of 12 months. Of the 16 patients, 14 had aseptic loosening, five of whom underwent a revision total ankle replacement and nine a hindfoot fusion. Of the two with infection, one underwent fusion and the other a below-knee amputation. There were no cases of wound breakdown, nonunion or malunion. Management of the failed total ankle replacement should be performed by experienced surgeons and ideally in units where multidisciplinary support is available. Currently, a hindfoot fusion appears to be preferable to a revision total ankle replacement.

  10. Trends in Ankle Arthroscopy and Its Use in the Management of Pathologic Conditions of the Lateral Ankle in the United States: A National Database Study.

    PubMed

    Werner, Brian C; Burrus, M Tyrrell; Park, Joseph S; Perumal, Venkat; Gwathmey, F Winston

    2015-07-01

    This study aimed to investigate current trends in ankle arthroscopy across time, sex, age, and region of the United States as well as the use of ankle arthroscopy in the management of lateral ankle instability. Patients who underwent ankle arthroscopy and those who underwent ankle arthroscopy and lateral ankle ligament repair or peroneal retinacular repair from 2007 through 2011 were identified using the PearlDiver national database. These searches yielded volumes of unique patients, sex and age distribution, and regional volumes of patients. Χ-square linear-by-linear association analysis was used for comparisons, with P < .05 considered significant. We identified 15,366 ankle arthroscopy procedures in the database from 2007 to 2011. Over the 5-year study period, there was a significant increase in the overall number of ankle arthroscopies being performed, from 2,814 in 2007 to 3,314 in 2011 (P < .0001). Female patients had ankle arthroscopy more frequently than did male patients (P = .027). The majority of patients who had ankle arthroscopy were between the ages of 30 and 49 years. The use of ankle arthroscopy during lateral ligament repair procedures increased from 37.2% in 2007 to 43.7% in 2011 (P < .0001). The incidence of combined ankle arthroscopy and peroneal tendon retinacular repair increased 50%, from 2.8/100 ankle arthroscopies in 2007 to 4.2/100 ankle arthroscopies in 2011 (P < .0001). The incidence of ankle arthroscopy increased significantly from 2007 to 2011, outpacing shoulder, knee, and elbow arthroscopy. Ankle arthroscopy was performed more frequently in female patients and most commonly in patients younger than 50 years. The use of ankle arthroscopy in the surgical management of lateral ankle instability also increased significantly. The incidence of concomitant ankle arthroscopy and lateral ligament repair increased significantly, as did the incidence of concomitant ankle arthroscopy and repair of peroneal tendon subluxation. Level IV

  11. Neuromuscular control and rehabilitation of the unstable ankle

    PubMed Central

    Hung, You-jou

    2015-01-01

    Lateral ankle sprain is a common orthopedic injury with a very high recurrence rate in athletes. After decades of research, it is still unclear what contributes to the high recurrence rate of ankle sprain, and what is the most effective intervention to reduce the incident of initial and recurrent injuries. In addition, clinicians often implement balance training as part of the rehabilitation protocol in hopes of enhancing the neuromuscular control and proprioception of the ankle joint. However, there is no consensus on whether the neuromuscular control and proprioception are compromised in unstable ankles. To reduce the prevalence of ankle sprains, the effectiveness of engaging balance training to enhance the neuromuscular control and proprioception of the ankle joint is also questionable. PMID:26085985

  12. Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments

    PubMed Central

    Crevoisier, Xavier; Assal, Mathieu; Stanekova, Katarina

    2016-01-01

    The pathogenesis of hallux valgus deformity is multifactorial. Conservative treatment can alleviate pain but is unable to correct the deformity. Surgical treatment must be adapted to the type and severity of the deformity. Success of surgical treatment ranges from 80% to 95%, and complication rates range from 10% to 30%. Ankle osteoarthrosis most commonly occurs as a consequence of trauma. Ankle arthrodesis and total ankle replacement are the most common surgical treatments of end stage ankle osteoarthrosis. Both types of surgery result in similar clinical improvement at midterm; however, gait analysis has demonstrated the superiority of total ankle replacement over arthrodesis. More recently, conservative surgery (extraarticular alignment osteotomies) around the ankle has gained popularity in treating early- to mid-stage ankle osteoarthrosis. Adult acquired flatfoot deformity is a consequence of posterior tibial tendon dysfunction in 80% of cases. Classification is based upon the function of the tibialis posterior tendon, the reducibility of the deformity, and the condition of the ankle joint. Conservative treatment includes orthotics and eccentric muscle training. Functional surgery is indicated for treatment in the early stages. In case of fixed deformity, corrective and stabilising surgery is performed. Cite this article: Crevoisier X, Assal M, Stanekova K. Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments. EFORT Open Rev 2016;1:58–64. DOI: 10.1302/2058-5241.1.000015. PMID:28461929

  13. Ankle sprain complications: MRI evaluation.

    PubMed

    Martin, Barney

    2008-04-01

    Sprains are disruptions of the ligamentous anatomy about a joint. The ankle sprain is one of the most common injuries seen in podiatric and orthopedic practice. It usually is incurred from an inversion force on the ankle, but eversion forces also can traumatize the ankle. Many times, this injury is taken for granted because of the frequency of its presentation. The patient usually is given appropriate initial care, but the patient can experience continued or residual pain. Podiatrists have found this problem is common and have come to recognize that secondary or accessory injuries occur that slow the natural recovery of this injury.

  14. Evidence-based treatment for ankle injuries: a clinical perspective

    PubMed Central

    Lin, Chung-Wei Christine; Hiller, Claire E; de Bie, Rob A

    2010-01-01

    The most common ankle injuries are ankle sprain and ankle fracture. This review discusses treatments for ankle sprain (including the management of the acute sprain and chronic instability) and ankle fracture, using evidence from recent systematic reviews and randomized controlled trials. After ankle sprain, there is evidence for the use of functional support and non-steroidal anti-inflammatory drugs. There is weak evidence suggesting that the use of manual therapy may lead to positive short-term effects. Electro-physical agents do not appear to enhance outcomes and are not recommended. Exercise may reduce the occurrence of recurrent ankle sprains and may be effective in managing chronic ankle instability. After surgical fixation for ankle fracture, an early introduction of activity, administered via early weight-bearing or exercise during the immobilization period, may lead to better outcomes. However, the use of a brace or orthosis to enable exercise during the immobilization period may also lead to a higher rate of adverse events, suggesting that this treatment regimen needs to be applied judiciously. After the immobilization period, the focus of treatment for ankle fracture should be on a progressive exercise program. PMID:21655420

  15. CHCHD10 mutations p.R15L and p.G66V cause motoneuron disease by haploinsufficiency.

    PubMed

    Brockmann, Sarah J; Freischmidt, Axel; Oeckl, Patrick; Müller, Kathrin; Ponna, Srinivas K; Helferich, Anika M; Paone, Christoph; Reinders, Jörg; Kojer, Kerstin; Orth, Michael; Jokela, Manu; Auranen, Mari; Udd, Bjarne; Hermann, Andreas; Danzer, Karin M; Lichtner, Peter; Walther, Paul; Ludolph, Albert C; Andersen, Peter M; Otto, Markus; Kursula, Petri; Just, Steffen; Weishaupt, Jochen H

    2018-02-15

    Mutations in the mitochondrially located protein CHCHD10 cause motoneuron disease by an unknown mechanism. In this study, we investigate the mutations p.R15L and p.G66V in comparison to wild-type CHCHD10 and the non-pathogenic variant p.P34S in vitro, in patient cells as well as in the vertebrate in vivo model zebrafish. We demonstrate a reduction of CHCHD10 protein levels in p.R15L and p.G66V mutant patient cells to approximately 50%. Quantitative real-time PCR revealed that expression of CHCHD10 p.R15L, but not of CHCHD10 p.G66V, is already abrogated at the mRNA level. Altered secondary structure and rapid protein degradation are observed with regard to the CHCHD10 p.G66V mutant. In contrast, no significant differences in expression, degradation rate or secondary structure of non-pathogenic CHCHD10 p.P34S are detected when compared with wild-type protein. Knockdown of CHCHD10 expression in zebrafish to about 50% causes motoneuron pathology, abnormal myofibrillar structure and motility deficits in vivo. Thus, our data show that the CHCHD10 mutations p.R15L and p.G66V cause motoneuron disease primarily based on haploinsufficiency of CHCHD10. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Pseudoaneurysm as a complication of ankle arthroscopy.

    PubMed

    Mariani, P P; Mancini, L; Giorgini, T L

    2001-04-01

    We describe a case of pseudoaneurysm of the anterior tibial artery as a complication after arthroscopic ankle synovectomy, in which standard anterolateral and anteromedial portals were used. Pseudoaneurysm has been previously reported as a complication in ankle arthroscopy with the use of the anterocentral portal. Previously described anatomic variations of the tibial artery and its close relationship with the anterior ankle capsule may complicate arthroscopic surgery, especially when aggressive synovectomy is performed. Anterior tibial artery aneurysm is a rare complication of ankle arthroscopy, but its potential catastrophic sequelae must not be underestimated.

  17. Development of an ankle torque measurement device for measuring ankle torque during walking.

    PubMed

    Tanino, Genichi; Tomita, Yutaka; Mizuno, Shiho; Maeda, Hirofumi; Miyasaka, Hiroyuki; Orand, Abbas; Takeda, Kotaro; Sonoda, Shigeru

    2015-05-01

    [Purpose] To develop a device for measuring the torque of an ankle joint during walking in order to quantify the characteristics of spasticity of the ankle and to verify the functionality of the device by testing it on the gait of an able-bodied individual and an equinovarus patient. [Subjects and Methods] An adjustable posterior strut (APS) ankle-foot orthosis (AFO) was used in which two torque sensors were mounted on the aluminum strut for measuring the anterior-posterior (AP) and medial-lateral (ML) directions. Two switches were also mounted at the heel and toe in order to detect the gait phase. An able-bodied individual and a left hemiplegic patient with equinovarus participated. They wore the device and walked on a treadmill to investigate the device's functionality. [Results] Linear relationships between the torques and the corresponding output of the torque sensors were observed. Upon the analyses of gait of an able-body subject and a hemiplegic patient, we observed toque matrices in both AP and ML directions during the gait of the both subjects. [Conclusion] We developed a device capable of measuring the torque in the AP and ML directions of ankle joints during gait.

  18. [Concomitant injuries after upper ankle joint dislocations].

    PubMed

    Dann, K; Wahler, G; Neubauer, N; Steiner, R; Titze, W; Wagner, M

    1996-09-01

    Functional treatment with the Air Stirrup Ankle Brace recommended by C. N. Stover in 1979 can reduce pathological inversion of the ankle joint. In our retrospective study of 109 patients treated by this kind of ankle brace we found 96 patients (88%) with excellent results. Only 13 patients (12%) reported moderate to good results. To detect and characterize their painful conditions of ankles we did a clinical, radiological and MRI-Investigation. In only 2 cases we found a moderate instability after clinical investigation, anterior stress roentgenogram and talar tilt. By using the MRI-investigation 1.0 Tesla with a 512 x 360 Matrix we could find 10 cases with osteochondral lesions of the ankle. In 7 cases there was separated ossicle in the fibulotalar joint, in 1 case we detected a fracture of the processus anterior tali, in another case we could see a posttraumatic lesion of the talus and calcaneus with bone bruise and at least one osteochondral fracture of the distal tibia. The capability of the MRI to detect particularly osteo-chondral lesions of the talus and the tibiofibular joint was shown in 10 of 13 cases. Therefore we recommend to do an MRI-investigation on all patients after ankle sprain if there are painful conditions within the ankle after conservative treatment.

  19. The Incidence of Ankle Sprains in Orienteering.

    ERIC Educational Resources Information Center

    Ekstrand, Jan; And Others

    1990-01-01

    Investigates relationship between ankle sprains and participation time in competitive orienteering. Examined 15,474 competitors in races in the Swedish O-ringen 5-day event in 1987. Injuries requiring medical attention were analyzed, showing 137 (23.9 percent) ankle sprains. Injury incidence was 8.4/10,000 hours. Incidence of ankle sprains was…

  20. Ambulatory measurement of ankle kinetics for clinical applications.

    PubMed

    Rouhani, H; Favre, J; Crevoisier, X; Aminian, K

    2011-10-13

    This study aimed to design and validate the measurement of ankle kinetics (force, moment, and power) during consecutive gait cycles and in the field using an ambulatory system. An ambulatory system consisting of plantar pressure insole and inertial sensors (3D gyroscopes and 3D accelerometers) on foot and shank was used. To test this system, 12 patients and 10 healthy elderly subjects wore shoes embedding this system and walked many times across a gait lab including a force-plate surrounded by seven cameras considered as the reference system. Then, the participants walked two 50-meter trials where only the ambulatory system was used. Ankle force components and sagittal moment of ankle measured by ambulatory system showed correlation coefficient (R) and normalized RMS error (NRMSE) of more than 0.94 and less than 13% in comparison with the references system for both patients and healthy subjects. Transverse moment of ankle and ankle power showed R>0.85 and NRMSE<23%. These parameters also showed high repeatability (CMC>0.7). In contrast, the ankle coronal moment of ankle demonstrated high error and lower repeatability. Except for ankle coronal moment, the kinetic features obtained by the ambulatory system could distinguish the patients with ankle osteoarthritis from healthy subjects when measured in 50-meter trials. The proposed ambulatory system can be easily accessible in most clinics and could assess main ankle kinetics quantities with acceptable error and repeatability for clinical evaluations. This system is therefore suggested for field measurement in clinical applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Persistent cauda equina syndrome after caudal epidural injection under severe spinal stenosis: a case report

    PubMed Central

    Seo, Young Tak; Kong, Hyun Ho; Lee, Goo Joo; Bang, Heui Je

    2017-01-01

    Caudal epidural injection (CEI) is one of the most common treatments for low-back pain with sciatica. CEI rarely leads to neurologic complications. We report a case of persistent cauda equina syndrome after CEI. A 44-year-old male patient with severe L4 and L5 spinal ste-nosis underwent CEI for low-back pain and sciatica. The CEI solution consisted of bupivacaine, hyaluronidase, triamcinolone acetonide, and normal saline. He experienced motor weakness and sensory loss in both lower extremities and neurogenic bladder for more than 1 year after the procedure. His ankle dorsiflexors, big-toe extensors, and ankle plantar flexors on both sides were checked and categorized as motor-power Medical Research Council grade 0. His bilateral ankle-jerk reflection was absent. An electrophysiological study showed lumbosacral polyradiculopathy affecting both sides of the L5 and S1 nerve roots. A urodynamic study revealed hypoactive neurogenic bladder affecting both sacral roots. PMID:28652808

  2. Persistent cauda equina syndrome after caudal epidural injection under severe spinal stenosis: a case report.

    PubMed

    Seo, Young Tak; Kong, Hyun Ho; Lee, Goo Joo; Bang, Heui Je

    2017-01-01

    Caudal epidural injection (CEI) is one of the most common treatments for low-back pain with sciatica. CEI rarely leads to neurologic complications. We report a case of persistent cauda equina syndrome after CEI. A 44-year-old male patient with severe L4 and L5 spinal ste-nosis underwent CEI for low-back pain and sciatica. The CEI solution consisted of bupivacaine, hyaluronidase, triamcinolone acetonide, and normal saline. He experienced motor weakness and sensory loss in both lower extremities and neurogenic bladder for more than 1 year after the procedure. His ankle dorsiflexors, big-toe extensors, and ankle plantar flexors on both sides were checked and categorized as motor-power Medical Research Council grade 0. His bilateral ankle-jerk reflection was absent. An electrophysiological study showed lumbosacral polyradiculopathy affecting both sides of the L5 and S1 nerve roots. A urodynamic study revealed hypoactive neurogenic bladder affecting both sacral roots.

  3. Ankle impingement syndromes: an imaging review

    PubMed Central

    Tafur, Monica; Ahmed, Sonya S; Huang, Brady K; Chang, Eric Y

    2017-01-01

    Ankle impingement syndromes encompass a broad spectrum of post-traumatic and chronic degenerative changes that present with pain on specific movements about the ankle joint. Both amateur and professional athletes are disproportionately affected by these conditions, and while conservative measures can potentially treat an impingement syndrome, definitive therapy is often alleviated surgically. Imaging (including conventional radiography, ultrasound, CT and MRI) plays an invaluable role in the diagnosis and pre-surgical work-up. An anatomically based classification system is useful in these syndromes, as the aetiology, sites of pathology and preferred treatment methods are similarly based on anatomic locations about the ankle. This review focuses on the anatomic locations, pathophysiology, imaging considerations and brief discussion of therapies for each of the major anatomic ankle impingement syndromes. PMID:27885856

  4. Immediate Effects of Ankle Balance Taping with Kinesiology Tape for Amateur Soccer Players with Lateral Ankle Sprain: A Randomized Cross-Over Design

    PubMed Central

    Kim, Myoung Kwon; Shin, Young Jun

    2017-01-01

    Background The objective of this study was to investigate the immediate effect on gait function when ankle balance taping is applied to amateur soccer players with lateral ankle sprain. Material/Methods A cross-over randomized design was used. Twenty-two soccer players with an ankle sprain underwent 3 interventions in a random order. Subjects were randomly assigned to ankle balance taping, placebo taping, and no taping groups. The assessment was performed using the GAITRite portable walkway system, which records the location and timing of each footfall during ambulation. Results Significant differences were found in the velocity, step length, stride length, and H-H base support among the 3 different taping methods (p<0.05). The ankle balance taping group showed significantly greater velocity, step length, and stride length in comparison to the placebo and no taping group. The ankle balance taping group showed a statistically significant decrease (p<0.05) in the H-H base support compared to the placebo and no taping groups, and the placebo group showed significantly greater velocity in comparison to the no taping group (p<0.05). Conclusions We conclude that ankle balance taping that uses kinesiology tape instantly increased the walking ability of amateur soccer players with lateral ankle sprain. Therefore, ankle balance taping is a useful alternative to prevent and treat ankle sprain of soccer players. PMID:29158472

  5. Biomechanical Evaluation of a Prototype Foot/Ankle Prosthesis

    PubMed Central

    Quesada, P. M.; Pitkin, M.; Colvin, J.

    2016-01-01

    In this paper, we report on our pilot evaluation of a prototype foot/ankle prosthesis. This prototype has been designed and fabricated with the intention of providing decreased ankle joint stiffness during the middle portion of the stance phase of gait, and increased (i.e., more normal) knee range of motion during stance. Our evaluation involved fitting the existing prototype foot/ankle prosthesis, as well as a traditional solid ankle cushioned heel (SACH) foot, to an otherwise healthy volunteer with a below-knee (BK) amputation. We measured this individual’s lower extremity joint kinematics and kinetics during walking using a video motion analysis system and force platform. These measurements permitted direct comparison of prosthetic ankle joint stiffness and involved side knee joint motion, as well as prosthetic ankle joint moment and power. PMID:10779119

  6. Peroneal nerve palsy after ankle sprain: an update.

    PubMed

    Mitsiokapa, Evanthia; Mavrogenis, Andreas F; Drakopoulos, Dionysis; Mauffrey, Cyril; Scarlat, Marius

    2017-01-01

    Ankle sprains are extremely common in the general population and the most common injuries in athletes. Although rare, peroneal nerve palsy may occur simultaneously with ankle sprain. The exact incidence of nerve injury after ankle sprain is not known; few cases of peroneal nerve palsy associated with ankle sprains have been reported in the literature. The function of the peroneal nerve should be evaluated in all patients with a history of inversion ankle sprain as part of the initial and follow-up evaluation, even if the initial neurological status is normal, because delayed peroneal nerve palsy is possible. This article discusses the incidence, pathophysiology, evaluation, diagnosis and differential diagnosis, and management of the patients with peroneal nerve palsy after ankle sprain aiming to increase the awareness of the treating physicians for this nerve injury.

  7. Foot and ankle function after tibial overlengthening.

    PubMed

    Emara, Khaled M; Diab, Ramy Ahmed; El Ghazali, Sherif; Farouk, Amr; El Kersh, Mohamed Ahmed

    2014-01-01

    Lengthening the tibia more than 25% of its original length can be indicated for proximal femoral deficiency, poliomyelitis, or femoral infected nonunion. Such lengthening of the tibia can adversely affect the ankle or foot shape and function. The present study aimed to assess the effect of tibial lengthening of more than 25% of its original length on the foot and ankle shape and function compared with the preoperative condition. This was a retrospective study of 13 children with severe proximal focal femoral deficiency, Aitken classification type D, who had undergone limb lengthening from June 2000 to June 2008 using Ilizarov external fixators. The techniques used in tibial lengthening included lengthening without intramedullary rodding and lengthening over a nail. The foot assessment was done preoperatively, at fixator removal, and then annually for 3 years, documenting the range of motion and deformity of the ankle and subtalar joints and big toe and the navicular height, calcaneal pitch angle, and talo-first metatarsal angle. At fixator removal, all cases showed equinocavovarus deformity, with decreased ankle, subtalar, and big toe motion. The mean American Orthopedic Foot and Ankle Society score was significantly reduced. During follow-up, the range of motion, foot deformity, and American Orthopedic Foot and Ankle Society score improved, reaching nearly to the preoperative condition by 2 years of follow-up. The results of our study have shown that tibial overlengthening has an adverse effect on foot and ankle function. This effect was reversible in the patients included in the present study. Lengthening of more than 25% can be safely done after careful discussion with the patients and their families about the probable effects of lengthening on foot and ankle function. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Population prevalence and distribution of ankle pain and symptomatic radiographic ankle osteoarthritis in community dwelling older adults: A systematic review and cross-sectional study

    PubMed Central

    Murray, Charlotte; Rathod, Trishna; Bowen, Catherine J.; Menz, Hylton B.; Roddy, Edward

    2018-01-01

    Objectives To identify by systematic review published prevalence estimates of radiographic ankle osteoarthritis (OA) and to subsequently estimate the prevalence of ankle pain and symptomatic, radiographic ankle OA within community-dwelling older adults from North Staffordshire, UK. Methods Electronic databases were searched using terms for ankle, osteoarthritis and radiography. Data regarding population, radiographic methods, definitions and prevalence estimates of ankle OA were extracted from papers meeting predetermined selection criteria. Adults aged ≥50 years and registered with four general practices in North Staffordshire were mailed a health questionnaire. Ankle pain in the previous month was determined using a foot and ankle pain manikin. Respondents reporting pain in or around the foot in the last 12 months were invited to attend a research clinic where weight-bearing, antero-posterior and lateral ankle radiographs were obtained and scored for OA using a standardised atlas. Prevalence estimates for ankle pain and symptomatic, radiographic ankle OA were calculated using multiple imputation and weighted logistic regression, and stratified by age, gender and socioeconomic status. Results Eighteen studies were included in the systematic review. The methods of radiographic classification of ankle OA were poorly reported and showed heterogeneity. No true general population prevalence estimates of radiographic ankle OA were found, estimates in select sporting and medical community-dwelling populations ranged from 0.0–97.1%. 5109 participants responded to the health survey questionnaire (adjusted response 56%). Radiographs were obtained in 557 participants. The prevalence of ankle pain was 11.7% (10.8,12.6) and symptomatic, radiographic ankle OA grade≥2 was 3.4% (2.3, 4.5) (grade≥1: 8.8% (7.9,9.8); grade = 3: 1.9% (1.0,2.7). Prevalence was higher in females, younger adults (50–64 years) and those with routine/manual occupations. Conclusion No general

  9. Trends of Concurrent Ankle Arthroscopy at the Time of Operative Treatment of Ankle Fracture: A National Database Review.

    PubMed

    Ackermann, Jakob; Fraser, Ethan J; Murawski, Christopher D; Desai, Payal; Vig, Khushdeep; Kennedy, John G

    2016-04-01

    The purpose of this study was to report trends associated with concurrent ankle arthroscopy at the time of operative treatment of ankle fracture. The current procedural terminology (CPT) billing codes were used to search the PearlDiver Patient Record Database and identify all patients who were treated for acute ankle fracture in the United States. The Medicare Standard Analytic Files were searchable between 2005 and 2011 and the United Healthcare Orthopedic Dataset from 2007 to 2011. Annual trends were expressed only between 2007 and 2011, as it was the common time period among both databases. Demographic factors were identified for all procedures as well as the cost aspect using the Medicare data set. In total, 32 307 patients underwent open reduction internal fixation (ORIF) of an ankle fracture, of whom 313 (1.0%) had an ankle arthroscopy performed simultaneously. Of those 313 cases, 70 (22.4%) patients received microfracture treatment. Between 2005 and 2011, 85 203 patients were treated for an ankle fracture whether via ORIF or closed treatment. Of these, a total of 566 patients underwent arthroscopic treatment within 7 years. The prevalence of arthroscopy after ankle fracture decreased significantly by 45% from 2007 to 2011 (P< .0001). When ORIF and microfracture were performed concurrently, the total average charge for both procedures drops to $4253.00 and average reimbursement to $818.00 compared with approximately $4964.00 and $1069.00, respectively, when they were performed subsequently. Despite good evidence in favor of arthroscopy at the time of ankle fracture treatment, it appears that only a small proportion of surgeons in the United States perform these procedures concurrently. Therapeutic, Level IV: Retrospective. © 2015 The Author(s).

  10. Prolonged stretching of the ankle plantarflexors elicits muscle-tendon adaptations relevant to ankle gait kinetics in children with spastic cerebral palsy.

    PubMed

    Martín Lorenzo, Teresa; Rocon, Eduardo; Martínez Caballero, Ignacio; Ramírez Barragán, Ana; Lerma Lara, Sergio

    2017-11-01

    Tissue related ankle hyper-resistance has been reported to contribute to equinus gait in children with spastic cerebral palsy. Hence, ankle plantarflexor stretching programs have been developed in order to restore passive ankle dorsiflexion. Despite high quality evidence on the limited effects of stretching on passive joint mobility, further muscle-tendon adaptations have been reported which may impact gait performance. As such, children with spastic cerebral palsy subject to long-term manual static stretching achieved dorsiflexion gains through the reduction of muscle and fascicle strain whilst preserving tendon strain, and prolonged use of ankle-foot orthoses achieved similar dorsiflexion gains through increased tendon strain whilst preserving muscle and fascicle strain. The latter concurred with normalization of early stance plantarflexor moment yet reductions in push-off plantarflexor moment given the increase in tendon compliance. Therefore, similar limited gains in passive ankle joint mobility in response to stretching may be achieved either by preserving/restoring optimal muscle-tendon function, or at the expense of muscle-tendon function and thus contributing gait impairments. The largest increase in ankle passive joint mobility in children with SCP has been obtained through prolonged plantarflexor stretching through ankle casting combined with botulinum neurotoxin type A. However, to our knowledge, there are no published studies on muscle-tendinous adaptations to ankle casting combined with botulinum toxin type A and its effect on ankle joint gait kinetics. Therefore, we hypothesized that ankle casting elicits muscle-tendon adaptations which concur with altered ankle joint kinetics during the stance phase of gait in children with SCP. More information is needed about the relationships between muscle structure and function, and the effect of specific interventions designed to alter muscle properties and associated functional outcomes in children with

  11. Neuromodulation of hypoglossal motoneurons: cellular and developmental mechanisms.

    PubMed

    Bayliss, D A; Viana, F; Talley, E M; Berger, A J

    1997-11-01

    Hypoglossal motoneurons (HMs) in the caudal brainstem have a respiratory-related activity pattern and contribute to control of upper airway resistance. In this review, we focus primarily on signalling mechanisms utilized by neurotransmitters to enhance HM excitability. In particular, we consider: (1) the membrane depolarization induced by a number of different putative transmitters [thyrotropin-releasing hormone (TRH), serotonin (5-HT), norepinephrine (NE)]; and (2) the inhibition of a calcium-dependent spike after hyperpolarization (AHP) by 5-HT and its effect on firing behavior. Potential functional consequences on HM behavior of these different neurotransmitter effects is discussed. In addition, we describe postnatal changes in transmitter effects and suggest potential cellular mechanisms to explain those developmental changes. Most of the data discussed are derived from in vitro electrophysiological recordings performed in preparations from neonatal and adult rats.

  12. Distraction-free ankle arthroscopy for anterolateral impingement.

    PubMed

    Rouvillain, Jean Louis; Daoud, Wael; Donica, Adrian; Garron, Emmanuel; Uzel, André Pierre

    2014-08-01

    The origin of chronic pain after external ankle sprain is better known with arthroscopy's contribution. Chronic hypertrophic synovitis of the anterolateral ankle region is seemingly the cause, resulting in "anterolateral ankle impingement." But is partial synovectomy with fibrosis resection under arthroscopy always possible without any distraction? Are results affected? This retrospective study concerned only patients with soft tissue ankle impingement. All cases with bone and joint diseases were excluded. The final sample of 24 patients had a mean age of 35 years (21-54 years) and presented anterolateral mechanical pain associated with oedema following external ankle sprain. Medical and rehabilitative treatment was undertaken for more than 6 months before arthroscopy. Average time between trauma and arthroscopy was 21 months (5-60 months). Clinical examination revealed no ankle instability or laxity. Debridement with joint lavage was systematically performed under arthroscopy without any distraction. Average patient follow-up was 22 months (12-92 months). All patients had a good Kitaoka score, with 22 patients registering excellent results. There were no septic complications or algodystrophy. Two transient hypoesthesias were observed in the dorsal surface and lateral border of the foot with full postoperative recovery at 6 months. Distraction was never used and simple dorsiflexion was sufficient to perform arthroscopic debridement. In this study, anterolateral ankle impingement diagnosis was primarily clinical. Arthroscopic treatment yielded significant benefits on pain, oedema and resumption of sport activities. Arthroscopic treatment of anterolateral ankle impingements is thus possible with simple dorsiflexion and no distraction, resulting in a possible decrease in complication rates. Level of evidence Retrospective cohort study, Level IV.

  13. Peroneus quartus and functional ankle instability.

    PubMed

    Lotito, G; Pruvost, J; Collado, H; Coudreuse, J-M; Bensoussan, L; Curvale, G; Viton, J-M; Delarque, A

    2011-07-01

    Physical and rehabilitation medicine physicians commonly see patients with chronic functional ankle instability. The main anatomical structures involved in ankle stability are the peroneus (fibularis) brevis and peroneus longus muscles. Several anatomical muscle-tendon variations have been described in the literature as being sometimes responsible for this instability, the peroneus quartus muscle being the most frequent. The objective of this clinical study is to discuss the implication of the bilateral peroneus quartus muscle in functional ankle instability. This 26-year-old patient was seen in PM&R consultation for recurrent episodes of lateral ankle sprains. The clinical examination found a moderate hyperlaxity on the right side in bilateral ankle varus. We also noted a bilateral weakness of the peroneus muscles. Additional imaging examinations showed a supernumerary bilateral peroneus quartus. The electroneuromyogram of the peroneus muscles was normal. In the literature the incidence of a supernumerary peroneus quartus muscle varies from 0 to 21.7%. Most times this muscle is asymptomatic and is only fortuitously discovered. However some cases of chronic ankle pain or instability have been reported in the literature. It seems relevant to discuss, around the clinical case of this patient, the impact of this muscle on ankle instability especially when faced with lingering weakness of the peroneus brevis and longus muscles in spite of eccentric strength training and in the absence of any neurological impairment. One of the hypotheses, previously described in the literature, would be the overcrowding effect resulting in a true conflict by reducing the available space for the peroneal muscles in the peroneal sheath. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  14. Management of acute and chronic ankle instability.

    PubMed

    Maffulli, Nicola; Ferran, Nicholas A

    2008-10-01

    Acute lateral ankle ligament injuries are common. If left untreated, they can result in chronic instability. Nonsurgical measures, including functional rehabilitation, are the management methods of choice for acute injuries, with surgical intervention reserved for high-demand athletes. Chronic lateral ankle instability is multifactorial. Failed nonsurgical management after appropriate rehabilitation is an indication for surgery. Of the many surgical options available, anatomic repair of the anterior talofibular and calcaneofibular ligaments is recommended when the quality of the ruptured ligaments permits. Anatomic reconstruction with autograft or allograft should be performed when the ruptured ligaments are attenuated. Ankle arthroscopy is an important adjunct to ligamentous repair and should be performed at the time of repair to identify and address intra-articular conditions associated with chronic ankle instability. Tenodesis procedures are not recommended because they may disturb ankle and hindfoot biomechanics.

  15. Tachykininergic slow depolarization of motoneurones evoked by descending fibres in the neonatal rat spinal cord.

    PubMed Central

    Kurihara, T; Yoshioka, K; Otsuka, M

    1995-01-01

    1. In the isolated spinal cord of the neonatal rat, repetitive electrical stimulation of the upper cervical region elicited a prolonged depolarization of lumbar motoneurones (L3-5) lasting 1-2 min, which was recorded extracellularly from ventral roots, or intracellularly. 2. This depolarizing response was markedly depressed by the excitatory amino acid receptor antagonists D-(-)-2-amino-5-phosphonovaleric acid (D-APV, 30 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM). The remaining response was further depressed by a 5-hydroxytryptamine (5-HT) receptor antagonist, ketanserin (3 microM). 3. In the presence of these antagonists, a small part of the depolarizing response of slow time course remained, and this response was partially blocked by the tachykinin NK1 receptor antagonists GR71251 (0.3-5 microM) and RP67580 (0.3-1 microM). In contrast, RP68651 (0.3-1 microM), the inactive enantiomer of RP67580, had no effect on the depolarizing response. 4. The slow depolarizing response in the presence of D-APV, CNQX and ketanserin was markedly potentiated by a peptidase inhibitor, thiorphan (1 microM). 5. This descending fibre-evoked slow depolarization became smaller after prolonged treatment (5-7 h) with 5,7-dihydroxytryptamine (10 microM), a neurotoxin for 5-HT neurones. Under such conditions, the effects of thiorphan and GR71251 on the slow depolarization were virtually absent. 6. Under the action of D-APV, CNQX and ketanserin, applications of tachykinins, substance P and neurokinin A produced depolarizing responses of lumbar motoneurones, and the responses were depressed by GR71251 and potentiated by thiorphan. 7. These results suggest that tachykinins contained in serotonergic fibres serve as neurotransmitters mediating the descending fibre-evoked slow excitatory postsynaptic potentials in motoneurones. PMID:7562617

  16. Tachykininergic slow depolarization of motoneurones evoked by descending fibres in the neonatal rat spinal cord.

    PubMed

    Kurihara, T; Yoshioka, K; Otsuka, M

    1995-06-15

    1. In the isolated spinal cord of the neonatal rat, repetitive electrical stimulation of the upper cervical region elicited a prolonged depolarization of lumbar motoneurones (L3-5) lasting 1-2 min, which was recorded extracellularly from ventral roots, or intracellularly. 2. This depolarizing response was markedly depressed by the excitatory amino acid receptor antagonists D-(-)-2-amino-5-phosphonovaleric acid (D-APV, 30 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM). The remaining response was further depressed by a 5-hydroxytryptamine (5-HT) receptor antagonist, ketanserin (3 microM). 3. In the presence of these antagonists, a small part of the depolarizing response of slow time course remained, and this response was partially blocked by the tachykinin NK1 receptor antagonists GR71251 (0.3-5 microM) and RP67580 (0.3-1 microM). In contrast, RP68651 (0.3-1 microM), the inactive enantiomer of RP67580, had no effect on the depolarizing response. 4. The slow depolarizing response in the presence of D-APV, CNQX and ketanserin was markedly potentiated by a peptidase inhibitor, thiorphan (1 microM). 5. This descending fibre-evoked slow depolarization became smaller after prolonged treatment (5-7 h) with 5,7-dihydroxytryptamine (10 microM), a neurotoxin for 5-HT neurones. Under such conditions, the effects of thiorphan and GR71251 on the slow depolarization were virtually absent. 6. Under the action of D-APV, CNQX and ketanserin, applications of tachykinins, substance P and neurokinin A produced depolarizing responses of lumbar motoneurones, and the responses were depressed by GR71251 and potentiated by thiorphan. 7. These results suggest that tachykinins contained in serotonergic fibres serve as neurotransmitters mediating the descending fibre-evoked slow excitatory postsynaptic potentials in motoneurones.

  17. Operative Fixation Options for Elective and Diabetic Ankle Arthrodesis.

    PubMed

    Ramanujam, Crystal L; Stapleton, John J; Zgonis, Thomas

    2017-07-01

    Ankle arthrodesis remains one of the most definitive treatment options for end-stage arthritis, paralysis, posttraumatic and postinfectious conditions, failed total ankle arthroplasty, and severe deformities. The general aims of ankle arthrodesis are to decrease pain and instability, correct the accompanying deformity, and create a stable plantigrade foot. Several surgical approaches have been reported for ankle arthrodesis with internal fixation options. External fixation has also evolved for ankle arthrodesis in certain clinical scenarios. This article provides a comprehensive analysis of midterm to long-term outcomes for ankle arthrodesis using internal and/or external fixation each for elective and diabetic conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Ankle replacement

    MedlinePlus

    ... C, Anderson PA, eds. Skeletal Trauma: Basic Science, Management, and Reconstruction . 5th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 68. Murphy GA. Total ankle arthroplasty. In: Azar FM, Beaty JH, Canale ...

  19. Effects of ankle strengthening exercise program on an unstable supporting surface on proprioception and balance in adults with functional ankle instability.

    PubMed

    Ha, Sun-Young; Han, Jun-Ho; Sung, Yun-Hee

    2018-04-01

    The present study was conducted to investigate the effect of ankle strengthening exercise applied on unstable supporting surfaces on the proprioceptive sense and balance in adults with functional ankle instability. As for the study method, 30 adults with functional ankle instability were randomly assigned to an ankle strengthening exercise group and a stretching group on unstable supporting surfaces, and the interventions were implemented for 40 min. Before and after the interventions, a digital dual inclinometer was used to measure the proprioceptive sense of the ankle, the Balancia program was used to measure static balance ability, and the functional reach test was used to measure dynamic balance ability. In the results, both proprioceptive sense and static dynamic balance ability were significantly different between before and after the intervention in the experimental group ( P <0.05). When such results are put together, it can be seen that ankle strengthening exercise applied on unstable supporting surfaces may be presented as an effective treatment method for enhancing the proprioceptive sense and balance ability in adults with functional ankle instability.

  20. Understanding acute ankle ligamentous sprain injury in sports

    PubMed Central

    Fong, Daniel TP; Chan, Yue-Yan; Mok, Kam-Ming; Yung, Patrick SH; Chan, Kai-Ming

    2009-01-01

    This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL) which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprain injury, prescribing orthosis decreases the risk while increased exercise intensity in soccer raises the risk. For intrinsic factors, a foot size with increased width, an increased ankle eversion to inversion strength, plantarflexion strength and ratio between dorsiflexion and plantarflexion strength, and limb dominance could increase the ankle sprain injury risk. Players with a previous sprain history, players wearing shoes with air cells, players who do not stretch before exercising, players with inferior single leg balance, and overweight players are 4.9, 4.3, 2.6, 2.4 and 3.9 times more likely to sustain an ankle sprain injury. The aetiology of most ankle sprain injuries is incorrect foot positioning at landing – a medially-deviated vertical ground reaction force causes an explosive supination or inversion moment at the subtalar joint in a short time (about 50 ms). Another aetiology is the delayed reaction time of the peroneal muscles at the lateral aspect of the ankle (60–90 ms). The failure supination or inversion torque is about 41–45 Nm to cause ligamentous rupture in simulated spraining tests on cadaver. A previous case report revealed that the ankle joint reached 48 degrees inversion and 10 degrees internal rotation during an accidental grade I ankle ligamentous sprain injury during a dynamic cutting trial in laboratory. Diagnosis techniques and grading systems vary, but the management of ankle ligamentous sprain injury is mainly conservative. Immobilization should not

  1. Ankle impingement syndromes.

    PubMed

    Umans, Hilary

    2002-06-01

    The term "ankle impingement" encompasses a broad range of conditions that are typically post-traumatic and often chronic. Various forms of mechanical impingement can result from synovial proliferation, bone spur formation, or ligamentous scarring and hypertrophy. Since symptoms and physical findings can mimic a variety of disorders, accurate diagnosis may remain elusive, and proper effective therapy may be delayed. The objective of this article is to define and elucidate the etiology of the various forms of ankle impingement, clarify the range of associated osseous and soft-tissue pathology, and describe the imaging features and therapeutic options.

  2. Dendrites are dispensable for basic motoneuron function but essential for fine tuning of behavior.

    PubMed

    Ryglewski, Stefanie; Kadas, Dimitrios; Hutchinson, Katie; Schuetzler, Natalie; Vonhoff, Fernando; Duch, Carsten

    2014-12-16

    Dendrites are highly complex 3D structures that define neuronal morphology and connectivity and are the predominant sites for synaptic input. Defects in dendritic structure are highly consistent correlates of brain diseases. However, the precise consequences of dendritic structure defects for neuronal function and behavioral performance remain unknown. Here we probe dendritic function by using genetic tools to selectively abolish dendrites in identified Drosophila wing motoneurons without affecting other neuronal properties. We find that these motoneuron dendrites are unexpectedly dispensable for synaptic targeting, qualitatively normal neuronal activity patterns during behavior, and basic behavioral performance. However, significant performance deficits in sophisticated motor behaviors, such as flight altitude control and switching between discrete courtship song elements, scale with the degree of dendritic defect. To our knowledge, our observations provide the first direct evidence that complex dendrite architecture is critically required for fine-tuning and adaptability within robust, evolutionarily constrained behavioral programs that are vital for mating success and survival. We speculate that the observed scaling of performance deficits with the degree of structural defect is consistent with gradual increases in intellectual disability during continuously advancing structural deficiencies in progressive neurological disorders.

  3. Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

    PubMed Central

    Menelaou, Evdokia; Paul, Latoya T.; Perera, Surangi N.; Svoboda, Kurt R.

    2015-01-01

    Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMN). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30µM). Previous work showed that the paralytic mutant zebrafish known as sofa potato, exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. PMID:25668718

  4. [EFFECTIVENESS OF ARTHROSCOPY FOR ANKLE IMPINGEMENT SYNDROME].

    PubMed

    Han, Guansheng; Xu, Bin; Geng, Chunhui; Cheng, Xinde

    2014-06-01

    To explore the effectiveness of arthroscopy for ankle impingement syndrome. Between March 2009 and April 2013, 30 patients with ankle impingement syndrome were treated. Among them, there were 22 males and 8 females with an average age of 28.6 years (range, 16-55 years). Twenty-six patients had a history of obvious ankle sprains. The disease duration was 6-62 months (mean, 21.5 months). All cases had ankle pain, limitation of activity, and positive results of ankle impact test. According to Meislin scoring criteria, 5 cases were rated as good, 8 cases as medium, and 17 cases as poor; the excellent and good rate was 16.7%. American Orthopedic Foot and Ankle Society (AOFAS) score was 43.3 ± 5.1. Visual analogue scale (VAS) score was 6.7 ± 2.3. Preoperative X-ray film showed ankle loose bodies and hyperplasia osteophyte in 6 cases, and lateral malleolus old avulsion fracture in 4 cases. MRI showed soft tissue in the ankle joint in the 17 cases, and articular cartilage injury of tibiotalar joint and bone marrow edema in 7 cases. The location, degree, and organization of the impact were observed under arthroscopy. The joint debridement, removal of loose body and osteophyte, plasty of articular cartilage, and plasma radiofrequency ablation of lateral and medial ligaments were performed. All incisions healed primarily. No infection of skin and joint, or neurological and vascular injury was found. All patients were followed up 6-32 months (mean, 19.5 months). According to Meislin scoring criteria at last follow-up, 16 cases were rated as excellent, 11 cases as good, and 3 cases as medium; the excellent and good rate was 90.0%, showing significant difference when compared with preoperative value (Z = 6.045, P = 0.000). AOFAS score was 89.8 ± 4.3, showing significant difference when compared with preoperative score (t = 38.180, P = 0.000). VAS score was 2.8 ± 1.6, showing significant difference when compared with preoperative score (t = 7.624, P = 0.000). A clear

  5. Changes in active ankle dorsiflexion range of motion after acute inversion ankle sprain.

    PubMed

    Youdas, James W; McLean, Timothy J; Krause, David A; Hollman, John H

    2009-08-01

    Posterior calf stretching is believed to improve active ankle dorsiflexion range of motion (AADFROM) after acute ankle-inversion sprain. To describe AADFROM at baseline (postinjury) and at 2-wk time periods for 6 wk after acute inversion sprain. Randomized trial. Sports clinic. 11 men and 11 women (age range 11-54 y) with acute inversion sprain. Standardized home exercise program for acute inversion sprain. AADFROM with the knee extended. Time main effect on AADFROM was significant (F3,57 = 108, P < .001). At baseline, mean active sagittal-plane motion of the ankle was 6 degrees of plantar flexion, whereas at 2, 4, and 6 wk AADFROM was 7 degrees, 11 degrees, and 11 degrees, respectively. AADFROM increased significantly from baseline to week 2 and from week 2 to week 4. Normal AADFROM was restored within 4 wk after acute inversion sprain.

  6. [Interposition arthrodesis of the ankle].

    PubMed

    Vienne, Patrick

    2005-10-01

    Bony fusion of the ankle in a functionally favorable position for restitution of a painless weight bearing while avoiding a leg length discrepancy. Disabling, painful osteoarthritis of the ankle with extensive bone defect secondary to trauma, infection, or serious deformities such as congenital malformations or diabetic osteoarthropathies. Acute joint infection. Severe arterial occlusive disease of the involved limb. Lateral approach to the distal fibula. Fibular osteotomy 7 cm proximal to the tip of the lateral malleolus and posterior flipping of the distal fibula. Exposure of the ankle. Removal of all articular cartilage and debridement of the bone defect. Determination of the size of the defect and harvesting of a corresponding tricortical bone graft from the iliac crest. Also harvesting of autogenous cancellous bone either from the iliac crest or from the lateral part of the proximal tibia. Insertion of the tricortical bone graft and filling of the remaining defect with cancellous bone. Fixation with three 6.5-mm titanium lag screws. Depending on the extent of the defect additional stabilization of the bone graft with a titanium plate. Fixation of the lateral fibula on talus and tibia with two 3.5-mm titanium screws for additional support. Wound closure in layers. Split below-knee cast with the ankle in neutral position. Between January 2002 and January 2004 this technique was used in five patients with extensive bone defects (four women, one man, average age 57 years [42-77 years]). No intra- or early postoperative complications. The AOFAS (American Orthopedic Foot and Ankle Society) Score was improved from 23 points preoperatively to 76 points postoperatively (average follow-up time of 25 months). Two patients developed a nonunion and underwent a revision with an ankle arthrodesis nail. A valgus malposition after arthrodesis in one patient was corrected with a supramalleolar osteotomy.

  7. Complex ankle arthrodesis: Review of the literature

    PubMed Central

    Rabinovich, Remy V; Haleem, Amgad M; Rozbruch, S Robert

    2015-01-01

    Complex ankle arthrodesis is defined as an ankle fusion that is at high risk of delayed and nonunion secondary to patient comorbidities and/or local ankle/hindfoot factors. Risk factors that contribute to defining this group of patients can be divided into systemic factors and local factors pertaining to co-existing ankle or hindfoot pathology. Orthopaedic surgeons should be aware of these risk factors and their association with patients’ outcomes after complex ankle fusions. Both external and internal fixations have demonstrated positive outcomes with regards to achieving stable fixation and minimizing infection. Recent innovations in the application of biophysical agents and devices have shown promising results as adjuncts for healing. Both osteoconductive and osteoinductive agents have been effectively utilized as biological adjuncts for bone healing with low complication rates. Devices such as pulsed electromagnetic field bone stimulators, internal direct current stimulators and low-intensity pulsed ultrasound bone stimulators have been associated with faster bone healing and improved outcomes scores when compared with controls. The aim of this review article is to present a comprehensive approach to the management of complex ankle fusions, including the use of biophysical adjuncts for healing and a proposed algorithm for their treatment. PMID:26396936

  8. Arthroscopic ankle arthrodesis with intra-articular distraction.

    PubMed

    Kim, Hyong Nyun; Jeon, June Young; Noh, Kyu Cheol; Kim, Hong Kyun; Dong, Quanyu; Park, Yong Wook

    2014-01-01

    Arthroscopic ankle arthrodesis has shown high rates of union comparable to those with open arthrodesis but with substantially less postoperative morbidity, shorter operative times, less blood loss, and shorter hospital stays. To easily perform arthroscopic resection of the articular cartilage, sufficient distraction of the joint is necessary to insert the arthroscope and instruments. However, sometimes, standard noninvasive ankle distraction will not be sufficient in post-traumatic ankle arthritis, with the development of arthrofibrosis and joint contracture after severe ankle trauma. In the present report, we describe a technique to distract the ankle joint by inserting a 4.6-mm stainless steel cannula with a blunt trocar inside the joint. The cannula allowed sufficient intra-articular distraction, and, at the same time, a 4.0-mm arthroscope can be inserted through the cannula to view the joint. Screws can be inserted to fix the joint under fluoroscopic guidance without changing the patient's position or removing the noninvasive distraction device and leg holder, which are often necessary during standard arthroscopic arthrodesis with noninvasive distraction. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Developing a Framework for Ankle Function: A Delphi Study

    PubMed Central

    Snyder, Kelli R.; Evans, Todd A.; Neibert, Peter J.

    2014-01-01

    Context: Addressing clinical outcomes is paramount to providing effective health care, yet there is no consensus regarding the appropriate outcomes to address after ankle injuries. Compounding the problem is the repetitive nature of lateral ankle sprains, referred to as functional (FAI) or chronic (CAI) ankle instability. Although they are commonly used terms in practice and research, FAI and CAI are inconsistently defined and assessed. Objective: To establish definitions of a healthy/normal/noninjured ankle, FAI, and CAI, as well as their characteristics and assessment techniques. Design: Delphi study. Setting: Telephone interviews and electronic surveys. Patients or Other Participants: Sixteen experts representing the fields of ankle function and treatment, ankle research, and outcomes assessment and research were selected as panelists. Data Collection and Analysis: A telephone interview produced feedback regarding the definition of, functional characteristics of, and assessment techniques for a healthy/normal/noninjured ankle, an unhealthy/acutely injured ankle, and FAI/CAI. Those data were compiled, reduced, and returned through electronic surveys and were either included by reaching consensus (80% agreement) or excluded. Results: The definitions of a healthy/normal/noninjured ankle and FAI reached consensus. Experts did not agree on a definition of CAI. Eleven functional characteristics of a healthy/normal/noninjured ankle, 32 functional characteristics of an unhealthy/acutely injured ankle, and 13 characteristics of FAI were agreed upon. Conclusions: Although a consensus was reached regarding the definitions and functional characteristics of a healthy/normal/noninjured ankle and FAI, the experts could only agree on 1 characteristic to include in the FAI definition. Several experts did, however, provide additional comments that reinforced the differences in the interpretation of those concepts. Although the experts could not agree on the definition of CAI, its

  10. Developing a framework for ankle function: a delphi study.

    PubMed

    Snyder, Kelli R; Evans, Todd A; Neibert, Peter J

    2014-01-01

    Addressing clinical outcomes is paramount to providing effective health care, yet there is no consensus regarding the appropriate outcomes to address after ankle injuries. Compounding the problem is the repetitive nature of lateral ankle sprains, referred to as functional (FAI) or chronic (CAI) ankle instability. Although they are commonly used terms in practice and research, FAI and CAI are inconsistently defined and assessed. To establish definitions of a healthy/normal/noninjured ankle, FAI, and CAI, as well as their characteristics and assessment techniques. Delphi study. Telephone interviews and electronic surveys. Sixteen experts representing the fields of ankle function and treatment, ankle research, and outcomes assessment and research were selected as panelists. A telephone interview produced feedback regarding the definition of, functional characteristics of, and assessment techniques for a healthy/normal/noninjured ankle, an unhealthy/acutely injured ankle, and FAI/CAI. Those data were compiled, reduced, and returned through electronic surveys and were either included by reaching consensus (80% agreement) or excluded. The definitions of a healthy/normal/noninjured ankle and FAI reached consensus. Experts did not agree on a definition of CAI. Eleven functional characteristics of a healthy/normal/noninjured ankle, 32 functional characteristics of an unhealthy/acutely injured ankle, and 13 characteristics of FAI were agreed upon. Although a consensus was reached regarding the definitions and functional characteristics of a healthy/normal/noninjured ankle and FAI, the experts could only agree on 1 characteristic to include in the FAI definition. Several experts did, however, provide additional comments that reinforced the differences in the interpretation of those concepts. Although the experts could not agree on the definition of CAI, its characteristics, or the preferred use of the terms FAI and CAI, our findings provide progress toward establishing

  11. Realignment Surgery for Malunited Ankle Fracture.

    PubMed

    Guo, Chang-Jun; Li, Xing-Cheng; Hu, Mu; Xu, Yang; Xu, Xiang-Yang

    2017-02-01

    To investigate the characteristics and the results of realignment surgery for the treatment of malunited ankle fracture. Thirty-three patients with malunited fractures of the ankle who underwent reconstructive surgery at our hospital from January 2010 to January 2014 were reviewed. The tibial anterior surface angle (TAS), the tibiotalar tilt angle (TTA), the malleolar angle (MA), and the tibial lateral surface angle (TLS) were measured. Clinical assessment was performed with use of the American Orthopaedic Foot and Ankle Society (AOFAS) scale and visual analogue scale (VAS) scores, and the osteoarthritis stage was determined radiographically with the modified Takakura classification system. The Wilcoxon matched-pairs test was used to analyze the difference between the preoperative and the postoperative data. The mean follow-up was 36 months (range, 20-60 months). The mean age at the time of realignment surgery was 37.1 years (range, 18-62 years). Compared with preoperation, the TAS at the last follow-up showed a significant increase (88.50° ± 4.47° vs. 90.80° ± 3.49°, P = 0.0035); similar results were observed in TTA (1.62° ± 1.66° vs. 0.83° ± 0.90°, P < 0.01) and MA (82.30° ± 8.03° vs. 78.70° ± 4.76°, P = 0.005). At the last follow-up, the mean AOFAS score was significantly increased compared with the score at preoperation (44.5 ± 13.7 vs. 78.0 ± 8.9, P < 0.01). Significant differences in VAS scores were found at the last follow-up (6.76 ± 1.03 vs. 2.03 ± 1.21, P < 0.01). There was no significant difference in the Takakura grade between the preoperation and the last follow-up. One patient had increased talar tilt postsurgery; the postoperative talar tilt angle of this patient was 20°. One patient had progressive ankle osteoarthritis, and was treated by ankle joint distraction. Realignment surgery for a malunited ankle fracture can reduce pain, improve function, and delay ankle arthrodesis or total ankle replacement. Postoperative large talar

  12. [Chronic ankle instability in sports -- a review for sports physicians].

    PubMed

    Valderrabano, V; Leumann, A; Pagenstert, G; Frigg, A; Ebneter, L; Hintermann, B

    2006-12-01

    Chronic ankle instability represents a typical sports injury which can mostly be seen in basketball, soccer, orienteering and other high risk sports. 20 to 40 % of the acute ankle sprains develop into chronic ankle instability. From a sports orthopaedic point of view, chronic ankle instability can be subdivided into a lateral, medial or a combination of both so called rotational ankle instability. From a pathophysiological point of view, chronic ankle instability can be either mechanical with a structural ligament lesion or functional with loss of the neuromuscular control. For the sports physician, the chronic ankle instability is a difficult entity as the diagnosis is usually complex and the therapy usually surgical. This review on chronic ankle instability addresses pathomechanism, diagnostics, indications for conservative and surgical treatments, and possible long-term sequelae, as ligamentous osteoarthritis.

  13. Single-leg drop landing movement strategies in participants with chronic ankle instability compared with lateral ankle sprain 'copers'.

    PubMed

    Doherty, Cailbhe; Bleakley, Chris; Hertel, Jay; Caulfield, Brian; Ryan, John; Delahunt, Eamonn

    2016-04-01

    To compare the movement patterns and underlying energetics of individuals with chronic ankle instability (CAI) to ankle sprain 'copers' during a landing task. Twenty-eight (age 23.2 ± 4.9 years; body mass 75.5 ± 13.9 kg; height 1.7 ± 0.1 m) participants with CAI and 42 (age 22.7 ± 1.7 years; body mass 73.4 ± 11.3 kg; height 1.7 ± 0.1 m) ankle sprain 'copers' were evaluated 1 year after incurring a first-time lateral ankle sprain injury. Kinematics and kinetics of the hip, knee and ankle joints from 200 ms pre-initial contact (IC) to 200 ms post-IC, in addition to the vertical component of the landing ground reaction force, were acquired during performance of a drop land task. The CAI group adopted a position of increased hip flexion during the landing descent on their involved limb. This coincided with a reduced post-IC flexor pattern at the hip and increased overall hip joint stiffness compared to copers (-0.01 ± 0.05 vs. 0.02 ± 0.05°/Nm kg(-1), p = 0.03). Individuals with CAI display alterations in hip joint kinematics and energetics during a unipodal landing task compared to LAS 'copers'. These alterations may be responsible for the increased risk of injury experienced by individuals with CAI during landing manoeuvres. Thus, clinicians must recognise the potential for joints proximal to the affected ankle to contribute to impaired function following an acute lateral ankle sprain injury and to develop rehabilitation protocols accordingly. Level III.

  14. [Acute injuries of lateral ankle joint ligaments].

    PubMed

    Lacko, M; Sidor, Z; Stolfa, S; Cellár, R; Vasko, G

    2010-08-01

    Acute injuries of the lateral ankle ligaments are one of the most common form of injury involving the musculoskeletal apparatus. Treatment usually range from cast immobilisation or acute surgical repair to functional rehabilitation. The aim of our study was to evaluate the incidence of different grades of acute injuries of lateral ligaments of the ankle joint in our patients group and to compare the results of non surgical versus surgical treatment of third grade injuries. 3148 patients were treated for acute lateral ankle sprain in a period of 5 years at our department. Each patient had stress X-ray of the ankle for evaluation of instability at the first visit. From the 234 patients with third grade injury, 39 were enrolled in our study with non surgical treatment and 18 with surgical treatment. Each group was divided regarding to the age in two subgroups. Functional outcome was evaluated 12 and 24 months after injury with AOFAS clinical rating scale and Sports Ankle Rating System--Single Assessment Numeric Evaluation. Statistical analysis was done with Pearson's Chi quadrate test with P < 0.05. First grade injury was present in 62%, second grade in 31% and only 7% of the patients had third grade injury of the lateral ankle ligaments. Further only third grade injuries were studied. Statistically significant better results were seen in patients under the age of 25, in the patient group with surgical treatment compared to patients over 25 years of age. Also statistically significant better results were seen in patient with surgical treatment to non surgical treatment in each age group. No significant difference was observed in the non surgical treatment group regarding to age. Although the injuries of the ankle ligaments belong to the most common injuries of the musculoskeletal system, there is no consensus in the treatment of such disorders. Our experiences and the results of our study show, that surgical treatment in indicated cases provides better results in

  15. Numerical model for healthy and injured ankle ligaments.

    PubMed

    Forestiero, Antonella; Carniel, Emanuele Luigi; Fontanella, Chiara Giulia; Natali, Arturo Nicola

    2017-06-01

    The aim of this work is to provide a computational tool for the investigation of ankle mechanics under different loading conditions. The attention is focused on the biomechanical role of ankle ligaments that are fundamental for joints stability. A finite element model of the human foot is developed starting from Computed Tomography and Magnetic Resonance Imaging, using particular attention to the definition of ankle ligaments. A refined fiber-reinforced visco-hyperelastic constitutive model is assumed to characterize the mechanical response of ligaments. Numerical analyses that interpret anterior drawer and the talar tilt tests reported in literature are performed. The numerical results are in agreement with the range of values obtained by experimental tests confirming the accuracy of the procedure adopted. The increase of the ankle range of motion after some ligaments rupture is also evaluated, leading to the capability of the numerical models to interpret the damage conditions. The developed computational model provides a tool for the investigation of foot and ankle functionality in terms of stress-strain of the tissues and in terms of ankle motion, considering different types of damage to ankle ligaments.

  16. Intra-articular fibrous band of the ankle: an uncommon cause of post-traumatic ankle pain.

    PubMed

    Slavotinek, J P; Zadow, S; Martin, D K

    2006-12-01

    A case of an intra-articular fibrous band of the ankle is presented with emphasis on the MR imaging appearances. This entity is an important but uncommon cause of post-traumatic ankle pain and is well recognized within the arthroscopy literature, but there is little if any documentation of this condition in the imaging literature.

  17. Biomechanical response to ankle-foot orthosis stiffness during running.

    PubMed

    Russell Esposito, Elizabeth; Choi, Harmony S; Owens, Johnny G; Blanck, Ryan V; Wilken, Jason M

    2015-12-01

    The Intrepid Dynamic Exoskeletal Orthosis (IDEO) is an ankle-foot orthosis developed to address the high rates of delayed amputation in the military. Its use has enabled many wounded Service Members to run again. During running, stiffness is thought to influence an orthosis' energy storage and return mechanical properties. This study examined the effect of orthosis stiffness on running biomechanics in patients with lower limb impairments who had undergone unilateral limb salvage. Ten patients with lower limb impairments underwent gait analysis at a self-selected running velocity. 1. Nominal (clinically-prescribed), 2. Stiff (20% stiffer than nominal), and 3. Compliant (20% less stiff than nominal) ankle-foot orthosis stiffnesses were tested. Ankle joint stiffness was greatest in the stiffest strut and lowest in the compliant strut, however ankle mechanical work remained unchanged. Speed, stride length, cycle time, joint angles, moments, powers, and ground reaction forces were not significantly different among stiffness conditions. Ankle joint kinematics and ankle, knee and hip kinetics were different between limbs. Ankle power, in particular, was lower in the injured limb. Ankle-foot orthosis stiffness affected ankle joint stiffness but did not influence other biomechanical parameters of running in individuals with unilateral limb salvage. Foot strike asymmetries may have influenced the kinetics of running. Therefore, a range of stiffness may be clinically appropriate when prescribing ankle-foot orthoses for active individuals with limb salvage. Published by Elsevier Ltd.

  18. Ankle Problems

    MedlinePlus

    ... Long-term Abdominal Pain (Stomach Pain), Short-term Ankle Problems Breast Problems in Men Breast Problems in Women Chest Pain in Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea ...

  19. The mid-term outcome of total ankle arthroplasty and ankle fusion in rheumatoid arthritis: a systematic review.

    PubMed

    van Heiningen, Jacqueline; Vliet Vlieland, Thea P M; van der Heide, Huub J L

    2013-10-26

    While arthrodesis is the standard treatment of a severely arthritic ankle joint, total ankle arthroplasty has become a popular alternative. This review provides clinical outcomes and complications of both interventions in patients with rheumatoid arthritis. Studies were obtained from Pubmed, Embase and Web of Science (January 1980-June 2011) and additional manual search. original clinical study, > 5 rheumatoid arthritis (population), internal fixation arthrodesis or three-component mobile bearing prosthesis (intervention), ankle scoring system (outcome). The clinical outcome score, complication- and failure rates were extracted and the methodological quality of the studies was analysed. 17 observational studies of 868 citations were included. The effect size concerning total ankle arthroplasty ranged between 1.9 and 6.0, for arthrodesis the effect sizes were 4.0 and 4.7. Reoperation due to implant failure or reoperation due to non-union, was 11% and 12% for respectively total ankle arthroplasty and arthrodesis. The methodological quality of the studies was low (mean 6.4 out of a maximum of 14 points) and was lower for arthrodesis (mean 4.8) as compared to arthroplasty (mean 7.8) (p = 0.04). 17 observational and no (randomized) controlled clinical trials are published on the effectiveness of arthroplasty or arthrodesis of the ankle in rheumatoid arthritis. Regardless of the methodological limitations it can be concluded that both interventions show clinical improvement and in line with current literature neither procedure is superior to the other.

  20. Energetic Passivity of the Human Ankle Joint.

    PubMed

    Lee, Hyunglae; Hogan, Neville

    2016-12-01

    Understanding the passive or nonpassive behavior of the neuromuscular system is important to design and control robots that physically interact with humans, since it provides quantitative information to secure coupled stability while maximizing performance. This has become more important than ever apace with the increasing demand for robotic technologies in neurorehabilitation. This paper presents a quantitative characterization of passive and nonpassive behavior of the ankle of young healthy subjects, which provides a baseline for future studies in persons with neurological impairments and information for future developments of rehabilitation robots, such as exoskeletal devices and powered prostheses. Measurements using a wearable ankle robot actuating 2 degrees-of-freedom of the ankle combined with curl analysis and passivity analysis enabled characterization of both quasi-static and steady-state dynamic behavior of the ankle, unavailable from single DOF studies. Despite active neuromuscular control over a wide range of muscle activation, in young healthy subjects passive or dissipative ankle behavior predominated.

  1. Ankle arthroscopy: outcome in 79 consecutive patients.

    PubMed

    Amendola, A; Petrik, J; Webster-Bogaert, S

    1996-10-01

    Seventy-nine consecutive ankle arthroscopies were analyzed at a minimum 2-year follow-up to evaluate the risks and benefits of the procedure. All arthroscopies were performed over a 2-year period by a single surgeon using the same nonskeletal traction technique. Forty-four arthroscopies were performed for therapeutic reasons only, whereas 35 were performed for both diagnostic and therapeutic purposes. Clinical examination with visual analog scores were used for assessment preoperatively and postoperatively. The diagnoses were osteochondral lesions of the talus in 21; post-ankle fracture scarring in 14, osteoarthritis and chondromalacia in 11, anterior bony impingement in 14; anterolateral soft tissue impingement or synovitis in 15; miscellaneous diagnosis in 4. Overall, 63 of 79 patients benefited in some way from the procedure. There were diagnostic benefits in 27 of 35 (77%) of ankles in which the diagnosis was clarified by the arthroscopy. In those ankles in which the procedure was performed for therapeutic purposes only, 36 of 44 (82%) of the patients benefited. Those patients with an underlying diagnosis of osteoarthritis of the ankle, posttraumatic chondromalacia and arthrofibrosis, or who were on disability and worker's compensation benefits, had poor results, whereas patients with a localized osteochondral lesion of the talus, localized bony or soft tissue impingement, or localized lateral plica had the best results. There were three significant neurological complications from ankle arthroscopy in this series. Two patients developed a postoperative partial deep peroneal nerve neuropraxia, and one patient had superficial peroneal nerve irritation at the site of the anterolateral portal. Ankle arthroscopy appears to be a relatively low-risk procedure with substantial benefits, particularly in localized disease of the ankle joint. Skeletal distraction was not used in any of these cases.

  2. Incidence and Cost of Ankle Sprains in United States Emergency Departments

    PubMed Central

    Shah, Shweta; Thomas, Abbey C.; Noone, Joshua M.; Blanchette, Christopher M.; Wikstrom, Erik A.

    2016-01-01

    Background: Ankle sprains represent a common injury in emergency departments, but little is known about common complications, procedures, and charges associated with ankle sprains in emergency departments. Hypothesis: There will be a higher incidence of ankle sprains among younger populations (≤25 years old) and in female patients. Complications and procedures will differ between ankle sprain types. Lateral ankle sprains will have lower health care charges relative to medial and high ankle sprains. Study Design: Descriptive epidemiological study. Level of Evidence: Level 3. Methods: A cross-sectional study of the 2010 Nationwide Emergency Department Sample was conducted. Outcomes such as charges, complications, and procedures were compared using propensity score matching between lateral and medial as well as lateral and high ankle sprains. Results: The sample contained 225,114 ankle sprains. Female patients sustained more lateral ankle sprains (57%). After propensity score adjustment, lateral sprains incurred greater charges than medial ankle sprains (median [interquartile range], $1008 [$702-$1408] vs $914 [$741-$1108]; P < 0.01). Among complications, pain in the limb (1.92% vs 0.52%, P = 0.03), sprain of the foot (2.96% vs 0.70%, P < 0.01), and abrasion of the hip/leg (1.57% vs 0.35%, P = 0.03) were more common in lateral than medial ankle sprain events. Among procedures, medial ankle sprains were more likely to include diagnostic radiology (97.91% vs 83.62%, P < 0.01) and less likely to include medications than lateral ankle sprains (0.87% vs 2.79%, P < 0.01). Hospitalizations were more common following high ankle sprains than lateral ankle sprains (24 [6.06%] vs 1 [0.25%], P < 0.01). Conclusion: Ankle sprain emergency department visits account for significant health care charges in the United States. Age- and sex-related differences persist among the types of ankle sprains. Clinical Relevance: The health care charges associated with ankle sprains indicate the

  3. Systematic review of chronic ankle instability in children

    PubMed Central

    2014-01-01

    Background Chronic ankle instability (CAI) is a disabling condition often encountered after ankle injury. Three main components of CAI exist; perceived instability; mechanical instability (increased ankle ligament laxity); and recurrent sprain. Literature evaluating CAI has been heavily focused on adults, with little attention to CAI in children. Hence, the objective of this study was to systematically review the prevalence of CAI in children. Methods Studies were retrieved from major databases from earliest records to March 2013. References from identified articles were also examined. Studies involving participants with CAI, classified by authors as children, were considered for inclusion. Papers investigating traumatic instability or instability arising from fractures were excluded. Two independent examiners undertook all stages of screening, data extraction and methodological quality assessments. Screening discrepancies were resolved by reaching consensus. Results Following the removal of duplicates, 14,263 papers were screened for eligibility against inclusion and exclusion criteria. Nine full papers were included in the review. Symptoms of CAI evaluated included perceived and mechanical ankle instability along with recurrent ankle sprain. In children with a history of ankle sprain, perceived instability was reported in 23-71% whilst mechanical instability was found in 18-47% of children. A history of recurrent ankle sprain was found in 22% of children. Conclusion Due to the long-lasting impacts of CAI, future research into the measurement and incidence of ankle instability in children is recommended. PMID:24641786

  4. The role of series ankle elasticity in bipedal walking

    PubMed Central

    Zelik, Karl E.; Huang, Tzu-Wei P.; Adamczyk, Peter G.; Kuo, Arthur D.

    2014-01-01

    The elastic stretch-shortening cycle of the Achilles tendon during walking can reduce the active work demands on the plantarflexor muscles in series. However, this does not explain why or when this ankle work, whether by muscle or tendon, needs to be performed during gait. We therefore employ a simple bipedal walking model to investigate how ankle work and series elasticity impact economical locomotion. Our model shows that ankle elasticity can use passive dynamics to aid push-off late in single support, redirecting the body's center-of-mass (COM) motion upward. An appropriately timed, elastic push-off helps to reduce dissipative collision losses at contralateral heelstrike, and therefore the positive work needed to offset those losses and power steady walking. Thus, the model demonstrates how elastic ankle work can reduce the total energetic demands of walking, including work required from more proximal knee and hip muscles. We found that the key requirement for using ankle elasticity to achieve economical gait is the proper ratio of ankle stiffness to foot length. Optimal combination of these parameters ensures proper timing of elastic energy release prior to contralateral heelstrike, and sufficient energy storage to redirect the COM velocity. In fact, there exist parameter combinations that theoretically yield collision-free walking, thus requiring zero active work, albeit with relatively high ankle torques. Ankle elasticity also allows the hip to power economical walking by contributing indirectly to push-off. Whether walking is powered by the ankle or hip, ankle elasticity may aid walking economy by reducing collision losses. PMID:24365635

  5. The role of series ankle elasticity in bipedal walking.

    PubMed

    Zelik, Karl E; Huang, Tzu-Wei P; Adamczyk, Peter G; Kuo, Arthur D

    2014-04-07

    The elastic stretch-shortening cycle of the Achilles tendon during walking can reduce the active work demands on the plantarflexor muscles in series. However, this does not explain why or when this ankle work, whether by muscle or tendon, needs to be performed during gait. We therefore employ a simple bipedal walking model to investigate how ankle work and series elasticity impact economical locomotion. Our model shows that ankle elasticity can use passive dynamics to aid push-off late in single support, redirecting the body's center-of-mass (COM) motion upward. An appropriately timed, elastic push-off helps to reduce dissipative collision losses at contralateral heelstrike, and therefore the positive work needed to offset those losses and power steady walking. Thus, the model demonstrates how elastic ankle work can reduce the total energetic demands of walking, including work required from more proximal knee and hip muscles. We found that the key requirement for using ankle elasticity to achieve economical gait is the proper ratio of ankle stiffness to foot length. Optimal combination of these parameters ensures proper timing of elastic energy release prior to contralateral heelstrike, and sufficient energy storage to redirect the COM velocity. In fact, there exist parameter combinations that theoretically yield collision-free walking, thus requiring zero active work, albeit with relatively high ankle torques. Ankle elasticity also allows the hip to power economical walking by contributing indirectly to push-off. Whether walking is powered by the ankle or hip, ankle elasticity may aid walking economy by reducing collision losses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Synovial osteochondromatosis involvement in post-traumatic ankle injury.

    PubMed

    Lee, Daniel K; Louk, Louis; Bell, Bryan L

    2008-01-01

    Ankle involvement by synovial chondromatosis is unusual. It is unknown whether a post-traumatic event to the ankle induces the formation and development of these lesions. Synovial osteochondromatosis associated with post-traumatic ankle events are rare but suggest trauma to the synovial tissues as being causative, although this has never been statistically confirmed owing to the lack of reports and frequency. We report a case of primary synovial osteochondromatosis involving the tibiotalar joint with painful symptoms after a history of ankle injury, including magnetic resonance imaging findings of this unusual condition.

  7. Contributing factors to chronic ankle instability.

    PubMed

    Hubbard, Tricia J; Kramer, Lauren C; Denegar, Craig R; Hertel, Jay

    2007-03-01

    The development of repetitive ankle sprains and persistent symptoms after initial ankle sprain has been termed chronic ankle instability (CAI). There is no clear indication of which measures are most important in discriminating between individuals with and without CAI. Thirty subjects with unilateral CAI and controls had measures of ankle laxity and hypomobility, static and dynamic balance, ankle and hip strength, lower extremity alignments, and flexibility taken on both limbs. Based on comparisons of CAI ankles and side-matched limbs in controls, the measures significantly predictive of CAI were increased inversion laxity (r(2) change = 0.203), increased anterior laxity (r(2) change = 0.11), more missed balance trials (r(2) change = 0.094), and lower plantarflexion to dorsiflexion peak torque (r(2) change = 0.052). Symmetry indices comparing the side-to-side differences of each measure also were calculated for each dependent variable and compared between groups. The measures significantly predictive of CAI were decreased anterior reach (r(2) change = 0.185), decreased plantarflexion peak torque (r(2) change = 0.099), decreased posterior medial reach (r(2) change = 0.094), and increased inversion laxity (r(2) change = 0.041). The results of this study elucidate the specific measures that best discriminate between individuals with and without CAI. Both mechanical (anterior and inversion laxity) and functional (strength, dynamic balance) insufficiencies significantly contribute to the etiology of CAI. Prevention of CAI may be possible with proper initial management of the acute injury with rehabilitation aimed at those factors that best discriminate between individuals with and without CAI.

  8. Multivariable Dynamic Ankle Mechanical Impedance With Active Muscles

    PubMed Central

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2015-01-01

    Multivariable dynamic ankle mechanical impedance in two coupled degrees-of-freedom (DOFs) was quantified when muscles were active. Measurements were performed at five different target activation levels of tibialis anterior and soleus, from 10% to 30% of maximum voluntary contraction (MVC) with increments of 5% MVC. Interestingly, several ankle behaviors characterized in our previous study of the relaxed ankle were observed with muscles active: ankle mechanical impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness; stiffness was greater in the sagittal plane than in the frontal plane at all activation conditions for all subjects; and the coupling between dorsiflexion–plantarflexion and inversion–eversion was small—the two DOF measurements were well explained by a strictly diagonal impedance matrix. In general, ankle stiffness increased linearly with muscle activation in all directions in the 2-D space formed by the sagittal and frontal planes, but more in the sagittal than in the frontal plane, resulting in an accentuated “peanut shape.” This characterization of young healthy subjects’ ankle mechanical impedance with active muscles will serve as a baseline to investigate pathophysiological ankle behaviors of biomechanically and/or neurologically impaired patients. PMID:25203497

  9. Ball and Socket Ankle: Mechanism and Computational Evidence of Concept.

    PubMed

    Jastifer, James R; Gustafson, Peter A; Labomascus, Aaron; Snoap, Tyler

    The ball and socket ankle joint is a morphologically abnormal joint characterized by rounding of the articular surface of the talus. Other than anecdotal observation, little evidence has been presented to describe the development of this deformity. The purpose of the present study was to review ankle and subtalar joint mechanics and to kinematically examine the functional combination of these joints as a mechanism of the ball and socket ankle deformity. We reviewed functional representations of the ankle joint, subtalar joint, and ball and socket ankle deformity. A computational study of joint kinematics was then performed using a 3-dimensional model derived from a computed tomography scan of a ball and socket deformity. The joint kinematics were captured by creating a "virtual map" of the combined kinematics of the ankle and subtalar joints in the respective models. The ball and socket ankle deformity produces functionally similar kinematics to a combination of the ankle and subtalar joints. The findings of the present study support the notion that a possible cause of the ball and socket deformity is bony adaptation that compensates for a functional deficit of the ankle and subtalar joints. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Intrinsic ankle stiffness during standing increases with ankle torque and passive stretch of the Achilles tendon

    PubMed Central

    Gill, Jaspret

    2018-01-01

    Individuals may stand with a range of ankle angles. Furthermore, shoes or floor surfaces may elevate or depress their heels. Here we ask how these situations impact ankle stiffness and balance. We performed two studies (each with 10 participants) in which the triceps surae, Achilles tendon and aponeurosis were stretched either passively, by rotating the support surface, or actively by leaning forward. Participants stood freely on footplates which could rotate around the ankle joint axis. Brief, small stiffness-measuring perturbations (<0.7 deg; 140 ms) were applied at intervals of 4–5 s. In study 1, participants stood at selected angles of forward lean. In study 2, normal standing was compared with passive dorsiflexion induced by 15 deg toes-up tilt of the support surface. Smaller perturbations produced higher stiffness estimates, but for all perturbation sizes stiffness increased with active torque or passive stretch. Sway was minimally affected by stretch or lean, suggesting that this did not underlie the alterations in stiffness. In quiet stance, maximum ankle stiffness is limited by the tendon. As tendon strain increases, it becomes stiffer, causing an increase in overall ankle stiffness, which would explain the effects of leaning. However, stiffness also increased considerably with passive stretch, despite a modest torque increase. We discuss possible explanations for this increase. PMID:29558469

  11. Validity of the Foot and Ankle Ability Measure in athletes with chronic ankle instability.

    PubMed

    Carcia, Christopher R; Martin, RobRoy L; Drouin, Joshua M

    2008-01-01

    The Foot and Ankle Ability Measure (FAAM) is a region-specific, non-disease-specific outcome instrument that possesses many of the clinimetric qualities recommended for an outcome instrument. Evidence of validity to support the use of the FAAM is available in individuals with a wide array of ankle and foot disorders. However, additional evidence to support the use of the FAAM for those with chronic ankle instability (CAI) is needed. To provide evidence of construct validity for the FAAM based on hypothesis testing in athletes with CAI. Between-groups comparison. Athletic training room. Thirty National Collegiate Athletic Association Division II athletes (16 men, 14 women) from one university. The FAAM including activities of daily living (ADL) and sports subscales and the global and categorical ratings of function. For both the ADL and sports subscales, FAAM scores were greater in healthy participants (100 +/- 0.0 and 99 +/- 3.5, respectively) than in subjects with CAI (88 +/- 7.7 and 76 +/- 12.7, respectively; P < .001). Similarly, for both ADL and sports subscales, FAAM scores were greater in athletes who indicated that their ankles were normal (98 +/- 6.3 and 96 +/- 6.9, respectively) than in those who classified their ankles as either nearly normal or abnormal (87 +/- 6.6 and 71 +/- 11.1, respectively; P < .001). We found relationships between FAAM scores and self-reported global ratings of function for both ADL and sports subscales. Relationships were stronger when all athletes, rather than just those with CAI, were included in the analyses. The FAAM may be used to detect self-reported functional deficits related to CAI.

  12. Rehabilitation of the Ankle After Acute Sprain or Chronic Instability.

    PubMed

    Mattacola, Carl G; Dwyer, Maureen K

    2002-12-01

    OBJECTIVE: To outline rehabilitation concepts that are applicable to acute and chronic injury of the ankle, to provide evidence for current techniques used in the rehabilitation of the ankle, and to describe a functional rehabilitation program that progresses from basic to advanced, while taking into consideration empirical data from the literature and clinical practice. BACKGROUND: Important considerations in the rehabilitation of ankle injuries include controlling the acute inflammatory process, regaining full ankle range of motion, increasing muscle strength and power, and improving proprioceptive abilities. These goals can be achieved through various modalities, flexibility exercises, and progressive strength- and balance-training exercises. In this article, we discuss the deleterious effects of ankle injury on ankle-joint proprioception and muscular strength and how these variables can be quantifiably measured to follow progress through a rehabilitation program. Evidence to support the effectiveness of applying orthotics and ankle braces during the acute and subacute phases of ankle rehabilitation is provided, along with recommendations for functional rehabilitation of ankle injuries, including a structured progression of exercises. RECOMMENDATIONS: Early functional rehabilitation of the ankle should include range-of-motion exercises and isometric and isotonic strength-training exercises. In the intermediate stage of rehabilitation, a progression of proprioception-training exercises should be incorporated. Advanced rehabilitation should focus on sport-specific activities to prepare the athlete for return to competition. Although it is important to individualize each rehabilitation program, this well-structured template for ankle rehabilitation can be adapted as needed.

  13. Rehabilitation of the Ankle After Acute Sprain or Chronic Instability

    PubMed Central

    Mattacola, Carl G.; Dwyer, Maureen K.

    2002-01-01

    Objective: To outline rehabilitation concepts that are applicable to acute and chronic injury of the ankle, to provide evidence for current techniques used in the rehabilitation of the ankle, and to describe a functional rehabilitation program that progresses from basic to advanced, while taking into consideration empirical data from the literature and clinical practice. Background: Important considerations in the rehabilitation of ankle injuries include controlling the acute inflammatory process, regaining full ankle range of motion, increasing muscle strength and power, and improving proprioceptive abilities. These goals can be achieved through various modalities, flexibility exercises, and progressive strength- and balance-training exercises. In this article, we discuss the deleterious effects of ankle injury on ankle-joint proprioception and muscular strength and how these variables can be quantifiably measured to follow progress through a rehabilitation program. Evidence to support the effectiveness of applying orthotics and ankle braces during the acute and subacute phases of ankle rehabilitation is provided, along with recommendations for functional rehabilitation of ankle injuries, including a structured progression of exercises. Recommendations: Early functional rehabilitation of the ankle should include range-of-motion exercises and isometric and isotonic strength-training exercises. In the intermediate stage of rehabilitation, a progression of proprioception-training exercises should be incorporated. Advanced rehabilitation should focus on sport-specific activities to prepare the athlete for return to competition. Although it is important to individualize each rehabilitation program, this well-structured template for ankle rehabilitation can be adapted as needed. PMID:12937563

  14. Complications of ankle fracture in patients with diabetes.

    PubMed

    Chaudhary, Saad B; Liporace, Frank A; Gandhi, Ankur; Donley, Brian G; Pinzur, Michael S; Lin, Sheldon S

    2008-03-01

    Ankle fractures in patients with diabetes mellitus have long been recognized as a challenge to practicing clinicians. Complications of impaired wound healing, infection, malunion, delayed union, nonunion, and Charcot arthropathy are prevalent in this patient population. Controversy exists as to whether diabetic ankle fractures are best treated noninvasively or by open reduction and internal fixation. Patients with diabetes are at significant risk for soft-tissue complications. In addition, diabetic ankle fractures heal, but significant delays in bone healing exist. Also, Charcot ankle arthropathy occurs more commonly in patients who were initially undiagnosed and had a delay in immobilization and in patients treated nonsurgically for displaced ankle fractures. Several techniques have been described to minimize complications associated with diabetic ankle fractures (eg, rigid external fixation, use of Kirschner wires or Steinmann pins to increase rigidity). Regardless of the specifics of treatment, adherence to the basic principles of preoperative planning, meticulous soft-tissue management, and attention to stable, rigid fixation with prolonged, protected immobilization are paramount in minimizing problems and yielding good functional outcomes.

  15. Effects of foot orthoses on patients with chronic ankle instability.

    PubMed

    Richie, Douglas H

    2007-01-01

    Chronic instability of the ankle can be the result of mechanical and functional deficits. An acute ankle sprain can cause mechanical and functional instability, which may or may not respond to standard rehabilitation programs. Chronic instability results when there is persistent joint laxity of the ankle or when one or more components of neuromuscular control of the ankle are compromised. A loss of balance or postural control seems to be the most consistent finding among athletes with chronic instability of the ankle. Recent research in patients with acute and chronic ankle instability has revealed positive effects of foot orthoses on postural control. This article reviews the current research relevant to the use of foot orthoses in patients with chronic ankle instability and clarifies the suggested benefits and the shortcomings of these investigations.

  16. Treatment of ankle fractures--our results.

    PubMed

    Vranic, Haris; Hadzimehmedagic, Amel; Gavrankapetanovic, Ismet; Zjakic, Amir; Talic, Adnana

    2010-01-01

    Break ankle today is becoming more frequent. There is a dilemma to operate immediately upon receipt or delayed surgical treatment for a day or two. This work aims at showing the importance of the anatomy, mechanism of injury, injury classification, diagnostic and therapeutic methods in treatment of brake ankle from our experience. In the past year in our clinic there were 30 patients treated for all types of ankle fractures, and these patients were divided in two groups. Patients of the first group are those immediately operated, and the second group were with delayed surgery. The results showed that the patients of the first group had better healing, fewer complications, better and faster rehabilitation. Second groups of patients were with complications in terms dehiscence of wounds, bad healing fracture and DVT. Our results showed that better result in the treatment of ankle fractures is achieved by aggressive treatment immediately after trauma, with reconstruction of articular surface and tibiofibular syndesmosis with early rehabilitation.

  17. Joint mobilization acutely improves landing kinematics in chronic ankle instability.

    PubMed

    Delahunt, Eamonn; Cusack, Kim; Wilson, Laura; Doherty, Cailbhe

    2013-03-01

    The objective of this study is to examine the acute effect of ankle joint mobilizations akin to those performed in everyday clinical practice on sagittal plane ankle joint kinematics during a single-leg drop landing in participants with chronic ankle instability (CAI). Fifteen participants with self-reported CAI (defined as <24 on the Cumberland Ankle Instability Tool) performed three single-leg drop landings under two different conditions: 1) premobilization and, 2) immediately, postmobilization. The mobilizations performed included Mulligan talocrural joint dorsiflexion mobilization with movement, Mulligan inferior tibiofibular joint mobilization, and Maitland anteroposterior talocrural joint mobilization. Three CODA cx1 units (Charnwood Dynamics Ltd., Leicestershire, UK) were used to provide information on ankle joint sagittal plane angular displacement. The dependent variable under investigation was the angle of ankle joint plantarflexion at the point of initial contact during the drop landing. There was a statistically significant acute decrease in the angle of ankle joint plantarflexion from premobilization (34.89° ± 4.18°) to postmobilization (31.90° ± 5.89°), t(14) = 2.62, P < 0.05 (two-tailed). The mean decrease in the angle of ankle joint plantarflexion as a result of the ankle joint mobilization was 2.98° with a 95% confidence interval ranging from 0.54 to 5.43. The eta squared statistic (0.32) indicated a large effect size. These results indicate that mobilization acted to acutely reduce the angle of ankle joint plantarflexion at initial contact during a single-leg drop landing. Mobilization applied to participants with CAI has a mechanical effect on the ankle joint, thus facilitating a more favorable positioning of the ankle joint when landing from a jump.

  18. Relationship between mechanical ankle joint laxity and subjective function.

    PubMed

    Hubbard-Turner, Tricia

    2012-10-01

    An increase in ankle joint laxity has been reported in patients with chronic ankle instability (CAI). However, it is not known if this increase in joint laxity is responsible for the subjective level of functional deficits also reported in these patients. One hundred twenty subjects with unilateral CAI (55 males, 65 females; age, 20.6 ± 1.5 years; mass, 74.5 ± 13.6 kg; height, 174.2 ± 9.7 cm) participated in the study. Mechanical joint stability was measured with an instrumented ankle arthrometer. The arthrometer measured ankle joint motion for anterior/posterior translation and inversion/eversion angular displacement. Subjective level of function was assessed with the foot and ankle disability index (FADI) and foot and ankle disability index sport (FADIS). Bivariate correlations using Pearson Product Moments were made between all dependent variables taken on the unstable ankles. The strongest relationship was between anterior laxity and the FADIS (r = -0.88, p < 0.0001). As scores on the FADIS decreased, anterior laxity increased. Similar significant results were reported for anterior laxity and the FADI (r = -0.65, p = 0.013), as well as inversion laxity and the FADI (r = -0.53, p = 0.017) and FADIS (r = -0.45, p = 0.013). These data demonstrate that there appears to be a relationship between anterior and inversion ankle laxity and subjective function in those with CAI. Although numerous insufficiencies develop after an ankle sprain, increased laxity may cause some of the subjective functional deficits reported in those with CAI. Strategies to prevent increased laxity following ankle sprain may improve the patient's subjective level of function.

  19. Lateral ankle injury. Literature review and report of two cases.

    PubMed

    Pollard, Henry; Sim, Patrick; McHardy, Andrew

    2002-07-01

    Injury to the ankle joint is the most common peripheral joint injury. The sports that most commonly produce high ankle injury rates in their participating athletes include: basketball, netball, and the various codes of football. To provide an up to date understanding of manual therapy relevant to lateral ligament injury of the ankle. A discussion of the types of ligament injury and common complicating factors that present with lateral ankle pain is presented along with a review of relevant anatomy, assessment and treatment. Also included is a discussion of the efficacy of manual therapy in the treatment of ankle sprain. A detailed knowledge of the anatomy of the ankle as well as the early recognition of factors that may delay the rate of healing are important considerations when developing a management plan for inversion sprains of the ankle. This area appears to be under-researched however it was found that movement therapy and its various forms appear to be the most efficient and most effective method of treating uncomplicated ankle injury. Future investigations should involve a study to determine the effect chiropractic treatment (manipulation) may have on the injured ankle.

  20. Multivariable dynamic ankle mechanical impedance with relaxed muscles.

    PubMed

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2014-11-01

    Neurological or biomechanical disorders may distort ankle mechanical impedance and thereby impair locomotor function. This paper presents a quantitative characterization of multivariable ankle mechanical impedance of young healthy subjects when their muscles were relaxed, to serve as a baseline to compare with pathophysiological ankle properties of biomechanically and/or neurologically impaired patients. Measurements using a highly backdrivable wearable ankle robot combined with multi-input multi-output stochastic system identification methods enabled reliable characterization of ankle mechanical impedance in two degrees-of-freedom (DOFs) simultaneously, the sagittal and frontal planes. The characterization included important ankle properties unavailable from single DOF studies: coupling between DOFs and anisotropy as a function of frequency. Ankle impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness in both seated (knee flexed) and standing (knee straightened) postures. Stiffness in the sagittal plane was greater than in the frontal plane and furthermore, was greater when standing than when seated, most likely due to the stretch of bi-articular muscles (medial and lateral gastrocnemius). Very low off-diagonal partial coherences implied negligible coupling between dorsiflexion-plantarflexion and inversion-eversion. The directions of principal axes were tilted slightly counterclockwise from the original joint coordinates. The directional variation (anisotropy) of ankle impedance in the 2-D space formed by rotations in the sagittal and frontal planes exhibited a characteristic "peanut" shape, weak in inversion-eversion over a wide range of frequencies from the stiffness dominated region up to the inertia dominated region. Implications for the assessment of neurological and biomechanical impairments are discussed.

  1. A powered prosthetic ankle joint for walking and running.

    PubMed

    Grimmer, Martin; Holgate, Matthew; Holgate, Robert; Boehler, Alexander; Ward, Jeffrey; Hollander, Kevin; Sugar, Thomas; Seyfarth, André

    2016-12-19

    Current prosthetic ankle joints are designed either for walking or for running. In order to mimic the capabilities of an able-bodied, a powered prosthetic ankle for walking and running was designed. A powered system has the potential to reduce the limitations in range of motion and positive work output of passive walking and running feet. To perform the experiments a controller capable of transitions between standing, walking, and running with speed adaptations was developed. In the first case study the system was mounted on an ankle bypass in parallel with the foot of a non-amputee subject. By this method the functionality of hardware and controller was proven. The Walk-Run ankle was capable of mimicking desired torque and angle trajectories in walking and running up to 2.6 m/s. At 4 m/s running, ankle angle could be matched while ankle torque could not. Limited ankle output power resulting from a suboptimal spring stiffness value was identified as a main reason. Further studies have to show to what extent the findings can be transferred to amputees.

  2. Postural steadiness and ankle force variability in peripheral neuropathy

    PubMed Central

    Paxton, Roger J.; Feldman-Kothe, Caitlin; Trabert, Megan K.; Hitchcock, Leah N.; Reiser, Raoul F.; Tracy, Brian L.

    2015-01-01

    Introduction The purpose was to determine the effect of peripheral neuropathy (PN) on motor output variability for ankle muscles of older adults, and the relation between ankle motor variability and postural stability in PN patients. Methods Older adults with (O-PN) and without PN (O), and young adults (Y) underwent assessment of standing postural stability and ankle muscle force steadiness. Results O-PN displayed impaired ankle muscle force control and postural stability compared with O and Y groups. For O-PN, the amplitude of plantarflexor force fluctuations was moderately correlated with postural stability under no-vision conditions (r = 0.54, P = 0.01). Discussion The correlation of variations in ankle force with postural stability in PN suggests a contribution of ankle muscle dyscontrol to the postural instability that impacts physical function for older adults with PN. PMID:26284897

  3. Balance decrements are associated with age-related muscle property changes.

    PubMed

    Hasson, Christopher J; van Emmerik, Richard E A; Caldwell, Graham E

    2014-08-01

    In this study, a comprehensive evaluation of static and dynamic balance abilities was performed in young and older adults and regression analysis was used to test whether age-related variations in individual ankle muscle mechanical properties could explain differences in balance performance. The mechanical properties included estimates of the maximal isometric force capability, force-length, force-velocity, and series elastic properties of the dorsiflexors and individual plantarflexor muscles (gastrocnemius and soleus). As expected, the older adults performed more poorly on most balance tasks. Muscular maximal isometric force, optimal fiber length, tendon slack length, and velocity-dependent force capabilities accounted for up to 60% of the age-related variation in performance on the static and dynamic balance tests. In general, the plantarflexors had a stronger predictive role than the dorsiflexors. Plantarflexor stiffness was strongly related to general balance performance, particularly in quiet stance; but this effect did not depend on age. Together, these results suggest that age-related differences in balance performance are explained in part by alterations in muscular mechanical properties.

  4. Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior

    PubMed Central

    Amerinatanzi, Amirhesam; Zamanian, Hashem; Shayesteh Moghaddam, Narges

    2017-01-01

    Hinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor muscle activity, and muscle atrophy. Since the ankle torque-angle loop has a non-linear profile, the use of a superelastic NiTi spring within the hinge, due to its nonlinear behavior, could recreate a close-to-normal stiffness of the normal ankle joint, which, in turn, could create a more natural walk. The focus of this study is to evaluate the performance of a superelastic NiTi spring versus a conventional Stainless Steel spring in a hinge mechanism of a custom-fit HAFO. To this aim, a custom-fit HAFO was fabricated via the fast casting technique. Then, motion analysis was performed for two healthy subjects (Case I and Case II): (i) subjects with bare foot; (ii) subjects wearing a conventional HAFO with no spring; (iii) subjects wearing a conventional Stainless Steel-based HAFO; and (iv) subjects wearing a NiTi spring-based HAFO. The data related to the ankle angle and the amount of moment applied to the ankle during walking were recorded using Cortex software and used for the evaluations. Finally, Finite Element Analysis (FEA) was performed to evaluate the safety of the designed HAFO. The NiTi spring offers a higher range of motion (7.9 versus 4.14 degree) and an increased level of moment (0.55 versus 0.36 N·m/kg). Furthermore, a NiTi spring offers an ankle torque-angle loop closer to that of the healthy subjects. PMID:29215571

  5. Application of the Superelastic NiTi Spring in Ankle Foot Orthosis (AFO) to Create Normal Ankle Joint Behavior.

    PubMed

    Amerinatanzi, Amirhesam; Zamanian, Hashem; Shayesteh Moghaddam, Narges; Jahadakbar, Ahmadreza; Elahinia, Mohammad

    2017-12-07

    Hinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor muscle activity, and muscle atrophy. Since the ankle torque-angle loop has a non-linear profile, the use of a superelastic NiTi spring within the hinge, due to its nonlinear behavior, could recreate a close-to-normal stiffness of the normal ankle joint, which, in turn, could create a more natural walk. The focus of this study is to evaluate the performance of a superelastic NiTi spring versus a conventional Stainless Steel spring in a hinge mechanism of a custom-fit HAFO. To this aim, a custom-fit HAFO was fabricated via the fast casting technique. Then, motion analysis was performed for two healthy subjects (Case I and Case II): (i) subjects with bare foot; (ii) subjects wearing a conventional HAFO with no spring; (iii) subjects wearing a conventional Stainless Steel-based HAFO; and (iv) subjects wearing a NiTi spring-based HAFO. The data related to the ankle angle and the amount of moment applied to the ankle during walking were recorded using Cortex software and used for the evaluations. Finally, Finite Element Analysis (FEA) was performed to evaluate the safety of the designed HAFO. The NiTi spring offers a higher range of motion (7.9 versus 4.14 degree) and an increased level of moment (0.55 versus 0.36 N·m/kg). Furthermore, a NiTi spring offers an ankle torque-angle loop closer to that of the healthy subjects.

  6. The volatile anesthetic methoxyflurane protects motoneurons against excitotoxicity in an in vitro model of rat spinal cord injury.

    PubMed

    Shabbir, A; Bianchetti, E; Nistri, A

    2015-01-29

    Neuroprotection of the spinal cord during the early phase of injury is an important goal to determine a favorable outcome by prevention of delayed pathological events, including excitotoxicity, which otherwise extend the primary damage and amplify the often irreversible loss of motor function. While intensive care and neurosurgical intervention are important treatments, effective neuroprotection requires further experimental studies focused to target vulnerable neurons, particularly motoneurons. The present investigation examined whether the volatile general anesthetic methoxyflurane might protect spinal locomotor networks from kainate-evoked excitotoxicity using an in vitro rat spinal cord preparation as a model. The protocols involved 1h excitotoxic stimulation on day 1 followed by electrophysiological and immunohistochemical testing on day 2. A single administration of methoxyflurane applied together with kainate (1h), or 30 or even 60 min later prevented any depression of spinal reflexes, loss of motoneuron excitability, and histological damage. Methoxyflurane per se temporarily decreased synaptic transmission and motoneuron excitability, effects readily reversible on washout. Spinal locomotor activity recorded as alternating electrical discharges from lumbar motor pools was fully preserved on the second day after application of methoxyflurane together with (or after) kainate. These data suggest that a volatile general anesthetic could provide strong electrophysiological and histological neuroprotection that enabled expression of locomotor network activity 1 day after the excitotoxic challenge. It is hypothesized that the benefits of early neurosurgery for acute spinal cord injury (SCI) might be enhanced if, in addition to injury decompression and stabilization, the protective role of general anesthesia is exploited. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. [The effect of supervised rehabilitation on ankle joint function and the risk of recurrence after acute ankle distortion].

    PubMed

    Barkler, E H; Magnusson, S P; Becher, K; Bieler, T; Aagaard, P; Kjaer, M; Saugbjerg, P A

    2001-06-04

    The effect of an early rehabilitation programme, including postural training, on ankle joint function after an ankle ligament sprain was investigated prospectively. Ninety-two subjects, matched for age, sex, and level of sports activity, were randomised to a control or training group. All subjects received the same standard information about early ankle mobilisation. In addition, the training group participated in supervised physical therapy rehabilitation (one hour, twice weekly) with emphasis on balance training. Postural sway, position sense, and isometric ankle strength were measured six weeks and four months after the injury, and at 12 months data on re-injury were collected. In both the training group and the control group, there were a significant difference between the injured and the uninjured side for all variables except for position sense at six weeks. The side-to-side differences in per cent were similar for both groups for all variables (p > 0.05) at six weeks, and there were no such differences at four months. Re-injury occurred in 11/38 (29%) is the control group, but in only 2/29 (7%) in the training group (p < 0.05). These data showed that an ankle injury led to reduced ankle strength and postural control at six weeks, but that these variables had become normal at four months, irrespective of supervised rehabilitation. However, the findings also showed that supervised rehabilitation may reduce the number of re-injuries, and may therefore play a role in injury prevention.

  8. Sport and activity restrictions following total ankle replacement: A survey of orthopaedic foot and ankle specialists.

    PubMed

    Macaulay, Alec A; VanValkenburg, Scott M; DiGiovanni, Christopher W

    2015-12-01

    Despite an increasing utilization of total ankle replacement, surgeons have little guidance with regards to physical activity and sport participation recommendations following the procedure. Orthopaedic foot and ankle specialists were surveyed as to the activity and sports restrictions they place on their patients following ankle replacement. Fifty sports and activities were included and the results were used to derive a set of consensus recommendations. Of the 1063 surgeons that were sent the survey, 173 responded, yielding a response rate of 16.3%. In general, surgeons were comfortable with aerobic or low impact sports and activities. Boot immobilized sports represented a grey area with the determination of whether or not to allow them based largely on the prior experience of the patient. High impact, cutting and jumping sports and activities were largely discouraged. Young age, high BMI and poor bone quality led surgeons to be more restrictive. These consensus recommendations serve as a useful guideline for surgeons and help patients set appropriate expectations for the procedure. Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  9. Reliability and discriminative validity of sudden ankle inversion measurements in patients with chronic ankle instability.

    PubMed

    Eechaute, Christophe; Vaes, Peter; Duquet, William; Van Gheluwe, Bart

    2009-07-01

    Studies investigating peroneal muscle reaction times in chronically unstable ankle joints present conflicting results. The degree of reliability and accuracy of these measurements is unknown in patients with chronic ankle instability (CAI). 40 patients with CAI and 30 healthy subjects were tested using a sudden ankle inversion of 50 degrees while standing on a trapdoor device. Sudden ankle inversion measurements were registered using electromyography, accelerometry and electrogoniometry. For reliability testing, intra-class coefficients (ICCs; model 3,1) and standard errors of measurements of the latency time, motor response time and electromechanical delay of the peroneus longus muscle, the time and angular position of onset of decelerations, the mean and maximum inversion speed and the total inversion time were calculated in 15 patients with CAI. To assess between-group differences, t-tests for independent samples (p<.05) were used. ICCs ranged from .20 (angular position of onset of the second deceleration) to .98 (electromechanical delay of the peroneus longus muscle). Significant between-group differences were observed in only 2 of the 12 variables (for the electromechanical delay of the peroneus longus muscle, p=.001; time of onset of the second deceleration, p=.040). The latency time and motor response time of the peroneus longus muscle, the total inversion time and the mean inversion speed demonstrate acceptable reliability in healthy subjects and patients. The latency time and motor response time of the peroneus longus muscle are not delayed in patients with CAI. Ankle inversion measurements are not discriminative for CAI.

  10. Ipsilateral hip abductor weakness after inversion ankle sprain.

    PubMed

    Friel, Karen; McLean, Nancy; Myers, Christine; Caceres, Maria

    2006-01-01

    Hip stability and strength are important for proper gait mechanics and foot position during heel strike. To determine the relationships between hip muscle strength and chronic ankle sprains and hip muscle strength and ankle range of motion. Ex post facto design with the uninvolved limb serving as the control. Laboratory. A total of 23 subjects with unilateral chronic ankle sprain were recruited. Subjects had at least 2 ipsilateral ankle sprains and were bearing full weight, with the most recent injury occurring at least 3 months earlier. They were not undergoing formal or informal rehabilitation at the time of the study. We obtained goniometric measurements for all planes of motion at the ankle. Handheld dynamometry was used to assess the strength of the hip abductor and hip extensor muscles in both limbs. Hip abductor muscle strength and plantar flexion were significantly less on the involved side than the uninvolved side (P < .001 in each case). Strength of the involved hip abductor and hip extensor muscles was significantly correlated (r = 0.539, P < .01). No significant difference was noted in hip extensor muscle strength between sides (P = .19). Our subjects with unilateral chronic ankle sprains had weaker hip abduction strength and less plantar-flexion range of motion on the involved sides. Clinicians should consider exercises to increase hip abduction strength when developing rehabilitation programs for patients with ankle sprains.

  11. Ankle arthroscopy

    MedlinePlus

    ... you very sleepy during the operation. During the procedure, the surgeon does the following: Inserts the arthroscope into your ankle through a small incision. The scope is connected to a video monitor in the operating room. This allows the surgeon to view the ...

  12. Analysis of PITFL injuries in rotationally unstable ankle fractures.

    PubMed

    Warner, Stephen J; Garner, Matthew R; Schottel, Patrick C; Hinds, Richard M; Loftus, Michael L; Lorich, Dean G

    2015-04-01

    Reduction and stabilization of the syndesmosis in unstable ankle fractures is important for ankle mortise congruity and restoration of normal tibiotalar contact forces. Of the syndesmotic ligaments, the posterior inferior tibiofibular ligament (PITFL) provides the most strength for maintaining syndesmotic stability, and previous work has demonstrated the significance of restoring PITFL function when it remains attached to a posterior malleolus fracture fragment. However, little is known regarding the nature of a PITFL injury in the absence of a posterior malleolus fracture. The goal of this study was to describe the PITFL injury pattern based on magnetic resonance imaging (MRI) and intraoperative observation. A prospective database of all operatively treated ankle fractures by a single surgeon was used to identify all supination-external rotation (SER) types III and IV ankle fracture patients with complete preoperative orthogonal ankle radiographs and MRI. All patients with a posterior malleolus fracture were excluded. Using a combination of preoperative imaging and intraoperative findings, we analyzed the nature of injuries to the PITFL. In total, 185 SER III and IV operatively treated ankle fractures with complete imaging were initially identified. Analysis of the preoperative imaging and operative reports revealed 34% (63/185) had a posterior malleolus fracture and were excluded. From the remaining 122 ankle fractures, the PITFL was delaminated from the posterior malleolus in 97% (119/122) of cases. A smaller proportion (3%; 3/122) had an intrasubstance PITFL rupture. Accurate and stable syndesmotic reduction is a significant component of restoring the ankle mortise after unstable ankle fractures. In our large cohort of rotationally unstable ankle fractures without posterior malleolus fractures, we found that most PITFL injuries occur as a delamination off the posterior malleolus. This predictable PITFL injury pattern may be used to guide new methods for

  13. Ankle Sprain Treatment

    MedlinePlus

    ... strengthening exercise"). Resume low-impact aerobic training; maintain general fitness. III Phase III treatment focuses on restoring ankle proprioception (balance and position awareness) as well as agility and ...

  14. Validity of the Foot and Ankle Ability Measure in Athletes With Chronic Ankle Instability

    PubMed Central

    Carcia, Christopher R; Martin, RobRoy L; Drouin, Joshua M

    2008-01-01

    Context: The Foot and Ankle Ability Measure (FAAM) is a region-specific, non–disease-specific outcome instrument that possesses many of the clinimetric qualities recommended for an outcome instrument. Evidence of validity to support the use of the FAAM is available in individuals with a wide array of ankle and foot disorders. However, additional evidence to support the use of the FAAM for those with chronic ankle instability (CAI) is needed. Objective: To provide evidence of construct validity for the FAAM based on hypothesis testing in athletes with CAI. Design: Between-groups comparison. Setting: Athletic training room. Patients or Other Participants: Thirty National Collegiate Athletic Association Division II athletes (16 men, 14 women) from one university. Main Outcome Measure(s): The FAAM including activities of daily living (ADL) and sports subscales and the global and categorical ratings of function. Results: For both the ADL and sports subscales, FAAM scores were greater in healthy participants (100 ± 0.0 and 99 ± 3.5, respectively) than in subjects with CAI (88 ± 7.7 and 76 ± 12.7, respectively; P < .001). Similarly, for both ADL and sports subscales, FAAM scores were greater in athletes who indicated that their ankles were normal (98 ± 6.3 and 96 ± 6.9, respectively) than in those who classified their ankles as either nearly normal or abnormal (87 ± 6.6 and 71 ± 11.1, respectively; P < .001). We found relationships between FAAM scores and self-reported global ratings of function for both ADL and sports subscales. Relationships were stronger when all athletes, rather than just those with CAI, were included in the analyses. Conclusions: The FAAM may be used to detect self-reported functional deficits related to CAI. PMID:18345343

  15. [Ankle arthrodesis using the cable technique].

    PubMed

    Labitzke, Reiner

    2005-10-01

    Arthrodesis of the ankle with a cable technique for restitution of pain-free gait with the foot in functional alignment. Painful osteoarthritis of the ankle unresponsive to conservative and surgical treatment or in instances where these treatments do not seem sensible. Osteomyelitis, acute arthritis, neuropathic arthropathy. Exposure of the ankle through bilateral longitudinal incisions. Resection of malleoli and of articular surfaces of tibia and talus correcting at the same time any malalignment. Insertion of two cortical screws into the lateral aspect of the tibia and one each into talar body and neck. All four screws must protrude the opposite cortex. Around the neck of each anterior and posterior pair of screws as well as around the tips of the protruding screws cables are placed, tensioned, and tightened in a crimp. An arthrodesis of the ankle was performed in 25 patients (25 ankles). The goal of surgery was reached in 21 patients at 6-8 weeks postoperatively. Two patients had to undergo a revision using the same method to secure a bony fusion. In another two the failure was due to a wrong indication; in both a bony fusion occurred after external fixation. Using the Mazur Score the patients reached an average of 74 points and with the MHH Score ("Medizinische Hochschule Hannover" [Hanover Medical School]) an average of 78 points, both attesting to a good result.

  16. Foot and ankle problems in Muay Thai kickboxers.

    PubMed

    Vaseenon, Tanawat; Intharasompan, Piyapong; Wattanarojanapom, Thongaek; Theeraamphon, Nipon; Auephanviriyakul, Sansanee; Phisitkul, Phinit

    2015-01-01

    Muay Thai kickboxing is a common sport that uses the foot and ankle in fighting. Muay Thai kickboxing trainees usually receive training in Thailand Foot and ankle problems in this group ofpeople who usually train barefoot remain unexplored To evaluate the prevalence of common foot and ankle problems in Muay Thai kick boxers. The present study is a cross-sectional survey of Muay Thai kick boxers practicing in northern Thailand. Interviews were conducted and foot and ankle examinations were evaluated Foot morphology was examined using a Harris mat footprint. One hundred and twenty-three Muay Thai kickbox ersinnine training gyms were included in this study. Common foot and ankle problems found in the Muay Thai kick boxers were callosity (59%), gastrocnemius contracture (57%), toe deformities (49.3%), wounds (10%) and heel pain (9%). Callosity was most commonly found on the forefoot (77.5%), on the plantar first metatarsal (55.3%) and on the big toe (33.3%). An association was found between a tight heel cord and a history of foot injury with prolonged periods of weekly training. Toe deformities such as hallux rigidus (37.6%) were also associated with prolonged periods of training (p = 0.001). No correlation was found between type of foot arch and foot and ankle problems. Plantar forefoot callosities and wounds as well as toe deformities including tight heel cords are some of the foot and ankle problems commonly found in Muay Thai kick boxers. They are associated with prolonged periods of barefoot training. The unique pattern of training and of the kicks in Muay Thai might be a path mechanism, leading to the development of foot and ankle problems.

  17. Multivariable Dynamic Ankle Mechanical Impedance With Relaxed Muscles

    PubMed Central

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2015-01-01

    Neurological or biomechanical disorders may distort ankle mechanical impedance and thereby impair locomotor function. This paper presents a quantitative characterization of multivariable ankle mechanical impedance of young healthy subjects when their muscles were relaxed, to serve as a baseline to compare with pathophysiological ankle properties of biomechanically and/or neurologically impaired patients. Measurements using a highly backdrivable wearable ankle robot combined with multi-input multi-output stochastic system identification methods enabled reliable characterization of ankle mechanical impedance in two degrees-of-freedom (DOFs) simultaneously, the sagittal and frontal planes. The characterization included important ankle properties unavailable from single DOF studies: coupling between DOFs and anisotropy as a function of frequency. Ankle impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness in both seated (knee flexed) and standing (knee straightened) postures. Stiffness in the sagittal plane was greater than in the frontal plane and furthermore, was greater when standing than when seated, most likely due to the stretch of bi-articular muscles (medial and lateral gastrocnemius). Very low off-diagonal partial coherences implied negligible coupling between dorsiflexion-plantarflexion and inversion-eversion. The directions of principal axes were tilted slightly counterclockwise from the original joint coordinates. The directional variation (anisotropy) of ankle impedance in the 2-D space formed by rotations in the sagittal and frontal planes exhibited a characteristic “peanut” shape, weak in inversion-eversion over a wide range of frequencies from the stiffness dominated region up to the inertia dominated region. Implications for the assessment of neurological and biomechanical impairments are discussed. PMID:24686292

  18. Adaptive sports ankle prosthetics. Interview by Sarah A. Curran.

    PubMed

    Lyle, David K

    2012-09-01

    Participating in sport at all levels is gaining a dedicated following and this is also apparent in individuals with an amputation. Currently, there is a wide variety of ankle prostheses available which attempt to provide function, control, and comfort, as well as good aesthetic appeal. Participation in sport, however, increases the demands placed upon ankle prostheses. This can compromise function and performance, and constrain the opportunities of participation in various outdoor and water sports. In acknowledging this limitation and the need to develop more versatile ankle prostheses, this article introduces the evolution of a prototype ankle prosthesis referred to as "Adaptive Sports Ankle." The ankle prosthesis, which is compatible with any foot pyramid adapter, offers the same range of motion as the normal human ankle joint and is made up of components that are chemical and corrosion resistant. These design features that are specifically created to accommodate below-the-knee amputees provide an ideal prosthesis for those wishing to lead an active lifestyle and participate in aquatic (i.e. swimming, surfing, and scuba diving), snowboarding, and equestrian activities. Although it is acknowledged that there is a need to establish research on the Adaptive Sports Ankle, its introduction to the market will enhance and expand opportunities of those individuals with a lower limb amputation to lead an active and healthy lifestyle.

  19. Ankle arthritis: review of diagnosis and operative management.

    PubMed

    Grunfeld, Robert; Aydogan, Umur; Juliano, Paul

    2014-03-01

    The diagnostic and therapeutic options for ankle arthritis are reviewed. The current standard of care for nonoperative options include the use of nonsteroidal antiinflammatory drugs, corticosteroid injections, orthotics, and ankle braces. Other modalities lack high-quality research studies to delineate their appropriateness and effectiveness. The gold standard for operative intervention in end-stage degenerative arthritis remains arthrodesis, but evidence for the superiority in functional outcomes of total ankle arthroplasty is increasing. The next few years will enable more informed decisions and, with more prospective high-quality studies, the most appropriate patient population for total ankle arthroplasty can be identified. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Bone alterations are associated with ankle osteoarthritis joint pain

    PubMed Central

    Nakamura, Yukio; Uchiyama, Shigeharu; Kamimura, Mikio; Komatsu, Masatoshi; Ikegami, Shota; Kato, Hiroyuki

    2016-01-01

    The etiology of ankle osteoarthritis (OA) is largely unknown. We analyzed 24 ankle OA of 21 patients diagnosed by plain radiographs using magnetic resonance imaging (MRI). Ankle joint pain disappeared in 22 out of 24 joints by conservative treatment. MRI bone signal changes in and around the ankle joints were observed in 22 of 24 joints. Bone signal changes along the joint line were seen in 10 of 11 joints as a Kellgren-Lawrence (KL) grade of II to IV. Such signal changes were witnessed in only 4 of 13 joints with KL grade 0 or I. In the talocrural joint, bone alterations occurred in both tibia and talus bones through the joint line in cases of KL grade III or IV, while focal bone alterations were present in the talus only in KL grade I or II cases. Sixteen of 24 joints exhibited intraosseous bone signal changes, which tended to correspond to joint pain of any ankle OA stage. Our results suggest that bone alterations around the ankle joint might be one of the etiologies of OA and associated with ankle joint pain. PMID:26776564

  1. Bone alterations are associated with ankle osteoarthritis joint pain.

    PubMed

    Nakamura, Yukio; Uchiyama, Shigeharu; Kamimura, Mikio; Komatsu, Masatoshi; Ikegami, Shota; Kato, Hiroyuki

    2016-01-18

    The etiology of ankle osteoarthritis (OA) is largely unknown. We analyzed 24 ankle OA of 21 patients diagnosed by plain radiographs using magnetic resonance imaging (MRI). Ankle joint pain disappeared in 22 out of 24 joints by conservative treatment. MRI bone signal changes in and around the ankle joints were observed in 22 of 24 joints. Bone signal changes along the joint line were seen in 10 of 11 joints as a Kellgren-Lawrence (KL) grade of II to IV. Such signal changes were witnessed in only 4 of 13 joints with KL grade 0 or I. In the talocrural joint, bone alterations occurred in both tibia and talus bones through the joint line in cases of KL grade III or IV, while focal bone alterations were present in the talus only in KL grade I or II cases. Sixteen of 24 joints exhibited intraosseous bone signal changes, which tended to correspond to joint pain of any ankle OA stage. Our results suggest that bone alterations around the ankle joint might be one of the etiologies of OA and associated with ankle joint pain.

  2. 2016 consensus statement of the International Ankle Consortium: prevalence, impact and long-term consequences of lateral ankle sprains.

    PubMed

    Gribble, Phillip A; Bleakley, Chris M; Caulfield, Brian M; Docherty, Carrie L; Fourchet, François; Fong, Daniel Tik-Pui; Hertel, Jay; Hiller, Claire E; Kaminski, Thomas W; McKeon, Patrick O; Refshauge, Kathryn M; Verhagen, Evert A; Vicenzino, Bill T; Wikstrom, Erik A; Delahunt, Eamonn

    2016-12-01

    The Executive Committee of the International Ankle Consortium presents this 2016 position paper with recommendations for information implementation and continued research based on the paradigm that lateral ankle sprain (LAS), and the development of chronic ankle instability (CAI), serve as a conduit to a significant global healthcare burden. We intend our recommendations to serve as a mechanism to promote efforts to improve prevention and early management of LAS. We believe this will reduce the prevalence of CAI and associated sequelae that have led to the broader public health burdens of decreased physical activity and early onset ankle joint post-traumatic osteoarthritis. Ultimately, this can contribute to healthier lifestyles and promotion of physical activity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  3. Rehabilitation of Ankle and Foot Injuries in Athletes

    PubMed Central

    Chinn, Lisa; Hertel, Jay

    2009-01-01

    Foot and ankle injuries are extremely common among athletes and other physically active individuals. Rehabilitation programs that emphasize the use of therapeutic exercise to restore joint range of motion, muscle strength, neuromuscular coordination, and gait mechanics have been shown to have clinical success for patients suffering various foot and ankle pathologies. Rehabilitation programs are discussed for ankle sprains, plantar fasciitis, Achilles tendonitis, and turf toe. PMID:19945591

  4. Interventions for treating chronic ankle instability.

    PubMed

    de Vries, Jasper S; Krips, Rover; Sierevelt, Inger N; Blankevoort, Leendert; van Dijk, C N

    2011-08-10

    Chronic lateral ankle instability occurs in 10% to 20% of people after an acute ankle sprain. Initial treatment is conservative but if this fails and ligament laxity is present, surgical intervention is considered. To compare different treatments, conservative or surgical, for chronic lateral ankle instability. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL and reference lists of articles, all to February 2010. All identified randomised and quasi-randomised controlled trials of interventions for chronic lateral ankle instability were included. Two review authors independently assessed risk of bias and extracted data from each study. Where appropriate, results of comparable studies were pooled. Ten randomised controlled trials were included. Limitations in the design, conduct and reporting of these trials resulted in unclear or high risk of bias assessments relating to allocation concealment, assessor blinding, incomplete and selective outcome reporting. Only limited pooling of the data was possible.Neuromuscular training was the basis of conservative treatment evaluated in four trials. Neuromuscular training compared with no training resulted in better ankle function scores at the end of four weeks training (Ankle Joint Functional Assessment Tool (AJFAT): mean difference (MD) 3.00, 95% CI 0.3 to 5.70; 1 trial, 19 participants; Foot and Ankle Disability Index (FADI) data: MD 8.83, 95% CI 4.46 to 13.20; 2 trials, 56 participants). The fourth trial (19 participants) found no significant difference in the functional outcome after six weeks training programme on a cyclo-ergometer with a bi-directional compared with a traditional uni-directional pedal. Longer-term follow-up data were not available for these four trials.Four studies compared surgical procedures for chronic ankle instability. One trial (40 participants) found more nerve injuries after tenodesis

  5. Multi-segment foot landing kinematics in subjects with chronic ankle instability.

    PubMed

    De Ridder, Roel; Willems, Tine; Vanrenterghem, Jos; Robinson, Mark A; Palmans, Tanneke; Roosen, Philip

    2015-07-01

    Chronic ankle instability has been associated with altered joint kinematics at the ankle, knee and hip. However, no studies have investigated possible kinematic deviations at more distal segments of the foot. The purpose of this study was to evaluate if subjects with ankle instability and copers show altered foot and ankle kinematics and altered kinetics during a landing task when compared to controls. Ninety-six subjects (38 subjects with chronic ankle instability, 28 copers and 30 controls) performed a vertical drop and side jump task. Foot kinematics were obtained using the Ghent Foot Model and a single-segment foot model. Group differences were evaluated using statistical parametric mapping and analysis of variance. Subjects with ankle instability had a more inverted midfoot position in relation to the rearfoot when compared to controls during the side jump. They also had a greater midfoot inversion/eversion range of motion than copers during the vertical drop. Copers exhibited less plantar flexion/dorsiflexion range of motion in the lateral and medial forefoot. Furthermore, the ankle instability and coper group exhibited less ankle plantar flexion at touchdown. Additionally, the ankle instability group demonstrated a decreased plantar flexion/dorsiflexion range of motion at the ankle compared to the control group. Analysis of ground reaction forces showed a higher vertical peak and loading rate during the vertical drop in subjects with ankle instability. Subjects with chronic ankle instability displayed an altered, stiffer kinematic landing strategy and related alterations in landing kinetics, which might predispose them for episodes of giving way and actual ankle sprains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Ipsilateral Hip Abductor Weakness After Inversion Ankle Sprain

    PubMed Central

    Friel, Karen; McLean, Nancy; Myers, Christine; Caceres, Maria

    2006-01-01

    Context: Hip stability and strength are important for proper gait mechanics and foot position during heel strike. Objective: To determine the relationships between hip muscle strength and chronic ankle sprains and hip muscle strength and ankle range of motion. Design: Ex post facto design with the uninvolved limb serving as the control. Setting: Laboratory. Patients or Other Participants: A total of 23 subjects with unilateral chronic ankle sprain were recruited. Subjects had at least 2 ipsilateral ankle sprains and were bearing full weight, with the most recent injury occurring at least 3 months earlier. They were not undergoing formal or informal rehabilitation at the time of the study. Main Outcome Measure(s): We obtained goniometric measurements for all planes of motion at the ankle. Handheld dynamometry was used to assess the strength of the hip abductor and hip extensor muscles in both limbs. Results: Hip abductor muscle strength and plantar flexion were significantly less on the involved side than the uninvolved side (P < .001 in each case). Strength of the involved hip abductor and hip extensor muscles was significantly correlated (r = 0.539, P < .01). No significant difference was noted in hip extensor muscle strength between sides (P = .19). Conclusions: Our subjects with unilateral chronic ankle sprains had weaker hip abduction strength and less plantar-flexion range of motion on the involved sides. Clinicians should consider exercises to increase hip abduction strength when developing rehabilitation programs for patients with ankle sprains. PMID:16619098

  7. Managing ankle ligament sprains and tears: current opinion

    PubMed Central

    McGovern, Ryan P; Martin, RobRoy L

    2016-01-01

    The purpose of this paper is to present a current review of pathoanatomical features, differential diagnosis, objective assessment, intervention, and clinical course associated with managing lateral ankle ligament sprains. Proper diagnosis and identification of affected structures should be obtained through history and objective assessment. From this information, an individualized evidence-based intervention plan can be developed to enable recovery while decreasing the risk of reinjury. An appropriate evaluation is needed not only to determine the correct diagnosis but also to allow for grading and determining the prognosis of the injury in those with an acute lateral ankle sprain. Examination should include an assessment of impairments as well as a measure of activity and participation. Evidence-based interventions for those with an acute lateral ankle sprain should include weight bearing with bracing, manual therapy, progressive therapeutic exercises, and cryotherapy. For those with chronic ankle instability (CAI), interventions should include manual therapy and a comprehensive rehabilitation program. It is essential to understand the normal clinical course for athletes who sustain a lateral ankle sprain as well as risk factors for an acute injury and CAI. Risk factors for both an acute lateral ankle sprain and CAI include not using an external support and not participating in an appropriate exercise program. Incorporating the latest evidence-based rehabilitation techniques provides the best course of treatment for athletes with an acute ankle sprain or CAI. PMID:27042147

  8. Ankle manual therapy for individuals with post-acute ankle sprains: description of a randomized, placebo-controlled clinical trial.

    PubMed

    Davenport, Todd E; Kulig, Kornelia; Fisher, Beth E

    2010-10-19

    Ankle sprains are common within the general population and can result in prolonged disablement. Limited talocrural dorsiflexion range of motion (DF ROM) is a common consequence of ankle sprain. Limited talocrural DF ROM may contribute to persistent symptoms, disability, and an elevated risk for re-injury. As a result, many health care practitioners use hands-on passive procedures with the intention of improving talocrural joint DF ROM in individuals following ankle sprains. Dosage of passive hands-on procedures involves a continuum of treatment speeds. Recent evidence suggests both slow- and fast-speed treatments may be effective to address disablement following ankle sprains. However, these interventions have yet to be longitudinally compared against a placebo study condition. We developed a randomized, placebo-controlled clinical trial designed to test the hypotheses that hands-on treatment procedures administered to individuals following ankle sprains during the post-acute injury period can improve short-, intermediate-, and long-term disablement, as well as reduce the risk for re-injury. This study is designed to measure the clinical effects of hands-on passive stretching treatment procedures directed to the talocrural joint that vary in treatment speed during the post-acute injury period, compared to hands-on placebo control intervention. http://www.clinicaltrials.gov identifier NCT00888498.

  9. Proprioception and ankle injuries in soccer.

    PubMed

    Ergen, Emin; Ulkar, Bülent

    2008-01-01

    Because soccer attracts many participants and leads to a substantial number of injuries, especially of the lower extremities, it is important to study possibilities for injury prevention and proper rehabilitation to return safely to activities. Ankle sprains can be prevented by external ankle supports and proprioceptive-coordination training, especially in athletes with previous ankle sprains. Proprioception is a broad concept that includes balance and postural control with visual and vestibular contributions, joint kinesthesia, position sense, and muscle reaction time. Proprioceptive feedback is crucial in the conscious and unconscious awareness of a joint or limb in motion. Enhancement of functional joint stability by proprioceptive (or neuromuscular) training is important both in prevention and rehabilitation of athletic injuries.

  10. The preventive effect of a soccer-specific ankle brace on acute lateral ankle sprains in girls amateur soccer players: study protocol of a cluster-randomised controlled trial.

    PubMed

    Thijs, Karin; Huisstede, Bionka; Goedhart, Edwin; Backx, Frank

    2017-07-27

    Acute lateral ankle sprains are the single most often diagnosed injury in female soccer players and often result in an inability to play. This highlights the need for effective prevention strategies. Proprioceptive training and/or the use of an external support to decrease inversion of the ankle joint can prevent or reduce the number of acute lateral ankle sprains. The effectiveness of a soccer-specific ankle brace in reducing first-time and recurrent acute lateral ankle sprains has never been investigated in girl soccer players. If effective, ankle braces could be introduced into soccer. Cluster-randomised controlled trial. Girl amateur soccer players (aged 14-18 years) will be allocated to an intervention or control group. The intervention group will be instructed to wear soccer-specific ankle braces on both ankles during soccer training and matches; the control group will continue playing soccer as usual. Primary outcomes are the incidence and severity of acute lateral ankle sprains. Secondary outcomes are the prognostic value of generalised joint hypermobility and functional stability on the risk of acute lateral ankle sprains and compliance with the intervention. The findings from this study may provide evidence to support the use of a soccer-specific ankle brace to prevent lateral ankle sprains during soccer. We hypothesise that this brace will reduce the incidence of ankle sprains among young amateur girl soccer players by 50%. The prevention of such injuries will be beneficial to players, clubs and society. The Netherlands Trial Register (NTR): NTR6045; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Recycling energy to restore impaired ankle function during human walking.

    PubMed

    Collins, Steven H; Kuo, Arthur D

    2010-02-17

    Humans normally dissipate significant energy during walking, largely at the transitions between steps. The ankle then acts to restore energy during push-off, which may be the reason that ankle impairment nearly always leads to poorer walking economy. The replacement of lost energy is necessary for steady gait, in which mechanical energy is constant on average, external dissipation is negligible, and no net work is performed over a stride. However, dissipation and replacement by muscles might not be necessary if energy were instead captured and reused by an assistive device. We developed a microprocessor-controlled artificial foot that captures some of the energy that is normally dissipated by the leg and "recycles" it as positive ankle work. In tests on subjects walking with an artificially-impaired ankle, a conventional prosthesis reduced ankle push-off work and increased net metabolic energy expenditure by 23% compared to normal walking. Energy recycling restored ankle push-off to normal and reduced the net metabolic energy penalty to 14%. These results suggest that reduced ankle push-off contributes to the increased metabolic energy expenditure accompanying ankle impairments, and demonstrate that energy recycling can be used to reduce such cost.

  12. The effects of tibiofibularis anterior ligaments on ankle joint biomechanics.

    PubMed

    Karakaşlı, Ahmet; Erduran, Mehmet; Baktıroğlu, Lütfü; Büdeyri, Aydın; Yıldız, Didem Venüs; Havıtçıoğlu, Hasan

    2015-03-01

    The aim of this study was to evaluate the biomechanical behavior of anterior inferior tibiofibularis ligament (AITFL) deficient human ankle under axial loading of ankle at stance phase of gait. In order to investigate the contribution of AITFL to ankle stability, an in vitro sequential experimental setup was simulated. The measurement of posterior displacement of distal tibia and anterior displacement of the foot, in neutral position, secondary to axial compression, was performed by two non-contact video extensometers. Eight freshly frozen, anatomically intact, cadaveric human ankle specimens were included and tested. An axial compression test machine was utilized from 0 to 800 Newtonswith a loading speed of 5 mm/min in order to simulate the axial weight-bearing sequence of the ankle at stance phase of human gait. There was a statistically significant difference between anteroposterior displacement values for AITFL-Intact and AITFL-Dissected specimens (p≤0.05). Mean AITFL-Intact and mean AITFL-Dissected ankle anteroposterior displacement was 1.28±0.47 mm and 2.06±0.7 mm, respectively. This study determined some numerical and quantitative data about the biomechanical properties of AITFL in neutral foot position. In the emergency department, diagnosis and treatment of AITFL injury, due to ankle distortion, is important. In AITFL injuries, ankle biomechanics is affected, and ankle instability occurs.

  13. Assessment and management of patients with ankle injuries.

    PubMed

    Walker, Jennie

    2014-08-19

    Foot and ankle injuries are common and can have a significant effect on an individual's daily activities. Nurses have an important role in the assessment, management, ongoing care and support of patients with ankle injuries. An understanding of the anatomy and physiology of the ankle enables nurses to identify significant injuries, which may result in serious complications, and communicate effectively with the multidisciplinary team to improve patient care and outcomes.

  14. Parachute ankle brace and extrinsic injury risk factors during parachuting.

    PubMed

    Knapik, Joseph J; Darakjy, Salima; Swedler, David; Amoroso, Paul; Jones, Bruce H

    2008-04-01

    This study examined the injury prevention effectiveness of the parachute ankle brace (PAB) while controlling for known extrinsic risk factors. Injuries among airborne students who wore the PAB during parachute descents were compared with injuries among those who did not. Injury risk factors from administrative records included wind speed, combat loads, and time of day (day/night). Injuries were collected in the drop zone. A total of 596 injuries occurred in 102,784 parachute descents. In univariate analysis, students not wearing the PAB (Controls) were 2.00 [95% confidence interval (95% CI) = 1.32-3.02] times more likely to experience an ankle sprain, 1.83 (95% CI = 1.04-3.24) times more likely to experience an ankle fracture, and 1.92 (95% CI = 1.38-2.67) times more likely to experience an ankle injury of any type. PAB wearers and Controls had a similar incidence of lower body injuries exclusive of the ankle [risk ratio (Control/PAB) = 0.92, 95% CI = 0.65-1.30]. After accounting for known extrinsic injury risk factors, Controls were 1.90 (95% CI = 1.24-2.90) times more likely than PAB wearers to experience an ankle sprain, 1.47 (95% CI = 0.82- 2.63) times more likely to experience an ankle fracture, and 1.75 (95% CI = 1.25-2.48) times more likely to experience an ankle injury of any type. The incidence of parachute entanglements that persisted until the jumpers reached the ground were similar among PAB wearers and Controls IRR (Control/PAB) = 1.17, 95% CI = 0.61-2.29]. After controlling for known injury risk factors, the PAB protected against ankle injuries, and especially ankle sprains, while not influencing parachute entanglements or lower body injuries exclusive of the ankle.

  15. CLINICAL COMMENTARY ON MIDFOOT AND FOREFOOT INVOLVEMENT IN LATERAL ANKLE SPRAINS AND CHRONIC ANKLE INSTABILITY. PART 2: CLINICAL CONSIDERATIONS

    PubMed Central

    Feger, Mark A.; Hertel, Jay

    2016-01-01

    Lateral ankle sprains (LAS) and chronic ankle instability (CAI) are common musculoskeletal injuries that are a result of inversion injury during sport. The midfoot and forefoot is frequently injured during a LAS, is often overlooked during clinical examination, and maybe contributory to the development of CAI. The purpose of part two of this clinical commentary and current concept review is to increase clinician's awareness of the contribution of midfoot and forefoot impairment to functional limitation and disability of individuals who experience LAS and CAI and to facilitate future research in this area. The importance of multisegmented foot and ankle assessment from a clinical and research perspective is stressed. Select physical assessment and manual therapeutic techniques are presented to assist the clinician in examination and treatment of the ankle-foot complex in patients with LAS and CAI. PMID:27999731

  16. Gait Kinematics After Taping in Participants With Chronic Ankle Instability

    PubMed Central

    Chinn, Lisa; Dicharry, Jay; Hart, Joseph M.; Saliba, Susan; Wilder, Robert; Hertel, Jay

    2014-01-01

    Context: Chronic ankle instability is characterized by repetitive lateral ankle sprains. Prophylactic ankle taping is a common intervention used to reduce the risk of ankle sprains. However, little research has been conducted to evaluate the effect ankle taping has on gait kinematics. Objective: To investigate the effect of taping on ankle and knee kinematics during walking and jogging in participants with chronic ankle instability. Design: Controlled laboratory study. Setting: Motion analysis laboratory. Patients or Participants: A total of 15 individuals (8 men, 7 women; age = 26.9 ± 6.8 years, height = 171.7 ± 6.3 cm, mass = 73.5 ± 10.7 kg) with self-reported chronic ankle instability volunteered. They had an average of 5.3 ± 3.1 incidences of ankle sprain. Intervention(s): Participants walked and jogged in shoes on a treadmill while untaped and taped. The tape technique was a traditional preventive taping procedure. Conditions were randomized. Main Outcome Measure(s): Frontal-plane and sagittal-plane ankle and sagittal-plane knee kinematics were recorded throughout the entire gait cycle. Group means and 90% confidence intervals were calculated, plotted, and inspected for percentages of the gait cycle in which the confidence intervals did not overlap. Results: During walking, participants were less plantar flexed from 64% to 69% of the gait cycle (mean difference = 5.73° ± 0.54°) and less inverted from 51% to 61% (mean difference = 4.34° ± 0.65°) and 76% to 81% (mean difference = 5.55° ± 0.54°) of the gait cycle when taped. During jogging, participants were less dorsiflexed from 12% to 21% (mean difference = 4.91° ± 0.18°) and less inverted from 47% to 58% (mean difference = 6.52° ± 0.12°) of the gait cycle when taped. No sagittal-plane knee kinematic differences were found. Conclusions: In those with chronic ankle instability, taping resulted in a more neutral ankle position during walking and jogging in shoes on a treadmill. This change in

  17. Effects of Preventative Ankle Taping on Planned Change-of-Direction and Reactive Agility Performance and Ankle Muscle Activity in Basketballers

    PubMed Central

    Jeffriess, Matthew D.; Schultz, Adrian B.; McGann, Tye S.; Callaghan, Samuel J.; Lockie, Robert G.

    2015-01-01

    This study investigated the effects of preventative ankle taping on planned change-of-direction and reactive agility performance and peak ankle muscle activity in basketballers. Twenty male basketballers (age = 22.30 ± 3.97 years; height = 1.84 ± 0.09 meters; body mass = 85.96 ± 11.88 kilograms) with no ankle pathologies attended two testing sessions. Within each session, subjects completed six planned and six reactive randomized trials (three to the left and three to the right for each condition) of the Y-shaped agility test, which was recorded by timing lights. In one session, subjects had both ankles un-taped. In the other, both ankles were taped using a modified subtalar sling. Peak tibialis anterior, peroneus longus (PL), peroneus brevis (PB), and soleus muscle activity was recorded for both the inside and outside legs across stance phase during the directional change, which was normalized against 10-meter sprint muscle activity (nEMG). Both the inside and outside cut legs during the change-of-direction step were investigated. Repeated measures ANOVA determined performance time and nEMG differences between un-taped and taped conditions. There were no differences in planned change-of-direction or reactive agility times between the conditions. Inside cut leg PL nEMG decreased when taped for the planned left, reactive left, and reactive right cuts (p = 0.01). Outside leg PB and soleus nEMG increased during the taped planned left cut (p = 0.02). There were no other nEMG changes during the cuts with taping. Taping did not affect change-of-direction or agility performance. Inside leg PL activity was decreased, possibly due to the tape following the line of muscle action. This may reduce the kinetic demand for the PL during cuts. In conclusion, ankle taping did not significantly affect planned change-of-direction or reactive agility performance, and did not demonstrate large changes in activity of the muscle complex in healthy basketballers. Key points Ankle

  18. Noninvasive and painless magnetic stimulation of nerves improved brain motor function and mobility in a cerebral palsy case.

    PubMed

    Flamand, Véronique H; Schneider, Cyril

    2014-10-01

    Motor deficits in cerebral palsy disturb functional independence. This study tested whether noninvasive and painless repetitive peripheral magnetic stimulation could improve motor function in a 7-year-old boy with spastic hemiparetic cerebral palsy. Stimulation was applied over different nerves of the lower limbs for 5 sessions. We measured the concurrent aftereffects of this intervention on ankle motor control, gait (walking velocity, stride length, cadence, cycle duration), and function of brain motor pathways. We observed a decrease of ankle plantar flexors resistance to stretch, an increase of active dorsiflexion range of movement, and improvements of corticospinal control of ankle dorsiflexors. Joint mobility changes were still present 15 days after the end of stimulation, when all gait parameters were also improved. Resistance to stretch was still lower than prestimulation values 45 days after the end of stimulation. This case illustrates the sustained effects of repetitive peripheral magnetic stimulation on brain plasticity, motor function, and gait. It suggests a potential impact for physical rehabilitation in cerebral palsy. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. [Advances on biomechanics and kinematics of sprain of ankle joint].

    PubMed

    Zhao, Yong; Wang, Gang

    2015-04-01

    Ankle sprains are orthopedic clinical common disease, accounting for joint ligament sprain of the first place. If treatment is not timely or appropriate, the joint pain and instability maybe develop, and even bone arthritis maybe develop. The mechanism of injury of ankle joint, anatomical basis has been fully study at present, and the diagnostic problem is very clear. Along with the development of science and technology, biological modeling and three-dimensional finite element, three-dimensional motion capture system,digital technology study, electromyographic signal study were used for the basic research of sprain of ankle. Biomechanical and kinematic study of ankle sprain has received adequate attention, combined with the mechanism research of ankle sprain,and to explore the the biomechanics and kinematics research progress of the sprain of ankle joint.

  20. Rehabilitation of syndesmotic (high) ankle sprains.

    PubMed

    Williams, Glenn N; Allen, Eric J

    2010-11-01

    High ankle sprains are common in athletes who play contact sports. Most high ankle sprains are treated nonsurgically with a rehabilitation program. All years of PUBMED, Cochrane Database of Systematic Reviews, CINAHL PLUS, SPORTDiscuss, Google Scholar, and Web of Science were searched to August 2010, cross-referencing existing publications. Keywords included syndesmosis ankle sprain or high ankle sprain and the following terms: rehabilitation, treatment, cryotherapy, braces, orthosis, therapeutic modalities, joint mobilization, massage, pain, pain medications, TENS (ie, transcutaneous electric nerve stimulation), acupuncture, aquatic therapy, strength, neuromuscular training, perturbation training, and outcomes. Level of evidence, 5. A 3-phase rehabilitation program is described. The acute phase is directed at protecting the joint while minimizing pain, inflammation, muscle weakness, and loss of motion. Most patients are treated with some form of immobilization and have weightbearing restrictions. A range of therapeutic modalities are used to minimize pain and inflammation. Gentle mobilization and resistance exercises are used to gain mobility and maintain muscle size and strength. The subacute phase is directed at normalizing range of motion, strength, and function in activities of daily living. Progressive mobilization and strengthening are hallmarks of this phase. Neuromuscular training is begun and becomes the central component of rehabilitation. The advanced training phase focuses on preparing the patient for return to sports participation. Perturbation of support surfaces, agility drills, plyometrics, and sport-specific training are central components of this phase. The rehabilitation guidelines discussed may assist clinicians in managing syndesmotic ankle sprains.

  1. Parachute Ankle Brace Effectiveness Evaluation

    DTIC Science & Technology

    2010-05-01

    increase in the risk of other injuries (2, 7, 11). There were no differences in risk of ankle injury comparing periods when brace use was not...2006. The exclusions based on age and missing data were thought to represent coding errors . (Figure 2.1) 5 Figure 2.1 PAS Extens ion Project...similar to the referent (data not shown). Rate ratios were similar after adjustment for age at start of training, rank, duration of service, ankle

  2. Ankle Sprains

    MedlinePlus

    ... sports, exercising, or doing any other kind of physical activity. Watch your step when you're walking or running on uneven ... doing, or take extra care to watch your step when you're tired. If you've had ... physical activities. Using tape, ankle braces, or high-top shoes ...

  3. Foot and Ankle Osteoid Osteomas.

    PubMed

    Gurkan, Volkan; Erdogan, Ozgur

    2018-03-02

    Foot and ankle osteoid osteomas (OOs) are often cancellous or subperiosteal and rarely present with a periosteal reaction. Additionally, the large number of disorders included in the differential diagnosis and the nonspecific findings on radiographs complicate the diagnosis. We performed a manual search of the senior surgeon's hospitals' operating room records for the terms "benign bone tumor," "foot," "ankle," and "osteoid osteoma" from January 2003 until December 2014. Of 87 surgically treated patients with lower extremity OOs, 9 patients (11%) with foot or ankle OOs were included. The mean age at presentation was 21 (range 6 to 30) years; all 9 (11%) patients were male. The patients were evaluated for swelling, pain, trauma history, night pain, response to pain relievers, duration of complaints, and interval to diagnosis. The mean follow-up period was 48 ± 24 months, and no recurrences had developed. The mean American Orthopaedic Foot and Ankle Society scale score was 59.04 ± 11 before surgery and 91.56 ± 6 after surgery. The difference was statistically significant at p ≤ .0003. Most previous studies have been limited to case reports. The need for findings from a case series was an essential determinant of our decision to report our results. Patients usually have been treated conservatively, often for a long period. However, delays in treatment cause social, economic, and psychological damage. In conclusion, the presence of atypical findings on radiographs has resulted in a preference for magnetic resonance imaging instead of computed tomography; however, the diffuse soft tissue edema observed on MRI can lead to the use of long-term immobilization and a delay in the diagnosis. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  4. A real-time computational model for estimating kinematics of ankle ligaments.

    PubMed

    Zhang, Mingming; Davies, T Claire; Zhang, Yanxin; Xie, Sheng Quan

    2016-01-01

    An accurate assessment of ankle ligament kinematics is crucial in understanding the injury mechanisms and can help to improve the treatment of an injured ankle, especially when used in conjunction with robot-assisted therapy. A number of computational models have been developed and validated for assessing the kinematics of ankle ligaments. However, few of them can do real-time assessment to allow for an input into robotic rehabilitation programs. An ankle computational model was proposed and validated to quantify the kinematics of ankle ligaments as the foot moves in real-time. This model consists of three bone segments with three rotational degrees of freedom (DOFs) and 12 ankle ligaments. This model uses inputs for three position variables that can be measured from sensors in many ankle robotic devices that detect postures within the foot-ankle environment and outputs the kinematics of ankle ligaments. Validation of this model in terms of ligament length and strain was conducted by comparing it with published data on cadaver anatomy and magnetic resonance imaging. The model based on ligament lengths and strains is in concurrence with those from the published studies but is sensitive to ligament attachment positions. This ankle computational model has the potential to be used in robot-assisted therapy for real-time assessment of ligament kinematics. The results provide information regarding the quantification of kinematics associated with ankle ligaments related to the disability level and can be used for optimizing the robotic training trajectory.

  5. Isolated posterior high ankle sprain: a report of three cases.

    PubMed

    Botchu, Rajesh; Allen, Patricia; Rennie, Winston J

    2013-12-01

    High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management.

  6. The Effects of the Swede-O, New Cross, and McDavid Ankle Braces and Adhesive Ankle Taping on Speed, Balance, Agility, and Vertical Jump

    PubMed Central

    Paris, David L.

    1992-01-01

    Scores from motor performance tests were compared using subjects with taped and untaped ankles. Previous studies have shown that taped ankle support may be detrimental in vertical and standing broad jumping performance. Conflicting data have been published on the effects of commercial ankle braces on various motor tasks. The performances of 18 elite soccer players in selected tests of speed, balance, agility, and vertical jumping were compared under conditions of untaped, nonelastic adhesive taped, Swede-O-braced, New Cross-braced, and McDavid-braced ankles. Vertical jump performance was significantly reduced when subjects wore New Cross braces. There were no significant differences in tests of speed, balance, and agility among any of the support conditions. Until now, nonelastic adhesive tape has been the preferred method of prophylactic ankle support. I conclude that certain commercial ankle braces may be used as a support alternative during selected activities. ImagesFig 1. PMID:16558170

  7. Gait Improvements After Peroneal or Tibial Nerve Transfer in Patients with Foot Drop: A Retrospective Study

    PubMed Central

    Somasundaram, Chandra

    2017-01-01

    Background: Injury to the common peroneal nerve disrupts the motor control pathway to ankle dorsiflexors and evertors, as well as toe extensors, resulting in pathological gait and foot drop. Direct external compression on the fibular head is the most frequent cause of peroneal nerve impairment and has poor prognosis. Methods and Patients: Here, we report the surgical outcome of 21 patients with foot drop (9 males and 12 females) who underwent nerve transfer procedure of either the superficial peroneal nerve or the tibial nerve fascicles to the motor branch of the tibialis anterior and to the deep peroneal nerve. They had at least 6 months postoperative follow-up (mean = 17; range, 6-32 months). Results: Among 21 patients who had no ankle dorsiflexion (BMRC 0/5) preoperatively, 9 patients had successful restoration of ankle dorsiflexion (BMRC 4 to 4+/5), 7 patients had BMRC 2 to 3+/5, and 4 patients had no or poor restoration of dorsiflexion (BMRC 0 to 1+/5) but achieved good ankle eversion (BMRC 3 to 4+/5). Overall statistically significant clinical improvement of ankle dorsiflexion and eversion from preoperative BMRC grade 2.6 ± 0.5 to postoperative BMRC grade 3.6 ± 0.7 (P = .0000004) was achieved. Conclusion: Overall statistically significant clinical improvement of ankle dorsiflexion and eversion was achieved in 80% of our study patients. Most of these patients gained antigravity and were able to walk with minimal steppage gait. In the other 4 patients (20%), there was good improvement in ankle eversion but poor or no ankle dorsiflexion. PMID:29018508

  8. Gait Improvements After Peroneal or Tibial Nerve Transfer in Patients with Foot Drop: A Retrospective Study.

    PubMed

    Nath, Rahul K; Somasundaram, Chandra

    2017-01-01

    Background: Injury to the common peroneal nerve disrupts the motor control pathway to ankle dorsiflexors and evertors, as well as toe extensors, resulting in pathological gait and foot drop. Direct external compression on the fibular head is the most frequent cause of peroneal nerve impairment and has poor prognosis. Methods and Patients: Here, we report the surgical outcome of 21 patients with foot drop (9 males and 12 females) who underwent nerve transfer procedure of either the superficial peroneal nerve or the tibial nerve fascicles to the motor branch of the tibialis anterior and to the deep peroneal nerve. They had at least 6 months postoperative follow-up (mean = 17; range, 6-32 months). Results: Among 21 patients who had no ankle dorsiflexion (BMRC 0/5) preoperatively, 9 patients had successful restoration of ankle dorsiflexion (BMRC 4 to 4+/5), 7 patients had BMRC 2 to 3+/5, and 4 patients had no or poor restoration of dorsiflexion (BMRC 0 to 1+/5) but achieved good ankle eversion (BMRC 3 to 4+/5). Overall statistically significant clinical improvement of ankle dorsiflexion and eversion from preoperative BMRC grade 2.6 ± 0.5 to postoperative BMRC grade 3.6 ± 0.7 ( P = .0000004) was achieved. Conclusion: Overall statistically significant clinical improvement of ankle dorsiflexion and eversion was achieved in 80% of our study patients. Most of these patients gained antigravity and were able to walk with minimal steppage gait. In the other 4 patients (20%), there was good improvement in ankle eversion but poor or no ankle dorsiflexion.

  9. Syndesmosis and lateral ankle sprains in the National Football League.

    PubMed

    Osbahr, Daryl C; Drakos, Mark C; O'Loughlin, Padhraig F; Lyman, Stephen; Barnes, Ronnie P; Kennedy, John G; Warren, Russell F

    2013-11-01

    Syndesmosis sprains in the National Football League (NFL) can be a persistent source of disability, especially compared with lateral ankle injuries. This study evaluated syndesmosis and lateral ankle sprains in NFL players to allow for better identification and management of these injuries. Syndesmosis and lateral ankle sprains from a single NFL team database were reviewed over a 15-year period, and 32 NFL team physicians completed a questionnaire detailing their management approach. A comparative analysis was performed analyzing several variables, including diagnosis, treatment methods, and time lost from sports participation. Thirty-six syndesmosis and 53 lateral ankle sprains occurred in the cohort of NFL players. The injury mechanism typically resulted from direct impact in the syndesmosis and torsion in the lateral ankle sprain group (P=.034). All players were managed nonoperatively. The mean time lost from participation was 15.4 days in the syndesmosis and 6.5 days in the lateral ankle sprain groups (P⩽.001). National Football League team physicians varied treatment for syndesmosis sprains depending on the category of diastasis but recommended nonoperative management for lateral ankle sprains. Syndesmosis sprains in the NFL can be a source of significant disability compared with lateral ankle sprains. Successful return to play with nonoperative management is frequently achieved for syndesmosis and lateral ankle sprains depending on injury severity. With modern treatment algorithms for syndesmosis sprains, more aggressive nonoperative treatment is advocated. Although the current study shows that syndesmosis injuries require longer rehabilitation periods when compared with lateral ankle sprains, the time lost from participation may not be as prolonged as previously reported. Copyright 2013, SLACK Incorporated.

  10. [Theoretical origin and clinical application of wrist-ankle acupuncture therapy].

    PubMed

    Wang, Qiong; Zhou, Qinghui

    2017-05-12

    The theory of wrist-ankle acupuncture is consistent with traditional meridian-collateral theory. For example, the body divisions of wrist-ankle acupuncture are corresponding to the distribution of 12 cutaneous regions of meridians, the needling sites of it are to the running courses of 12 meridians; the indications of it are to those of 12 meridians. The needling sites of wrist-ankle acupuncture are relevant with some special acupoints of acupuncture theory. For example, the 12-needling sites of wrist-ankle acupuncture are located similar to those of 12 meridian points and have very similar indications. The needling sites of it are located in the wrist and ankle regions, in which the five- shu points are located nearby, for meridian disorders. Most luo -connecting points are located near to the needling sites of wrist-ankle acupuncture or the needle tip points to. Additionally, the needling method of wrist-ankle acupuncture is consistent with some of the subcutaneous needling methods in traditional acupuncture therapy. On the basis of the aspects mentioned above, it is explained that wrist-ankle acupuncture is the development of traditional acupuncture and cannot be independent from the traditional theories of acupuncture and meridians. It is necessary to seek for the evidence from the traditional theories of TCM. The traditional theories of TCM are summarized from clinical practice, which can be newly verified from the practice of wrist-ankle acupuncture.

  11. Bilateral Proprioceptive Evaluation in Individuals With Unilateral Chronic Ankle Instability

    PubMed Central

    Sousa, Andreia S. P.; Leite, João; Costa, Bianca; Santos, Rubim

    2017-01-01

    Context: Despite extensive research on chronic ankle instability, the findings regarding proprioception have been conflicting and focused only on the injured limb. Also, the different components of proprioception have been evaluated in isolation. Objective: To evaluate bilateral ankle proprioception in individuals with unilateral ankle instability. Design: Cohort study. Setting: Research laboratory center in a university. Patients or Other Participants: Twenty-four individuals with a history of unilateral ankle sprain and chronic ankle instability (mechanical ankle instability group, n = 10; functional ankle instability [FAI] group, n = 14) and 20 controls. Main Outcome Measure(s): Ankle active and passive joint position sense, kinesthesia, and force sense. Results: We observed a significant interaction between the effects of limb and group for kinesthesia (F = 3.27, P = .049). Increased error values were observed in the injured limb of the FAI group compared with the control group (P = .031, Cohen d = 0.47). Differences were also evident for force sense (F = 9.31, P < .001): the FAI group demonstrated increased error versus the control group (injured limb: P < .001, Cohen d = 1.28; uninjured limb: P = .009, Cohen d = 0.89) and the mechanical ankle instability group (uninjured limb: P = .023, Cohen d = 0.76). Conclusions: Individuals with unilateral FAI had increased error ipsilaterally (injured limb) for inversion movement detection (kinesthesia) and evertor force sense and increased error contralaterally (uninjured limb) for evertor force sense. PMID:28318316

  12. The implementation effectiveness of the 'Strengthen your ankle' smartphone application for the prevention of ankle sprains: design of a randomized controlled trial.

    PubMed

    Van Reijen, Miriam; Vriend, Ingrid I; Zuidema, Victor; van Mechelen, Willem; Verhagen, Evert A

    2014-01-07

    Ankle sprains continue to pose a significant burden to the individual athlete, as well as to society as a whole. However, despite ankle sprains being the single most common sports injury and despite an active approach by various Dutch organisations in implementing preventive measures, large-scale community uptake of these preventive measures, and thus actual prevention of ankle sprains, is lagging well behind. In an attempt to bridge this implementation gap, the Dutch Consumer Safety Institute VeiligheidNL developed a freely available interactive App ('Strenghten your ankle' translated in Dutch as: 'Versterk je enkel; available for iOS and Android) that contains - next to general advice on bracing and taping - a proven cost-effective neuromuscular program. The 'Strengthen your ankle' App has not been evaluated against the 'regular' prevention approach in which the neuromuscular program is advocated through written material. The aim of the current project is to evaluate the implementation value of the 'Strengthen your ankle' App as compared to the usual practice of providing injured athletes with written materials. In addition, as a secondary outcome measure, the cost-effectiveness will be assessed against usual practice. The proposed study will be a randomised controlled trial. After stratification for medical caregiver, athletes will be randomised to two study groups. One group will receive a standardized eight-week proprioceptive training program that has proven to be cost-effective to prevent recurrent ankle injuries, consisting of a balance board (machU/ MSG Europe BVBA), and a traditional instructional booklet. The other group will receive the same exercise program and balance board. However, for this group the instructional booklet is exchanged by the interactive 'Strengthen your ankle' App. This trial is the first randomized controlled trial to study the implementation effectiveness of an App for proprioceptive balance board training program in comparison to

  13. Minimal clinically important difference and the effect of clinical variables on the ankle osteoarthritis scale in surgically treated end-stage ankle arthritis.

    PubMed

    Coe, Marcus P; Sutherland, Jason M; Penner, Murray J; Younger, Alastair; Wing, Kevin J

    2015-05-20

    There is much debate regarding the best outcome tool for use in foot and ankle surgery, specifically in patients with ankle arthritis. The Ankle Osteoarthritis Scale (AOS) is a validated, disease-specific score. The goals of this study were to investigate the clinical performance of the AOS and to determine a minimal clinically important difference (MCID) for it, using a large cohort of 238 patients undergoing surgery for end-stage ankle arthritis. Patients treated with total ankle arthroplasty or ankle arthrodesis were prospectively followed for a minimum of two years at a single site. Data on demographics, comorbidities, AOS score, Short Form-36 results, and the relationship between expectations and satisfaction were collected at baseline (preoperatively), at six and twelve months, and then yearly thereafter. A linear regression analysis examined the variables affecting the change in AOS scores between baseline and the two-year follow-up. An MCID in the AOS change score was then determined by employing an anchor question, which asked patients to rate their relief from symptoms after surgery. Surgical treatment of end-stage ankle arthritis resulted in a mean improvement (and standard deviation) of 31.2 ± 22.7 points in the AOS score two years after surgery. The MCID of the AOS change score was a mean of 28.0 ± 17.9 points. The change in AOS score was significantly affected by the preoperative AOS score, smoking, back pain, and age. Patients undergoing arthroplasty or arthrodesis for end-stage ankle arthritis experienced a mean improvement in AOS score that was greater than the estimated MCID (31.2 versus 28.0 points). Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  14. Direct measurement of the intrinsic ankle stiffness during standing.

    PubMed

    Vlutters, M; Boonstra, T A; Schouten, A C; van der Kooij, H

    2015-05-01

    Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic ankle-foot stiffness to balance, and the ankle-foot stiffness amplitude dependency remain a topic of debate in the literature. We therefore developed an experimental protocol to directly measure the bilateral intrinsic ankle-foot stiffness during standing balance, and determine its amplitude dependency. By applying fast (40 ms) ramp-and-hold support surface rotations (0.005-0.08 rad) during standing, reflexive contributions could be excluded, and the amplitude dependency of the intrinsic ankle-foot stiffness was investigated. Results showed that reflexive activity could not have biased the torque used for estimating the intrinsic stiffness. Furthermore, subjects required less recovery action to restore balance after bilateral rotations in opposite directions compared to rotations in the same direction. The intrinsic ankle-foot stiffness appears insufficient to ensure balance, ranging from 0.93±0.09 to 0.44±0.06 (normalized to critical stiffness 'mgh'). This implies that changes in muscle activation are required to maintain balance. The non-linear stiffness decrease with increasing rotation amplitude supports the previous published research. With the proposed method reflexive effects can be ruled out from the measured torque without any model assumptions, allowing direct estimation of intrinsic stiffness during standing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Ankle moment generation and maximum-effort curved sprinting performance.

    PubMed

    Luo, Geng; Stefanyshyn, Darren

    2012-11-15

    Turning at high speed along acute curves is crucial for athletic performance. One determinant of curved sprinting speed is the ground reaction force that can be created by the supporting limb; the moment generated at the ankle joint may influence such force generation. Body lean associated with curved sprints positions the ankle joints in extreme in-/eversion, and may hinder the ankle moment generation. To examine the influence of ankle moment generation on curved sprinting performance, 17 male subjects performed maximum-effort curved sprints in footwear with and without a wedge. The wedged footwear was constructed with the intention to align the ankle joints closer to their neutral frontal-plane configuration during counter-clockwise curved sprints so greater joint moments might be generated. We found, with the wedged footwear, the average eversion angle of the inside leg ankle was reduced, and the plantarflexion moment generation increased significantly. Meanwhile, the knee extension moment remained unchanged. With the wedged footwear, stance-average centripetal ground reaction force increased significantly while no difference in the vertical ground reaction force was detected. The subjects created a greater centripetal ground reaction impulse in the wedged footwear despite a shortened stance phase when compared to the control. Stance-average curved sprinting speed improved by 4.3% with the wedged footwear. The changes in ankle moment and curved sprinting speed observed in the current study supports the notion that the moment generation at the ankle joint may be a performance constraint for curved sprinting. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Orthopaedic management of haemophilia arthropathy of the ankle.

    PubMed

    Pasta, G; Forsyth, A; Merchan, C R; Mortazavi, S M J; Silva, M; Mulder, K; Mancuso, E; Perfetto, O; Heim, M; Caviglia, H; Solimeno, L

    2008-07-01

    Joint bleeding, or haemarthrosis, is the most common type of bleeding episode experienced by individuals with haemophilia A and B. This leads to changes within the joints, including synovial proliferation, which results in further bleeding and chronic synovitis. Blood in the joint can also directly damage the cartilage, and with repeated bleeding, there is progressive destruction of both cartilage and bone. The end result is known as haemophilic arthropathy. The joints most commonly affected are the knees, elbows and ankles, although any synovial joint may be involved. In the ankle, both the tibiotalar and subtalar joints may be affected and joint bleeding and arthropathy can lead to a number of deformities. Haemophilic arthropathy can be prevented through regular factor replacement prophylaxis and implementing physiotherapy. However, when necessary, there are multiple surgical and non-surgical options available. In early ankle arthropathy with absent or minimal joint changes, both radioisotopic and chemical synoviorthesis can be used to reduce the hypertrophied synovium. These procedures can decrease the frequency of bleeding episodes, minimizing the risk of articular cartilage damage. Achilles tendon lengthening can be performed, in isolation or in combination with other surgical measures, to correct Achilles tendon contractures. Both arthroscopic and open synovectomies are available as a means to remove the friable villous layer of the synovium and are often indicated when bleeding episodes cannot be properly controlled by factor replacement therapy or synoviorthesis. In the later stages of ankle arthropathy, other surgical options may be considered. Debridement may be indicated when there are loose pieces of cartilage or anterior osteophytes, and can help to improve the joint function, even in the presence of articular cartilage damage. Supramalleolar tibial osteotomy may be indicated in patients with a valgus deformity of the hindfoot without degenerative

  17. Ankle manual therapy for individuals with post-acute ankle sprains: description of a randomized, placebo-controlled clinical trial

    PubMed Central

    2010-01-01

    Background Ankle sprains are common within the general population and can result in prolonged disablement. Limited talocrural dorsiflexion range of motion (DF ROM) is a common consequence of ankle sprain. Limited talocrural DF ROM may contribute to persistent symptoms, disability, and an elevated risk for re-injury. As a result, many health care practitioners use hands-on passive procedures with the intention of improving talocrural joint DF ROM in individuals following ankle sprains. Dosage of passive hands-on procedures involves a continuum of treatment speeds. Recent evidence suggests both slow- and fast-speed treatments may be effective to address disablement following ankle sprains. However, these interventions have yet to be longitudinally compared against a placebo study condition. Methods/Design We developed a randomized, placebo-controlled clinical trial designed to test the hypotheses that hands-on treatment procedures administered to individuals following ankle sprains during the post-acute injury period can improve short-, intermediate-, and long-term disablement, as well as reduce the risk for re-injury. Discussion This study is designed to measure the clinical effects of hands-on passive stretching treatment procedures directed to the talocrural joint that vary in treatment speed during the post-acute injury period, compared to hands-on placebo control intervention. Trial Registration http://www.clinicaltrials.gov identifier NCT00888498. PMID:20958995

  18. Sensory-Targeted Ankle Rehabilitation Strategies for Chronic Ankle Instability.

    PubMed

    McKeon, Patrick O; Wikstrom, Erik A

    2016-05-01

    Deficient sensory input from damaged ankle ligament receptors is thought to contribute to sensorimotor deficits in those with chronic ankle instability (CAI). Targeting other viable sensory receptors may then enhance sensorimotor control in these patients. The purpose of this randomized controlled trial was to evaluate the effects of 2 wk of sensory-targeted ankle rehabilitation strategies (STARS) on patient- and clinician-oriented outcomes in those with CAI. Eighty patients with self-reported CAI participated. All patients completed patient-oriented questionnaires capturing self-reported function as well as the weight-bearing lunge test and an eyes-closed single-limb balance test. After baseline testing, patients were randomly allocated to four STARS groups: joint mobilization, plantar massage, triceps surae stretching, or control. Each patient in the intervention groups received six 5-min treatments of their respective STARS over 2 wk. All subjects were reassessed on patient- and clinician-oriented measures immediately after the intervention and completed a 1-month follow-up that consisted of patient-oriented measures. Change scores of the three STARS groups were compared with the control using independent t-tests and Hedges' g effect sizes with 95% confidence intervals. The joint mobilization group had the greatest weight-bearing lunge test improvement. Plantar massage had the most meaningful single-limb balance improvement. All STARS groups improved patient-oriented outcomes with joint mobilization having the most meaningful effect immediately after the intervention and plantar massage at the 1-month follow-up. Each STARS treatment offers unique contributions to the patient- and clinician-oriented rehabilitation outcomes of those with CAI. Both joint mobilization and plantar massage appear to demonstrate the greatest potential to improve sensorimotor function in those with CAI.

  19. Predicting balance improvements following STARS treatments in chronic ankle instability participants.

    PubMed

    Wikstrom, Erik A; McKeon, Patrick O

    2017-04-01

    Sensory Targeted Ankle Rehabilitation Strategies that stimulate sensory receptors improve postural control in chronic ankle instability participants. However, not all participants have equal responses. Therefore, identifying predictors of treatment success is needed to improve clinician efficiency when treating chronic ankle instability. Therefore, the purpose was to identify predictors of successfully improving postural control in chronic ankle instability participants. Secondary data analysis. Fifty-nine participants with self-reported chronic ankle instability participated. The condition was defined as a history of at least two episodes of "giving way" within the past 6 months; and limitations in self-reported function as measured by the Foot and Ankle Ability Measure. Participants were randomized into three treatment groups (plantar massage, ankle joint mobilization, calf stretching) that received 6, 5-min treatment sessions over a 2-week period. The main outcome measure was treatment success, defined as a participant exceeding the minimal detectable change score for a clinician-oriented single limb balance test. Participants with ≥3 balance test errors had a 73% probability of treatment success following ankle joint mobilizations. Participants with a self-reported function between limb difference <16.07% and who made >2.5 errors had a 99% probability of treatment success following plantar massage. Those who sustained ≥11 ankle sprains had a 94% treatment success probability following calf stretching. Self-reported functional deficits, worse single limb balance, and number of previous ankle sprains are important characteristics when determining if chronic ankle instability participants will have an increased probability of treatment success. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  20. Cellular and synaptic effect of substance P on neonatal phrenic motoneurons.

    PubMed

    Ptak, K; Konrad, M; Di Pasquale, E; Tell, F; Hilaire, G; Monteau, R

    2000-01-01

    Experiments were carried out on the in vitro brainstem-spinal cord preparation of the newborn rat to analyse the effects of substance P (SP) on phrenic motoneuron (PMN) activity. In current-clamp mode, SP significantly depolarized PMNs, increased their input resistance, decreased the rheobase current and shifted the firing frequency-intensity relationships leftwards, but did not affect spike frequency adaptation or single spike configuration. The neurokinin receptor agonist NK1 had SP-mimetic effects, whereas the NK3 and NK2 receptor agonists were less effective and ineffective, respectively. In a tetrodotoxin-containing aCSF, only SP or the NK1 receptor agonist were still active. No depolarization was observed when the NK1 receptor agonist was applied in the presence of muscarine. In voltage-clamp mode, SP or the NK1 receptor agonist produced an inward current (ISP) which was not significantly reduced by extracellular application of tetraethylammonium, Co2+, 4-aminopyridine or Cs+. In aCSF containing tetrodotoxin, Co2+ and Cs+, ISP was blocked by muscarine. No PMN displayed any M-type potassium current but only a current showing no voltage sensitivity over the range -100 to 0 mV, reversing near the expected EK +, hence consistent with a leak current. SP application to the spinal cord only (using a partitioned chamber) significantly increased the phrenic activity. Pretreatment with the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP5) decreased the C4 discharge duration and blocked the effect of SP, thus exhibiting an NMDA potentiation by SP. In conclusion, SP modulates postsynaptically the response of phrenic motoneurons to the inspiratory drive through the reduction of a leak conductance and the potentiation of the NMDA component of the synaptic input.

  1. Prevalence of chronic ankle instability in high school and division I athletes.

    PubMed

    Tanen, Leah; Docherty, Carrie L; Van Der Pol, Barbara; Simon, Janet; Schrader, John

    2014-02-01

    The purpose of this study was to determine the prevalence of chronic ankle instability among high school and collegiate athletes. Descriptive epidemiological survey. Athletes from four high schools and a division I university were contacted to participate. For collegiate athletes, a questionnaire packet was distributed during preparticipation physicals. For high school athletes, parental consent was obtained and then questionnaires were distributed during preparticipation physicals, parent meetings, or individual team meetings. All athletes completed the Cumberland Ankle Instability Tool for both their left and right ankles. Subjects also provided general demographic data and completed the Ankle Instability Instrument regarding history of lateral ankle sprains and giving way. Athletes were identified as having chronic ankle instability if they scored less than 24 on the Cumberland Ankle Instability Tool. Of the 512 athletes who completed and returned surveys, 23.4% were identified as having chronic ankle instability. High school athletes were more likely to have chronic ankle instability than their collegiate counterparts (P < .001). Chronic ankle instability was more prevalent among women than among men in both high school (P = .01) and collegiate settings (P = .01). Findings of this study revealed differences in the distribution of chronic ankle instability that warrant further study.

  2. Return to sports after ankle fractures: a systematic review.

    PubMed

    Del Buono, Angelo; Smith, Rebecca; Coco, Manuela; Woolley, Laurence; Denaro, Vincenzo; Maffulli, Nicola

    2013-01-01

    This review aims to provide information on the time athletes will take to resume sports activity following ankle fractures. We systematically searched Medline (PubMED), EMBASE, CINHAL, Cochrane, Sports Discus and Google scholar databases using the combined keywords 'ankle fractures', 'ankle injuries', 'athletes', 'sports', 'return to sport', 'recovery', 'operative fixation', 'pinning', 'return to activity' to identify articles published in English, Spanish, French, Portuguese and Italian. Seven retrospective studies fulfilled our inclusion criteria. Of the 793 patients, 469 (59%) were males and 324 (41%) were females, and of the 356 ankle fractures we obtained information on, 338 were acute and 18 stress fractures. The general principles were to undertake open reduction and internal fixation of acute fractures, and manage stress fractures conservatively unless a thin fracture line was visible on radiographs. The best timing to return to sports after an acute ankle fracture is still undefined, given the heterogeneity of the outcome measures and results. The time to return to sports after an acute stress injury ranged from 3 to 51 weeks. When facing athletes with ankle fractures, associated injuries have to be assessed and addressed to improve current treatment lines and satisfy future expectancies. The best timing to return to sports after an ankle fracture has not been established yet. The ideas of the return to activity parameter and surgeon databases including sports-related information could induce research to progress.

  3. Gastrocnemius operating length with ankle foot orthoses in cerebral palsy.

    PubMed

    Choi, Hwan; Wren, Tishya Anne Leong; Steele, Katherine Muterspaugh

    2017-06-01

    Many individuals with cerebral palsy wear ankle foot orthoses during daily life. Orthoses influence joint motion, but how they impact muscle remains unclear. In particular, the gastrocnemius is commonly stiff in cerebral palsy. Understanding whether orthoses stretch or shorten this muscle during daily life may inform orthosis design and rehabilitation. This study investigated the impact of different ankle foot orthoses on gastrocnemius operating length during walking in children with cerebral palsy. Case series, within subject comparison of gastrocnemius operating length while walking barefoot and with two types of ankle foot orthoses. We performed gait analyses for 11 children with cerebral palsy. Each child was fit with two types of orthoses: a dynamic ankle foot orthosis (Cascade dynamic ankle foot orthosis) and an adjustable dynamic response ankle foot orthosis (Ultraflex ankle foot orthosis). Musculoskeletal modeling was used to quantify gastrocnemius musculotendon operating length and velocity with each orthosis. Walking with ankle foot orthoses could stretch the gastrocnemius more than barefoot walking for some individuals; however, there was significant variability between participants and orthoses. At least one type of orthosis stretched the gastrocnemius during walking for 4/6 and 3/5 of the Gross Motor Functional Classification System Level I and III participants, respectively. AFOs also reduced peak gastrocnemius lengthening velocity compared to barefoot walking for some participants, with greater reductions among the Gross Motor Functional Classification System Level III participants. Changes in gastrocnemius operating length and lengthening velocity were related to changes in ankle and knee kinematics during gait. Ankle foot orthoses impact gastrocnemius operating length during walking and, with proper design, may assist with stretching tight muscles in daily life. Clinical relevance Determining whether ankle foot orthoses stretch tight muscles can

  4. Lateral and syndesmotic ankle sprain injuries: a narrative literature review

    PubMed Central

    Dubin, Joshua C.; Comeau, Doug; McClelland, Rebecca I.; Dubin, Rachel A.; Ferrel, Ernest

    2011-01-01

    Objective The purpose of this article is to review the literature that discusses normal anatomy and biomechanics of the foot and ankle, mechanisms that may result in a lateral ankle sprain or syndesmotic sprain, and assessment and diagnostic procedures, and to present a treatment algorithm based on normal ligament healing principles. Methods Literature was searched for years 2000 to 2010 in PubMed and CINAHL. Key search terms were ankle sprain$, ankle injury and ankle injuries, inversion injury, proprioception, rehabilitation, physical therapy, anterior talofibular ligament, syndesmosis, syndesmotic injury, and ligament healing. Discussion Most ankle sprains respond favorably to nonsurgical treatment, such as those offered by physical therapists, doctors of chiropractic, and rehabilitation specialists. A comprehensive history and examination aid in diagnosing the severity and type of ankle sprain. Based on the diagnosis and an understanding of ligament healing properties, a progressive treatment regimen can be developed. During the acute inflammatory phase, the goal of care is to reduce inflammation and pain and to protect the ligament from further injury. During the reparative and remodeling phase, the goal is to progress the rehabilitation appropriately to facilitate healing and restore the mechanical strength and proprioception. Radiographic imaging techniques may need to be used to rule out fractures, complete ligament tears, or instability of the ankle mortise. A period of immobilization and ambulating with crutches in a nonweightbearing gait may be necessary to allow for proper ligament healing before commencing a more active treatment approach. Surgery should be considered in the case of grade 3 syndesmotic sprain injuries or those ankle sprains that are recalcitrant to conservative care. Conclusion An accurate diagnosis and prompt treatment can minimize an athlete's time lost from sport and prevent future reinjury. Most ankle sprains can be successfully

  5. [Stable ankle joint fractures. Indication for surgical or conservative management?].

    PubMed

    Richter, J; Schulze, W; Muhr, G

    1999-06-01

    In German literature, ankle joint fractures are mostly classified in three groups according to Weber. In cases of the type A, the fracture line runs below, in cases of type B at height of the syndesmotic ligaments. C-type fractures are typically seen above this region. However, this practical and simple classification allows no inferences at accompanying injuries which in turn influence the functional outcome. We observed isolated fractures of the lateral malleolus in more than 60% of all type B-fractures, as soon as in the majority the type A-fractures. Since isolated medial ankle fractures occur very rarely, careful exclusion of further injuries is advisable here. In order to differentiate stable ones from unstable type B ankle injuries, we carry out a manual stress test, if there is less than 2 mm fracture dislocation and a congruent ankle mortise. In this manner we could find that stable lateral ankle fractures are characterized with a combination of an intact dorsal syndesmotic and medial ligament. Stable type B and undisplaced type A fractures were treated conservatively with an ankle brace (Aircast?). Unstable ankle injuries were treated by ORIF. Conservative treatment for undisplaced medial malleolar fractures is recommended, if x-rays showed less than 2 mm dislocation which allows a tibio-talare impingement. Biomechanical investigations could prove a significant increase in ankle joint stability, when an axial load of 300 N was applied to various horizontal loads. The talus does not follow automatically a displaced fibular fracture. The dorsal syndesmotic and the medial deltoid ligaments control ankle joint stability.

  6. In Vivo Talocrural Joint Contact Mechanics With Functional Ankle Instability.

    PubMed

    Kobayashi, Takumi; Suzuki, Eiichi; Yamazaki, Naohito; Suzukawa, Makoto; Akaike, Atsushi; Shimizu, Kuniaki; Gamada, Kazuyoshi

    2015-12-01

    Functional ankle instability (FAI) may involve abnormal kinematics and contact mechanics during ankle internal rotation. Understanding of these abnormalities is important to prevent secondary problems in patients with FAI. However, there are no in vivo studies that have investigated talocrural joint contact mechanics during weightbearing ankle internal rotation. The objective of this study to determine talocrural contact mechanics during weightbearing ankle internal rotation in patients with FAI. Twelve male subjects with unilateral FAI (age range, 18-26 years) were enrolled. Computed tomography and fluoroscopic imaging of both lower extremities were obtained during weightbearing passive ankle joint complex rotation. Three-dimensional bone models created from the computed tomographic images were matched to the fluoroscopic images to compute 6 degrees of freedom for talocrural joint kinematics. The closest contact area in the talocrural joint in ankle neutral rotation and maximum internal rotation during either dorsiflexion or plantar flexion was determined using geometric bone models and talocrural joint kinematics data. The closest contact area in the talus shifted anteromedially during ankle dorsiflexion-internal rotation, whereas it shifted posteromedially during ankle plantar flexion-internal rotation. The closest contact area in FAI joints was significantly more medial than that in healthy joints during maximum ankle internal rotation and was associated with excessive talocrural internal rotation or inversion. This study demonstrated abnormal talocrural kinematics and contact mechanics in FAI subjects. Such abnormal kinematics may contribute to abnormal contact mechanics and may increase cartilage stress in FAI joints. Therapeutic, Level IV: cross-sectional case-control study. © 2015 The Author(s).

  7. Pseudoaneurysm of the Anterior Tibial Artery following Ankle Arthroscopy in a Soccer Player.

    PubMed

    Tonogai, Ichiro; Matsuura, Tetsuya; Iwame, Toshiyuki; Wada, Keizo; Takasago, Tomoya; Goto, Tomohiro; Hamada, Daisuke; Kawatani, Yohei; Fujimoto, Eiki; Kitagawa, Tetsuya; Takao, Shyoichiro; Iwamoto, Seiji; Yamanaka, Moriaki; Harada, Masafumi; Sairyo, Koichi

    2017-01-01

    Ankle arthroscopy carries a lower risk of vascular complications when standard anterolateral and anteromedial portals are used. However, the thickness of the fat pad at the anterior ankle affords little protection for the thin-walled anterior tibial artery, rendering it susceptible to indirect damage during procedures performed on the anterior ankle joint. To our knowledge, only 11 cases of pseudoaneurysm involving the anterior tibial artery after ankle arthroscopy have been described in the literature. Here we reported a rare case of a 19-year-old soccer player who presented with pseudoaneurysm of the anterior tibial artery following ankle arthroscopy using an ankle distraction method and underwent anastomosis for the anterior tibial artery injury. Excessive distraction of the ankle puts the neurovascular structures at greater risk for iatrogenic injury of the anterior tibial artery during ankle arthroscopy. Surgeons should look carefully for postoperative ankle swelling and pain after ankle arthroscopy.

  8. Pseudoaneurysm of the Anterior Tibial Artery following Ankle Arthroscopy in a Soccer Player

    PubMed Central

    Iwame, Toshiyuki; Hamada, Daisuke; Fujimoto, Eiki; Kitagawa, Tetsuya; Takao, Shyoichiro; Iwamoto, Seiji; Yamanaka, Moriaki; Harada, Masafumi

    2017-01-01

    Ankle arthroscopy carries a lower risk of vascular complications when standard anterolateral and anteromedial portals are used. However, the thickness of the fat pad at the anterior ankle affords little protection for the thin-walled anterior tibial artery, rendering it susceptible to indirect damage during procedures performed on the anterior ankle joint. To our knowledge, only 11 cases of pseudoaneurysm involving the anterior tibial artery after ankle arthroscopy have been described in the literature. Here we reported a rare case of a 19-year-old soccer player who presented with pseudoaneurysm of the anterior tibial artery following ankle arthroscopy using an ankle distraction method and underwent anastomosis for the anterior tibial artery injury. Excessive distraction of the ankle puts the neurovascular structures at greater risk for iatrogenic injury of the anterior tibial artery during ankle arthroscopy. Surgeons should look carefully for postoperative ankle swelling and pain after ankle arthroscopy. PMID:28607785

  9. Effects of focal ankle joint cooling on unipedal static balance in individuals with and without chronic ankle instability.

    PubMed

    Kim, Kyung-Min; Hart, Joseph M; Saliba, Susan A; Hertel, Jay

    2015-01-01

    Application of cryotherapy over an injured joint has been shown to improve muscle function, yet it is unknown how ankle cryotherapy affects postural control. Our purpose was to determine the effects of a 20-min focal ankle joint cooling on unipedal static stance in individuals with and without chronic ankle instability (CAI). Fifteen young subjects with CAI (9 males, 6 females) and 15 healthy gender-matched controls participated. All subjects underwent two intervention sessions on different days in which they had a 1.5L plastic bag filled with either crushed ice (active treatment) or candy corn (sham) applied to the ankle. Unipedal stance with eyes closed for 10s were assessed with a forceplate before and after each intervention. Center of pressure (COP) data were used to compute 10 specific dependent measures including velocity, area, standard deviation (SD), and percent range of COP excursions, and mean and SD of time-to-boundary (TTB) minima in the anterior-posterior (AP) and mediolateral directions. For each measure a three-way (Group-Intervention-Time) repeated ANOVAs found no significant interactions and main effects involving intervention (all Ps > 0.05). There were group main effects found for mean velocity (F(1,28) = 6.46, P = .017), area (F(1,28) = 12.83, P = .001), and mean of TTB minima in the AP direction (F(1,28) = 5.19, P = .031) indicating that the CAI group demonstrated greater postural instability compared to the healthy group. Postural control of unipedal stance was not significantly altered following focal ankle joint cooling in groups both with and without CAI. Ankle joint cryotherapy was neither beneficial nor harmful to single leg balance. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Prenatal development of the foot and ankle.

    PubMed

    Bareither, D

    1995-12-01

    The general development of the lower limb and the specific development of the foot and ankle are discussed for each horizon in the embryonic and fetal periods of development. Lower limb general development is discussed only to the extent necessary for the understanding of foot and ankle development.

  11. Osteochondral lesions about the ankle.

    PubMed

    Naran, Ketan N; Zoga, Adam C

    2008-11-01

    Osteochondral lesions (OCLs) about the foot and ankle often manifest clinically as prolonged joint pain after trauma, often an ankle sprain, which is refractory to conventional, conservative therapeutic treatment. Noncontrast MR imaging is the standard of care imaging modality for diagnosing and classifying osteochondral lesions, but equivocal or difficult lesions can be assessed more specifically with direct MR arthrography or in conjunction with multidetector CT. Once an OCL has been identified, the imager should make every effort to determine whether it is stable or potentially unstable.

  12. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium.

    PubMed

    Gribble, Phillip A; Delahunt, Eamonn; Bleakley, Chris; Caulfield, Brian; Docherty, Carrie L; Fourchet, François; Fong, Daniel; Hertel, Jay; Hiller, Claire; Kaminski, Thomas W; McKeon, Patrick O; Refshauge, Kathryn M; van der Wees, Philip; Vicenzino, Bill; Wikstrom, Erik A

    2013-08-01

    The International Ankle Consortium is an international community of researchers and clinicians whose primary scholastic purpose is to promote scholarship and dissemination of research-informed knowledge related to pathologies of the ankle complex. The constituents of the International Ankle Consortium and other similar organizations have yet to properly define the clinical phenomenon known as chronic ankle instability (CAI) and its related characteristics for consistent patient recruitment and advancement of research in this area. Although research on CAI and awareness of its impact on society and healthcare systems have grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalize this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI, with justifications using the best available evidence.

  13. Commercially available trabecular metal ankle interpositional spacer for tibiotalocalcaneal arthrodesis secondary to severe bone loss of the ankle.

    PubMed

    Horisberger, Monika; Paul, Jochen; Wiewiorski, Martin; Henninger, Heath B; Khalifa, Muhammad S; Barg, Alexej; Valderrabano, Victor

    2014-01-01

    Retrograde tibiotalocalcaneal nailing arthrodesis has proved to be a viable salvage procedure; however, extended bone loss around the ankle has been associated with high rates of nonunion and considerable shortening of the hindfoot. We present the surgical technique and the first 2 cases in which a trabecular metal™ interpositional spacer, specifically designed for tibiotalocalcaneal nailing arthrodesis, was used. The spacer can be implanted using either an anterior or a lateral approach. An integrated hole in the spacer allows a retrograde nail to be inserted, which provides excellent primary stability of the construct. Trabecular metal™ is a well-established and well-described material used to supplement deficient bone stock in surgery of the spine, hip, and knee. It has shown excellent incorporation and reduces the need for auto- and allografts. The trabecular metal™ interpositional ankle spacer is the first trabecular metal spacer designed specifically for ankle surgery. Its shape and variable size will make it a valuable tool for reconstructing bone loss in tibiotalocalcaneal nailing arthrodesis. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Relationships between self-reported ankle function and modulation of Hoffmann reflex in patients with chronic ankle instability.

    PubMed

    Kim, Kyung-Min; Hart, Joseph M; Saliba, Susan A; Hertel, Jay

    2016-01-01

    To examine relationships between self-reported ankle function and Hoffmann (H) reflex modulation during changes in body positions in patients with chronic ankle instability (CAI). Observational. Laboratory. Thirty-one young adults with CAI (19 males, 12 females) participated. There were two subscales of Foot and Ankle Ability Measure (FAAM) to quantify self-reported ankle function during activities of daily living (ADL) and sports activities. Maximum H-reflexes (H-max) and motor waves (M-max) from soleus and fibularis longus were recorded while participants lied prone and stood in bipedal and unipedal stances. For each muscle, percent change scores in Hmax:Mmax ratios were calculated between each pair of positions: prone-to-bipedal, bipedal-to-unipedal, and prone-to-unipedal, and used as a measure of H-reflex modulation. Pearson correlation coefficients were calculated between FAAM and H-reflex modulation measures. There were significant correlations between: (1) FAAM-ADL and soleus prone-to-unipedal modulation (r = 0.384, p = 0.04), (2) FAAM-Sport and soleus prone-to-unipedal modulation (r = 0.505, p = 0.005), (3) FAAM-Sport and fibular bipedal-to-unipedal modulation (r = 0.377, p = 0.05), and (4) FAAM-Sport and fibular prone-to-unipedal modulation (r = 0.396, p = 0.04). CAI patients presented moderate, positive relationships between self-reported ankle function and H-reflex modulation during changes in body positions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Ankle sprain.

    PubMed

    Struijs, Peter Aa; Kerkhoffs, Gino Mmj

    2010-05-13

    Injury of the lateral ligament complex of the ankle joint occurs in about one in 10,000 people a day, accounting for a quarter of all sports injuries. We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatment strategies for acute ankle ligament ruptures? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 38 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: cold treatment, diathermy, functional treatment, homeopathic ointment, immobilisation, physiotherapy, surgery, and ultrasound.

  16. Ankle sprain

    PubMed Central

    2010-01-01

    Introduction Injury of the lateral ligament complex of the ankle joint occurs in about one in 10,000 people a day, accounting for a quarter of all sports injuries. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatment strategies for acute ankle ligament ruptures? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 38 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: cold treatment, diathermy, functional treatment, homeopathic ointment, immobilisation, physiotherapy, surgery, and ultrasound. PMID:21718566

  17. Ankle surgery: focus on arthroscopy.

    PubMed

    Cavallo, M; Natali, S; Ruffilli, A; Buda, R; Vannini, F; Castagnini, F; Ferranti, E; Giannini, S

    2013-12-01

    The ankle joint can be affected by several diseases, with clinical presentation varying from mild pain or swelling to inability, becoming in some cases a serious problem in daily life activities. Arthroscopy is a widely performed procedure in orthopedic surgery, due to the low invasivity compared to the more traditional open field surgery. The ankle joint presents anatomical specificities, like small space and tangential view that make arthroscopy more difficult. From 2000 more than 600 ankle arthroscopies were performed at our institution. The treated pathologies were mostly impingement syndrome and osteochondral lesions, and in lower percentage instabilities and ankle fractures. In the impingement, the AOFAS scores at FU showed an increase compared to scores collected preoperatively, with improvement of symptoms in most of the cases, good or excellent results in 80 % of cases. In ligament injuries, AOFAS score significatively improved at the maximum follow-up. In fractures all patients had an excellent AOFAS score at maximum follow-up, with complete return to their pre-injury activities. In osteochondral injuries, the clinical results showed a progressive improvement over time with  the different performed procedures. Control MRI and bioptic samples showed a good regeneration of the cartilage and bone tissue in the lesion site. The encouraging obtained clinical results, in line with the literature, show how the arthroscopic technique, after an adequate learning curve, may represent a precious aid for the orthopedic surgeon and for the patient's outcome. Case series, Level IV.

  18. Amyotrophic lateral sclerosis immunoglobulins increase intracellular calcium in a motoneuron cell line.

    PubMed

    Colom, L V; Alexianu, M E; Mosier, D R; Smith, R G; Appel, S H

    1997-08-01

    A hybrid motoneuron cell line (VSC4.1) was used as a model system to study the relationship between alterations in intracellular calcium and subsequent cell death induced by immunoglobulin fractions purified from sera of patients with ALS. Using fluo-3 fluorescence imaging, immunoglobulins from 8 of 10 patients with ALS were found to induce transient increases in intracellular calcium ([Ca2+]i) in differentiated VSC4.1 cells. These transient [Ca2+]i increases required extracellular calcium entry through voltage-gated calcium channels sensitive to synthetic FTX and to high concentrations (>1 microM) of omega-agatoxin IVa. The incidence of transient [Ca2+]i increases induced by ALS immunoglobulins correlated with the extent of cytotoxicity induced by the same ALS immunoglobulins in parallel cultures of VSC4.1 cells. Furthermore, manipulations which blocked transient [Ca2+]i increases (addition of synthetic FTX or omega-agatoxin IVa) also inhibited the cytotoxic effects of ALS immunoglobulins. No transient calcium increases were observed in VSC4.1 cells following addition of immunoglobulins from 7 neurologic disease control patients. However, transient [Ca2+]i increases were observed following addition of immunoglobulins from 4 of 5 patients with myasthenia gravis (MG). The [Ca2+]i changes induced by MG immunoglobulins were not blocked by s-FTX, suggesting that they result from a different mechanism than those induced by ALS immunoglobulins. These results suggest that immunoglobulins from patients with ALS can induce transient increases in intracellular calcium in a motoneuron cell line, which may represent early events in the cascade of processes leading to injury and death of susceptible cells.

  19. The effect of changing plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke

    PubMed Central

    Kobayashi, Toshiki; Singer, Madeline L.; Orendurff, Michael S.; Gao, Fan; Daly, Wayne K.; Foreman, K. Bo

    2015-01-01

    Background The adjustment of plantarflexion resistive moment of an articulated ankle-foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated ankle-foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the ankle-foot orthosis. Increasing the plantarflexion resistive moment of the ankle-foot orthosis induced significant decreases both in the peak ankle plantarflexion angle (P<0.01) and the peak knee extension angle (P<0.05). Also, the increase induced significant increases in the internal dorsiflexion moment of the ankle joint (P<0.01) and significantly decreased the internal flexion moment of the knee joint (P<0.01). Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated ankle-foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated ankle-foot orthosis for improved orthotic care in individual patients. PMID:26149007

  20. The effect of changing plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments while walking in patients post stroke.

    PubMed

    Kobayashi, Toshiki; Singer, Madeline L; Orendurff, Michael S; Gao, Fan; Daly, Wayne K; Foreman, K Bo

    2015-10-01

    The adjustment of plantarflexion resistive moment of an articulated ankle-foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments in patients post stroke. Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated ankle-foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. The ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the ankle-foot orthosis. Increasing the plantarflexion resistive moment of the ankle-foot orthosis induced significant decreases both in the peak ankle plantarflexion angle (P<0.01) and the peak knee extension angle (P<0.05). Also, the increase induced significant increases in the internal dorsiflexion moment of the ankle joint (P<0.01) and significantly decreased the internal flexion moment of the knee joint (P<0.01). These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated ankle-foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated ankle-foot orthosis for improved orthotic care in individual patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Recent Developments in the Treatment of Ankle and Subtalar Instability

    PubMed Central

    Sugimoto, Kazuya

    2017-01-01

    It was nearly a centenary ago that severe ankle sprain was recognized as an injury of the ankle ligament(s). With the recent technological advances and tools in imaging and surgical procedures, the management of ankle sprains - including subtalar injuries - has drastically improved. The repair or reconstruction of ankle ligaments is getting more anatomical and less invasive than previously. More specifically, ligamentous reconstruction with tendon graft has been the gold standard in the management of severely damaged ligament, however, it does not reproduce the original ultrastructure of the ankle ligaments. The anatomical ligament structure of a ligament comprises a ligament with enthesis at both ends and the structure should also exhibit proprioceptive function. To date, it remains impossible to reconstruct a functionally intact and anatomical ligament. Cooperation of the regenerative medicine and surgical technology in expected to improve reconstructions of the ankle ligament, however, we need more time to develop a technology in reproducing the ideal ligament complex. PMID:28979582

  2. Development of a New Robotic Ankle Rehabilitation Platform for Hemiplegic Patients after Stroke

    PubMed Central

    Duan, Lihong

    2018-01-01

    A large amount of hemiplegic survivors are suffering from motor impairment. Ankle rehabilitation exercises act an important role in recovering patients' walking ability after stroke. Currently, patients mainly perform ankle exercise to reobtain range of motion (ROM) and strength of the ankle joint under a therapist's assistance by manual operation. However, therapists suffer from high work intensity, and most of the existed rehabilitation devices focus on ankle functional training and ignore the importance of neurological rehabilitation in the early hemiplegic stage. In this paper, a new robotic ankle rehabilitation platform (RARP) is proposed to assist patients in executing ankle exercise. The robotic platform consists of two three-DOF symmetric layer-stacking mechanisms, which can execute ankle internal/external rotation, dorsiflexion/plantarflexion, and inversion/eversion exercise while the rotation center of the distal zone of the robotic platform always coincides with patients' ankle pivot center. Three exercise modes including constant-speed exercise, constant torque-impedance exercise, and awareness exercise are developed to execute ankle training corresponding to different rehabilitation stages. Experiments corresponding to these three ankle exercise modes are performed, the result demonstrated that the RARP is capable of executing ankle rehabilitation, and the novel awareness exercise mode motivates patients to proactively participate in ankle training. PMID:29736231

  3. [Dislocation of the ankle without simoustaneously fracture of the bones].

    PubMed

    Qayyum, Faiza; Qayyum, Abbas Ali; Sahlstrüm, Sven Arne

    2014-09-01

    The ankle is a unique modified saddle joint that, together with the subtalar joint, provides range of motion in several physical planes while maintaining stability. The ankle complex functions as a pivoting structure positioned to bear the entire weight of the body which leaves it vulnerable to injuries. Pure dislocation without associated fracture is rare; however, cases of isolated ankle dislocation without fracture have been reported. We report a case of a closed ankle dislocation without an associated fracture in a 17-year-old boy.

  4. A Biomechanical Comparison of 3 Different Arthroscopic Lateral Ankle Stabilization Techniques in 36 Cadaveric Ankles.

    PubMed

    Cottom, James M; Baker, Joseph S; Richardson, Phillip E; Maker, Jared M

    Arthroscopic lateral ankle stabilization has become an increasingly popular option among foot and ankle surgeons to address lateral ankle instability, because it combines a modified Broström-Gould procedure with the ability to address any intra-articular pathologic findings at the same session. The present study evaluated 3 different constructs in a cadaveric model. Thirty-six fresh frozen cadaver limbs were used, and the anterior talofibular ligament was identified and sectioned. The specimens were then placed into 1 of 3 groups. Group 1 received a repair with a single-row, 2-suture anchor construct; group 2 received repair with a novel, double-row, 4-anchor knotless construct; and group 3 received repair with a double-row, 3-anchor construct. Specimens were then tested for stiffness and load to ultimate failure using a customized jig. Stiffness was measured in each of the groups and was 12.10 ± 5.43 (range 5.50 to 22.24) N/mm for group 1, 13.40 ± 7.98 (range 6.71 to 36.28) N/mm for group 2, and 12.55 ± 4.00 (range 6.48 to 22.14) N/mm for group 3. No significant differences were found among the 3 groups in terms of stiffness (p = .939, 1-way analysis of variance, ɑ = 0.05). The groups were tested to failure, with observed force measurements of 156.43 ± 30.39 (range 83.69 to 192.00) N for group 1, 206.62 ± 55.62 (range 141.37 to 300.29) N for group 2, and 246.82 ± 82.37 (range 164.26 to 384.93) N for group 3. Statistically significant differences were noted between groups 1 and 3 (p = .006, 1-way analysis of variance, ɑ = 0.05). The results of the present study have shown that a previously reported arthroscopic lateral ankle stabilization procedure, when modified with an additional proximal suture anchor into the fibula, results in a statistically significant increase in strength in terms of the maximum load to failure. Additionally, we have described a previously unreported, knotless technique for arthroscopic lateral ankle

  5. A unified perspective on ankle push-off in human walking.

    PubMed

    Zelik, Karl E; Adamczyk, Peter G

    2016-12-01

    Muscle-tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two possibilities are not mutually exclusive. If we ask either question independently, the answer is the same: yes! (1) Does ankle push-off primarily contribute to leg swing acceleration? Yes. (2) Does ankle push-off primarily contribute to COM acceleration? Yes. Here, we summarize the historical debate, then synthesize the seemingly polarized perspectives and demonstrate that both descriptions are valid. The principal means by which ankle push-off affects COM mechanics is by a localized action that increases the speed and kinetic energy of the trailing push-off limb. Because the limb is included in body COM computations, this localized segmental acceleration also accelerates the COM, and most of the segmental energy change also appears as COM energy change. Interpretation of ankle mechanics should abandon an either/or contrast of leg swing versus COM acceleration. Instead, ankle push-off should be interpreted in light of both mutually consistent effects. This unified perspective informs our fundamental understanding of the role of ankle push-off, and has important implications for the design of clinical interventions (e.g. prostheses, orthoses) intended to restore locomotor function to individuals with disabilities. © 2016. Published by The Company of Biologists Ltd.

  6. A unified perspective on ankle push-off in human walking

    PubMed Central

    Adamczyk, Peter G.

    2016-01-01

    ABSTRACT Muscle–tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two possibilities are not mutually exclusive. If we ask either question independently, the answer is the same: yes! (1) Does ankle push-off primarily contribute to leg swing acceleration? Yes. (2) Does ankle push-off primarily contribute to COM acceleration? Yes. Here, we summarize the historical debate, then synthesize the seemingly polarized perspectives and demonstrate that both descriptions are valid. The principal means by which ankle push-off affects COM mechanics is by a localized action that increases the speed and kinetic energy of the trailing push-off limb. Because the limb is included in body COM computations, this localized segmental acceleration also accelerates the COM, and most of the segmental energy change also appears as COM energy change. Interpretation of ankle mechanics should abandon an either/or contrast of leg swing versus COM acceleration. Instead, ankle push-off should be interpreted in light of both mutually consistent effects. This unified perspective informs our fundamental understanding of the role of ankle push-off, and has important implications for the design of clinical interventions (e.g. prostheses, orthoses) intended to restore locomotor function to individuals with disabilities. PMID:27903626

  7. Dense TRPV2 immunoreactivity defines a subset of motoneurons in the dorsal lateral nucleus of the spinal cord, the nucleus ambiguus and the trigeminal motor nucleus in rat

    PubMed Central

    LeWinter, Robin D.; Scherrer, Grégory; Basbaum, Allan I.

    2008-01-01

    The transient receptor potential cation channel TRPV2 is a member of the TRPV family of proteins and is a homologue of the capsaicin/vanilloid receptor (TRPV1). Like TRPV1, TRPV2 is expressed in a subset of dorsal root ganglia (DRG) neurons that project to superficial laminae of the spinal cord dorsal horn. Because noxious heat (>52°C) activates TRPV2 in transfected cells this channel has been implicated in the processing of high intensity thermal pain messages in vivo. In contrast to TRPV1, however, which is restricted to small diameter DRG neurons, there is significant TRPV2 immunoreactivity in a variety of CNS regions. The present report focuses on a subset of neurons in the brainstem and spinal cord of the rat including the dorsal lateral nucleus (DLN) of the spinal cord, the nucleus ambiguus, and the motor trigeminal nucleus. Double label immunocytochemistry with markers of motoneurons, combined with retrograde labeling, established that these cells are, in fact, motoneurons. With the exception of their smaller diameter, these cells did not differ from other motoneurons, which are only lightly TRPV2-immunoreactive. As for the majority of DLN neurons, the densely-labeled populations co-express androgen receptor and follow normal DLN ontogeny. The functional significance of the very intense TRPV2 expression in these three distinct spinal cord and brainstem motoneurons groups remains to be determined. PMID:18063314

  8. Ankle fractures have features of an osteoporotic fracture.

    PubMed

    Lee, K M; Chung, C Y; Kwon, S S; Won, S H; Lee, S Y; Chung, M K; Park, M S

    2013-11-01

    We report the bone attenuation of ankle joint measured on computed tomography (CT) and the cause of injury in patients with ankle fractures. The results showed age- and gender-dependent low bone attenuation and low-energy trauma in elderly females, which suggest the osteoporotic features of ankle fractures. This study was performed to investigate the osteoporotic features of ankle fracture in terms of bone attenuation and cause of injury. One hundred ninety-four patients (mean age 51.0 years, standard deviation 15.8 years; 98 males and 96 females) with ankle fracture were included. All patients underwent CT examination, and causes of injury (high/low-energy trauma) were recorded. Mean bone attenuations of the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis were measured on CT images. Patients were divided into younger age (<50 years) and older age (≥50 years) groups, and mean bone attenuation and causes of injury were compared between the two groups in each gender. Proportion of low-energy trauma was higher in the older age group than in the younger age group, but the difference was only significant in female gender (p = 0.011). The older age group showed significantly lower bone attenuation in the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis than the younger age group in both genders. The older age group showed more complex pattern of fractures than the younger age group. With increasing age, bone attenuations tended to decrease and the difference of bone attenuation between the genders tended to increase in the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis. Ankle fracture had features of osteoporotic fracture that is characterized by age- and gender-dependent low bone attenuation. Ankle fracture should not be excluded from the clinical and research interest as well as from the benefit of osteoporosis management.

  9. Scandinavian Total Ankle Replacement: 15-Year Follow-up.

    PubMed

    Palanca, Ariel; Mann, Roger A; Mann, Jeffrey A; Haskell, Andrew

    2018-02-01

    Over the past decade, total ankle arthroplasty (TAA) has become a mainstay in the treatment of end-stage ankle arthritis. Currently in its fourth generation, the Scandanavian Total Ankle Replacement (STAR) is the only 3-piece mobile bearing ankle prosthesis available in the United States. Our current study reports implant survivorship at 15 years and patient outcomes for a subset of these survivors available for study. Eighty-four TAAs were performed between 1998 and 2000. Metal component survivorship at 15 years was calculated with a Kaplan-Meier curve. Twenty-four (29%) of 84 patients were available for participation with a minimum 15-year follow-up. Any radiographic changes were documented. All additional procedures and complications were recorded. Clinical findings, self-reported performance and pain evaluations, and AOFAS ankle/hindfoot scores were noted. Metal implant survival was 73% at 15 years. Of the 24 patients available for clinical evaluation, 18 of 24 patients (70.7%) had no change in prosthetic alignment from the immediate postoperative radiograph. Only 1 subtalar fusion was required for symptomatic adjacent joint arthritis. Three patients sustained a broken polyethylene component. AOFAS scores improved from an average of 39.6 points preoperatively, to an average of 71.6. More than half (52.4%) of patients with retained implants required an additional surgical procedure; 3 required 2 additional procedures. The average time to subsequent procedure was 10.2 years. Our small cohort demonstrated STAR ankles with retention at 9 years were highly likely to survive to 15 years, and patients continued to have significant improvement in pain relief and minimal decrease in function. At 15 years from TAA, metal survivorship was 73%. As with all ankle replacements, supplementary procedures were common. Level IV, case series.

  10. Distraction systems for ankle arthroscopy.

    PubMed

    Palladino, S J

    1994-07-01

    It is clear that for most of the routine pathology addressed with ankle arthroscopy, including most talar dome transchondral fractures, manual distraction (or none at all) is all that is necessary to successfully complete the procedure. There is little need to add the expense and potential complications associated with some distraction systems. However, some cases involve pathology or surgical techniques that either would be better addressed with distraction or absolutely demand distraction. It is recommended that invasive ankle distraction be reserved for (1) cases in which noninvasive distraction has not yielded adequate field visualization or instrument maneuvering room, (2) cases of preoperatively documented pathology involving the posterior talar dome (including some medial talar dome fractures) or inferior tibial surface, or (3) arthroscopic ankle fusion. Consideration should be given to providing 6 to 12 weeks of protected function of the extremity to avoid delayed fracture presentation. In general, the invasive distraction system should be reserved for those cases that would not ordinarily be managed with aggressive rehabilitation and early return to activities. For those cases where the benefits of distraction are desired (some dome fractures, meniscoid lesions, gutter pathology, and adhesive capsulitis) and aggressive rehabilitation with early return to activities may be planned, noninvasive distraction systems are now available that offer a sustainable joint separation of good magnitude. With the growing availability and effectiveness of the commercial noninvasive ankle distractors, I do not disagree with Stone and Guhl98 when they advocate the use of noninvasive distraction for routine arthroscopic procedures, with conversion to invasive distraction should there be insufficient joint separation. In summary, providing optimal field visualization and maneuvering room for instrumentation is essential for the successful performance of arthroscopic ankle

  11. Prophylactic Ankle Bracing in Military Settings: A Review of the Literature.

    PubMed

    Newman, Thomas M; Gay, Michael R; Buckley, W E

    2017-03-01

    Within athletics and the military, ankle sprains are one of the most common injuries with the potential for long-term functional deficits. Incidence rates for ankle sprains within the military are one of the leading causes of limited duty days, especially during basic combat training, parachute training exercises, and in cadet populations. In 2008, the Department of Defense U.S. Army Center for Health Promotion and Preventative Medicine report recommended that military personnel should wear semirigid ankle braces during parachuting, basketball, soccer, and other similar high-risk activities to reduce ankle sprain injuries. This recommendation was developed using a majority of athletic references with limited data stemming from military works. Of these included military studies, none presented data on ankle braces and their effects on performance, especially in military-specific environments. The purpose of this review was to provide an up-to-date account on the use of ankle braces in military populations and effects on performance measures. A comprehensive online systematic review of the literature was conducted to delineate the current use of ankle braces in the military and how they specifically affect functional performance measures. The scope of this study eliminated military studies that were not prospective in nature or did not incorporate subjects wearing military equipment (i.e., combat boots). It was determined that little progress has been made in validating the use of semirigid ankle braces in military populations other than in instances such as parachuting and only in reducing the number ankle injuries. To date, only one study has looked specifically at the use of ankle braces and its effects on performance measures in a military sample. With the high incidence rate and increased risk for subsequent reinjury, ankle sprains are an economic and force readiness burden to the U.S. Armed Forces. This study was conducted to determine whether additional

  12. Chronic ankle instability: Arthroscopic anatomical repair.

    PubMed

    Arroyo-Hernández, M; Mellado-Romero, M; Páramo-Díaz, P; García-Lamas, L; Vilà-Rico, J

    Ankle sprains are one of the most common injuries. Despite appropriate conservative treatment, approximately 20-40% of patients continue to have chronic ankle instability and pain. In 75-80% of cases there is an isolated rupture of the anterior talofibular ligament. A retrospective observational study was conducted on 21 patients surgically treated for chronic ankle instability by means of an arthroscopic anatomical repair, between May 2012 and January 2013. There were 15 men and 6 women, with a mean age of 30.43 years (range 18-48). The mean follow-up was 29 months (range 25-33). All patients were treated by arthroscopic anatomical repair of anterior talofibular ligament. Four (19%) patients were found to have varus hindfoot deformity. Associated injuries were present in 13 (62%) patients. There were 6 cases of osteochondral lesions, 3 cases of posterior ankle impingement syndrome, and 6 cases of peroneal pathology. All these injuries were surgically treated in the same surgical time. A clinical-functional study was performed using the American Orthopaedic Foot and Ankle Society (AOFAS) score. The mean score before surgery was 66.12 (range 60-71), and after surgery it increased up to a mean of 96.95 (range 90-100). All patients were able to return to their previous sport activity within a mean of 21.5 weeks (range 17-28). Complications were found in 3 (14%) patients. Arthroscopic anatomical ligament repair technique has excellent clinical-functional results with a low percentage of complications, and enables patients to return to their previous sport activity within a short period of time. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Review on design and control aspects of ankle rehabilitation robots.

    PubMed

    Jamwal, Prashant K; Hussain, Shahid; Xie, Sheng Q

    2015-03-01

    Ankle rehabilitation robots can play an important role in improving outcomes of the rehabilitation treatment by assisting therapists and patients in number of ways. Consequently, few robot designs have been proposed by researchers which fall under either of the two categories, namely, wearable robots or platform-based robots. This paper presents a review of both kinds of ankle robots along with a brief analysis of their design, actuation and control approaches. While reviewing these designs it was observed that most of them are undesirably inspired by industrial robot designs. Taking note of the design concerns of current ankle robots, few improvements in the ankle robot designs have also been suggested. Conventional position control or force control approaches, being used in the existing ankle robots, have been reviewed. Apparently, opportunities of improvement also exist in the actuation as well as control of ankle robots. Subsequently, a discussion on most recent research in the development of novel actuators and advanced controllers based on appropriate physical and cognitive human-robot interaction has also been included in this review. Implications for Rehabilitation Ankle joint functions are restricted/impaired as a consequence of stroke or injury during sports or otherwise. Robots can help in reinstating functions faster and can also work as tool for recording rehabilitation data useful for further analysis. Evolution of ankle robots with respect to their design and control aspects has been discussed in the present paper and a novel design with futuristic control approach has been proposed.

  14. Surgical procedures in patients with haemophilic arthropathy of the ankle.

    PubMed

    Barg, A; Morris, S C; Schneider, S W; Phisitkul, P; Saltzman, C L

    2016-05-01

    In haemophilia, the ankle joint is one of the most common and earliest joints affected by recurrent bleeding, commonly resulting in end-stage ankle osteoarthritis during early adulthood. The surgical treatment of haemophilic ankle arthropathy is challenging. This review aims to highlight the literature addressing clinical outcomes following the most common approaches for different stages of haemophilia-induced ankle osteoarthritis: arthroscopic debridement, joint distraction arthroplasty, supramalleolar osteotomies, total ankle replacement, and ankle arthrodesis. A systematic literature review was performed using established medical literature databases. The following information was retrieved from the literature: patients' demographics, surgical technique, duration of follow-up, clinical outcome including pain relief and complication rate. A total of 42 clinical studies published between 1978 and 2015 were included in the systematic literature review. Eight and 34 studies had prospective and retrospective design, respectively. The most common studies were level IV studies (64.3%). The orthopaedic treatment of patients with haemophilic ankle osteoarthritis is often challenging and requires complete and careful preoperative assessment. In general, both joint-preserving and joint non-preserving procedure types can be performed. All specific relative and absolute contraindications should be considered to achieve appropriate postoperative outcomes. The current literature demonstrated that orthopaedic surgeries, with appropriate indication, in patients with haemophilic ankle arthropathy result in good postoperative results comparable to those observed in non-haemophiliacs. The surgical treatment should be performed in a setting with the ability to have multidisciplinary management, including expertise in haematology. © 2016 John Wiley & Sons Ltd.

  15. The correlation of the morphological changes of ankle point and ankle joint function after surgery on the Ruedi-Allgouer type III Pilon fracture: A case series study.

    PubMed

    Zhou, Yifei; Cai, Leyi; Lu, Xiaolang; Yu, Yang; Hong, Jianjun

    2017-08-01

    To analyze the relationship between imaging findings and postoperative curative effect by measuring the morphology of the ankle mortise in patients with the Ruedi-Allgouer type III Pilon fractures. Forty-seven patients with Ruedi-Allgouer type III Pilon fractures who underwent surgical treatment from January 2011 to January 2015 were retrospectively analyzed. At the last follow-up, x-rays of the affected ankle and the healthy side were measured. According to the Kitaoka score of ankle joint function at the last follow-up. All patients were followed up for 18-24 months (mean 21 months). This study demonstrated that compared with the healthy side, the index of the width, depth, and coronal/sagittal angles of the ankle mortise were significantly different (P < 0.05) in the 47 patients except for the index of height (P > 0.05). According to the Kitaoka score, the difference between the affected and the healthy sides of each index of the ankle mortise was compared between the 3 groups. That is, the intraoperative treatment of the width and depth of the ankle mortise as well as the coronal and sagittal angles of the ankle mortise were significantly correlated with the postoperative curative effect. The intraoperative treatment of ankle mortise width, depth, and ankle coronal/sagittal angle in patients with severe Pilon fractures has a significant impact on postoperative efficacy. In order to prevent the occurrence of traumatic arthritis, the anatomical morphology of the ankle should be restored as much as possible in the course of surgery. Copyright © 2017. Published by Elsevier Ltd.

  16. Radiologic changes of ankle joint after total knee arthroplasty.

    PubMed

    Lee, Jung Hee; Jeong, Bi O

    2012-12-01

    The authors noticed that ankle joint osteoarthritis was not uncommon when lower extremity malalignment, such as a knee varus deformity, was present as a result of severe osteoarthritis of the knee. The purpose of this study was to analyze radiologic changes of the ankle joint after total knee arthroplasty. This study included 142 cases in 110 patients who underwent total knee arthroplasty and were followed for at least 3 years. The varus knee group included 128 cases and the valgus knee group included 14 cases. On anteroposterior standing lower extremity radiographs, varus and valgus angles of the knee were measured preoperatively and at the last follow-up. The angle between the ground surface and the distal tibial plafond as well as the upper talus was also measured. In addition, tibial anterior surface angle, talar tilt, space between the medial malleolar distal tip and the medial articular surface of the talus, and medial tibiotalar joint space of the ankle joint were measured. Out of 142 cases, 50 (35.2%) had arthritis in the ankle before total knee arthroplasty and 31 (21.8%) had newly developed or progressive arthritis after surgery. In particular, the varus knee group demonstrated statistically significant differences in preoperative varus deformity, preoperative talar tilt, and postoperative correction angle between the cases that developed or had progressive arthritis and those that did not show any changes (p < .05). After total knee arthroplasty, arthritis developed or progressed in the ankle of many cases radiographically. In particular, when the preoperative talar tilt increased medial to the ankle or the postoperative correction angle was large, the incidence of arthritis in the ankle joint increased. The authors recommend more cautious follow-up on the symptoms of the ankle joint after total knee arthroplasty.

  17. Manipulation method for the treatment of ankle equinus.

    PubMed

    Dananberg, H J; Shearstone, J; Guillano, M

    2000-09-01

    Ankle equinus is a well-known clinical entity that has previously been shown to compound a variety of foot and ankle conditions. Treatments for this disorder have included surgery to lengthen the Achilles tendon and daily stretching. This article describes a method of manual manipulation that can immediately and substantially increase ankle joint dorsiflexion. Patients treated with manipulation in the current study demonstrated nearly twice as much dorsiflexion motion as that demonstrated by patients in a prior study who were treated with a 5-minute daily stretching program for 6 months.

  18. 21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

  19. 21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

  20. 21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...