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Sample records for activity knee motion

  1. Thigh Muscle Activity, Knee Motion, and Impact Force During Side-Step Pivoting in Agility-Trained Female Basketball Players

    PubMed Central

    Wilderman, Danielle R; Ross, Scott E; Padua, Darin A

    2009-01-01

    Context: Improving neuromuscular control of hamstrings muscles might have implications for decreasing anterior cruciate ligament injuries in females. Objective: To examine the effects of a 6-week agility training program on quadriceps and hamstrings muscle activation, knee flexion angles, and peak vertical ground reaction force. Design: Prospective, randomized clinical research trial. Setting: Sports medicine research laboratory. Patients or Other Participants: Thirty female intramural basketball players with no history of knee injury (age  =  21.07 ± 2.82 years, height  =  171.27 ± 4.66 cm, mass  =  66.36 ± 7.41 kg). Intervention(s): Participants were assigned to an agility training group or a control group that did not participate in agility training. Participants in the agility training group trained 4 times per week for 6 weeks. Main Outcome Measure(s): We used surface electromyography to assess muscle activation for the rectus femoris, vastus medialis oblique, medial hamstrings, and lateral hamstrings for 50 milliseconds before initial ground contact and while the foot was in contact with the ground during a side-step pivot maneuver. Knee flexion angles (at initial ground contact, maximum knee flexion, knee flexion displacement) and peak vertical ground reaction force also were assessed during this maneuver. Results: Participants in the training group increased medial hamstrings activation during ground contact after the 6-week agility training program. Both groups decreased their vastus medialis oblique muscle activation during ground contact. Knee flexion angles and peak vertical ground reaction force did not change for either group. Conclusions: Agility training improved medial hamstrings activity in female intramural basketball players during a side-step pivot maneuver. Agility training that improves hamstrings activity might have implications for reducing anterior cruciate ligament sprain injury associated with side-step pivots. PMID

  2. Development of a knee joint motion simulator to evaluate deep knee flexion of artificial knee joints.

    PubMed

    Takano, Y; Ueno, M; Kiguchi, K; Ito, J; Mawatari, M; Hotokebuchi, T

    2008-01-01

    A purpose of this study is to examine the effect that quadriceps femoris force gives to rotation angle and joint reaction force of total knee prosthesis during deep knee flexion such as a unique sitting style called 'seiza' in Japanese. For the evaluation, we developed the knee motion simulator which could bend to 180 degrees continually simulating the passive flexion performed by clinicians. A total knee prosthesis, which is a specially-devised posterior stabilized type and capable of flexion up to 180 degrees, was inserted into bone model. And this prosthesis pulled by three kinds of quadriceps femoris forces to perform parameter study. The results obtained in this study were showed the same tendency with those in the past cadaveric experiment. It is suggested that the rotation angle and joint reaction force of total knee prosthesis are affected by shape of prosthesis, a vector of quadriceps femoris force, and bony aliments during deep knee flexion.

  3. Accuracy of knee range of motion assessment after total knee arthroplasty.

    PubMed

    Lavernia, Carlos; D'Apuzzo, Michele; Rossi, Mark D; Lee, David

    2008-09-01

    Measurement of knee joint range of motion (ROM) is important to assess after total knee arthroplasty. Our objective was to determine level of agreement and accuracy between observers with different knowledge on total ROM after total knee arthroplasty. Forty-one patients underwent x-ray of active and passive knee ROM (gold standard). Five different raters evaluated observed and measured ROM: orthopedic surgeon, clinical fellow, physician assistant, research fellow, and a physical therapist. A 1-way analysis of variance was used to determine differences in ROM between raters over both conditions. Limit of agreement for each rater for both active and passive total ROM under both conditions was calculated. Analysis of variance indicated a difference between raters for all conditions (range, P = .004 to P < or =.0001). The trend for all raters was to overestimate ROM at higher ranges. Assessment of ROM through direct observation without a goniometer provides inaccurate findings.

  4. [Effectiveness of continuous passive motion after total knee replacement].

    PubMed

    Trzeciak, Tomasz; Richter, Magdalena; Ruszkowski, Krzysztof

    2011-01-01

    Continuous passive motion (CPM) is frequently used method in the early post-operative rehabilitation in patients after knee surgery. Aim of this study was to evaluate the effectiveness of CPM after primary total knee arthroplasty. Efficacy was assesed in terms of clinical score and functional recovery. 93 patients (101 knee joints) undergoing total knee replacement were assigned into two groups. The experimental group received continuous passive motion and active exercises. A control group received conventional physical therapy only. CPM was initiated in the first day after surgery, for 120 minutes, starting with 0-40 degrees range of motion, increased as tolerated (mean 10 degrees per day) and maintained during the hospital stay. Outcome measures were those included in Knee Society Score (KSS). Functional recovery was evaluated using WOMAC. All subjects were evaluated once before the surgery and on 10th day postoperatively. Mean clinical score (KSS) at the day 10 was 70 +/- 15 points in the experimental group and 74 +/- 12 in a control group. There were no statistical difference between the two groups for any outcome measures. CPM group mean range of motion was 83 degrees +/- 14 degrees and a group without CPM 77 degrees +/- 21 degrees. KSS functional score was 66 +/- 9 points in the experimental group compared to 62 +/- 7 points in a control group. Subjective estimation of pain level, joint stiffness and function showed no statistical difference between the two groups regarding total and subscale scores. Mean total score was 24 +/- 19 points in the CPM group and 22 +/- 17 in a group without CPM. These findings show that CPM had no significant advantage in terms of improving clinical measurements. However, there was beneficial effect on subjective assessment of pain level, joint stiffness and functional ability.

  5. Kinematic motion of the anterior cruciate ligament deficient knee during functionally high and low demanding tasks.

    PubMed

    Takeda, Kentaro; Hasegawa, Takayuki; Kiriyama, Yoshimori; Matsumoto, Hideo; Otani, Toshiro; Toyama, Yoshiaki; Nagura, Takeo

    2014-07-18

    The purpose of this study was to determine whether mechanical adaptations were present in patients with anterior cruciate ligament (ACL)-deficient knees during high-demand activities. Twenty-two subjects with unilateral ACL deficiency (11 males and 11 females, 19.6 months after injury) performed five different activities at a comfortable speed (level walking, ascending and descending steps, jogging, jogging to a 90-degree side cutting toward the opposite direction of the tested side). Three-dimensional knee kinematics for the ACL-deficient knees and uninjured contralateral knees were evaluated using the Point Cluster Technique. There was no significant difference in knee flexion angle, but an offset toward the knee in less valgus and more external tibial rotation was observed in the ACL-deficient knee. The tendency was more obvious in high demand motions, and a significant difference was clearly observed in the side cutting motions. These motion patterns, with the knee in less valgus and more external tibial rotation, are proposed to be an adaptive movement to avoid pivot shift dynamically, and reveal evidence in support of a dynamic adaptive motion occurring in ACL-deficient knees.

  6. Factors affecting postoperative range of motion after total knee arthroplasty.

    PubMed

    Gatha, Nehal M; Clarke, Henry D; Fuchs, Robin; Scuderi, Giles R; Insall, John N

    2004-10-01

    One hundred thirty five patients with osteoarthritis who underwent total knee arthroplasty (TKA) were evaluated to determine whether specific pre- and postoperative variables were correlated with the postoperative range of motion. Age, sex, pre- and postoperative range of motion, pre- and postoperative Knee Society scores, intraoperative patellar thickness before and after resurfacing, pre- and postoperative radiographic patellar height (as determined by the Insall-Salvati and Blackburn-Peel ratios), and preoperative radiographic alignment were recorded for each patient. Regression analysis was performed to identify whether any variables were correlated with the postoperative range of motion or Knee Society scores. The only variable that was significantly correlated with postoperative range of motion was the preoperative range of motion. This study suggests that among the variables evaluated, the preoperative range of motion was the only significant predictor of postoperative range of motion.

  7. [Physical activity for knee osteoarthritis.

    PubMed

    Nagao, Masashi; Ishijima, Muneaki; Kaneko, Haruka; Takazawa, Yuji; Ikeda, Hiroshi; Kaneko, Kazuo

    Elder populations have been increasing in Japan and estimated 24 million people have knee osteoarthritis(OA). Recently, people have diverse sociological background and demand for participating sports has been growing. People may participate sports to prevent some diseases such as locomotive syndrome. According to the recent studies, excessive high impact sports increase the risk of OA, while daily life exercise decrease the risk. Epidemiological approach demonstrated that reduced knee extension muscle strength increases the risk of OA. We reviewed and discussed the recent topics including efficacy of physical therapy for knee OA and how much sports activities could be beneficial after knee surgery.

  8. Improvements in knee biomechanics during walking are associated with increased physical activity after total knee arthroplasty.

    PubMed

    Arnold, John B; Mackintosh, Shylie; Olds, Timothy S; Jones, Sara; Thewlis, Dominic

    2015-12-01

    Total knee arthroplasty (TKA) in people with knee osteoarthritis increases knee-specific and general physical function, but it has not been established if there is a relationship between changes in these elements of functional ability. This study investigated changes and relationships between knee biomechanics during walking, physical activity, and use of time after TKA. Fifteen people awaiting TKA underwent 3D gait analysis before and six months after surgery. Physical activity and use of time were determined in free-living conditions from a high resolution 24-h activity recall. After surgery, participants displayed significant improvements in sagittal plane knee biomechanics and improved their physical activity profiles, standing for 105 more minutes (p=0.001) and performing 64 min more inside chores on average per day (p=0.008). Changes in sagittal plane knee range of motion (ROM) and peak knee flexion positively correlated with changes in total daily energy expenditure, time spent undertaking moderate to vigorous physical activity, inside chores and passive transport (r=0.52-0.66, p=0.005-0.047). Restoration of knee function occurs in parallel and is associated with improvements in physical activity and use of time after TKA. Increased functional knee ROM is required to support improvements in total and context specific physical activity.

  9. Knee range of motion after total knee arthroplasty: how important is this as an outcome measure?

    PubMed

    Miner, Andrew L; Lingard, Elizabeth A; Wright, Elizabeth A; Sledge, Clement B; Katz, Jeffrey N

    2003-04-01

    We investigated the relationship of knee range of motion (ROM) and function in a prospective, observational study of primary total knee arthroplasty (TKA). Preoperative and 12-month data were collected on 684 patients, including knee ROM, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function questionnaire scores, patient satisfaction, and perceived improvement in quality of life (QOL). Only modest correlations were found between knee ROM and WOMAC function (r<0.34). At 12 months we found significantly worse WOMAC function scores for patients with <95 degrees flexion compared with patients with > or =95 degrees (mean, 61.9 vs 75.0; P<.0001). In linear regression models, WOMAC pain and function scores at 12 months were both correlates of patient satisfaction and perceived improvement in QOL (standardized beta>3.5; P<.0001), but knee flexion was not. For assessment of these outcomes, WOMAC function appears to be more important than knee flexion.

  10. Measurement of knee joint motion using digital imaging.

    PubMed

    Bennett, Damien; Hanratty, Brian; Thompson, Neville; Beverland, David

    2009-12-01

    The measurement of joint motion is common practice in many aspects of orthopaedic surgery. A number of techniques and instruments have been developed for this purpose. We describe a method of recording and measuring knee joint motion using digital imaging which demonstrated high inter-observer reliability (r > 0.948) and intra-observer repeatability (r > 0.906). This technique may offer some practical advantages over other methods of measuring joint motion.

  11. Repeat Manipulation Under Anesthesia For Persistent Stiffness After Total Knee Arthroplasty Achieves Functional Range of Motion.

    PubMed

    Ferrel, Jason R; Davis, Richard L; Agha, Obiajulu A J C; Politi, Joel R

    2015-05-01

    Poor range of motion may decrease a patient's ability to participate in activities of daily living after total knee arthroplasty. Manipulation under anesthesia has been shown to improve range of motion; however, some patients have persistent stiffness even after manipulation. The goal of this study was to evaluate the outcomes and complications of patients who underwent a second manipulation under anesthesia for persistent stiffness after total knee arthroplasty. The review of surgical records of two joint arthroplasty surgeons identified 226 knees in 210 patients who underwent a manipulation under anesthesia for poor range of motion after total knee arthroplasty. Of these patients, 16 patients underwent a second manipulation under anesthesia. For patients undergoing two manipulations under anesthesia procedures, at latest follow up (mean 539 days), mean extension improved from 10.50° to 2.50° (p=0.001) and mean flexion improved from 87.50° to 112.69° (p=0.001) respectively. SF-12 scores were available for 12 of 16 knees with a mean score of 34.42. Two of 16 patients (12.5%) experienced a complication. Three of 16 (18.8%) patients who underwent a second manipulation required a revision arthroplasty procedure. In conclusion, a second manipulation under anesthesia can achieve functional range of motion that is sustained after total knee arthroplasty.

  12. Muscle strength and knee range of motion after femoral lengthening

    PubMed Central

    Bhave, Anil; Shabtai, Lior; Woelber, Erik; Apelyan, Arman; Paley, Dror; Herzenberg, John E

    2017-01-01

    Background and purpose Femoral lengthening may result in decrease in knee range of motion (ROM) and quadriceps and hamstring muscle weakness. We evaluated preoperative and postoperative knee ROM, hamstring muscle strength, and quadriceps muscle strength in a diverse group of patients undergoing femoral lengthening. We hypothesized that lengthening would not result in a significant change in knee ROM or muscle strength. Patients and methods This prospective study of 48 patients (mean age 27 (9–60) years) compared ROM and muscle strength before and after femoral lengthening. Patient age, amount of lengthening, percent lengthening, level of osteotomy, fixation time, and method of lengthening were also evaluated regarding knee ROM and strength. The average length of follow-up was 2.9 (2.0–4.7) years. Results Mean amount of lengthening was 5.2 (2.4–11.0) cm. The difference between preoperative and final knee flexion ROM was 2° for the overall group. Congenital shortening cases lost an average of 5% or 6° of terminal knee flexion, developmental cases lost an average of 3% or 4°, and posttraumatic cases regained all motion. The difference in quadriceps strength at 45° preoperatively and after lengthening was not statistically or clinically significant (2.7 Nm; p = 0.06). Age, amount of lengthening, percent lengthening, osteotomy level, fixation time, and lengthening method had no statistically significant influence on knee ROM or quadriceps strength at final follow-up. Interpretation Most variables had no effect on ROM or strength, and higher age did not appear to be a limiting factor for femoral lengthening. Patients with congenital causes were most affected in terms of knee flexion. PMID:27892743

  13. Does a standard outpatient physiotherapy regime improve the range of knee motion after primary total knee arthroplasty?

    PubMed

    Mockford, Brian James; Thompson, Neville W; Humphreys, Patricia; Beverland, David E

    2008-12-01

    The aim of this study was to investigate whether a standard course of outpatient physiotherapy improves the range of knee motion after primary total knee arthroplasty. One hundred and fifty patients were randomly assigned into one of 2 groups. One group received outpatient physiotherapy for 6 weeks (group A). Another received no outpatient physiotherapy (group B). Range of knee motion was measured preoperatively and at 1-year review. Validated knee scores and an SF-12 health questionnaire were also recorded. Although patients in group A achieved a greater range of knee motion than those in group B, this was not statistically significant. No difference either was noted in any of the outcome measures used. In conclusion, outpatient physiotherapy does not improve the range of knee motion after primary total knee arthroplasty.

  14. Posterior cruciate ligament removal contributes to abnormal knee motion during posterior stabilized total knee arthroplasty.

    PubMed

    Cromie, Melinda J; Siston, Robert A; Giori, Nicholas J; Delp, Scott L

    2008-11-01

    Abnormal anterior translation of the femur on the tibia has been observed in mid flexion (20-60 degrees ) following posterior stabilized total knee arthroplasty. The underlying biomechanical causes of this abnormal motion remain unknown. The purpose of this study was to isolate the effects of posterior cruciate ligament removal on knee motion after total knee arthroplasty. We posed two questions: Does removing the posterior cruciate ligament introduce abnormal anterior femoral translation? Does implanting a posterior stabilized prosthesis change the kinematics from the cruciate deficient case? Using a navigation system, we measured passive knee kinematics of ten male osteoarthritic patients during surgery after initial exposure, after removing the anterior cruciate ligament, after removing the posterior cruciate ligament, and after implanting the prosthesis. Passively flexing and extending the knee, we calculated anterior femoral translation and the flexion angle at which femoral rollback began. Removing the posterior cruciate ligament doubled anterior translation (from 5.1 +/- 4.3 mm to 10.4 +/- 5.1 mm) and increased the flexion angle at which femoral rollback began (from 31.2 +/- 9.6 degrees to 49.3 +/- 7.3 degrees). Implanting the prosthesis increased the amount of anterior translation (to 16.1 +/- 4.4 mm), and did not change the flexion angle at which femoral rollback began. Abnormal anterior translation was observed in low and mid flexion (0-60 degrees) after removing the posterior cruciate ligament, and normal motion was not restored by the posterior stabilized prosthesis.

  15. [Recovery from total knee arthroplasty through continuous passive motion].

    PubMed

    Sánchez Mayo, B; Rodríguez-Mansilla, J; González Sánchez, B

    2015-01-01

    The purpose of this study was to know the effects of continuous passive mobilization in patients who underwent total knee arthroplasty. A search strategy was developed to retrieve all clinical trials, written in English and/or Spanish, published in the electronic search databases PubMed, Cochrane Library Plus, Dialnet, CSIC and PEDro. The inclusion criteria were: clinical trials published from January 2000 until November 2014 in English or Spanish. Out of 537 clinical trials that were potentially relevant, a total of 12 were included in this review. The evaluation of 1,153 patients shows that there is no significant difference in improving the range of the joint, pain, balance, motion, healing and hospital stay using continuous passive mobilization against the regular physiotherapy treatment for total knee arthroplasty. The application of continuous passive mobilization in the long-term does not provide any benefit in terms of the breadth of the range of the joint, pain and improvement of standing and motion in comparison with conventional postoperative physiotherapy treatment in total knee arthroplasty. In the short term an improvement is obtained in the range of joint motion in knee flexion.

  16. The influence of pain on knee motion in patients with osteoarthritis undergoing total knee arthroplasty.

    PubMed

    Bennett, Damien; Hanratty, Brian; Thompson, Neville; Beverland, David E

    2009-04-01

    Pain is the predominant symptom of degenerative knee arthritis and the main reason patients undergo total knee arthroplasty (TKA). Variation in patient response to pain has proved difficult to quantify. The effect of removing pain by testing TKA patients' range of motion (ROM) before and after the administration of anesthesia has not previously been analyzed. This study objectively quantifies the effect of eliminating pain on knee joint ROM for a typical group of TKA patients with osteoarthritis. We prospectively recruited 141 patients with osteoarthritis admitted for TKA to assess the inhibitory effect of pain on ROM. Passive maximum flexion, extension, and ROM were measured preoperatively before and after administration of anesthesia (spinal anesthetic followed by femoral and sciatic regional nerve blocks). Following pain abolition, passive maximum flexion increased by an average of 13.4 degrees (SD=11.9 degrees), passive maximum extension improved by an average of 3.0 degrees (SD=4.2 degrees), and passive ROM increased by an average of 16.4 degrees (SD=13.1 degrees). The change in each parameter was statistically significant (P<.0001). Improvements in flexion (P=.01) and ROM (P=.005) were significantly greater in women. Measurements taken before anesthesia reflect knee ROM that the patient will tolerate before pain becomes the limiting factor, while measurements taken after anesthesia is achieved suggest the knee ROM possible once pain is eliminated. Abolition of pain led to significant increases in knee flexion, extension, and ROM, suggesting that pain has a significant inhibitory effect on knee motion.

  17. Predicting Functional Performance and Range of Motion Outcomes After Total Knee Arthroplasty

    PubMed Central

    Bade, Michael J.; Kittelson, John M.; Kohrt, Wendy M.; Stevens-Lapsley, Jennifer E.

    2015-01-01

    Objective The aim of this study was to assess the predictive value of functional performance and range of motion measures on outcomes after total knee arthroplasty. Design This is a secondary analysis of two pooled prospective randomized controlled trials. Sixty-four subjects (32 men and 32 women) with end-stage knee osteoarthritis scheduled to undergo primary total knee arthroplasty were enrolled. Active knee flexion and extension range of motion, Timed Up and Go (TUG) test time, and 6-min walk test distance were assessed. Results Preoperative measures of knee flexion and extension were predictive of long-term flexion (β = 0.44, P < 0.001) and extension (β = 0.46, P < 0.001). Acute measures of knee flexion and extension were not predictive of long-term flexion (β= 0.09, P = 0.26) or extension (β = 0.04, P = 0.76). Preoperative TUG performance was predictive of long-term 6-min walk performance (β = −21, P < 0.001). Acute TUG performance was predictive of long-term functional performance on the 6-min walk test, after adjusting for the effects of sex and age (P = 0.02); however, once adjusted for preoperative TUG performance, acute TUG was no longer related to long-term 6-min walk performance (P = 0.65). Conclusions Acute postoperative measures of knee range of motion are of limited prognostic value, although preoperative measures have some prognostic value. However, acute measures of functional performance are of useful prognostic value, especially when preoperative functional performance data are unavailable. PMID:24508937

  18. Knee Extension Range of Motion at 4 Weeks Is Related to Knee Extension Loss at 12 Weeks After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Noll, Sarah; Garrison, J. Craig; Bothwell, James; Conway, John E.

    2015-01-01

    Background: The anterior cruciate ligament (ACL) is commonly torn, and surgical reconstruction is often required to allow a patient to return to their prior level of activity. Avoiding range of motion (ROM) loss is a common goal, but little research has been done to identify when ROM loss becomes detrimental to a patient’s future function. Purpose: To determine whether there is a relationship between early knee side-to-side extension difference after ACL reconstruction and knee side-to-side extension difference at 12 weeks. The hypothesis was that early (within the first 8 weeks) knee side-to-side extension difference will be predictive of knee side-to-side extension difference seen at 12 weeks. Study Design: Cohort study; Level of evidence, 3. Methods: Knee side-to-side extension difference measures were taken on 74 patients undergoing ACL reconstruction rehabilitation at the initial visit and 4, 8, and 12 weeks postoperatively. Visual analog scores (VAS) and International Knee Documentation Committee (IKDC) scores were also recorded at these time frames. Results: There was a strong relationship between knee extension ROM at 4 and 12 weeks (r = 0.639, P < .001) and 8 and 12 weeks (r = 0.742, P < .001). When the variables of knee extension ROM at initial visit and 4 and 8 weeks were entered into a regression analysis, the predictor variable explained 61% (R2 = 0.611) of variance for knee extension ROM at 12 weeks, with 4 weeks (R2 = 0.259) explaining the majority of this variance. Conclusion: This study found that a patient’s knee extension at 4 weeks was strongly correlated with knee extension at 12 weeks. Clinical Relevance: This information may be useful for clinicians treating athletic patients who are anxious for return to sport by providing them an initial goal to work toward in hopes of ensuring successful rehabilitation of their knee. PMID:26675061

  19. Dynamic activity dependence of in vivo normal knee kinematics.

    PubMed

    Moro-oka, Taka-aki; Hamai, Satoshi; Miura, Hiromasa; Shimoto, Takeshi; Higaki, Hidehiko; Fregly, Benjamin J; Iwamoto, Yukihide; Banks, Scott A

    2008-04-01

    Dynamic knee kinematics were analyzed for normal knees in three activities, including two different types of maximum knee flexion. Continuous X-ray images of kneel, squat, and stair climb motions were taken using a large flat panel detector. CT-derived bone models were used for model registration-based 3D kinematic measurement. Three-dimensional joint kinematics and contact locations were determined using three methods: bone-fixed coordinate systems, interrogation of CT-based bone model surfaces, and interrogation of MR-based articular cartilage model surfaces. The femur exhibited gradual external rotation throughout the flexion range. Tibiofemoral contact exhibited external rotation, with contact locations translating posterior while maintaining 15 degrees to 20 degrees external rotation from 20 degrees to 80 degrees of flexion. From 80 degrees to maximum flexion, contact locations showed a medial pivot pattern. Kinematics based on bone-fixed coordinate systems differed from kinematics based on interrogation of CT and MR surfaces. Knee kinematics varied significantly by activity, especially in deep flexion. No posterior subluxation occurred for either femoral condyle in maximum knee flexion. Normal knees accommodate a range of motions during various activities while maintaining geometric joint congruency.

  20. Data Collection and Analysis Using Wearable Sensors for Monitoring Knee Range of Motion after Total Knee Arthroplasty

    PubMed Central

    Chiang, Chih-Yen; Chen, Kun-Hui; Liu, Kai-Chun; Hsu, Steen Jun-Ping; Chan, Chia-Tai

    2017-01-01

    Total knee arthroplasty (TKA) is the most common treatment for degenerative osteoarthritis of that articulation. However, either in rehabilitation clinics or in hospital wards, the knee range of motion (ROM) can currently only be assessed using a goniometer. In order to provide continuous and objective measurements of knee ROM, we propose the use of wearable inertial sensors to record the knee ROM during the recovery progress. Digitalized and objective data can assist the surgeons to control the recovery status and flexibly adjust rehabilitation programs during the early acute inpatient stage. The more knee flexion ROM regained during the early inpatient period, the better the long-term knee recovery will be and the sooner early discharge can be achieved. The results of this work show that the proposed wearable sensor approach can provide an alternative for continuous monitoring and objective assessment of knee ROM recovery progress for TKA patients compared to the traditional goniometer measurements. PMID:28241434

  1. Relationship of spasticity to knee angular velocity and motion during gait in cerebral palsy.

    PubMed

    Damiano, Diane L; Laws, Edward; Carmines, Dave V; Abel, Mark F

    2006-01-01

    This study investigated the effects of spasticity in the hamstrings and quadriceps muscles on gait parameters including temporal spatial measures, knee position, excursion and angular velocity in 25 children with spastic diplegic cerebral palsy (CP) as compared to 17 age-matched peers. While subjects were instructed to relax, an isokinetic device alternately flexed and extended the left knee at one of the three constant velocities 30 degrees/s, 60 degrees/s and 120 degrees/s, while surface electromyography (EMG) electrodes over the biceps femoris and the rectus femoris recorded muscle activity. Patients then participated in 3D gait analysis at a self-selected speed. Results showed that, those with CP who exhibited heightened stretch responses (spasticity) in both muscles, had significantly slower knee angular velocities during the swing phase of gait as compared to those with and without CP who did not exhibit stretch responses at the joint and the tested speeds. The measured amount (torque) of the resistance to passive flexion or extension was not related to gait parameters in subjects with CP; however, the rate of change in resistance torque per unit angle change (stiffness) at the fastest test speed of 120 degrees/s showed weak to moderate relationships with knee angular velocity and motion during gait. For the subset of seven patients with CP who subsequently underwent a selective dorsal rhizotomy, knee angular extension and flexion velocity increased post-operatively, suggesting some degree of causality between spasticity and movement speed.

  2. Knee surgery assistance: patient model construction, motion simulation, and biomechanical visualization.

    PubMed

    Chen, J X; Wechsler, H; Pullen, J M; Zhu, Y; MacMahon, E B

    2001-09-01

    We present a new system that integrates computer graphics, physics-based modeling, and interactive visualization to assist knee study and surgical operation. First, we discuss generating patient-specific three-dimensional (3-D) knee models from patient's magnetic resonant images (MRIs). The 3-D model is obtained by deforming a reference model to match the MRI dataset. Second, we present simulating knee motion that visualizes patient-specific motion data on the patient-specific knee model. Third, we introduce visualizing biomechanical information on a patient-specific model. The focus is on visualizing contact area, contact forces, and menisci deformation. Traditional methods have difficulty in visualizing knee contact area without using invasive methods. The approach presented here provides an alternative of visualizing the knee contact area and forces without any risk to the patient. Finally, a virtual surgery can be performed. The constructed 3-D knee model is the basis of motion simulation, biomechanical visualization, and virtual surgery. Knee motion simulation determines the knee rotation angles as well as knee contact points. These parameters are used to solve the biomechanical model. Our results integrate 3-D construction, motion simulation, and biomechanical visualization into one system. Overall, the methodologies here are useful elements for future virtual medical systems where all the components of visualization, automated model generation, and surgery simulation come together.

  3. Loss of neuromuscular control related to motion in the acutely ACL-injured knee: an experimental study.

    PubMed

    Bonsfills, N; Gómez-Barrena, E; Raygoza, J J; Núñez, A

    2008-10-01

    Ligamentomuscular and muscular stretch reflexes are known to contribute to knee joint stability. After anterior cruciate ligament (ACL) injury, a more intense and adjusted muscular response is required to maintain joint stability, but this neuromuscular control of the knee has not been clearly proved. The aim of the study is to record electromyography (EMG) signal and muscular fibre length variations in quadriceps and hamstrings of the knee with and without ACL, and to analyze and integrate the ligament strain and the muscular reaction to forced anterior tibial translation (ATT). In 17 knees from 12 cats, EMG electrodes and ultrasonomicrometry crystals were inserted into four main periarticular muscles, with strain gauges on periarticular ligament insertions. Their output signal was compared before and after ACL surgical section in series of ATT (at 90 degrees and 30 degrees knee flexion), and also during knee flexion and extension. Linear regression analysis was performed between the EMG signal and muscular fibre length variations, and between the EMG signal and the strain on ligament insertions, in the search of this reflex neuromuscular response. In the ACL deficient knees, the studied muscles showed a poor adjustment to motion of EMG firing, inversely to controls. The muscle stretch reflexes showed poorer correlation with post-peak EMG activity than the ligaments. ATT control depended mainly on hamstrings activity in control knees, whereas in unstable knees, quadriceps activity was associated with more tibial translation. Acute ACL-deficient knees showed poor neuromuscular control with weak ligamentomuscular reflexes and no muscular stretch reflexes, suggesting the ineffectiveness of acute muscular reaction to provide early mechanical knee stabilization after injury.

  4. Is latero-medial patellar mobility related to the range of motion of the knee joint after total knee arthroplasty?

    PubMed

    Ota, Susumu; Nakashima, Takeshi; Morisaka, Ayako; Omachi, Takaaki; Ida, Kunio; Kawamura, Morio

    2010-12-01

    Diminished range of motion (ROM) of the knee joint after total knee arthroplasty (TKA) is thought to be related to reduced patellar mobility. This has not been confirmed clinically due to a lack of quantitative methods adequate for measuring patellar mobility. We investigated the relationship between patellar mobility by a reported quantitative method and knee joint ROM after TKA. Forty-nine patients [osteoarthritis--OA: 29 knees; rheumatoid arthritis--RA: 20 knees] were examined after TKA. Respective medial and lateral patellar mobility was measured 1 and 6 months postoperatively using a patellofemoral arthrometer (PFA). Knee joint ROM was also measured in each of those 2 sessions. Although the flexion and extension of the knee joints improved significantly from 1 to 6 months after TKA, the medial and lateral patellar displacements (LPDs) failed to improve during that same period. Moreover, only the changes in knee flexion and medial patellar displacement (MPD) between the two sessions were positively correlated (r = 0.31, p < 0.05). However, our findings demonstrated that medial and lateral patellar mobility had no sufficient longitudinal relationship with knee ROM after TKA.

  5. Knee kinematics in medial osteoarthritis during in vivo weight-bearing activities.

    PubMed

    Hamai, Satoshi; Moro-oka, Taka-Aki; Miura, Hiromasa; Shimoto, Takeshi; Higaki, Hidehiko; Fregly, Benjamin J; Iwamoto, Yukihide; Banks, Scott A

    2009-12-01

    Dynamic knee kinematics were analyzed for medial osteoarthritic (OA) knees in three activities, including two types of maximum knee flexion. Continuous x-ray images of kneeling, squatting, and stair climbing motions were taken using a large flat panel detector. CT-derived bone models were used for the model registration-based 3D kinematic measurements. Three-dimensional joint kinematics and contact locations were determined using two methods: bone-fixed coordinate systems and by interrogation of CT-based bone model surfaces. The femur exhibited gradual external rotation with knee flexion for kneeling and squatting activities, and gradual internal rotation with knee extension for stair climbing. From 100 degrees to 120 degrees flexion, contact locations showed a medial pivot pattern similar to normal knees. However, knees with medial OA displayed a femoral internal rotation bias and less posterior translation when compared with normal knees. A classic screw-home movement was not observed in OA knees near extension. Decreased variability with both activities and methods of calculation were demonstrated for all three activities. In conclusion, the weight-bearing kinematics of patients with medial OA differs from normal knees. Pathological changes of the articulating surfaces and the ligaments correspond to observed abnormalities in knee kinematics.

  6. Behavioral effect of knee joint motion on body's center of mass during human quiet standing.

    PubMed

    Yamamoto, Akio; Sasagawa, Shun; Oba, Naoko; Nakazawa, Kimitaka

    2015-01-01

    The balance control mechanism during upright standing has often been investigated using single- or double-link inverted pendulum models, involving the ankle joint only or both the ankle and hip joints, respectively. Several studies, however, have reported that knee joint motion during quiet standing cannot be ignored. This study aimed to investigate the degree to which knee joint motion contributes to the center of mass (COM) kinematics during quiet standing. Eight healthy adults were asked to stand quietly for 30s on a force platform. Angular displacements and accelerations of the ankle, knee, and hip joints were calculated from kinematic data obtained by a motion capture system. We found that the amplitude of the angular acceleration was smallest in the ankle joint and largest in the hip joint (ankle < knee < hip). These angular accelerations were then substituted into three biomechanical models with or without the knee joint to estimate COM acceleration in the anterior-posterior direction. Although the "without-knee" models greatly overestimated the COM acceleration, the COM acceleration estimated by the "with-knee" model was similar to the actual acceleration obtained from force platform measurement. These results indicate substantial effects of knee joint motion on the COM kinematics during quiet standing. We suggest that investigations based on the multi-joint model, including the knee joint, are required to reveal the physiologically plausible balance control mechanism implemented by the central nervous system.

  7. Passive knee kinematics before and after total knee arthroplasty: are we correcting pathologic motion?

    PubMed

    Mihalko, William M; Ali, Mounawar; Phillips, Matthew J; Bayers-Thering, Mary; Krackow, Kenneth A

    2008-01-01

    The change in coronal plane deformity throughout a range of flexion before and after total knee arthroplasty (TKA) has not been reported. Unlike most alignment assessments traditionally reporting coronal plane alignment in a standing position under static conditions, this study reports deformity throughout the flexion arc before and after deformity correction. One hundred fifty-two TKA patients using the anteroposterior axis for femoral component rotation and computer navigation techniques were included in the study. Deformity before TKA ranged from 17.5 degrees varus (deformity apex away from the midline) to 20.5 degrees valgus (deformity apex toward the midline) in full extension. Before TKA, deformity was not constant through an arc of motion and significantly decreased with flexion of 60 degrees and more (P < .01). The deformity after performing a TKA was not different (P = .478) throughout the flexion arc. The data determined that deformity is not constant throughout flexion in osteoarthritic knees preoperatively and that deformity throughout flexion can be corrected with the use of conventional alignment techniques during TKA.

  8. Reliability, Concurrent Validity, and Minimal Detectable Change for iPhone Goniometer App in Assessing Knee Range of Motion.

    PubMed

    Mehta, Saurabh P; Barker, Katherine; Bowman, Brett; Galloway, Heather; Oliashirazi, Nicole; Oliashirazi, Ali

    2016-11-28

    Much of the published works assessing the reliability of smartphone goniometer apps (SG) have poor generalizability since the reliability was assessed in healthy subjects. No research has established the values for standard error of measurement (SEM) or minimal detectable change (MDC) which have greater clinical utility to contextualize the range of motion (ROM) assessed using the SG. This research examined the test-retest reproducibility, concurrent validity, SEM, and MDC values for the iPhone goniometer app (i-Goni; June Software Inc., v.1.1, San Francisco, CA) in assessing knee ROM in patients with knee osteoarthritis or those after total knee replacement. A total of 60 participants underwent data collection which included the assessment of active knee ROM using the i-Goni and the universal goniometer (UG; EZ Read Jamar Goniometer, Patterson Medical, Warrenville, IL), knee muscle strength, and assessment of pain and lower extremity disability using quadruple numeric pain rating scale (Q-NPRS) and lower extremity functional scale (LEFS), respectively. Intraclass correlation coefficients (ICCs) were calculated to assess the reproducibility of the knee ROM assessed using the i-Goni and UG. Bland and Altman technique examined the agreement between these knee ROM. The SEM and MDC values were calculated for i-Goni assessed knee ROM to characterize the error in a single score and the index of true change, respectively. Pearson correlation coefficient examined concurrent relationships between the i-Goni and other measures. The ICC values for the knee flexion/extension ROM were superior for i-Goni (0.97/0.94) compared with the UG (0.95/0.87). The SEM values were smaller for i-Goni assessed knee flexion/extension (2.72/1.18 degrees) compared with UG assessed knee flexion/extension (3.41/1.62 degrees). Similarly, the MDC values were smaller for both these ROM for the i-Goni (6.3 and 2.72 degrees) suggesting smaller change required to infer true change in knee ROM. The i

  9. Dynamic Frequency Analyses of Lower Extremity Muscles during Sit-To-Stand Motion for the Patients with Knee Osteoarthritis

    PubMed Central

    Suzuki, Kentaro; Yagi, Masahide

    2016-01-01

    Objective Muscle activities during the sit-to-stand motion (STS) are characterized by coordinated movements between hip extensors and knee extensors. However, previous reports regarding the STS and lower extremity muscle activities have focused on some quantitative assessment, but little qualitative research. This study aimed to examine the muscle activities of the lower extremity both quantitatively and qualitatively. Methods Study participants included 13 patients with knee osteoarthritis (knee OA) and 11 age-matched asymptomatic controls. The task was STS from a chair with a height-adjustable seat. EMG activities were acquired using surface electromyogram. The root mean square signals normalized as a percentage of maximum voluntary isometric contraction values (RMS%MVC) and the mean power frequency (MPF) were calculated. Results During STS, knee OA patients had increased RMS%MVC of the vastus medialis and raised MPF of the rectus femoris before buttocks-off. Conclusion These findings suggest that STS of knee OA patients not only increased relative muscle activity of the vastus medialis, but also enlisted the rectus femoris in knee extension to improve muscle contraction force by activating more type II fibers to accomplish buttocks-off. PMID:26807578

  10. Quantifying the Consistency of Wearable Knee Acoustical Emission Measurements During Complex Motions.

    PubMed

    Toreyin, Hakan; Jeong, Hyeon Ki; Hersek, Sinan; Teague, Caitlin N; Inan, Omer T

    2016-09-01

    Knee-joint sounds could potentially be used to noninvasively probe the physical and/or physiological changes in the knee associated with rehabilitation following acute injury. In this paper, a system and methods for investigating the consistency of knee-joint sounds during complex motions in silent and loud background settings are presented. The wearable hardware component of the system consists of a microelectromechanical systems microphone and inertial rate sensors interfaced with a field programmable gate array-based real-time processor to capture knee-joint sound and angle information during three types of motion: flexion-extension (FE), sit-to-stand (SS), and walking (W) tasks. The data were post-processed to extract high-frequency and short-duration joint sounds (clicks) with particular waveform signatures. Such clicks were extracted in the presence of three different sources of interference: background, stepping, and rubbing noise. A histogram-vector Vn(→) was generated from the clicks in a motion-cycle n, where the bin range was 10°. The Euclidean distance between a vector and the arithmetic mean Vav(→) of all vectors in a recording normalized by the Vav(→) is used as a consistency metric dn. Measurements from eight healthy subjects performing FE, SS, and W show that the mean (of mean) consistency metric for all subjects during SS (μ [ μ (dn)] = 0.72 in silent, 0.85 in loud) is smaller compared with the FE (μ [ μ (dn)] = 1.02 in silent, 0.95 in loud) and W ( μ [ μ (dn)] = 0.94 in silent, 0.97 in loud) exercises, thereby implying more consistent click-generation during SS compared with the FE and W. Knee-joint sounds from one subject performing FE during five consecutive work-days (μ [ μ (dn) = 0.72) and five different times of a day (μ [ μ (dn) = 0.73) suggests high consistency of the clicks on different days and throughout a day. This work represents the first time, to the best of our knowledge, that joint sound consistency has been

  11. Patient Self-Assessed Passive Range of Motion of the Knee Cannot Replace Health Professional Measurements.

    PubMed

    Borgbjerg, Jens; Madsen, Frank; Odgaard, Anders

    2017-03-01

    The purpose of this study was to investigate whether patients can accurately self-assess their knee passive range of motion (PROM). A picture-based questionnaire for patient self-assessment of knee PROM was developed and posted to patients. The self-assessed PROM from 58 patients was compared with surgeon-assessed PROM using a short-arm goniometer. Agreement between the measurement methods was calculated with the Bland-Altman method. We calculated the sensitivity and specificity of patient-assessed PROM in dichotomously detecting knee motion impairment in both flexion (≤ 100 degrees) and extension (≥ 10-degree flexion contracture). Surgeon- and patient-assessed knee PROM showed a mean difference (95% limits of agreement) of -2.1 degrees (-42.5 to 38.3 degrees) for flexion and -8.1 degrees (-28.8 to 12.7 degrees) for extension. The sensitivity of patient self-assessed PROM in identifying knee flexion and extension impairments was 86 and 100%, respectively, whereas its specificity was 84 and 43%, respectively. Although wide limits of agreement were observed between surgeon- and patient-assessed knee PROM, the picture-based questionnaire for patient assessment of knee ROM was found to be a valid tool for dichotomously detecting knee motion impairment in flexion (≤ 100 degrees). However, the specificity of the questionnaire for detection of knee extension impairments (≥ 10-degree flexion contracture) was low, which limits is practical utility for this purpose.

  12. Auricular Acupressure for Managing Postoperative Pain and Knee Motion in Patients with Total Knee Replacement: A Randomized Sham Control Study

    PubMed Central

    Chang, Ling-hua; Hsu, Chung-Hua; Jong, Gwo-Ping; Ho, Shungtai; Tsay, Shiow-luan; Lin, Kuan-Chia

    2012-01-01

    Background. Postoperative pain management remains a significant challenge for all healthcare providers. A randomized controlled trial was conducted to examine the adjuvant effects of auricular acupressure on relieving postoperative pain and improving the passive range of motion in patients with total knee replacement (TKR). Method. Sixty-two patients who had undergone a TKR were randomly assigned to the acupressure group and the sham control group. The intervention was delivered three times a day for 3 days. A visual analog scale (VAS) and the Short-Form McGill Pain Questionnaire were used to assess pain intensity. Pain medication consumption was recorded, and the knee motion was measured using a goniometer. Results. The patients experienced a moderately severe level of pain postoperatively (VAS 58.66 ± 20.35) while being on the routine PCA. No differences were found in pain scores between the groups at all points. However, analgesic drug usage in the acupressure group patients was significantly lower than in the sham control group (P < 0.05), controlling for BMI, age, and pain score. On the 3rd day after surgery, the passive knee motion in the acupressure group patients was significantly better than in the sham control group patients (P < 0.05), controlling for BMI. Conclusion. The application of auricular acupressure at specific therapeutic points significantly reduces the opioid analgesia requirement and improves the knee motion in patients with TKR. PMID:22844334

  13. Continuous passive motion following total knee replacement: a prospective randomized trial with follow-up to 1 year.

    PubMed

    Leach, W; Reid, J; Murphy, F

    2006-10-01

    We have carried out a prospective randomised, single blind clinical trial to investigate the effect of continuous passive motion on range of knee flexion, lack of extension, pain levels and analgesic use after total knee replacement surgery. 85 subjects were randomly allocated to control or study group. All subjects followed the existing rehabilitation protocol, which permits immediate active range of motion exercises and mobilisation with the study group using continuous passive motion for 1 h, twice a day. Outcome measures employed were range of motion, pain assessed on a visual analogue scale and analgesic use according to the WHO ladder. Blinded evaluation was carried out preoperatively, at time of discharge from hospital, 6 weeks, 6 and 12 months postoperation. No significant difference was observed between groups at all time intervals for each outcome variable using Wilcoxon Rank sum tests. The results substantiate previous findings that short duration continuous passive motion following total knee arthroplasty does not influence outcome of range of motion or reported pain.

  14. Pathological Knee Joint Motion Analysis By High Speed Cinephotography

    NASA Astrophysics Data System (ADS)

    Baumann, Jurg U.

    1985-02-01

    The use of cinephotography for evaluation of disturbed knee joint function was compared in three groups of patients. While a sampling rate of 50 images per second was adequate for patients with neuromuscular disorders, a higher frequency of around 300 i.p.s. is necessary in osteoarthritis and ligamentous knee joint injuries, but the task of digitizing is prohibitive unless automated.

  15. The effects of kinesiology taping therapy on degenerative knee arthritis patients’ pain, function, and joint range of motion

    PubMed Central

    Lee, Kwansub; Yi, Chae-Woo; Lee, Sangyong

    2016-01-01

    [Purpose] The purpose of the present study was to examine the effects of kinesiology taping therapy on degenerative knee arthritis patients’ pain, function, and joint range of motion. [Subjects] To conduct the experiment in the present study, 30 patients with degenerative knee arthritis were divided into a control group (the conservative treatment group) of 15 patients, who received conservative physical therapy, and an experimental group (the kinesiology taping group) of 15 patients, who received kinesiology taping therapy. [Methods] All patients received treatment three times per week for four weeks. The kinesiology taping group had elastic tapes applied to the hamstring muscles, anterior tibialis, quadriceps femoris, and gastrocnemius. The range of motion was measured using joint goniometers, pain was measured using visual analog scales, and functional evaluation was conducted using the Korean Western Ontario and McMaster Universities Osteoarthritis Index. [Results] In intragroup comparisons of the kinesiology taping group and the conservative treatment group, the visual analog scale and Korean Western Ontario and McMaster Universities Osteoarthritis Index scores significantly decreased, and the range of motion increased more than significantly. In intergroup comparisons, the kinesiology taping group showed significantly lower visual analog scale and Korean Western Ontario and McMaster Universities Osteoarthritis Index scores and significantly larger ranges of motion than the conservative treatment group. [Conclusion] Kinesiology taping therapy is considered to be an effective nonsurgical intervention method for pain relief, daily living activities, and range of motion of degenerative knee arthritis patients. PMID:26957729

  16. Cruciate Retaining Implant With Biomimetic Articular Surface to Reproduce Activity Dependent Kinematics of the Normal Knee.

    PubMed

    Varadarajan, Kartik Mangudi M; Zumbrunn, Thomas; Rubash, Harry E; Malchau, Henrik; Li, Guoan; Muratoglu, Orhun K

    2015-12-01

    Alterations in normal knee kinematics following total knee arthroplasty (TKA) arise in part from the non-anatomic articular geometry of contemporary implants. In this study, the kinematics of a novel posterior cruciate-retaining (CR) implant with anatomic (biomimetic) articular surface, were compared to that of contemporary CR implants during various simulated activities. Across different simulated activities the biomimetic-CR mimicked normal kinematic patterns more closely than contemporary CR implants. In particular, during deep knee bend and chair-sit, the biomimetic-CR showed medial pivot motion, while other CR implants showed abnormal motion including lateral pivot or no pivot, and paradoxical anterior sliding. Further in vivo and clinical studies are needed to determine whether such biomimetic implants can truly help to achieve a more normal feeling knee and improved patient satisfaction.

  17. In-vivo three-dimensional knee kinematics during daily activities in dogs.

    PubMed

    Kim, Stanley E; Jones, Stephen C; Lewis, Daniel D; Banks, Scott A; Conrad, Bryan P; Tremolada, Giovanni; Abbasi, Abdullah Z; Coggeshall, Jason D; Pozzi, Antonio

    2015-11-01

    The canine knee is morphologically similar to the human knee and thus dogs have been used in experimental models to study human knee pathology. To date, there is limited data of normal canine 3D knee kinematics during daily activities. The objective of this study was to characterize 3D in-vivo femorotibial kinematics in normal dogs during commonly performed daily activities. Using single-plane fluoroscopy, six normal dogs were imaged performing walk, trot, sit, and stair ascent activities. CT-generated bone models were used for kinematic measurement using a 3D-to-2D model registration technique. Increasing knee flexion angle was typically associated with increasing tibial internal rotation, abduction and anterior translation during all four activities. The precise relationship between flexion angle and these movements varied both within and between activities. Significant differences in axial rotation and coronal angulation were found at the same flexion angle during different phases of the walk and trot. This was also found with anterior tibial translation during the trot only. Normal canine knees accommodate motion in all planes; precise kinematics within this envelope of motion are activity dependent. This data establishes the characteristics of normal 3D femorotibial joint kinematics in dogs that can be used as a comparison for future studies.

  18. Range of Motion of the Ankle According to Pushing Force, Gender and Knee Position

    PubMed Central

    Cho, Kang Hee; Lee, Hyunkeun

    2016-01-01

    Objective To investigate the difference of range of motion (ROM) of ankle according to pushing force, gender and knee position. Methods One hundred and twenty-eight healthy adults (55 men, 73 women) between the ages of 20 and 51, were included in the study. One examiner measured the passive range of motion (PROM) of ankle by Dualer IQ Inclinometers and Commander Muscle Testing. ROM of ankle dorsiflexion (DF) and plantarflexion (PF) according to change of pushing force and knee position were measured at prone position. Results There was significant correlation between ROM and pushing force, the more pushing force leads the more ROM at ankle DF and ankle PF. Knee flexion of 90° position showed low PF angle and high ankle DF angle, as compared to the at neutral position of knee joint. ROM of ankle DF for female was greater than for male, with no significant difference. ROM of ankle PF for female was greater than male regardless of the pushing force. Conclusion To our knowledge, this is the first study to assess the relationship between pushing force and ROM of ankle joint. There was significant correlation between ROM of ankle and pushing force. ROM of ankle PF for female estimated greater than male regardless of the pushing force and the number of measurement. The ROM of the ankle is measured differently according to the knee joint position. Pushing force, gender and knee joint position are required to be considered when measuring the ROM of ankle joint. PMID:27152277

  19. Remobilization does not restore immobilization-induced adhesion of capsule and restricted joint motion in rat knee joints.

    PubMed

    Ando, Akira; Suda, Hideaki; Hagiwara, Yoshihiro; Onoda, Yoshito; Chimoto, Eiichi; Itoi, Eiji

    2012-01-01

    Joint immobilization, which is used in orthopaedic treatments and observed in bedridden people, usually causes restricted joint motion. Decreased joint motion diminishes activities of daily living and increases burden of nursing-care. The purpose of this study was to clarify the reversibility of immobilization-induced capsular changes and restricted joint motion in rat knee joints. The unilateral knee joints of adult male rats were immobilized with an internal fixator for 1, 2, 4, 8, and 16 weeks as a model of immobilization after surgery or disuse of the joint. After the fixation devices were removed, the rats were allowed to move freely for 16 weeks. Sham-operated rats were used as controls. Sagittal sections at medial midcondylar regions were made and assessed with histological, histomorphometric, and immunohistochemical methods. Joint motion was measured using a custom-made device under x-ray control after removal of the periarticular muscles. In the 1/16-week and 2/16-week immobilization-remobilization (Im-Rm) groups, cord-like structures connecting the superior and inferior portions of the posterior capsule (partial adhesion) were observed without restricted joint motion. In the 4/16-, 8/16-, and 16/16-week Im-Rm groups, global adhesion of the posterior capsule and restricted joint motion were observed. The restricted joint motion was not completely restored after incision of the posterior capsule. These data indicate that immobilization alone causes irreversible capsular changes and arthrogenic restricted joint motion. Besides the joint capsule, other arthrogenic factors such as ligaments might influence the restricted joint motion. Prolonged immobilization over 4 weeks should be avoided to prevent irreversible joint contracture.

  20. Knee rotationplasty: motion of the body centre of mass during walking

    PubMed Central

    Rota, Viviana; Okita, Yusuke; Manfrini, Marco; Tesio, Luigi

    2016-01-01

    Knee rotationplasty (KRP) is a type of surgery in which the rotated ankle serves as a new knee after being removed for bone tumor. Although this limb salvage surgery is rarely indicated in properly selected patients, it may offer functional advantages over transfemoral amputation, and more durable results compared with a prosthesis. The walking mechanics of adult patients after KRP is believed to be close to that of below-knee amputees. In this study, we evaluated steady-state walking of KRP patients from the viewpoint of the overall muscle power needed to keep the body centre of mass in motion. Three adult patients after KRP, all athletes, were evaluated. Ground reactions during walking were recorded during six subsequent strides on a force treadmill. The positive mechanical work and power sustaining the motion of the centre of mass and the recovery of muscle energy due to the pendulum-like mechanism of walking were computed and compared with those obtained in previous studies from above-knee, below-knee amputees and healthy individuals. In KRP patients, walking was sustained by a muscle power output which was 1.4–3.6 times lower during the step performed on the rotated limb than on the subsequent step. The recovery of muscle energy was slightly lower (0.9) or higher (1.3–1.4 times) on the affected side. In two out of the three KRP patients, our findings were more similar to those from above-knee amputees than to those from below-knee amputees. After KRP, the rotated limb does not necessarily provide the same power provided by below-knee amputation. This may have a relevance for the paralympic classification of KRP athletes. PMID:27685013

  1. Knee Joint Contact Mechanics during Downhill Gait and its Relationship with Varus/Valgus Motion and Muscle Strength in Patients with Knee Osteoarthritis

    PubMed Central

    Farrokhi, Shawn; Voycheck, Carrie A.; Gustafson, Jonathan A.; Fitzgerald, G. Kelley; Tashman, Scott

    2015-01-01

    Objective The objective of this exploratory study was to evaluate tibiofemoral joint contact point excursions and velocities during downhill gait and assess the relationship between tibiofemoral joint contact mechanics with frontal-plane knee joint motion and lower extremity muscle weakness in patients with knee osteoarthritis (OA). Methods Dynamic stereo X-ray was used to quantify tibiofemoral joint contact mechanics and frontal-plane motion during the loading response phase of downhill gait in 11 patients with knee OA and 11 control volunteers. Quantitative testing of the quadriceps and the hip abductor muscles was also performed. Group differences in contact mechanics and frontal-plane motion excursions were compared using analysis of covariance with adjustments for body mass index. Differences in strength were compared using independent sample t-tests. Additionally, linear associations between contact mechanics with frontal-plane knee motion and muscle strength were evaluated using Pearson's correlation coefficients. Results Patients with knee OA demonstrated larger medial/lateral joint contact point excursions (p<0.02) and greater heel-strike joint contact point velocities (p<0.05) for the medial and lateral compartments compared to the control group. The peak medial/lateral joint contact point velocity of the medial compartment was also greater for patients with knee OA compared to their control counterparts (p=0.02). Additionally, patients with knee OA demonstrated significantly increased frontal-plane varus motion excursions (p<0.01) and greater quadriceps and hip abductor muscle weakness (p=0.03). In general, increased joint contact point excursions and velocities in patients with knee OA were linearly associated with greater frontal-plane varus motion excursions (p<0.04) but not with quadriceps or hip abductor strength. Conclusion Altered contact mechanics in patients with knee OA may be related to compromised frontal-plane joint stability but not with

  2. Rabbit knee model of post-traumatic joint contractures: the long-term natural history of motion loss and myofibroblasts.

    PubMed

    Hildebrand, Kevin A; Sutherland, Craig; Zhang, Mei

    2004-03-01

    Our objective is to describe the natural history of motion loss with time and myofibroblast numbers in a rabbit knee model of post-traumatic joint contractures. Twenty-eight skeletally mature New Zealand White female rabbits had five-mm-squares of cortical bone removed from the medial and lateral femoral condyles of the right knee. A Kirschner wire (K-wire) was used to immobilize the knee joint in maximum flexion. A second operation was performed 8 weeks later to remove the K-wire. The rabbits were divided into four groups depending on the time of remobilization; 0, 8, 16 or 32 weeks. The average flexion contracture of the experimental knees in the 0-week and 8-week remobilization groups (38 degrees and 33 degrees, respectively) were significantly greater when compared with the values of the unoperated contralateral knees (8 degrees). The average flexion contractures of the experimental knees in the 16-week and 32-week remobilization groups were also greater than the unoperated contralateral knees, although they were not statistically significant. The average flexion contractures of the 16-week and 32-week groups were 19 degrees and 18 degrees, respectively, indicating a stabilization of the motion loss. Myofibroblast numbers in the posterior joint capsules were elevated 4-5x in the knees with contractures when compared to the contralateral knees. The initial decrease in severity followed by stabilization of motion loss and the association of motion loss with myofibroblasts mimics the human scenario of permanent post-traumatic joint contractures.

  3. Self-reported knee instability and activity limitations in patients with knee osteoarthritis: results of the Amsterdam osteoarthritis cohort.

    PubMed

    van der Esch, Martin; Knoop, Jesper; van der Leeden, Marike; Voorneman, Ramon; Gerritsen, Martijn; Reiding, Dick; Romviel, Suzanne; Knol, Dirk L; Lems, Willem F; Dekker, Joost; Roorda, Leo D

    2012-10-01

    The objective of this study was to evaluate whether self-reported knee instability is associated with activity limitations in patients with knee osteoarthritis (OA), in addition to knee pain and muscle strength. A cohort of 248 patients diagnosed with knee OA was examined. Self-reported knee instability was defined as the perception of any episode of buckling, shifting, or giving way of the knee in the past 3 months. Knee pain was assessed using a numeric rating scale, and knee extensor and flexor strength were measured using an isokinetic dynamometer. Activity limitations were measured by using the Western Ontario and McMasters Universities Osteoarthritis Index physical function questionnaire, the timed Get Up and Go, and the timed stair climbing and three questionnaires evaluating walking, climbing stairs, and rising from a chair. Other potential determinants of activity limitations were also collected, including joint proprioception, joint laxity, age, sex, body mass index (BMI), disease duration, and radiographic disease severity. Regression analyses evaluated the effect of adding self-reported knee instability to knee pain and muscle strength, when examining associations with the activity limitations measures. Self-reported knee instability was common (65 %) in this cohort of patients with knee OA. Analyses revealed that self-reported knee instability is significantly associated with activity limitations, even after controlling for knee pain and muscle strength. Joint proprioception, joint laxity, age, sex, BMI, duration of complaints, and radiographic severity did not confound the associations. In conclusion, self-reported knee instability is associated with activity limitations in patients with knee OA, in addition to knee pain and muscle strength. Clinically, self-reported knee instability should be assessed in addition to knee pain and muscle strength.

  4. In vivo knee kinematics during stair and deep flexion activities in patients with bicruciate substituting total knee arthroplasty.

    PubMed

    Kuroyanagi, Yuji; Mu, Shang; Hamai, Satoshi; Robb, William J; Banks, Scott A

    2012-01-01

    Orthopedic surgeons and their patients continue to seek better functional outcomes after total knee arthroplasty. The bicruciate substituting (BCS) total knee arthroplasty design has been introduced to achieve more natural knee mechanics. The purpose of this study was to characterize kinematics in knees with BCS arthroplasty during deep flexion and stair activities using fluoroscopy and model-image registration. In 20 patients with 25 BCS knees, we observed average implant flexion of 128° during kneeling and consistent posterior condylar translations with knee flexion. Tibial rotations were qualitatively similar to those observed in the arthritic natural knee. Knee kinematics with BCS arthroplasty were qualitatively more similar to arthritic natural knees than knees with either posterior cruciate-retaining or posterior-stabilized arthroplasty.

  5. Clinical evaluation of 292 Genesis II posterior stabilized high-flexion total knee arthroplasty: range of motion and predictors.

    PubMed

    Fuchs, Mathijs C H W; Janssen, Rob P A

    2015-01-01

    The primary aim of the study was to evaluate the range of motion and complications after Genesis II total knee arthroplasty with high-flexion tibia insert (TKA-HF). Furthermore, difference in knee flexion between high flexion and standard inserts was compared. The hypothesis was that knee flexion is better after high-flexion TKA. A total of 292 TKA-HF were retrospectively reviewed. Mean follow-up was 24.3 months. The range of motion was compared between TKA-HF (high-flexion group) and a comparable cohort of 86 Genesis II TKA with a standard tibia insert (control group). Surgeries were performed by one experienced knee orthopedic surgeon. Knee flexion in the high-flexion group increased from 114.8° preoperatively to 118.0° postoperatively (P < 0.01). Knee extension in the high-flexion group increased from -4.5° preoperatively to -0.4° after surgery (P < 0.01). Mean knee flexion was 5.52° (± 1.46°) better in the high-flexion group compared with the control group (P < 0.01). Preoperative range of motion, body mass index, diabetes mellitus and patellofemoral pain significantly influenced range of motion. Few complications occurred after TKA-HF. The Genesis II TKA-HF showed good short-term results with limited complications. Knee flexion after Genesis II TKA-HF was better compared with a standard tibia insert.

  6. Multibody muscle driven model of an instrumented prosthetic knee during squat and toe rise motions.

    PubMed

    Stylianou, Antonis P; Guess, Trent M; Kia, Mohammad

    2013-04-01

    Detailed knowledge of knee joint kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. The need for dynamic computational models that link kinematics, muscle and ligament forces, and joint contacts has long been recognized but such body-level forward dynamic models do not exist in recent literature. A main barrier in using computational models in the clinic is the validation of the in vivo contact, muscle, and ligament loads. The purpose of this study was to develop a full body, muscle driven dynamic model with subject specific leg geometries and validate it during squat and toe-rise motions. The model predicted loads were compared to in vivo measurements acquired with an instrumented knee implant. Data for this study were provided by the "Grand Challenge Competition to Predict In-Vivo Knee Loads" for the 2012 American Society of Mechanical Engineers Summer Bioengineering Conference. Data included implant and bone geometries, ground reaction forces, EMG, and the instrumented knee implant measurements. The subject specific model was developed in the multibody framework. The knee model included three ligament bundles for the lateral collateral ligament (LCL) and the medial collateral ligament (MCL), and one bundle for the posterior cruciate ligament (PCL). The implanted tibia tray was segmented into 326 hexahedral elements and deformable contacts were defined between the elements and the femoral component. The model also included 45 muscles on each leg. Muscle forces were computed for the muscle driven simulation by a feedback controller that used the error between the current muscle length in the forward simulation and the muscle length recorded during a kinematics driven inverse simulation. The predicted tibia forces and torques, ground reaction forces, electromyography (EMG) patterns, and kinematics were compared to the experimentally

  7. Can an anterior quadriceps release improve range of motion in the stiff arthritic knee?

    PubMed

    Tarabichi, Samih; Tarabichi, Yasir

    2010-06-01

    We hypothesize that tethering adhesions of the quadriceps muscle are the major pathological structures responsible for a limited range of motion in the stiff arthritic knee. Forty-two modified quadriceps muscle releases were performed on 24 patients with advanced osteoarthritis scheduled for total knee arthroplasty. The ranges of motion were documented intraoperatively both before and immediately after the release. Passive flexion improved significantly in all patients (mean, 32.4 degrees of improvement, P < .001) following a modified quadriceps release, despite any presence of osteophytes or severe deformities. These results strongly implicate adhesions of the quadriceps muscle to the underlying femur, which prevent the distal excursion of the quadriceps tendon, as the restrictive pathology preventing deep flexion in patients with osteoarthritis.

  8. [Sport activity after hip and knee arthroplasty].

    PubMed

    Keren, Amit; Berkovich, Yaron; Berkovitch, Yaron; Soudry, Michael

    2013-11-01

    Joint arthroplasty is one of the commonest surgical procedures in orthopedic surgery. In recent years there was an increase in the number of procedures, patient satisfaction and implant survival. Originally, these operations were designed for old patients in order to relieve pain and to enable ambulation. Over the past few years, these operations have become common in younger patients which desire to return to activity, including sports activities. The importance of physical activity is a well known fact. In recent years it became clear that with the proper physical activity the outcomes of the operations are better. There are several types of arthroplasty. Many factors influence the outcome of the operation apart from the post-surgery physical activity. These factors include patient factors, surgical technique and type of arthroplasty. This review summarizes the recommendations for sports activities after hip and knee arthroplasties. These activities are evaluated according to surgeons' recommendations, stress applied on the implant and long term outcomes. The recommended sports activities after joint arthroplasties are walking, swimming and cycling. Soccer, basketball and jogging are not advised. Tennis, downhill skiing and horse riding are recommended with previous experience. There are many more sports activities that patients can participate in, and it is important that the patient discuss the different options prior to the operation. Since these operations are so common, many non-orthopedic physicians encounter these patients in their practice. They should be acquainted with the recommendations for sports activities and encourage them.

  9. Relationships between Muscle Architecture of Rectus Femoris and Functional Parameters of Knee Motion in Adults with Down Syndrome

    PubMed Central

    Micale, Marco; Cioni, Matteo

    2016-01-01

    This study was designed to measure in vivo muscle architecture of the rectus femoris in adults with Down syndrome, testing possible relationships with functional parameters of the knee motion. Ten adults with Down syndrome and ten typically developed participated in the study. Pennation angle and thickness of the rectus femoris and subcutaneous layer of the thigh were measured via ultrasound imaging. Knee kinematics and electromyographic activity of the rectus femoris were recorded during free leg dropping. Muscle thickness was reduced and subcutaneous layer was thicker in persons with Down syndrome with respect to typically developed adults, but there were no differences in the pennation angle. The area of the rectus femoris EMG activity during the leg flexion was greater in Down syndrome with respect to typically developed adults. The leg movement velocity was lower in Down people than in controls, but the knee excursion was similar between the groups. Functional parameters correlated with pennation angle in the persons with Down syndrome and with muscle thickness in typically developed persons. The description of muscle architecture and the relationships between morphological and functional parameters may provide insights on the limits and the opportunities to overcome the inherent biomechanical instability in Down syndrome. PMID:27896273

  10. Relationships between Muscle Architecture of Rectus Femoris and Functional Parameters of Knee Motion in Adults with Down Syndrome.

    PubMed

    Valle, Maria Stella; Casabona, Antonino; Micale, Marco; Cioni, Matteo

    2016-01-01

    This study was designed to measure in vivo muscle architecture of the rectus femoris in adults with Down syndrome, testing possible relationships with functional parameters of the knee motion. Ten adults with Down syndrome and ten typically developed participated in the study. Pennation angle and thickness of the rectus femoris and subcutaneous layer of the thigh were measured via ultrasound imaging. Knee kinematics and electromyographic activity of the rectus femoris were recorded during free leg dropping. Muscle thickness was reduced and subcutaneous layer was thicker in persons with Down syndrome with respect to typically developed adults, but there were no differences in the pennation angle. The area of the rectus femoris EMG activity during the leg flexion was greater in Down syndrome with respect to typically developed adults. The leg movement velocity was lower in Down people than in controls, but the knee excursion was similar between the groups. Functional parameters correlated with pennation angle in the persons with Down syndrome and with muscle thickness in typically developed persons. The description of muscle architecture and the relationships between morphological and functional parameters may provide insights on the limits and the opportunities to overcome the inherent biomechanical instability in Down syndrome.

  11. Relationship between knee alignment and the electromyographic activity of quadriceps muscles in patients with knee osteoarthritis

    PubMed Central

    Lim, Seong Hoon; Hong, Bo Young; Oh, Jee Hae; Lee, Jong In

    2015-01-01

    [Purpose] We evaluated the relationship between knee alignment and the electromyographic (EMG) activity of the vastus medialis (VM) to the vastus lateralis (VL) muscles in patients with knee osteoarthritis (OA) in a cross-sectional study. [Subjects and Methods] Forty subjects with knee OA were assessed by anatomic radiographic knee alignment and the VM/VL ratio was calculated. Surface EMG from both the VM and VL muscles were evaluated during maximal isometric contraction at 60° knee flexion. Simultaneously, peak quadriceps torque was assessed using an isokinetic dynamometer. Subjects were categorized into low, moderate, and high varus groups according to knee malalignment. The peak quadriceps torque and VM/VL ratio across groups, and their relationships with varus malalignment were analyzed. [Results] All subjects had medial compartment OA and the VM/VL ratio of all subjects was 1.31 ± 0.28 (mean ± SD). There were no significant differences in the peak quadriceps torque or VM/VL ratios across the groups nor were there any significant relationships with varus malalignment. [Conclusion] The VM/VL ratio and peak quadriceps torque were not associated with the severity of knee varus malalignment. PMID:25995602

  12. 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

  13. Design of a mechanism for converting the energy of knee motions by using electroactive polymers.

    PubMed

    Armbruster, Pascal; Oster, Yannick; Vogt, Marcel; Pylatiuk, Christian

    2017-03-04

    Harvesting energy from human body motions has become a promising option to prolong battery life for powering medical devices for autonomy. Up to now, different generating principles including dielectric electroactive polymers (DEAPs) have been suggested for energy conversion. However, there is a lack of mechanisms that are specifically designed to convert energy with DEAPs. In a proof of concept study, a mechanical system was designed for stretching DEAPs in those phases of the gait cycle, in which the muscles mainly perform negative work. Rotational movements of the knee joint are transformed into linear movements by using a cable pull. The DEAP can be charged during the stretching phase and discharged during releasing and allows for the conversion of kinetic energy into electric energy. To evaluate the concept, tests were conducted. It was found that the developed body energy harvesting (BEH) system has a performance in the range of 24-40 μW at normal walking speed. The converted energy is sufficient for powering sensors in medical devices such as active orthoses or prostheses.

  14. Designing for scale: development of the ReMotion Knee for global emerging markets.

    PubMed

    Hamner, Samuel R; Narayan, Vinesh G; Donaldson, Krista M

    2013-09-01

    Amputees living in developing countries have a profound need for affordable and reliable lower limb prosthetic devices. The World Health Organization estimates there are approximately 30 million amputees living in low-income countries, with up to 95% lacking access to prosthetic devices. Effective prosthetics can significantly affect the lives of these amputees by increasing opportunity for employment and providing improvements to long-term health and well-being. However, current solutions are inadequate: state-of-the-art solutions from the US and Europe are cost-prohibitive, while low-cost devices have been challenged by poor quality and/or unreliable performance, and have yet to achieve large scale impact. The introduction of new devices is hampered by the lack of a cohesive prosthetics industry in low-income areas; the current network of low-cost prosthetic clinics is informal and loosely organized with significant disparities in geography, patient volume and demographics, device procurement, clinical and logistical infrastructure, and funding. At D-Rev (Design Revolution) we are creating the ReMotion Knee, which is an affordable polycentric prosthetic knee joint that performs on par with devices in more industrialized regions, like the US and Europe. As of September 2012, over 4200 amputees have been fitted with the initial version of the ReMotion Knee through a partnership with the JaipurFoot Organization, with an 79% compliance rate after 2 years. We are currently scaling production of the ReMotion Knee using centralized manufacturing and distribution to serve the existing clinics in low-income countries and increase the availability of devices for amputees without access to appropriate care. At D-Rev, we develop products that target these customers through economically-sustainable models and provide a measurable impact in the lives of the world's amputees.

  15. The effects of electrical stimulation combined with continuous passive motion versus isometric exercise on symptoms, functional capacity, quality of life and balance in knee osteoarthritis: randomized clinical trial.

    PubMed

    Tok, Fatih; Aydemir, Koray; Peker, Fatma; Safaz, Ismail; Taşkaynatan, Mehmet Ali; Ozgül, Ahmet

    2011-02-01

    The aim of this study was to evaluate effects of electrical stimulation combined with continuous passive motion (CPM-ES) versus isometric exercise on symptoms, functional capacity, quality of life, muscle strength, knee and thigh circle measurements, and balance in knee osteoarthritis (OA). This is a randomized clinical trial. The study was done in Gulhane Military Medical Academy (GMMA) Rehabilitation Center. Forty patients with knee OA were included in this study. Participants were randomly assigned to two groups: 20 patients placed in Group 1 were treated with conventional physical therapy and CPM-ES combination; 20 patients in Group 2 were treated with conventional physical therapy and isometric exercise. Therapies were applied 3 weeks, 5 days per week. The following main outcome measures were done: values of pain (VAS was used), WOMAC, SF-36, knee and thigh circle measurements, isokinetic tests, dynamic and static balance tests were determined at baseline and after the treatment. There were no statistically significant differences in the tested variables between the groups for post-treatment values. Dynamic and static balance test improved statistically strongly significantly in both groups. The findings of this study demonstrate that knee OA patients could improve their balance function in both static and dynamic conditions after CPM-ES combination or isometric exercise therapy. The improvement might prevent knee OA patients from falling down and increase their sense of security during physical activities.

  16. Effect of anterior-posterior and internal-external motion restraint during knee wear simulation on a posterior stabilised knee design.

    PubMed

    Grupp, Thomas M; Saleh, Khaled J; Mihalko, William M; Hintner, Martin; Fritz, Bernhard; Schilling, Christoph; Schwiesau, Jens; Kaddick, Christian

    2013-02-01

    The objective of our study was to examine the effect of biphaseal AP translation and IE rotation restraint, using a system defined specifically for posterior stabilised knee designs, on wear, kinematics and particle release in comparison to linear motion restraint as required by the established ISO 14243-1:2002(E) protocol. In the ISOlinear groups, an AP motion restraint of 30 N/mm and an IE rotation restraint of 0.6 Nm/° were applied in the knee wear simulation. In the ISOgap biphaseal groups with PCL sacrificing implants, the restraining AP force was zero in a ±2.5mm range with, externally, a constant of 9.3N/mm applied proportionally to the AP translation of the tibia plateau, whereas the restraining IE torque was zero in a ±6° range with, externally, a constant of 0.13 Nm/° applied proportionally to the IE rotation of the tibia plateau. Using the ISOgap biphaseal protocol on a posterior stabilised knee design, we found an increase of 41% in AP translation and of 131% in IE rotation, resulting in a 3.2-fold higher wear rate compared to the results obtained using the ISOlinear protocol. Changes in AP translation and IE rotation ligament motion restraints have a high impact on knee joint kinematics and wear behaviour of a fixed bearing posterior stabilised knee design.

  17. Daily Spousal Influence on Physical Activity in Knee Osteoarthritis

    PubMed Central

    Martire, Lynn M.; Stephens, Mary Ann Parris; Mogle, Jacqueline; Schulz, Richard; Brach, Jennifer; Keefe, Francis J.

    2012-01-01

    Background Physical activity is critical for the management of knee osteoarthritis, and the spouse may play a role in encouraging or discouraging physical activity. Purpose To examine four types of spousal influence—spouses' daily activity, autonomy support, pressure, and persuasion--on the daily physical activity of adults living with knee osteoarthritis. Methods A total of 141 couples reported their daily experiences for 22 days using a handheld computer, and wore an accelerometer to measure moderate activity and steps. Results Spouses' autonomy support for patient physical activity, as well as their own level of activity, was concurrently associated with patients' greater daily moderate activity and steps. In addition, on days when male patients perceived that spouses exerted more pressure to be active, they spent less time in moderate activity. Conclusions Couple-oriented interventions for knee osteoarthritis should target physical activity in both partners and spousal strategies for helping patients stay active. PMID:23161472

  18. Catecholamine secretion and adrenal nerve activity in response to movements of normal and inflamed knee joints in cats.

    PubMed Central

    Sato, A; Sato, Y; Schmidt, R F

    1986-01-01

    The effects of articular stimulation on adrenal catecholamine secretion and adrenal sympathetic nerve activity were studied using halothane anaesthetized cats. Various natural passive movements were applied to the normal and inflamed knee joints. Rhythmic flexions and extensions as well as rhythmic inward and outward rotation of normal knee joints within their physiological range of motion did not change nerve activity or the secretion of adrenal catecholamines. Static outward rotation in the normal working range was also ineffective. However, as soon as this static rotation was extended into the noxious range, significant increases in both of these variables were elicited. In the acutely inflamed knee joint, various passive movements produced increases in both adrenal sympathetic and catecholamine secretion. Especially noteworthy was the finding that movements of the inflamed knee joint that were within the normal range of motion produced increases in all variables. Articularly induced increases in adrenal sympathetic nerve activity were diminished by severing various hind-limb somatic afferent nerves and abolished by complete denervation of the knee joint. Additionally, section of the adrenal sympathetic nerves eliminated the catecholamine secretion response. From these data it was concluded that the responses observed in these experiments were reflexes having an afferent limb in hind-limb nerves and an efferent limb in the adrenal sympathetic nerves. A contribution of supraspinal structures was suggested for the reflex responses of sympatho-adrenal medullary function evoked by knee joint stimulations, since spinal transection at the C2 level completely abolished the responses. PMID:3795070

  19. Greater Hip Extension but Not Hip Abduction Explosive Strength Is Associated With Lesser Hip Adduction and Knee Valgus Motion During a Single-Leg Jump-Cut

    PubMed Central

    Cronin, Baker; Johnson, Samuel T.; Chang, Eunwook; Pollard, Christine D.; Norcross, Marc F.

    2016-01-01

    Background: The relationships between hip abductor and extensor strength and frontal plane hip and knee motions that are associated with anterior cruciate ligament injury risk are equivocal. However, previous research on these relationships has evaluated relatively low-level movement tasks and peak torque rather than a time-critical strength measure such as the rate of torque development (RTD). Hypothesis: Females with greater hip abduction and extension RTD would exhibit lesser frontal plane hip and knee motion during a single-leg jump-cutting task. Study Design: Descriptive laboratory study. Methods: Forty recreationally active females performed maximal isometric contractions and single-leg jump-cuts. From recorded torque data, hip extension and abduction RTD was calculated from torque onset to 200 ms after onset. Three-dimensional motion analysis was used to quantify frontal plane hip and knee kinematics during the movement task. For each RTD measure, jump-cut biomechanics were compared between participants in the highest (high) and lowest (low) RTD tertiles. Results: No differences in frontal plane hip and knee kinematics were identified between high and low hip abduction RTD groups. However, those in the high hip extension RTD group exhibited lower hip adduction (high, 3.8° ± 3.0°; low, 6.5° ± 3.0°; P = .019) and knee valgus (high, –2.5° ± 2.3°; low, –4.4° ± 3.2°; P = .046) displacements during the jump-cut. Conclusion: In movements such as cutting that are performed with the hip in a relatively abducted and flexed position, the ability of the gluteus medius to control hip adduction may be compromised. However, the gluteus maximus, functioning as a hip abductor, may take on a pivotal role in controlling hip adduction and knee valgus motion during these types of tasks. Clinical Relevance: Training with a specific emphasis on increasing explosive strength of the hip extensors may be a means through which to improve frontal plane hip and knee

  20. Correlation between hip function and knee kinematics evaluated by three-dimensional motion analysis during lateral and medial side-hopping.

    PubMed

    Itoh, Hiromitsu; Takiguchi, Kohei; Shibata, Yohei; Okubo, Satoshi; Yoshiya, Shinichi; Kuroda, Ryosuke

    2016-09-01

    [Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated. Subsequently, the relationship between knee motion and the clinical parameters of the hip was analyzed. [Results] In the lateral touchdown phase, the knee was positioned in an abducted and externally rotated position, and increasing abduction moment was applied to the knee. An analysis of the interaction between knee motion and hip function showed that range of motion for hip internal rotation was significantly correlated with external rotation angle and external rotation/abduction moments of the knee during the lateral touchdown phase. [Conclusion] Range of motion for hip internal rotation should be taken into consideration for identifying the biomechanical characteristics in the side hop test results.

  1. Correlation between hip function and knee kinematics evaluated by three-dimensional motion analysis during lateral and medial side-hopping

    PubMed Central

    Itoh, Hiromitsu; Takiguchi, Kohei; Shibata, Yohei; Okubo, Satoshi; Yoshiya, Shinichi; Kuroda, Ryosuke

    2016-01-01

    [Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated. Subsequently, the relationship between knee motion and the clinical parameters of the hip was analyzed. [Results] In the lateral touchdown phase, the knee was positioned in an abducted and externally rotated position, and increasing abduction moment was applied to the knee. An analysis of the interaction between knee motion and hip function showed that range of motion for hip internal rotation was significantly correlated with external rotation angle and external rotation/abduction moments of the knee during the lateral touchdown phase. [Conclusion] Range of motion for hip internal rotation should be taken into consideration for identifying the biomechanical characteristics in the side hop test results. PMID:27799670

  2. The Association of Ankle Dorsiflexion Range of Motion With Hip and Knee Kinematics During the Lateral Step-down Test.

    PubMed

    Rabin, Alon; Portnoy, Sigal; Kozol, Zvi

    2016-11-01

    Study Design Controlled laboratory study. Background Altered hip and knee kinematics have been associated with several knee disorders, including anterior cruciate ligament tear, patellofemoral pain, and iliotibial band syndrome. Limited ankle dorsiflexion (DF) range of motion (ROM), which has been linked with some of these disorders, has also been associated with altered knee kinematics. Objective To explore the association of ankle DF ROM with hip and knee kinematics during a step-down task. Methods Thirty healthy participants underwent a 3-D analysis of hip and knee kinematics during a lateral step-down test, followed by measurement of ankle DF ROM in weight bearing (WB) and non-weight bearing (NWB). Participants were dichotomized using the median values into low- and high-DF subgroups within both WB and NWB. Hip and knee kinematics were compared between the low- and high-DF subgroups. Results Participants in the low-DF subgroups exhibited greater peak hip adduction (WB, P = .02; NWB, P<.01) and greater peak knee external rotation (WB, P = .02; NWB, P<.01) compared with participants in the high-DF subgroups. In addition, participants in the low-DF WB subgroup exhibited decreased peak knee flexion compared with participants in the high-DF WB subgroup (P<.01). Conclusion Individuals with lower ankle DF ROM exhibited hip and knee kinematics previously associated with several knee disorders, suggesting that this impairment may be involved in the pathogenesis of the same disorders. Assessment of ankle DF ROM may be useful as part of a preparticipation screening. Furthermore, deficits in ankle DF ROM may need to be addressed in individuals with altered movement patterns. J Orthop Sports Phys Ther 2016;46(11):-1. Epub 29 Sep 2016. doi:10.2519/jospt.2016.6621.

  3. Relationship between joint gap difference and range of motion in total knee arthroplasty: a prospective randomised study between different platforms.

    PubMed

    Higuchi, Hiroshi; Hatayama, Kazuhisa; Shimizu, Masaki; Kobayashi, Atsushi; Kobayashi, Tsutomu; Takagishi, Kenji

    2009-08-01

    The objective of this study was to investigate the range of motion (ROM) of the knee before and four years after total knee arthroplasty (TKA) with a mobile or fixed type of platform and to prospectively evaluate whether there was a difference in ligament balance between the platform types. The subjects were 68 patients involving 76 joints. The mobile type was used in 31 joints and fixed type in 45 joints by employing a prospective randomised method. The passive maximum ROM was measured using a goniometer before and four years after surgery. Also, the intraoperative knee ligament balance was measured. The postoperative extension ROM was significantly improved after TKA using a mobile bearing type compared with that employing a fixed bearing type. In TKA using the former, the intraoperative gap difference was not related to the postoperative flexion angle of the knee. However, they were related in TKA using a fixed bearing type, with a positive correlation regarding the flexion gap.

  4. Antagonistic active knee prosthesis. A metabolic cost of walking comparison with a variable-damping prosthetic knee.

    PubMed

    Martinez-Villalpando, Ernesto C; Mooney, Luke; Elliott, Grant; Herr, Hugh

    2011-01-01

    This paper examines the impact of a biomimetic active knee prosthesis on the metabolic costs associated with a unilateral transfemoral amputee walking at self selected speed. In this study we compare the antagonistic active knee prosthesis developed at MIT to an electronically controlled, variable-damping commercial knee prosthesis, the Otto Bock C-leg. Use of the active knee prosthesis resulted in both, a 17% increase in an amputee's average self selected walking speed from 1.12 m/s to 1.31 m/s, and a 6.8% reduction in metabolic cost. The results of this study suggest that an agonist-antagonist active knee prosthesis design with variable impedance control can offer walking energetic advantages over commercially available systems.

  5. The efficacy of continuous passive motion after total knee arthroplasty: a comparison of three protocols.

    PubMed

    Boese, C Kent; Weis, Marcia; Phillips, Tamra; Lawton-Peters, Sheila; Gallo, Theresa; Centeno, Leslie

    2014-06-01

    We conducted a randomized, controlled trial to determine the efficacy of CPM following total knee arthroplasty (TKA). Postoperative outcomes of interest were: swelling, drop in hemoglobin, self-reported pain scores, range of motion, and hospital length of stay. A total of 160 subjects were randomized into one of three treatment groups: CPM device on and moving from the immediate post-operative period, CPM device on and stationary at 90 degree flexion for the first night and then moving throughout the rest of their stay, and no CPM (N = 55, 51, and 54, respectfully). Subjects were followed during the first and second postoperative day until their first follow-up appointment approximately 3-4 weeks post-operatively. Cost of CPM was further evaluated. CPM provided no benefit to patients recovering from TKA.

  6. Dynamic splinting for knee flexion contracture following total knee arthroplasty: a case report.

    PubMed

    Finger, Eric; Willis, F Buck

    2008-12-29

    Total Knee Arthroplasty operations are increasing in frequency, and knee flexion contracture is a common pathology, both pre-existing and post-operative. A 61-year-old male presented with knee flexion contracture following a total knee arthroplasty. Physical therapy alone did not fully reduce the contracture and dynamic splinting was then prescribed for daily low-load, prolonged-duration stretch. After 28 physical therapy sessions, the active range of motion improved from -20 degrees to -12 degrees (stiff knee still lacking full extension), and after eight additional weeks with nightly wear of dynamic splint, the patient regained full knee extension, (active extension improved from -12 degrees to 0 degrees ).

  7. Accuracy of a custom physical activity and knee angle measurement sensor system for patients with neuromuscular disorders and gait abnormalities.

    PubMed

    Feldhege, Frank; Mau-Moeller, Anett; Lindner, Tobias; Hein, Albert; Markschies, Andreas; Zettl, Uwe Klaus; Bader, Rainer

    2015-05-06

    Long-term assessment of ambulatory behavior and joint motion are valuable tools for the evaluation of therapy effectiveness in patients with neuromuscular disorders and gait abnormalities. Even though there are several tools available to quantify ambulatory behavior in a home environment, reliable measurement of joint motion is still limited to laboratory tests. The aim of this study was to develop and evaluate a novel inertial sensor system for ambulatory behavior and joint motion measurement in the everyday environment. An algorithm for behavior classification, step detection, and knee angle calculation was developed. The validation protocol consisted of simulated daily activities in a laboratory environment. The tests were performed with ten healthy subjects and eleven patients with multiple sclerosis. Activity classification showed comparable performance to commercially available activPAL sensors. Step detection with our sensor system was more accurate. The calculated flexion-extension angle of the knee joint showed a root mean square error of less than 5° compared with results obtained using an electro-mechanical goniometer. This new system combines ambulatory behavior assessment and knee angle measurement for long-term measurement periods in a home environment. The wearable sensor system demonstrated high validity for behavior classification and knee joint angle measurement in a laboratory setting.

  8. Accuracy of a Custom Physical Activity and Knee Angle Measurement Sensor System for Patients with Neuromuscular Disorders and Gait Abnormalities

    PubMed Central

    Feldhege, Frank; Mau-Moeller, Anett; Lindner, Tobias; Hein, Albert; Markschies, Andreas; Zettl, Uwe Klaus; Bader, Rainer

    2015-01-01

    Long-term assessment of ambulatory behavior and joint motion are valuable tools for the evaluation of therapy effectiveness in patients with neuromuscular disorders and gait abnormalities. Even though there are several tools available to quantify ambulatory behavior in a home environment, reliable measurement of joint motion is still limited to laboratory tests. The aim of this study was to develop and evaluate a novel inertial sensor system for ambulatory behavior and joint motion measurement in the everyday environment. An algorithm for behavior classification, step detection, and knee angle calculation was developed. The validation protocol consisted of simulated daily activities in a laboratory environment. The tests were performed with ten healthy subjects and eleven patients with multiple sclerosis. Activity classification showed comparable performance to commercially available activPAL sensors. Step detection with our sensor system was more accurate. The calculated flexion-extension angle of the knee joint showed a root mean square error of less than 5° compared with results obtained using an electro-mechanical goniometer. This new system combines ambulatory behavior assessment and knee angle measurement for long-term measurement periods in a home environment. The wearable sensor system demonstrated high validity for behavior classification and knee joint angle measurement in a laboratory setting. PMID:25954954

  9. 78 FR 38098 - Proposed Information Collection (Knee and Lower Leg Disability Benefits Questionnaire) Activity...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-25

    ... AFFAIRS Proposed Information Collection (Knee and Lower Leg Disability Benefits Questionnaire) Activity... Disability Benefits Questionnaire)'' in any correspondence. During the comment period, comments may be viewed.... SUPPLEMENTARY INFORMATION: Title: Knee and Lower Leg Conditions Disability Benefits Questionnaire, VA Form...

  10. Total Knee Replacement

    MedlinePlus

    ... stability. The long thigh muscles give the knee strength. All remaining surfaces of the knee are covered ... physical examination. This will assess knee motion, stability, strength, and overall leg alignment. • X-rays. These images ...

  11. Can generic knee joint models improve the measurement of osteoarthritic knee kinematics during squatting activity?

    PubMed

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2017-01-01

    Knee joint kinematics derived from multi-body optimisation (MBO) still requires evaluation. The objective of this study was to corroborate model-derived kinematics of osteoarthritic knees obtained using four generic knee joint models used in musculoskeletal modelling - spherical, hinge, degree-of-freedom coupling curves and parallel mechanism - against reference knee kinematics measured by stereo-radiography. Root mean square errors ranged from 0.7° to 23.4° for knee rotations and from 0.6 to 9.0 mm for knee displacements. Model-derived knee kinematics computed from generic knee joint models was inaccurate. Future developments and experiments should improve the reliability of osteoarthritic knee models in MBO and musculoskeletal modelling.

  12. Biofeedback relaxation for pain associated with continuous passive motion in Taiwanese patients after total knee arthroplasty.

    PubMed

    Wang, Tsae-Jyy; Chang, Ching-Fen; Lou, Meei-Fang; Ao, Man-Kuan; Liu, Chiung-Chen; Liang, Shu-Yuan; Wu, Shu-Fang Vivienne; Tung, Heng-Hsing

    2015-02-01

    Effective pain management is crucial for patient recovery after total knee arthroplasty (TKA). Biofeedback therapy, which encourages relaxation and helps alleviate various conditions associated with stress, may help to decrease postoperative pain in patients undergoing TKA. A quasi- experimental design was used to investigate the efficacy of a biofeedback relaxation intervention in reducing pain associated with postoperative continuous passive motion (CPM) therapy. Sixty-six patients admitted to a general hospital in Taiwan for TKA were recruited and randomly assigned to the intervention or control group. The intervention group received biofeedback training twice daily for 5 days, concurrent with CPM therapy, whereas the control group did not receive the biofeedback intervention. Pain was measured using a numeric rating scale before and after each CPM therapy session on postoperative days 1 through 5. The CPM-elicited pain score was calculated by subtracting the pre-CPM pain score from the post-CPM pain score. Results of repeated-measures analysis of variance showed intervention group reported significantly less pain caused by CPM than did the control group (f = 29.70, p < 0.001). The study results provide preliminary support for biofeedback relaxation, a non-invasive and non-pharmacological intervention, as a complementary treatment option for pain management in this population.

  13. Evaluation of Postoperative Range of Motion and Functional Outcomes after Cruciate-Retaining and Posterior-Stabilized High-Flexion Total Knee Arthroplasty

    PubMed Central

    Han, Chang Wook; Yang, Ick Hwan; Lee, Woo Suk; Park, Kwan Kyu

    2012-01-01

    Purpose The purpose of this study was to compare postoperative range of motion and functional outcomes among patients who received high-flexion total knee arthroplasty using cruciate-retaining (CR-Flex) and posterior-stabilized (PS-Flex) type prostheses. Materials and Methods Among 127 patients (186 knees) who underwent high-flexion total knee arthroplasty between 2005 and 2007, 92 knees were placed in the CR-Flex group, and 94 knees were placed in the PS-Flex group. After two years of postoperative follow-up, clinical and radiographic data were reviewed. Postoperative non-weight-bearing range of knee motion, angle of flexion contracture and functional outcomes based on the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) functional sub-scale were assessed and compared between the two groups. Results After the 2-year postoperative period, the mean range of motion was 131° in the CR-Flex group and 133° in the PS-Flex group. There were no significant differences in postoperative range of motion between the two groups. Only age at operation and preoperative range of motion were significantly associated with postoperative range of motion after high-flexion total knee arthroplasty. Postoperative functional outcomes based on the WOMAC functional sub-scale were slightly better in the CR-Flex group (9.2±9.1 points) than in the PS-Flex group (11.9±9.6 points); however, this difference was not statistically significant (p=non-significant). Conclusion The retention or substitution of the posterior cruciate ligament does not affect postoperative range of motion (ROM) or functional outcomes, according to 2 years of postoperative follow-up of high-flexion total knee arthroplasty. PMID:22665348

  14. Good Early Results Obtained with a Guided-Motion Implant for Total Knee Arthroplasty: A Consecutive Case Series

    PubMed Central

    Hommel, Hagen; Wilke, Kai

    2017-01-01

    Background: Previous studies have shown a high incidence of complications with a bi-cruciate stabilized (BCS) guided-motion total knee arthroplasty (TKA) design, which led to recent modifications of the design by the manufacturer. Objective: The current study was undertaken to assess whether the use of this TKA system with an extension-first surgical technique is associated with a similar rate of short-term adverse outcome as reported in literature. Material and Methods: This retrospective study enrolled 257 consecutive patients (257 knees) undergoing TKA for osteoarthritis of the knee, with the first 153 receiving cemented Journey BCS I implants and the remaining 104 receiving cemented Journey BCS II implants when these became available. Results: Mean follow-up time for the cohort was 24.5 ± 7.8 months (range, 12 - 36 months). There were no cases of stiffness. Incidence of iliotibial friction syndrome was considered low: three (2.0%) knees in the BCS I group and two (1.9%) in the BCS II group (p = 0.676). Five (2.5%) knees presented with mild instability in midflexion, three (2.0%) in the BCS I group and two (1.9%) in the BCS II group (p = 0.676). One patient with a BCS I implant required reoperation for aseptic loosening 23 months postoperatively. At one-year follow-up, there were no clinically relevant differences in any of the clinical outcomes. Conclusion: When used in combination with an extension-first surgical technique, good early functional results with an acceptable rate of complications were obtained with both the original and the updated Journey BCS knee implant.

  15. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    PubMed

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension.

  16. Perioperative Rehabilitation Using a Knee Extension Device and Arthroscopic Debridement in the Treatment of Arthrofibrosis

    PubMed Central

    Biggs-Kinzer, Angie; Murphy, Brian; Shelbourne, K. Donald; Urch, Scott

    2010-01-01

    Background: Arthrofibrosis is a postoperative complication of intra-articular knee surgery that can be difficult to treat. Evidence suggests that maximizing knee range of motion may improve outcomes in patients with arthrofibrosis who undergo arthroscopic debridement. Hypothesis: Patients who achieve greater knee range of motion will have better subjective scores. Study Design: Retrospective case series analysis. Methods: A review of records was performed for 33 patients with arthrofibrosis who underwent knee arthroscopy and scar resection coupled with perioperative rehabilitation to maximize knee range of motion. Patient demographics and preoperative and postoperative range of motion measurements were extracted from the records. The International Knee Documentation Committee (IKDC) Subjective Knee Form was administered to assess pain, activity, and knee function. Patients performed a preoperative and postoperative rehabilitation program utilizing a knee extension device to maximize knee extension. Results: According to the IKDC range of motion criteria, 27 of 33 patients achieved normal knee extension, and 14 of 33 achieved normal knee flexion at a mean of 8.6 months after surgery. Patients with normal knee motion had a mean IKDC Subjective Knee Form score of 72.6 ± 13.6, which was significantly higher than patients who did not achieve normal motion (P = .04). Overall, mean IKDC Subjective Knee Form scores improved from 45.3 ± 16.7 preoperatively to 67.1 ± 18.0 postoperatively (P < .01) at a mean of 14.7 months after surgery. Conclusions: Perioperative rehabilitation that emphasizes restoration of normal knee range of motion appears to improve outcomes in patients with arthrofibrosis who undergo arthroscopic scar resection. In support of our hypothesis, patients who achieved greater knee range of motion had better subjective knee scores. PMID:23015970

  17. Exercise and physical activity in older adults with knee pain: a mixed methods study

    PubMed Central

    Nicholls, Elaine E.; Young, Julie; Hay, Elaine M.; Foster, Nadine E.

    2015-01-01

    Objectives. To describe and explore current exercise and physical activity behaviour in older adults with knee pain in the UK. Methods. A survey was mailed to 2234 adults ≥50 years of age registered with one general practice within the UK to determine the presence and severity of knee pain and levels of physical activity. Semi-structured interviews were conducted with 22 questionnaire responders with knee pain. Results. The questionnaire response rate was 59% (n = 1276) and 611 respondents reported knee pain. Only ∼40% of individuals with knee pain were sufficiently active to meet physical activity recommendations. Interviews revealed individual differences in the type and setting of physical activity completed and some self-monitored their symptoms in response to physical activity in order to guide future behaviour. Conclusion. Innovative interventions that can be adapted to suit individual needs and preferences are required to help older adults with knee pain become more physically active. PMID:25187640

  18. Effect of Planning on Trunk Motion and Knee Moments During a Side Step Cut Task

    NASA Astrophysics Data System (ADS)

    Houck, Jeff; Gorniak, Stacey; Nicholson, Kristen

    2004-03-01

    Recent studies suggest that alterations in knee biomechanics associated with unanticipated cutting tasks place athletes at higher risk of knee injuries. Besier et al observed alterations in knee moments during unanticipated cutting tasks that were consistent with in-vitro ACL injury mechanisms. During similar tasks, Patla et al observed lateral trunk lean and decreased foot placement, suggesting that full body center of mass control is perturbed during such tasks. The purpose of this study was to compare the trunk and knee frontal plane moments and evaluate a relationship between the two during unanticipated cutting tasks. The results of this study suggest that there is a relationship between the trunk and knee frontal plane moments during the first 200-400ms of the stance phase of gait.

  19. Effect of repeated manipulation on range of motion in patients with stiff total knee arthroplasty.

    PubMed

    Choi, Ho-Rim; Siliski, John M; Malchau, Henrik; Kwon, Young-Min

    2015-03-01

    Although manipulation under anesthesia (MUA) has been considered effective first-line treatment for stiff total knee arthroplasty (TKA), there is no consensus regarding the usefulness of repeated MUA. The purpose of this study was to investigate the usefulness of repeated MUA performed for patients in whom satisfactory range of motion (ROM) was not achieved by MUA. The authors retrospectively reviewed 15 patients who underwent repeated MUA after failure of initial MUA for stiff TKA. Demographic and ROM data were collected. A final ROM of less than 90° was considered a failed manipulation (failure group) and a final ROM of 90° or more was considered a successful manipulation (success group). Average pre-repeated MUA ROM (72.3°±19.5°) immediately improved to 112.3°±9.7° (P<.001) in the operating room, and final ROM was 89.6°±23.9°, an overall gain of 17.3° (P=.04). However, despite this overall ROM increase, a successful final ROM (90° or more) was achieved in approximately half of patients (7 of 13; 54%). There were no significant differences in demographics between the success and failure groups, except that there was significantly less pre-TKA ROM in the failure group (P=.02). There were no complications related to either the first or the repeated MUA procedures. The findings of this study suggest that repeated MUA can improve overall ROM for stiff TKA. The success rate of repeated MUA was less than that of primary MUA; however, it is a useful treatment modality for stiff TKA. Decreased pre-TKA ROM appeared to be associated with poor outcomes after repeated MUA.

  20. Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion

    PubMed Central

    Song, Young Dong; Jain, Nimash; Kang, Yeon Gwi; Kim, Tae Yune

    2016-01-01

    Purpose Correlations between maximum flexion and functional outcomes in total knee arthroplasty (TKA) patients are reportedly weak. We investigated whether there are differences between passive maximum flexion in nonweight bearing and other types of maximum flexion and whether the type of maximum flexion correlates with functional outcomes. Materials and Methods A total of 210 patients (359 knees) underwent preoperative evaluation and postoperative follow-up evaluations (6, 12, and 24 months) for the assessment of clinical outcomes including maximum knee flexion. Maximum flexion was measured under five conditions: passive nonweight bearing, passive weight bearing, active nonweight bearing, and active weight bearing with or without arm support. Data were analyzed for relationships between passive maximum flexion in nonweight bearing by Pearson correlation analyses, and a variance comparison between measurement techniques via paired t test. Results We observed substantial differences between passive maximum flexion in nonweight bearing and the other four maximum flexion types. At all time points, passive maximum flexion in nonweight bearing correlated poorly with active maximum flexion in weight bearing with or without arm support. Active maximum flexion in weight bearing better correlated with functional outcomes than the other maximum flexion types. Conclusions Our study suggests active maximum flexion in weight bearing should be reported together with passive maximum flexion in nonweight bearing in research on the knee motion arc after TKA. PMID:27274468

  1. Comparison of the long-term effectiveness of progressive neuromuscular facilitation and continuous passive motion therapies after total knee arthroplasty.

    PubMed

    Alaca, Nuray; Atalay, Ayçe; Güven, Zeynep

    2015-11-01

    [Purpose] The aim of this longitudinal study was to examine the long term functional effectiveness of proprioceptive neuromuscular facilitation (PNF) after total knee arthroplasty. [Subjects and Methods] We included 30 patients and they were randomly assigned to two groups. In addition to the standard rehabilitation program the PNF group received proprioceptive neuromuscular facilitation therapy and the CPM group received continuous passive motion therapy. The outcome measures included range of motion using a goniometer, pain scores using a numeric pain rating scale, days to reach functional benchmarks, the Beck depression scale and isokinetic torque and isometric strength measurements. [Results] There were no significant differences between the two groups in terms of baseline demographic data, clinical findings and length of stay. Days to reach range of motion benchmarks were similar in the two groups. Pain at the 8th week was slightly higher in the PNF group. With the exception of walking with a walker, days to reach functional benchmarks were statistically significantly fewer in patients of the PNF group despite similar isokinetic measurements. Administration of PNF resulted in earlier functional gains in patients after total knee arthroplasty. These functional accomplishments were more pronounced in the PNF group despite it having isokinetic torque measurements similar to those of the CPM group. [Conclusion] PNF techniques can positively affect functional outcomes over the long term.

  2. Comparison of the long-term effectiveness of progressive neuromuscular facilitation and continuous passive motion therapies after total knee arthroplasty

    PubMed Central

    Alaca, Nuray; Atalay, Ayçe; Güven, Zeynep

    2015-01-01

    [Purpose] The aim of this longitudinal study was to examine the long term functional effectiveness of proprioceptive neuromuscular facilitation (PNF) after total knee arthroplasty. [Subjects and Methods] We included 30 patients and they were randomly assigned to two groups. In addition to the standard rehabilitation program the PNF group received proprioceptive neuromuscular facilitation therapy and the CPM group received continuous passive motion therapy. The outcome measures included range of motion using a goniometer, pain scores using a numeric pain rating scale, days to reach functional benchmarks, the Beck depression scale and isokinetic torque and isometric strength measurements. [Results] There were no significant differences between the two groups in terms of baseline demographic data, clinical findings and length of stay. Days to reach range of motion benchmarks were similar in the two groups. Pain at the 8th week was slightly higher in the PNF group. With the exception of walking with a walker, days to reach functional benchmarks were statistically significantly fewer in patients of the PNF group despite similar isokinetic measurements. Administration of PNF resulted in earlier functional gains in patients after total knee arthroplasty. These functional accomplishments were more pronounced in the PNF group despite it having isokinetic torque measurements similar to those of the CPM group. [Conclusion] PNF techniques can positively affect functional outcomes over the long term. PMID:26696702

  3. Validation of a new computational 6-DOF knee simulator during dynamic activities.

    PubMed

    Fitzpatrick, Clare K; Maag, Chase; Clary, Chadd W; Metcalfe, Amber; Langhorn, Jason; Rullkoetter, Paul J

    2016-10-03

    A new six-degree-of-freedom (6-DOF) joint simulator has recently been developed which facilitates testing of implants under more realistic loading conditions than has been possible previously. However, typical wear testing can be very time-consuming, taking weeks or months to complete. A validated computational model is an ideal complement to these types of long-running tests. In this study, a computational counterpart to the new 6-DOF joint simulator was developed and validated. Total knee replacement components were evaluated in both physical and computational simulations, and joint mechanics were compared between the experiment and the model. Kinematic comparisons were carried out for two total knee replacement designs, under loading conditions representative of three different activities of daily living: deep knee bend, gait, and stepdown. The model accurately reproduced the motions obtained in the physical simulator, and appropriately differentiated between activities and between implant designs. Root-mean-square differences in anterior-posterior translations and internal-external rotations were less than 1.7mm and 1.4°, respectively, for both implant designs and all three dynamic activities. Contact area, and peak and average contact pressure predicted by the model matched experimental measurements with a root-mean-square accuracy of 20mm(2), 9MPa, and 1MPa, respectively. The computational model of the 6-DOF joint simulator will be a key tool in efficient evaluation of implant mechanics under loading conditions representative of the in vivo environment. These simulations may be used directly in comparison of devices, or may aid in facilitating optimal usage of the physical simulator through determining which activities and/or loading conditions best address specific clinical or design issues, for example, development of worst-case loading profiles for wear testing.

  4. A prosthetic knee using magnetorhelogical fluid damper for above-knee amputees

    NASA Astrophysics Data System (ADS)

    Park, Jinhyuk; Choi, Seung-Bok

    2015-04-01

    A prosthetic knee for above-knee (AK) amputees is categorized into two types; namely a passive and an active type. The passive prosthetic knee is generally made by elastic materials such as carbon fiber reinforced composite material, titanium and etc. The passive prosthetic knee easy to walk. But, it has disadvantages such that a knee joint motion is not similar to ordinary people. On the other hand, the active prosthetic knee can control the knee joint angle effectively because of mechanical actuator and microprocessor. The actuator should generate large damping force to support the weight of human body. But, generating the large torque using small actuator is difficult. To solve this problem, a semi-active type prosthetic knee has been researched. This paper proposes a semi-active prosthetic knee using a flow mode magneto-rheological (MR) damper for AK amputees. The proposed semi-active type prosthetic knee consists of the flow mode MR damper, hinge and prosthetic knee body. In order to support weight of human body, the required energy of MR damper is smaller than actuator of active prosthetic leg. And it can control the knee joint angle by inducing the magnetic field during the stance phase.

  5. Agonist and antagonist muscle activation during maximal and submaximal isokinetic fatigue tests of the knee extensors.

    PubMed

    Hassani, A; Patikas, D; Bassa, E; Hatzikotoulas, K; Kellis, E; Kotzamanidis, C

    2006-12-01

    The purpose of this study was to examine the differences in electromyographic activity of agonist and antagonist knee musculature between a maximal and a submaximal isokinetic fatigue protocol. Fourteen healthy males (age: 24.3+/-2.5 years) performed 25 maximal (MIFP) and 60 submaximal (SIFP) isokinetic concentric efforts of the knee extensors at 60 degrees s(-1), across a 90 degrees range of motion. The two protocols were performed a week apart. The EMG activity of vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) were recorded using surface electrodes. The peak torque (PT) and average EMG (aEMG) were expressed as percentages of pre-fatigue maximal value. One-way analysis of variance indicated a significant (p<0.05) decline of PT during the maximal (45.7%) and submaximal (46.8%) protocols. During the maximal test, the VM and VL aEMG initially increased and then decreased. In contrast, VM and VL aEMG continuously increased during submaximal testing (p<0.05). The antagonist (BF) aEMG remained constant during maximal test but it increased significantly and then declined during the submaximal testing. The above results indicate that agonist and antagonist activity depends on the intensity of the selected isokinetic fatigue test.

  6. Marker-free motion correction in weight-bearing cone-beam CT of the knee joint

    PubMed Central

    Berger, M.; Müller, K.; Aichert, A.; Unberath, M.; Thies, J.; Choi, J.-H.; Fahrig, R.; Maier, A.

    2016-01-01

    Purpose: To allow for a purely image-based motion estimation and compensation in weight-bearing cone-beam computed tomography of the knee joint. Methods: Weight-bearing imaging of the knee joint in a standing position poses additional requirements for the image reconstruction algorithm. In contrast to supine scans, patient motion needs to be estimated and compensated. The authors propose a method that is based on 2D/3D registration of left and right femur and tibia segmented from a prior, motion-free reconstruction acquired in supine position. Each segmented bone is first roughly aligned to the motion-corrupted reconstruction of a scan in standing or squatting position. Subsequently, a rigid 2D/3D registration is performed for each bone to each of K projection images, estimating 6 × 4 × K motion parameters. The motion of individual bones is combined into global motion fields using thin-plate-spline extrapolation. These can be incorporated into a motion-compensated reconstruction in the backprojection step. The authors performed visual and quantitative comparisons between a state-of-the-art marker-based (MB) method and two variants of the proposed method using gradient correlation (GC) and normalized gradient information (NGI) as similarity measure for the 2D/3D registration. Results: The authors evaluated their method on four acquisitions under different squatting positions of the same patient. All methods showed substantial improvement in image quality compared to the uncorrected reconstructions. Compared to NGI and MB, the GC method showed increased streaking artifacts due to misregistrations in lateral projection images. NGI and MB showed comparable image quality at the bone regions. Because the markers are attached to the skin, the MB method performed better at the surface of the legs where the authors observed slight streaking of the NGI and GC methods. For a quantitative evaluation, the authors computed the universal quality index (UQI) for all bone regions

  7. Effects of Low-Impact Dance on Blood Biochemistry, Bone Mineral Density, the Joint Range of Motion of Lower Extremities, Knee Extension Torque, and Fall in Females.

    PubMed

    Wu, Hui Ying; Tu, Jui Hung; Hsu, Chin Hsing; Tsao, Te Hung

    2016-01-01

    The effect of low-impact dance on blood metabolites, the joint range of motion (ROM) of the lower extremities, knee extension torque, bone mass density (BMD), the number of falls, and the confidence to perform daily activities (Modified Falls Efficacy Scale [MFES]) was examined in older sedentary women (age: 59 ± 4 years) before and after a 16-week intervention. Results showed that the average score for the MFES, some parameters of blood chemistry, and joint ROM were significantly improved after low-impact intervention. In addition to improvements in blood lipids and body fat percentages, the increases shown in the parameters regarding the lower extremities may contribute to confidence in performing common daily activities in older women, although the number of falls did not significantly differ between the two groups during the 16-week period.

  8. Does bracing influence brain activity during knee movement: an fMRI study.

    PubMed

    Thijs, Youri; Vingerhoets, Guy; Pattyn, Els; Rombaut, Lies; Witvrouw, Erik

    2010-08-01

    Studies have shown that proprioceptive inputs during active and passive arm movements are processed in the primary and secondary somatosensory cortex and supplementary motor area of the brain. At which level of the central nervous system proprioceptive signals coming from the knee are regulated remains to be elucidated. In order to investigate whether there is a detectable difference in brain activity when various proprioceptive inputs are exerted at the knee, functional magnetic resonance imaging (fMRI) was used. fMRI in 13 healthy, right leg-dominant female volunteers compared brain activation during flexion-extension movements of the right knee under three different conditions: with application of a tight knee brace, with application of a moderate tight knee sleeve, and without application of a brace or sleeve. Brain activation was detected in the primary sensorimotor cortex (left and right paracentral lobule) and in the left superior parietal lobule of the brain. There was a significantly higher level of brain activation with the application of the brace and sleeve, respectively, compared to the condition without a brace or sleeve. A significantly higher cortical activation was also seen when comparing the braced condition with the condition when a sleeve was applied. The results suggest that peripheral proprioceptive input to the knee joint by means of a brace or sleeve seems to influence brain activity during knee movement. The results of this study also show that the intensity of brain activation during knee movement can be influenced by the intensity of proprioceptive stimulation at the joint.

  9. Obesity effect on male active joint range of motion.

    PubMed

    Park, Woojin; Ramachandran, Jaiganesh; Weisman, Paul; Jung, Eui S

    2010-01-01

    Despite the prevalence of obesity, how obesity affects human physical capabilities is not well documented. As an effort toward addressing this, the current study investigated the obesity effect on joint range of motion (RoM) based on data collected from 20 obese and 20 non-obese males. In total, 30 inter-segmental motions occurring at the shoulder, elbow, knee and ankle joints and lumbar and cervical spine areas were examined. The obesity effect was found to be non-uniform across the joint motions. Obesity significantly reduced RoM for nine of the 30 motions: shoulder extensions and adductions, lumbar spine extension and lateral flexions and knee flexions. The largest significant RoM reduction was 38.9% for the left shoulder adduction. The smallest was 11.1% for the right knee flexion. The obesity-associated RoM reductions appear to be mainly due to the mechanical interposition and obstruction of inter-segmental motions caused by excess fat in the obese body. STATEMENT OF RELEVANCE: Currently, obesity is prevalent worldwide and its prevalence is expected to increase continually in the near future. This study empirically characterised the obesity effects on joint RoM to provide better understanding of the physical capabilities of the obese. The study findings will facilitate designing man-artefact systems that accommodate obese individuals.

  10. Self-similarity in active colloid motion

    NASA Astrophysics Data System (ADS)

    Constant, Colin; Sukhov, Sergey; Dogariu, Aristide

    The self-similarity of displacements among randomly evolving systems has been used to describe the foraging patterns of animals and predict the growth of financial systems. At micron scales, the motion of colloidal particles can be analyzed by sampling their spatial displacement in time. For self-similar systems in equilibrium, the mean squared displacement increases linearly in time. However, external forces can take the system out of equilibrium, creating active colloidal systems, and making this evolution more complex. A moment scaling spectrum of the distribution of particle displacements quantifies the degree of self-similarity in the colloid motion. We will demonstrate that, by varying the temporal and spatial characteristics of the external forces, one can control the degree of self-similarity in active colloid motion.

  11. Alpine Skiing With total knee ArthroPlasty (ASWAP): physical activity, knee function, pain, exertion, and well-being.

    PubMed

    Würth, S; Finkenzeller, T; Pötzelsberger, B; Müller, E; Amesberger, G

    2015-08-01

    This study focused on the psychological and quality of life aspects of resuming alpine skiing practice after total knee arthroplasty (TKA) in elderly skilled skiers. Two data pools were used in order to analyze psychological states: (a) at the beginning, at the end, and 8 weeks after a 12-week skiing intervention; and (b) concerning diurnal variations of states (i.e., skiing days compared with everyday life during intervention and retention phase). In particular, effects of skiing on amount of physical activity and perceived exertion, perceived pain and knee function, and subjective well-being were analyzed using a control group design. Results reveal that the skiing intervention substantially increases the amount of physical activity by the intervention group (122.30 ± 32.38 min/day), compared with the control group (75.14 ± 21.27 min/day) [F (2, 32) = 8.22, P < 0.01, η(2)  = 0.34)]. Additionally, the analyses of psychological states demonstrated that skiing goes along with enhanced well-being and no significant impact on perceived pain, exertion or knee function. In sum, alpine skiing can be recommended for older persons with TKA with respect to well-being, perceived pain and knee function, and perceived exertion.

  12. Endoplasmic reticulum stress activation during total knee arthroplasty

    PubMed Central

    Hocker, Austin D; Boileau, Ryan M; Lantz, Brick A; Jewett, Brian A; Gilbert, Jeffrey S; Dreyer, Hans C

    2013-01-01

    Total knee arthroplasty (TKA) is the most common remediation for knee pain from osteoarthritis (OA) and is performed 650,000 annually in the U.S. A tourniquet is commonly used during TKA which causes ischemia and reperfusion (I/R) to the lower limb but the effects of I/R on muscle are not fully understood. Previous reports suggest upregulation of cell stress and catabolism and downregulation of markers of cap-dependent translation during and after TKA. I/R has also been shown to cause endoplasmic reticulum (ER) stress and induce the unfolded protein response (UPR). We hypothesized that the UPR would be activated in response to ER stress during TKA. We obtained muscle biopsies from the vastus lateralis at baseline, before TKA; at maximal ischemia, prior to tourniquet deflation; and during reperfusion in the operating room. Phosphorylation of 4E-BP1 and AKT decreased during ischemia (−28%, P < 0.05; −20%, P < 0.05, respectively) along with an increase in eIF2α phosphorylation (64%, P < 0.05) suggesting decreased translation initiation. Cleaved ATF6 protein increased in ischemia (39%, P = 0.056) but returned to baseline during reperfusion. CASP3 activation increased during reperfusion compared to baseline (23%, P < 0.05). XBP1 splicing assays revealed an increase in spliced transcript during ischemia (31%, P < 0.05) which diminished during reperfusion. These results suggest that in response to I/R during TKA all three branches of the ER stress response are activated. PMID:24159375

  13. Effect of knee angle on quadriceps strength and activation after anterior cruciate ligament reconstruction

    PubMed Central

    Theuerkauf, Paul

    2015-01-01

    Quadriceps strength and activation deficits after anterior cruciate ligament (ACL) injury or surgery are typically evaluated at joint positions that are biomechanically advantageous to the quadriceps muscle. However, the effect of knee joint position and the associated changes in muscle length on strength and activation is currently unknown in this population. Here, we examined the effect of knee angle on quadriceps strength, activation, and electrically evoked torque in individuals with ACL reconstruction. Furthermore, we evaluated whether knee angle mediated the relationship between quadriceps weakness and functional performance after ACL reconstruction. Knee strength and activation were tested bilaterally at 90° and 45° of knee flexion in 11 subjects with ACL reconstruction using an interpolated triplet technique. The magnitude of electrically evoked torque at rest was used to quantify peripheral muscle contractile property changes, and the single-leg hop for distance test was used to evaluate functional performance. The results indicated that although quadriceps strength deficits were similar between knee angles, voluntary activation deficits were significantly higher in the reconstructed leg at 45° of knee flexion. On the contrary, the side-to-side evoked torque at rest ratio [i.e., (reconstructed/nonreconstructed) × 100] was significantly lower at 90° than at 45° of knee flexion. The association between quadriceps strength and functional performance was stronger at 45° of knee flexion. The results provide novel evidence that quadriceps activation is selectively affected at 45° of knee flexion and emphasize the importance of assessing quadriceps strength and activation at this position when feasible because it better captures activation deficits. PMID:25997949

  14. Preventing Knee Injuries

    MedlinePlus

    ... as a result of a twisting or pivoting motion. This injury may cause susceptibility to repeat injuries and knee instability, and therefore often requires surgery. Occasionally, a twisting or hyperextension force to the knee may result in a tibial ...

  15. Influence of restricted vision and knee joint range of motion on gait properties during level walking and stair ascent and descent.

    PubMed

    Demura, Tomohiro; Demura, Shin-ich

    2011-01-01

    Because elderly individuals experience marked declines in various physical functions (e.g., vision, joint function) simultaneously, it is difficult to clarify the individual effects of these functional declines on walking. However, by imposing vision and joint function restrictions on young men, the effects of these functional declines on walking can be clarified. The authors aimed to determine the effect of restricted vision and range of motion (ROM) of the knee joint on gait properties while walking and ascending or descending stairs. Fifteen healthy young adults performed level walking and stair ascent and descent during control, vision restriction, and knee joint ROM restriction conditions. During level walking, walking speed and step width decreased, and double support time increased significantly with vision and knee joint ROM restrictions. Stance time, step width, and walking angle increased only with knee joint ROM restriction. Stance time, swing time, and double support time were significantly longer in level walking, stair descent, and stair ascent, in that order. The effects of vision and knee joint ROM restrictions were significantly larger than the control conditions. In conclusion, vision and knee joint ROM restrictions affect gait during level walking and stair ascent and descent. This effect is marked in stair ascent with knee joint ROM restriction.

  16. Analysis of muscle activation patterns during transitions into and out of high knee flexion postures.

    PubMed

    Tennant, Liana M; Maly, Monica R; Callaghan, Jack P; Acker, Stacey M

    2014-10-01

    Increased risk of medial tibiofemoral osteoarthritis (OA) is linked to occupations that require frequent transitions into and out of postures which require high knee flexion (>90°). Muscle forces are major contributors to joint loading, and an association between compressive forces due to muscle activations and the degeneration of joint cartilage has been suggested. The purpose of this study was to evaluate muscle activation patterns of muscles crossing the knee during transitions into and out of full-flexion kneeling and squatting, sitting in a low chair, and gait. Both net and co-activation were greater when transitioning out of high flexion postures, with maximum activation occurring at knee angles greater than 100°. Compared to gait, co-activation levels during high flexion transitions were up to approximately 3 times greater. Co-activation was significantly greater in the lateral muscle group compared to the medial group during transitions into and out of high flexion postures. These results suggest that compression due to activation of the medial musculature of the knee may not be the link between high knee flexion postures and increased medial knee OA observed in occupational settings. Further research on a larger subject group and workers with varying degrees of knee OA is necessary.

  17. To use or not to use continuous passive motion post-total knee arthroplasty presenting functional assessment results in early recovery.

    PubMed

    Maniar, Rajesh N; Baviskar, Jayesh V; Singhi, Tushar; Rathi, Suyog S

    2012-02-01

    Continuous passive motion (CPM), though of doubtful value, is yet routinely practiced post-total knee arthroplasty (TKA). We prospectively distributed 84 patients with TKA to 1 of the 3 standard rehabilitation regimes: no-CPM, 1-day-CPM, and 3-day-CPM. We recorded a unique "Timed up and go" test besides pain, Western Ontario and McMaster Universities (WOMAC), short form-12 (SF-12), range of motion, knee and calf swelling, and wound healing parameters. Our standardized and elaborate measurements preoperatively and on postoperative days 3, 5, 14, 42, and 90 showed no statistically significant difference among the 3 groups in each parameter. We concluded that CPM gives no benefit in immediate functional recovery post-TKA, and in fact, the postoperative knee swelling persisted longer. We have since then discontinued its use in our patients without any untoward effect.

  18. Intestinal motor activity, endoluminal motion and transit.

    PubMed

    de Iorio, F; Malagelada, C; Azpiroz, F; Maluenda, M; Violanti, C; Igual, L; Vitrià, J; Malagelada, J-R

    2009-12-01

    A programme for evaluation of intestinal motility has been recently developed based on endoluminal image analysis using computer vision methodology and machine learning techniques. Our aim was to determine the effect of intestinal muscle inhibition on wall motion, dynamics of luminal content and transit in the small bowel. Fourteen healthy subjects ingested the endoscopic capsule (Pillcam, Given Imaging) in fasting conditions. Seven of them received glucagon (4.8 microg kg(-1) bolus followed by a 9.6 microg kg(-1) h(-1) infusion during 1 h) and in the other seven, fasting activity was recorded, as controls. This dose of glucagon has previously shown to inhibit both tonic and phasic intestinal motor activity. Endoluminal image and displacement was analyzed by means of a computer vision programme specifically developed for the evaluation of muscular activity (contractile and non-contractile patterns), intestinal contents, endoluminal motion and transit. Thirty-minute periods before, during and after glucagon infusion were analyzed and compared with equivalent periods in controls. No differences were found in the parameters measured during the baseline (pretest) periods when comparing glucagon and control experiments. During glucagon infusion, there was a significant reduction in contractile activity (0.2 +/- 0.1 vs 4.2 +/- 0.9 luminal closures per min, P < 0.05; 0.4 +/- 0.1 vs 3.4 +/- 1.2% of images with radial wrinkles, P < 0.05) and a significant reduction of endoluminal motion (82 +/- 9 vs 21 +/- 10% of static images, P < 0.05). Endoluminal image analysis, by means of computer vision and machine learning techniques, can reliably detect reduced intestinal muscle activity and motion.

  19. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY: A RANDOMIZED CROSS-OVER STUDY

    PubMed Central

    Wilquin, Lousia; Jakobsen, Thomas Linding; Holsgaard-Larsen, Anders; Bandholm, Thomas

    2017-01-01

    Background Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase agonist muscle activity, especially if the exercise is conducted using rapid muscle contractions. Purpose The purpose of this study was to examine if patients with total knee arthroplasty could perform rapid knee-extensions using a 10 RM load four to eight weeks after surgery, and the degree to which rapid knee-extensions were associated with greater voluntary quadriceps muscle activity during an experimental strength training session, compared to that elicited using slow knee-extensions. Study Design A randomized cross-over study. Methods Twenty-four patients (age 66.5) 4-8 weeks post total knee arthroplasty randomly performed one set of five rapid, and one set of five slow knee-extensions with the operated leg, using a load of their 10 repetition maximum, while surface electromyography recordings were obtained from the vastus medialis and lateralis of the quadriceps muscle. Results Data from 23 of the 24 included patients were analyzed. Muscle activity was significantly higher during rapid knee-extensions (120.2% [10th-90th percentile: 98.3-149.1]) compared to slow knee-extensions (106.0% [88.8-140.8]) for the vastus lateralis (p<0.01), but not for the vastus medialis (120.8% [90.4-134.0]) and (121.8% [93.0-133.0]) (p = 0.17), respectively. Slow and rapid knee-extensions were performed at a median angular velocity of 19.7 degrees/sec (13.7-24.4) and 51.4 degrees/sec (28.9-63.1), respectively Conclusion Four to eight weeks after their total knee arthroplasty, the patients in the present study were able to conduct rapid knee-extensions according to the experimental protocol with an approximately doubled angular velocity compared to slow knee-extensions. This was associated with

  20. Knee joint functional range of movement prior to and following total knee arthroplasty measured using flexible electrogoniometry.

    PubMed

    Myles, Christine M; Rowe, Philip J; Walker, Colin R C; Nutton, Richard W

    2002-08-01

    The functional ranges of movement of the knee were investigated in a group of patients with knee osteoarthritis (n = 42, mean age 70 years) before, 4 months and at 18-24 months after total knee arthroplasty and then compared with age matched normal subjects (n = 20, mean age 67 years). Flexible electrogoniometry was used to record the maximum flexion-extension angle, the minimum flexion-extension angle and flexion-extension excursions of both knees during eleven functional activities along with the active and passive knee joint range of motion measured using a manual goniometer. Over the eleven functional activities the patients pre-operatively exhibited 28% less knee joint excursion than normal age matched subjects. By 18-24 months following total knee arthroplasty only 2% of this deficit was recovered. Statistically this recovery was only significant in level walking, slope ascent and slope descent. A greater range of movement was measured in a non-weight bearing position than was used in weight bearing functional activity. It is concluded that total knee arthroplasty gives rise to little improvement in knee motion during functional activities and that functional range of movement of the knee remains limited when compared to normal knee function for a minimum of 18 months following operation.

  1. Water on the Knee

    MedlinePlus

    ... your knee joint. Some people call this condition "water on the knee." A swollen knee may be ... Choose low-impact exercise. Certain activities, such as water aerobics and swimming, don't place continuous weight- ...

  2. Superior results with continuous passive motion compared to active motion after periosteal transplantation. A retrospective study of human patella cartilage defect treatment.

    PubMed

    Alfredson, H; Lorentzon, R

    1999-01-01

    Fifty-seven consecutive patients (33 men and 24 women), with a mean age of 32 years (range 16-53 years), who suffered from an isolated full-thickness cartilage defect of the patella and disabling knee pain of long duration, were treated by autologous periosteal transplantation to the cartilage defect. The first 38 consecutive patients (group A) were postoperatively treated with continuous passive motion (CPM), and the next 19 consecutive patients (group B) were treated with active motion for the first 5 days postoperatively. In both groups, the initial regimens were followed by active motion, slowly progressive strength training, and slowly progressive weight bearing. In group A, after a mean follow-up of 51 months (range 33-92 months), 29 patients (76%) were graded as excellent or good, 7 patients (19%) were graded as fair, and 2 patients (5%) were graded as poor. In group B, after a mean follow-up of 21 months (range 14-28 months), 10 patients (53%) were graded as excellent or good, 6 patients (32%) were graded as fair, and 3 patients (15%) were graded as poor. Altogether, nine of the fair or poor cases (50%) were diagnosed with chondromalacia of the patella. Our results, after performing autologous periosteal transplantation in patients with full-thickness cartilage defects of the patella and disabling knee pain, are good if CPM is used postoperatively. The clinical results using active motion postoperatively are not acceptable, especially not in patients with chondromalacia of the patella.

  3. Knee stabilization in patients with medial compartment knee osteoarthritis

    PubMed Central

    Lewek, Michael D.; Ramsey, Dan K.; Snyder-Mackler, Lynn; Rudolph, Katherine S.

    2005-01-01

    OBJECTIVE Individuals with medial knee osteoarthritis (MKOA) experience knee laxity and instability. Muscle stabilization strategies may influence the long term integrity of the joint. In this study we determined how individuals with medial knee OA respond to a rapid valgus knee movement to investigate the relationship between muscle stabilization strategies and knee instability. METHODS Twenty one subjects with MKOA and genu varum, and 19 control subjects were tested. Subjects stood with the test limb on a moveable platform that translated laterally to rapidly stress the knee’s medial periarticular structures and create a potentially destabilizing feeling at the knee joint. Knee motion and muscle responses were recorded. Subjects rated their knee instability with a self-report questionnaire about knee instability during daily activities. RESULTS Prior to plate movement the OA subjects demonstrated more medial muscle co-contraction (p=0.014). Following plate movement the OA subjects shifted less weight off the test limb (p = 0.013) and had more medial co-contraction (p=0.037). Those without instability had higher VMMH co-contraction than those who reported more instability (p=0.038). Knee stability correlated positively with VMMH co-contraction prior to plate movement (r = 0.459; p = 0.042). CONCLUSION This study demonstrates that individuals with MKOA attempt to stabilize the knee with greater medial muscle co-contraction in response to laxity that appears on only the medial side of the joint. This strategy presumably contributes to higher joint compression and could exacerbate joint destruction and needs to be altered to slow or stop the progression of the OA disease process. PMID:16142714

  4. Effect of Anterior Tibiofemoral Glides on Knee Extension during Gait in Patients with Decreased Range of Motion after Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Hunt, Michael A.; Di Ciacca, Stephen R.; Jones, Ian C.; Padfield, Beverley

    2010-01-01

    ABSTRACT Purpose: The purpose of this preliminary investigation was to evaluate the effect of anterior tibiofemoral glides on maximal knee extension and selected spatiotemporal characteristics during gait in patients with knee extension deficits after anterior cruciate ligament (ACL) reconstruction. Methods: Twelve patients with knee-extension deficits after recent ACL reconstructions underwent quantitative gait analyses immediately before and after 10 minutes of repeated anterior tibiofemoral glides on the operative limb, and again after a 10-minute seated rest period. Results: Maximum knee extension during stance phase of the operative limb significantly increased immediately after the treatment (mean increase: 2.0°±4.1°, 95% CI: 0.6°–3.3°). Maximum knee extension decreased after the 10-minute rest period (mean decrease: 0.9°±1.8°, 95% CI: −0.1°–1.8°), although the decrease was not statistically significant. Small increases in operative limb step length, stride length, and gait speed were observed after the rest period compared to baseline values only. Conclusions: A single session of anterior tibiofemoral glides increases maximal knee extension during the stance phase of gait in patients with knee-extension deficits. Increases in knee extension are small and short-lived, however, suggesting that continued activity is required to maintain the observed improvements. PMID:21629602

  5. Position controlled Knee Rehabilitation Orthotic Device for Patients after Total Knee Replacement Arthroplasty

    NASA Astrophysics Data System (ADS)

    Wannaphan, Patsiri; Chanthasopeephan, Teeranoot

    2016-11-01

    Knee rehabilitation after total knee replacement arthroplasty is essential for patients during their post-surgery recovery period. This study is about designing one degree of freedom knee rehabilitation equipment to assist patients for their post-surgery exercise. The equipment is designed to be used in sitting position with flexion/extension of knee in sagittal plane. The range of knee joint motion is starting from 0 to 90 degrees angle for knee rehabilitation motion. The feature includes adjustable link for different human proportions and the torque feedback control at knee joint during rehabilitation and the control of flexion/extension speed. The motion of the rehabilitation equipment was set to move at low speed (18 degrees/sec) for knee rehabilitation. The rehabilitation link without additional load took one second to move from vertical hanging up to 90° while the corresponding torque increased from 0 Nm to 2 Nm at 90°. When extra load is added, the link took 1.5 seconds to move to 90° The torque is then increased from 0 Nm to 4 Nm. After a period of time, the speed of the motion can be varied. User can adjust the motion to 40 degrees/sec during recovery activity of the knee and users can increase the level of exercise or motion up to 60 degrees/sec to strengthen the muscles during throughout their rehabilitation program depends on each patient. Torque control is included to prevent injury. Patients can use the equipment for home exercise to help reduce the number of hospital visit while the patients can receive an appropriate therapy for their knee recovery program.

  6. Does the Q − H index show a stronger relationship than the H:Q ratio in regard to knee pain during daily activities in patients with knee osteoarthritis?

    PubMed Central

    Fujita, Remi; Matsui, Yasumoto; Harada, Atsushi; Takemura, Marie; Kondo, Izumi; Nemoto, Tetsuya; Sakai, Tadahiro; Hiraiwa, Hideki; Ota, Susumu

    2016-01-01

    [Purpose] The purpose of this study was to elucidate the relationship between knee muscle strength and knee pain in activities of daily living, based on consideration of the difference between extension and flexion strength (Q − H) and the hamstring:quadriceps (H:Q) ratio in patients with knee osteoarthritis. [Subjects and Methods] The participants were 78 females with knee osteoarthritis, and a total of 133 knees that had not been treated surgically were the targets of this research. The legs were divided according to dominance. Isometric knee extension and flexion muscle strength and knee pain during activities of daily living were measured. The H:Q ratio (flexion/extension muscle strength) and the difference between extension and flexion strength, (extension muscle strength/weight) minus (flexion muscle strength/weight), that is, Q − H, were calculated. The correlation between these indices and the knee pain score during activities of daily living was investigated. [Results] Greater knee pain during activities of daily living was related to lower knee extension muscle strength and Q − H in both the dominant and nondominant legs. Knee flexion muscle strength and the H:Q ratio were not significantly correlated with knee pain during any activities of daily living. [Conclusion] Knee extension muscle strength and Q − H were found to be significantly correlated with knee pain during activities of daily living, whereas the H:Q ratio was not. PMID:28174444

  7. Astym® Therapy for the Management of Recalcitrant Knee Joint Stiffness after Total Knee Arthroplasty.

    PubMed

    Bhave, Anil; Corcoran, James; Cherian, Jeffery J; Mont, Michael A

    2016-01-01

    Knee stiffness is a common complication after total knee arthroplasty (TKA). Despite studies published on the surgical management of reduced range of motion (ROM) after TKA, there is limited evidence on the nonoperative management of joint and soft tissue imbalances possibly contributing to reduced knee ROM. This report assesses changes in ROM, pain, function, and patellar tendon length after Astym® joint mobilization use. A 38-year-old male professional skier had a right TKA 3 months before presentation with 2 subsequent manipulations under anesthesia secondary to persistent knee stiffness. He had patellar baja on radiograph, a reduced arc of ROM, reduced patellar mobility and muscular extensibility, and pain to palpation along the patellar tendon. He had 12 visits of physical therapy with the use of Astym®, patellar mobilization, and tibio-femoral mobilizations with movement. The patient also used a customized knee device at home for prolonged knee extension stretching. The patient was treated for 12 visits, along with home use of customized bracing for knee extension. Significant improvements were seen in pain, function, and ROM. He returned to work full-time, ambulated prolonged distances, and negotiated stairs pain-free. He also demonstrated resolution of patellar baja radiographically. Conservative management of recalcitrant knee joint stiffness after primary TKA can be effective in restoring knee mobility and reducing pain and activity limitation. A multimodal approach using Astym® treatment, customized knee bracing, and targeted joint mobilization can be effective in resolving knee joint stiffness.

  8. [CPM--Continuous Passive Motion: treatment of injured or operated knee-joints using passive movement. A meta-analysis of current literature].

    PubMed

    Kirschner, P

    2004-04-01

    There is still a controversial discussion in literature about the use of motor driven splints in knee surgery--as the principle of continuous passive motion, CPM. For this reason it seemed useful for an evaluation to look through the papers which were published since 1990. It was obvious, that negative results were published often before this year, but this papers are still quoted standard works. In medical data bases subito-doc.de, medscape.com, medica.de and zbmed.de 230 papers were found by search CPM, continuous passive motion and arthromot. Coincidentally there was a search for authors who were already quoted in other papers. 36 papers concerning CPM after knee surgery were utilized. The role of CPM regarding the range of motion, swelling, duration of hospital stay, use of analgesics, costs, postoperative manipulations, wound healing and thrombo embolic complications was evaluated. Although the results of this partial retrospective, partial prospective, sometimes randomized or double blinded studies are in contradiction, there can only be found a trend to better results. New clinical studies for evidence based guidelines in the handling of continuous passive motion after knee surgery are necessary.

  9. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  10. Biotribology of a mobile bearing posterior stabilised knee design--effect of motion restraint on wear, tibio-femoral kinematics and particles.

    PubMed

    Grupp, Thomas M; Schroeder, Christian; Kyun Kim, Tae; Miehlke, Rolf K; Fritz, Bernhard; Jansson, Volkmar; Utzschneider, Sandra

    2014-07-18

    The objective of our study was to evaluate the impact of a biphaseal anterior-posterior (AP) and internal-external (IE) motion restraint system on the wear behaviour, tibio-femoral kinematics and particle release of a mobile bearing posterior stabilised knee design in comparison to the widely used linear restraint. in vitro wear simulation was performed using a posterior stabilised total knee replacement with a mobile rotating platform gliding surface design to compare the standard ISO 14243-1:2002 (E) protocol with a linear AP and IE motion restraint and the new ISO 14243-1:2009 (E) protocol with a biphaseal AP and IE motion restraint. For the mobile gliding surfaces, an increase in wear rate by more than a magnitude was measured applying the biphaseal protocol (8.5±1.6 mg/million cycles) in a direct comparison to the linear protocol (0.33±0.07 mg/million cycles), with statistically significant difference. The amplitudes of AP displacement were 3.22±0.47 mm for the biphaseal test, compared to 1.97±0.22 mm in the linear test and the amplitudes of the IE rotation angle had mean values of 7.32°±0.91° under the biphaseal setup, compared to 1.97°±0.14° under linear motion restraint test conditions. From our observations, we conclude that the changes in AP translation and IE rotation motion restraints from ISO linear to ISO biphaseal test conditions highly impact the knee joint kinematics and wear behaviour of a mobile bearing posterior stabilised knee design.

  11. The Immediate Effect of Lateral Wedge Insoles, With and Without a Subtalar Strap, on the Lateral Trunk Lean Motion in Patients With Knee Osteoarthritis

    PubMed Central

    Esfandiari, Elham; Kamyab, Mojtaba; Yazdi, Hamid Reza; Foroughi, Nasim; Sanjari, Mohammad Ali

    2013-01-01

    Background: Orthotic interventions for knee osteoarthritis (OA) aim to reduce mechanical loading on the medial compartment of the knee and may lessen the lateral trunk lean as the most important compensatory gait strategy. The lateral wedge insole is a known orthotic intervention for knee OA. However, the question whether the addition of a subtalar strap to the wedge improves its effect has not been addressed in the literature. Objective: To compare the effects of lateral wedge insoles, with and without a subtalar strap, on the lateral trunk lean in patients with knee OA. Methods: Twenty-three patients aged over 40 years, with grade I or II OA of the medial compartment of one knee, based on the American College of Rheumatology criteria, were included in this study. The patients were diagnosed with OA based on a clinical examination, and the diagnosis was confirmed with radiographs. A 3-dimensional motion measurement system was used to collect the gait data for 3 different conditions: (1) with no insole, (2) with a lateral wedge insole, and (3) with a lateral wedge insole and a subtalar strap. The immediate effect of the 3 test conditions on the lateral trunk lean was compared during a gait cycle a stance phase and at the point of midstance. Results: Based on the laboratory coordinate system, the 3 conditions had no significant effect on the lateral trunk lean during a gait cycle and a stance phase and at the point of midstance in patients with knee OA. Conclusion: The results of this study demonstrated that the lateral wedge insoles, with and without a subtalar strap, had no immediate effect on the lateral trunk lean in patients with knee OA. However, the long-term effect of lateral wedge insoles on the lateral trunk lean in these patients requires further investigation. PMID:24600533

  12. Possibilities and limitations of novel in-vitro knee simulator.

    PubMed

    Verstraete, Matthias A; Victor, Jan

    2015-09-18

    The ex-vivo evaluation of knee kinematics remains vital to understand the impact of surgical treatments such as total knee arthroplasty (TKA). To that extent, knee simulators have been developed. However, these simulators have mainly focused on the simulation of a squatting motion. The relevance of this motion pattern for patients' activities of daily living is however questionable as squatting is difficult for elderly patients. Walking, stairs and cycling are more relevant motion patterns. This paper presents the design and control of a simulator that allows to independently control the applied kinematic and kinetic boundary conditions to simulate these daily life activities. Thereby, the knee is left with five degrees of freedom; only the knee flexion is actively controlled. From a kinetic point of view, the quadriceps and hamstring muscles are loaded. Optionally, a varus/valgus moment can be applied, facilitating a dynamic evaluation of the knee's stability. The simulator is based on three control loops, whose synchronization appears satisfactory. The input for these control loops can be determined from either musculoskeletal simulations or in accordance to literature data for traditional knee simulators. This opens the door towards an improved understanding of the knee biomechanics and comparison between different applied motion and force patterns.

  13. Contribution of micro-motion to backside wear in a fixed bearing total knee arthroplasty.

    PubMed

    Levine, Rayna A C; Lewicki, Kathleen A; Currier, John H; Mayor, Michael B; Van Citters, Douglas W

    2016-11-01

    This study seeks to identify important factors related to backside wear of tibial inserts in vivo and determine an appropriate wear model for backside wear. An IRB approved database was queried for tibial inserts of a single design from one manufacturer that exhibited evidence of rotatory motion on the backside of the polyethylene. These devices were measured for volumetric wear using a previously established protocol. Features including the change in locking lip width and measurement of micro-motion marks were used to describe the motion pattern. Volumetric wear and implant characteristics were compared using linear regressions by modeling wear theories suggested by Archard and Wang to determine the most appropriate model for backside wear. The Wang model showed that duration, adjusted sliding distance, and cross-shear index accounted for approximately 58% of the volumetric wear variation while adjusted sliding distance and duration in vivo accounted for approximately 35% of the volumetric wear variation in the Archard model. Patient weight (p = 0.750), patient BMI (p = 0.680), and backside area (p = 0.784) of the tibial insert were all found to be non-significant in the Wang model. Similarly, patient weight (p = 0.233), patient BMI (p = 0.162), and backside area (p = 0.796) were found to be non-significant in the Archard model. Multidirectional micro-motion appears to contribute significantly to the wear of these components, supporting the Wang theory of cross-shear for polyethylene wear. Cross-shear of polymers on an unpolished titanium tray can lead to an increase in wear debris in the body. Care should be taken when designing locking mechanisms and tray designs. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1933-1940, 2016.

  14. Prosthetic Knee Systems

    MedlinePlus

    ... must give support when people stand, allow smooth motion when people walk, and permit movement when people ... of knees and their options for stability and motion control would work best for them. There are ...

  15. Runner's Knee

    MedlinePlus

    ... name just two. It's the most common overuse injury among runners, but it can also strike other athletes who do activities that require a lot of knee bending, such as biking, jumping, or skiing. Runner's knee happens when the kneecap (patella) tracks incorrectly over a ...

  16. Effect of Knee Position on Quadriceps Muscle Force Steadiness and Activation Strategies

    PubMed Central

    Krishnan, Chandramouli; Allen, Eric J.; Williams, Glenn N.

    2010-01-01

    Introduction This study investigated the effect of knee position on quadriceps force steadiness and activation strategies. Methods Quadriceps force steadiness was evaluated in twenty-two volunteers at two knee positions by testing their ability to regulate submaximal force. Muscle activation strategies were studied in both time and frequency domains using surface electromyography. Results Quadriceps force fluctuations and the associated agonist and antagonist activity were significantly higher at 90° than at 30° of flexion (P < 0.05). The quadriceps median frequency recorded at 30° was significantly higher than at 90° of flexion (P < 0.05). Regression analyses revealed that force steadiness was related to quadriceps activation and median frequency (P < 0.001), but not to hamstring coactivation (P > 0.05). Discussion The results indicate that knee position significantly affects quadriceps force steadiness and activation strategies. This finding may have important implications for designing a force control testing protocol and interpreting test results. PMID:21404288

  17. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. Part I. Numerical model-based optimization

    PubMed Central

    Choi, Jang-Hwan; Fahrig, Rebecca; Keil, Andreas; Besier, Thor F.; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Maier, Andreas

    2013-01-01

    Purpose: Human subjects in standing positions are apt to show much more involuntary motion than in supine positions. The authors aimed to simulate a complicated realistic lower body movement using the four-dimensional (4D) digital extended cardiac-torso (XCAT) phantom. The authors also investigated fiducial marker-based motion compensation methods in two-dimensional (2D) and three-dimensional (3D) space. The level of involuntary movement-induced artifacts and image quality improvement were investigated after applying each method. Methods: An optical tracking system with eight cameras and seven retroreflective markers enabled us to track involuntary motion of the lower body of nine healthy subjects holding a squat position at 60° of flexion. The XCAT-based knee model was developed using the 4D XCAT phantom and the optical tracking data acquired at 120 Hz. The authors divided the lower body in the XCAT into six parts and applied unique affine transforms to each so that the motion (6 degrees of freedom) could be synchronized with the optical markers’ location at each time frame. The control points of the XCAT were tessellated into triangles and 248 projection images were created based on intersections of each ray and monochromatic absorption. The tracking data sets with the largest motion (Subject 2) and the smallest motion (Subject 5) among the nine data sets were used to animate the XCAT knee model. The authors defined eight skin control points well distributed around the knees as pseudo-fiducial markers which functioned as a reference in motion correction. Motion compensation was done in the following ways: (1) simple projection shifting in 2D, (2) deformable projection warping in 2D, and (3) rigid body warping in 3D. Graphics hardware accelerated filtered backprojection was implemented and combined with the three correction methods in order to speed up the simulation process. Correction fidelity was evaluated as a function of number of markers used (4–12) and

  18. Using Kinesthetic Activities to Teach Ptolemaic and Copernican Retrograde Motion

    ERIC Educational Resources Information Center

    Richards, Ted

    2012-01-01

    This paper describes a method for teaching planetary retrograde motion, and the Ptolemaic and Copernican accounts of retrograde motion, by means of a series kinesthetic learning activities (KLAs). In the KLAs described, the students literally walk through the motions of the planets in both systems. A retrospective statistical analysis shows that…

  19. Design and control of a prosthetic leg for above-knee amputees operated in semi-active and active modes

    NASA Astrophysics Data System (ADS)

    Park, Jinhyuk; Yoon, Gun-Ha; Kang, Je-Won; Choi, Seung-Bok

    2016-08-01

    This paper proposes a new prosthesis operated in two different modes; the semi-active and active modes. The semi-active mode is achieved from a flow mode magneto-rheological (MR) damper, while the active mode is obtained from an electronically commutated (EC) motor. The knee joint part of the above knee prosthesis is equipped with the MR damper and EC motor. The MR damper generates reaction force by controlling the field-dependent yield stress of the MR fluid, while the EC motor actively controls the knee joint angle during gait cycle. In this work, the MR damper is designed as a two-end type flow mode mechanism without air chamber for compact size. On other hand, in order to predict desired knee joint angle to be controlled by EC motor, a polynomial prediction function using a statistical method is used. A nonlinear proportional-derivative controller integrated with the computed torque method is then designed and applied to both MR damper and EC motor to control the knee joint angle. It is demonstrated that the desired knee joint angle is well achieved in different walking velocities on the ground ground.

  20. Relationship Between Physical Activity and Health-Related Utility Among Knee Osteoarthritis Patients

    PubMed Central

    Manheim, Larry M.; Dunlop, Dorothy; Song, Jing; Semanik, Pamela; Lee, Jungwha; Chang, Rowland W.

    2012-01-01

    Objective To estimate the relationship between physical activity and health-related utility for people with knee OA and implications for designing cost effective interventions. Methods Use GEE regression analysis to estimate partial association of accelerometer-measured physical activity levels with health-related utility after controlling for demographics, health status, knee OA severity level, pain and functioning. Results Moving from lowest to middle tertile of physical activity levels is associated with .071 (p<.01) increase in health-related utility after controlling for demographics and .036 (p<.05) increase in utility after controlling for demographics, health status, knee OA severity level, weight, pain, and functional impairments. Conclusion Intervention programs that move individuals out of the lowest tertile of physical activity have the potential to be cost effective. PMID:22328141

  1. Changes in the activity of trunk and hip extensor muscles during bridge exercises with variations in unilateral knee joint angle

    PubMed Central

    Kim, Juseung; Park, Minchul

    2016-01-01

    [Purpose] This study compared abdominal and hip extensor muscle activity during a bridge exercise with various knee joint angles. [Subjects and Methods] Twenty-two healthy male subjects performed a bridge exercise in which the knee joint angle was altered. While subjects performed the bridge exercise, external oblique, internal oblique, gluteus maximus, and semitendinosus muscle activity was measured using electromyography. [Results] The bilateral external and internal oblique muscle activity was significantly higher at 0° knee flexion compared to 120°, 90°, and 60°. The bilateral gluteus maximus muscle activity was significantly different at 0° of knee flexion compared to 120°, 90°, and 60°. The ipsilateral semitendinosus muscle activity was significantly increased at 90° and 60° of knee flexion compared to 120°, and significantly decreased at 0° knee flexion compared with 120°, 90°, and 60°. The contralateral semitendinosus muscle activity was significantly higher at 60° of knee flexion than at 120°, and significantly higher at 0° of knee flexion than at 120°, 90°, and 60°. [Conclusion] Bridge exercises performed with knee flexion less than 90° may be used to train the ipsilateral semitendinosus. Furthermore, bridge exercise performed with one leg may be used to train abdominal and hip extensor muscles. PMID:27799688

  2. Effect of implant design on knee flexion.

    PubMed

    Dennis, Douglas A; Heekin, R David; Clark, Charles R; Murphy, Jeffrey A; O'Dell, Tammy L; Dwyer, Kimberly A

    2013-03-01

    From March 2006 to August 2008, 93 subjects (186 knees) underwent simultaneous bilateral total knee arthroplasty performed by eight surgeons at North American centers. This randomized study was conducted to determine whether non-weight-bearing passive flexion was superior for knees receiving a posterior stabilized high flexion device compared to a posterior stabilized standard device in the contra-lateral knee. Weight-bearing single leg active flexion was one secondary endpoint. Follow-up compliance was 92.5%. Results show small, but significant superiority in the motion metrics for the high flexion device compared to the standard device 12 months after surgery, especially for a subgroup of patients with pre-operative flexion less than 120° in both knees. Thus, the ideal candidate for the high flexion device may be one with lesser pre-operative flexion.

  3. [Locomotive syndrome and frailty. Total knee arthroplasty supports active life of the elderly].

    PubMed

    Watanabe, Toshifumi; Sekiya, Ichiro; Muneta, Takeshi

    2012-04-01

    For a society with an aging population, it is important to extend healthy life expectancy. Knee arthroplasty is one of the most successful and beneficial treatments for osteoarthritic knees, helping the elderly improve their activities of daily life. Previous reports have proved health-related quality of life improves dramatically with this surgery. In particular, pain and physical functioning scores improve significantly. Although the preoperative physical activity of each patient does affect the postoperative activity level, sufficient improvements can be expected for this procedure on the elderly. These effective improvements make the number of knee arthroplasties increase year to year. The elderly have high risks of postoperative medical complications. However, long term results are comparable or superior to those in younger patients. In elderly patients, pre-existing conditions should be carefully controlled, and postoperative complications, including infection and thrombosis, should be treated prophylactically to promote safety and postoperative recovery.

  4. Effects of hand and knee positions on muscular activity during trunk extension exercise with the Roman chair.

    PubMed

    Park, Se-yeon; Yoo, Won-gyu

    2014-12-01

    This experimental study was performed to investigate the effects of hand and knee positions on muscular activity during back extension exercises with the Roman chair. Eighteen asymptomatic male amateur athletes performed four prone back extension exercises with two hand positions (crossed-arms and behind-the-head), and two knee positions (extended knee and 90° flexed knee). Surface electromyography (sEMG) was performed to collect data from the lower trapezius (LT), latissimus dorsi (LD), erector spinae in the T12 paraspinal region (ES-T12), erector spinae at the L3 level (ES-L3), gluteus maximus (GM), and biceps femoris (BF). Two-way repeated analysis of variance with two within-subject factors (two hand positions and two knee positions) was used to determine the significance of differences between the exercise conditions, and which hand and knee positions resulted in greater activation with exercise variation. The root mean square sEMG values were normalized using the maximum voluntary isometric contraction (MVIC) and represented as the % of the maximum EMG (%mEMG). There was no significant interaction between knee and hand positions in the %mEMG data. The results showed that the hand position affected the normalized activation of LT; the behind-the-head position resulted in significantly greater muscle activation than the crossed-arms hand position (P<0.05). The activations of the LD, ES-T10, ES-L4, and GM were greater in the 90° flexed-knee position compared to the extended-knee position (P<0.05). Although back extension exercise using the Roman chair has been shown to effectively activate the extensor musculature, our results indicated that changing the knee and hand positions could activate specific muscles differently. To achieve greater activation of trunk extensor muscle during extension exercise with the Roman chair, the flexed-knee position is a useful means of increasing resistance.

  5. Mechanical correction of dynamometer moment for the effects of segment motion during isometric knee-extension tests.

    PubMed

    Tsaopoulos, Dimitrios E; Baltzopoulos, Vasilios; Richards, Paula J; Maganaris, Constantinos N

    2011-07-01

    The purpose of this study was to determine the effect of dynamometer and joint axis misalignment on measured isometric knee-extension moments using inverse dynamics based on the actual joint kinematic information derived from the real-time X-ray video and to compare the errors when the moments were calculated using measurements from external anatomical surface markers or obtained from the isokinetic dynamometer. Six healthy males participated in this study. They performed isometric contractions at 90° and 20° of knee flexion, gradually increasing to maximum effort. For the calculation of the actual knee-joint moment and the joint moment relative to the knee-joint center, determined using the external marker, two free body diagrams were used of the Cybex arm and the lower leg segment system. In the first free body diagram, the mean center of the circular profiles of the femoral epicondyles was used as the knee-joint center, whereas in the second diagram, the joint center was assumed to coincide with the external marker. Then, the calculated knee-joint moments were compared with those measured by the dynamometer. The results indicate that 1) the actual knee-joint moment was different from the dynamometer recorded moment (difference ranged between 1.9% and 4.3%) and the moment calculated using the skin marker (difference ranged between 2.5% and 3%), and 2) during isometric knee extension, the internal knee angle changed significantly from rest to the maximum contraction state by about 19°. Therefore, these differences cannot be neglected if the moment-knee-joint angle relationship or the muscle mechanical properties, such as length-tension relationship, need to be determined.

  6. Multiplanar Knee Laxity and Perceived Function During Activities of Daily Living and Sport

    PubMed Central

    Taylor, Jeffrey B.; Wang, Hsin-Min; Schmitz, Randy J.; Rhea, Christopher K.; Ross, Scott E.; Shultz, Sandra J.

    2015-01-01

    Context Greater knee-joint laxity may lead to a higher risk of knee injury, yet it is unknown whether results of self-reported outcome measures are associated with distinct knee-laxity profiles. Objective To identify the extent to which multiplanar knee laxity is associated with patient-reported outcomes of knee function in healthy individuals during activities of daily living and sport. Design Descriptive laboratory study. Setting University research laboratory. Patients or Other Participants Forty healthy individuals (20 men, 20 women; age = 18–31 years). Main Outcome Measure(s) All participants were given the Knee Outcome Survey Activities of Daily Living Scale (KOS-ADL) and Sports Activities Scale (KOS-SAS) and subsequently measured for knee laxity in the sagittal, frontal, and transverse planes. Separate backward stepwise regression analyses were performed to determine the extent to which multiplanar knee-laxity values predicted KOS-ADL and KOS-SAS scores within each sex. Results Women had higher magnitudes of anterior, posterior (POSTLAX), varus (VARLAX), valgus (VALLAX), and internal-rotation laxity than men and trended toward greater external rotation (ERLAX) laxity. Greater POSTLAX, less VALLAX, and greater VARLAX was associated with lower KOS-ADL scores (KOS-ADL = −4.8 [POSTLAX], + 3.3 [VALLAX] − 2.2 [VARLAX] + 100.4, R2 = 0.74, P < .001) and greater POSTLAX and less VALLAX was associated with lower KOS-SAS scores (KOS-SAS = −8.2 [POSTLAX], + 3.6 [VALLAX] + 96.4, R2 = 0.67, P < .001) in women. In men, greater POSTLAX and less ERLAX was associated with lower KOS-SAS scores (KOS-ADL = −4.7 [POSTLAX], + 0.9 [ERLAX] + 96.4, R2 = 0.49, P < .001). Conclusions The combination of POSTLAX with less relative VALLAX (women) or less relative ERLAX (men) was a strong predictor of KOS scores, suggesting that a self-reported outcome measure may be beneficial as part of a preparticipation screening battery to identify those with perceived functional deficits

  7. Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running.

    PubMed

    Timmins, R G; Opar, D A; Williams, M D; Schache, A G; Dear, N M; Shield, A J

    2014-08-01

    The aim of this study was to determine whether declines in knee flexor strength following overground repeat sprints were related to changes in hamstrings myoelectrical activity. Seventeen recreationally active men completed maximal isokinetic concentric and eccentric knee flexor strength assessments at 180°/s before and after repeat sprint running. Myoelectrical activity of the biceps femoris (BF) and medial hamstrings (MHs) was measured during all isokinetic contractions. Repeated measures mixed model [fixed factors = time (pre- and post-repeat sprint) and leg (dominant and nondominant), random factor = participants] design was fitted with the restricted maximal likelihood method. Repeat sprint running resulted in significant declines in eccentric, and concentric, knee flexor strength (eccentric = 26 ± 4 Nm, 15% P < 0.001; concentric 11 ± 2 Nm, 10% P < 0.001). Eccentric BF myoelectrical activity was significantly reduced (10%; P = 0.035). Concentric BF and all MH myoelectrical activity were not altered. The declines in maximal eccentric torque were associated with the change in eccentric BF myoelectrical activity (P = 0.013). Following repeat sprint running, there were preferential declines in the myoelectrical activity of the BF, which explained declines in eccentric knee flexor strength.

  8. Motion and Muscle Activity Are Affected by Instability Location During a Squat Exercise.

    PubMed

    Nairn, Brian C; Sutherland, Chad A; Drake, Janessa D M

    2017-03-01

    Nairn, BC, Sutherland, CA, and Drake, JDM. Motion and muscle activity are affected by instability location during a squat exercise. J Strength Cond Res 31(3): 677-685, 2017-Squat exercise training using instability devices has become increasingly popular for a multitude of reasons. Many devices generate instability at the feet and provide a bottom-up perturbation; however, the effect of a top-down instability device during a squat remains unclear. To induce instability at the upper body, a water-filled cylinder called the Attitube was used. This study analyzed the effects of instability location (top-down, bottom-up, and no instability) during a squat exercise in terms of kinematics and muscle activation. Ten male participants were instrumented with 75 reflective markers to track kinematics of the ankle, knee, hip, trunk, and the Bar/Attitube, and electromyography was recorded from 12 muscles bilaterally. Squats were performed with an Olympic bar on a stable surface, an Olympic bar on a BOSU ball (BALL, bottom-up), and the Attitube on solid ground (TUBE, top-down). The TUBE showed up to 1.5 times reduction in erector spinae activation and up to 1.5 times less trunk flexion while being performed at a slower velocity. There was also higher abdominal activation in the TUBE, with up to 2.8 times greater oblique activation compared with the stable condition. The BALL increased ankle eversion and knee flexion with higher muscle activation in gastrocnemius, biceps femoris, and quadriceps. Overall, changing the location of instability during a squat changed the motion and muscle activation patterns of the trunk and lower extremities. This provides information for future research into rehabilitation, learning proper squat technique, and for specific training scenarios.

  9. Prospective Randomized Trial of the Efficacy of Continuous Passive Motion Post Total Knee Arthroplasty: Experience of the Hospital for Special Surgery.

    PubMed

    Joshi, Rupali N; White, Peter B; Murray-Weir, Mary; Alexiades, Michael M; Sculco, Thomas P; Ranawat, Amar S

    2015-12-01

    Conflicting evidence has created substantial controversy regarding the use of continuous passive motion (CPM) in the in-patient setting post total knee arthroplasty (TKA). A total of 109 patients were randomly assigned to two groups, CPM or no CPM, applied after TKA. All patients received the same physical therapy protocol (3 sessions per day), with the only exception being the CPM. Both groups had a knee flexion of 115° at 6 weeks and 120° at 3 months, with no significant differences (P=0.69 and P=0.41, respectively). Length of stay was significantly less for the group who did not receive CPM. The use of CPM had no clinically relevant benefits with respect to AROM, clinical outcomes or discharge disposition and was associated with a cost of $235.50 per TKA.

  10. People can understand descriptions of motion without activating visual motion brain regions

    PubMed Central

    Dravida, Swethasri; Saxe, Rebecca; Bedny, Marina

    2013-01-01

    What is the relationship between our perceptual and linguistic neural representations of the same event? We approached this question by asking whether visual perception of motion and understanding linguistic depictions of motion rely on the same neural architecture. The same group of participants took part in two language tasks and one visual task. In task 1, participants made semantic similarity judgments with high motion (e.g., “to bounce”) and low motion (e.g., “to look”) words. In task 2, participants made plausibility judgments for passages describing movement (“A centaur hurled a spear … ”) or cognitive events (“A gentleman loved cheese …”). Task 3 was a visual motion localizer in which participants viewed animations of point-light walkers, randomly moving dots, and stationary dots changing in luminance. Based on the visual motion localizer we identified classic visual motion areas of the temporal (MT/MST and STS) and parietal cortex (inferior and superior parietal lobules). We find that these visual cortical areas are largely distinct from neural responses to linguistic depictions of motion. Motion words did not activate any part of the visual motion system. Motion passages produced a small response in the right superior parietal lobule, but none of the temporal motion regions. These results suggest that (1) as compared to words, rich language stimuli such as passages are more likely to evoke mental imagery and more likely to affect perceptual circuits and (2) effects of language on the visual system are more likely in secondary perceptual areas as compared to early sensory areas. We conclude that language and visual perception constitute distinct but interacting systems. PMID:24009592

  11. Instabilities, motion and deformation of active fluid droplets

    NASA Astrophysics Data System (ADS)

    Whitfield, Carl A.; Hawkins, Rhoda J.

    2016-12-01

    We consider two minimal models of active fluid droplets that exhibit complex dynamics including steady motion, deformation, rotation and oscillating motion. First we consider a droplet with a concentration of active contractile matter adsorbed to its boundary. We analytically predict activity driven instabilities in the concentration profile, and compare them to the dynamics we find from simulations. Secondly, we consider a droplet of active polar fluid of constant concentration. In this system we predict, motion and deformation of the droplets in certain activity ranges due to instabilities in the polarisation field. Both these systems show spontaneous transitions to motility and deformation which resemble dynamics of the cell cytoskeleton in animal cells.

  12. Role of gastrocnemius activation in knee joint biomechanics: gastrocnemius acts as an ACL antagonist.

    PubMed

    Adouni, M; Shirazi-Adl, A; Marouane, H

    2016-01-01

    Gastrocnemius is a premier muscle crossing the knee, but its role in knee biomechanics and on the anterior cruciate ligament (ACL) remains less clear when compared to hamstrings and quadriceps. The effect of changes in gastrocnemius force at late stance when it peaks on the knee joint response and ACL force was initially investigated using a lower extremity musculoskeletal model driven by gait kinematics-kinetics. The tibiofemoral joint under isolated isometric contraction of gastrocnemius was subsequently analyzed at different force levels and flexion angles (0°-90°). Changes in gastrocnemius force at late stance markedly influenced hamstrings forces. Gastrocnemius acted as ACL antagonist by substantially increasing its force. Simulations under isolated contraction of gastrocnemius confirmed this role at all flexion angles, in particular, at extreme knee flexion angles (0° and 90°). Constraint on varus/valgus rotations substantially decreased this effect. Although hamstrings and gastrocnemius are both knee joint flexors, they play opposite roles in respectively protecting or loading ACL. Although the quadriceps is also recognized as antagonist of ACL, at larger joint flexion and in contrast to quadriceps, activity in gastrocnemius substantially increased ACL forces (anteromedial bundle). The fact that gastrocnemius is an antagonist of ACL should help in effective prevention and management of ACL injuries.

  13. Using Kinesthetic Activities to Teach Ptolemaic and Copernican Retrograde Motion

    NASA Astrophysics Data System (ADS)

    Richards, Ted

    2012-06-01

    This paper describes a method for teaching planetary retrograde motion, and the Ptolemaic and Copernican accounts of retrograde motion, by means of a series kinesthetic learning activities (KLAs). In the KLAs described, the students literally walk through the motions of the planets in both systems. A retrospective statistical analysis shows that students who participated in these activities performed better on examination questions pertaining to retrograde motion than students who did not. Potential explanations for this result, including the breaking of classroom routine, the effect of body movement on conceptual memory, and egocentric spatial proprioception, are considered.

  14. Knee Instability and Basic and Advanced Function Decline in Persons with Knee Osteoarthritis

    PubMed Central

    Sharma, Leena; Chmiel, Joan S.; Almagor, Orit; Moisio, Kirsten; Chang, Alison H.; Belisle, Laura; Zhang, Yunhui; Hayes, Karen W.

    2015-01-01

    Objective Manifestations of instability in knee OA include low overall knee confidence, low confidence that the knees will not buckle, buckling, and excessive motion during gait. Confidence and buckling may particularly influence activity choices, contributing to events leading to disability. Buckling is more likely to affect advanced than basic functional tasks. In this prospective, longitudinal study, we tested the hypotheses: overall knee confidence, buckling confidence, buckling, and frontal plane motion during gait are associated with advanced 2-year function outcome in persons with knee OA. Methods Persons with knee OA were queried about overall knee confidence (higher worse), buckling confidence, and knee buckling, and underwent quantitative gait analysis to quantify varus-valgus excursion and angular velocity. Physical function was assessed using the LLFDI Basic and Advanced Lower Extremity Domain scores. Logistic regression was used to evaluate the relationship between baseline instability measures and baseline-to-2-year function outcome, adjusting for potential confounders. Results 212 persons (mean age 64.6 years, 76.9% women) comprised the sample. Buckling was significantly associated with poor advanced (adjusted OR 2.08, 95% CI: 1.03–4.20) but not basic function outcome. Overall knee confidence was significantly associated with advanced outcome (adjusted OR 1.65, 95% CI: 1.01–2.70), while associations between buckling confidence and both outcomes approached significance. Neither varus-valgus excursion nor angular velocity during gait was associated with either outcome. Conclusion Knee buckling and confidence were each associated with poor 2-year advanced function outcome. Current treatment does not address these modifiable factors; interventions to address them may improve outcome in knee OA. PMID:25732594

  15. Differences between actual and expected leisure activities after total knee arthroplasty for osteoarthritis.

    PubMed

    Jones, Dina L; Bhanegaonkar, Abhijeet J; Billings, Anthony A; Kriska, Andrea M; Irrgang, James J; Crossett, Lawrence S; Kwoh, C Kent

    2012-08-01

    This prospective cohort study determined the type, frequency, intensity, and duration of actual vs expected leisure activity among a cohort undergoing total knee arthroplasty. Data on actual and expected participation in 36 leisure activities were collected preoperatively and at 12 months in 90 patients with knee osteoarthritis. Despite high expectations, there were statistically and clinically significant differences between actual and expected activity at 12 months suggesting that expectations may not have been fulfilled. The differences were equivalent to walking 14 less miles per week than expected, which is more than the amount of activity recommended in national physical activity guidelines. Perhaps an educational intervention could be implemented to help patients establish appropriate and realistic leisure activity expectations before surgery.

  16. Runner's Knee

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Runner's Knee KidsHealth > For Teens > Runner's Knee A A A ... told he had runner's knee. What Is Runner's Knee? Runner's knee is the term doctors use for ...

  17. Knee pain

    MedlinePlus

    Pain - knee ... Knee pain can have different causes. Being overweight puts you at greater risk for knee problems. Overusing your knee can trigger knee problems that cause pain. If you have a history of arthritis, it ...

  18. Anterior cruciate ligament injury after more than 20 years: I. Physical activity level and knee function.

    PubMed

    Tengman, E; Brax Olofsson, L; Nilsson, K G; Tegner, Y; Lundgren, L; Häger, C K

    2014-12-01

    Little is known about physical activity level and knee function including jump capacity and fear of movement/reinjury more than 20 years after injury of the anterior cruciate ligament (ACL). Seventy persons with unilateral ACL injury participated (23 ± 2 years post-injury): 33 treated with physiotherapy in combination with surgical reconstruction (ACLR ), and 37 treated with physiotherapy alone (ACLPT ). These were compared with 33 age- and gender-matched controls. Assessment included knee-specific and general physical activity level [Tegner activity scale, International Physical Activity Questionnaire (IPAQ)], knee function [Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS)], jump capacity (one-leg hop, vertical jump, side hops), and fear of movement/reinjury [Tampa Scale for Kinesiophobia (TSK)]. Outcomes were related to degree of osteoarthritis (OA). ACL-injured had lower Lysholm, KOOS, and Tegner scores than controls (P < 0.001), while IPAQ score was similar. ACL-injured demonstrated inferior jump capacity in injured compared with noninjured leg (6-25%, P < 0.001-P = 0.010 in the different jumps), while noninjured leg had equal jump capacity as controls. ACL groups scored 33 ± 7 and 32 ± 7 of 68 on TSK. Lower scores on Lysholm and KOOS symptom were seen for persons with moderate-to-high OA than for no-or-low OA, while there were no differences for physical activity and jump capacity. Regardless of treatment, there are still negative knee-related effects of ACL injury more than 20 years later.

  19. Why Patients Do Not Participate in Sports Activities After Total Knee Arthroplasty

    PubMed Central

    Chang, Moon Jong; Kang, Yeon Gwi; Chung, Byung June; Chang, Chong Bum; Kim, Tae Kyun

    2015-01-01

    Background It is important to identify the reasons or factors preventing patients from participating in sports activities after total knee arthroplasty (TKA) to improve patient satisfaction and general health that can be gained from regular sports activities. Purpose To determine the reasons for lack of participation in regular sports activities after TKA as perceived by patients and to identify specific factors involved. Study Design Case series; Level of evidence, 4. Methods A total of 369 patients with a follow-up longer than 1 year after TKA were included in this retrospective study. A postal survey regarding sports activities was conducted using a questionnaire gathering information such as sociodemographic data, activity levels, and sports activities after TKA. The reasons perceived by patients for not participating in sports activities were determined. Patients unable to participate in sports activities were compared with patients able to do so in terms of sociodemographic data and pre- and postoperative outcomes. Results Of the 369 patients, 88 (24%) replied that they could not participate in a sports activity. Among the perceived reasons, reasons not related to the replaced knee were more frequent than those related to the replaced knee (76% vs 24%). Symptoms related to the spine or other joints composed 25% of the total perceived reasons. The presence of medical comorbidities accounted for 16%, while symptoms in the nonreplaced knee represented 8% of the reasons. In terms of patient factors, multivariate logistic regression revealed that male sex, a floor-based (ie, non-Western) lifestyle with greater demands on knee flexion, and worse postoperative University of California at Los Angeles activity scale were associated with nonregular sports activity levels. Conclusion The perceived reasons and patient factors hindering regular sports activities after TKA were not restricted to problems with the replaced knee. Nonetheless, orthopaedic surgeons may have a

  20. Physical Function and Physical Activity in Obese Adults After Total Knee Arthroplasty.

    PubMed

    Smith, Webb A; Zucker-Levin, Audrey; Mihalko, William M; Williams, Michael; Loftin, Mark; Gurney, James G

    2017-04-01

    Obese patients are more likely to have osteoarthritis and total knee arthroplasty (TKA). This investigation sought to evaluate physical function, activity level, and quality of life (QOL). Obese participants near 1-year postsurgical follow-up appointment were recruited. Evaluation included QOL and activity questionnaire, medical histories, anthropometrics, strength, and aerobic capacity. Sixty participants completed assessments. Obese TKA patients have physical performance limitations and low physical activity levels 1 year after surgery and completion of postoperative rehabilitation.

  1. Acute effects of instrument assisted soft tissue mobilization vs. foam rolling on knee and hip range of motion in soccer players.

    PubMed

    Markovic, Goran

    2015-10-01

    The aim of the present investigation was to evaluate the acute effects of foam rolling (FR) and a new form of instrument-assisted soft tissue mobilization (IASTM), Fascial Abrasion Technique ™ (FAT) on hip and knee range of motion in soccer players. Twenty male soccer players randomly allocated into FR and FAT group (n = 10 each). Passive knee flexion and straight leg raise tests were measured before, immediately after and 24 h after intervention (FR or FAT). The FR group applied a 2-min quadriceps and hamstrings rolling, while FAT group received a 2-min application of FAT to the quadriceps and hamstrings muscles. Both groups significantly improved knee and hip ROM (p < 0.05), with higher gains observed in FAT group (10-19% vs. 5-9%). At 24 h post-treatment, only FAT group preserved most of the gains in ROM (7-13%; p < 0.05). These results support the use of the newly developed IASMT, Fascial Abrasion Technique ™ and FR for increasing lower extremity ROM of athletes.

  2. Dynamic Contact Mechanics on the Tibial Plateau of the Human Knee During Activities of Daily Living

    PubMed Central

    Gilbert, Susannah; Chen, Tony; Hutchinson, Ian D.; Choi, Dan; Voigt, Clifford; Warren, Russell F.; Maher, Suzanne A.

    2013-01-01

    Despite significant advances in scaffold design, manufacture, and development, it remains unclear what forces these scaffolds must withstand when implanted into the heavily loaded environment of the knee joint. The objective of this study was to fully quantify the dynamic contact mechanics across the tibial plateau of the human knee joint during gait and stair climbing. Our model consisted of a modified Stanmore knee simulator (to apply multi-directional dynamic forces), a two-camera motion capture system (to record joint kinematics), an electronic sensor (to record contact stresses on the tibial plateau), and a suite of post-processing algorithms. During gait, peak contact stresses on the medial plateau occurred in areas of cartilage-cartilage contact; while during stair climb, peak contact stresses were located in the posterior aspect of the plateau, under the meniscus. On the lateral plateau, during gait and in early stair-climb, peak contact stresses occurred under the meniscus, while in late stair-climb, peak contact stresses were experienced in the zone of cartilage-cartilage contact. At 45% of the gait cycle, and 20% and 48% of the stair-climb cycle, peak stresses were simultaneously experienced on both the medial and lateral compartment, suggesting that these phases of loading warrant particular consideration in any simulation intended to evaluate scaffold performance. Our study suggests that in order to design a scaffold capable of restoring ‘normal’ contact mechanics to the injured knees, the mechanics of the intended site of implantation should be taken into account in any pre-clinical testing regime. PMID:24296275

  3. TSG-6 Activity as a Novel Biomarker of Progression in Knee Osteoarthritis

    PubMed Central

    Wisniewski, Hans-Georg; Colón, Elisa; Liublinska, Viktoriia; Karia, Raj J.; Stabler, Thomas V.; Attur, Mukundan; Abramson, Steven B.; Band, Philip A.; Kraus, Virginia B.

    2014-01-01

    Objective To establish whether there is an association between TSG-6 activity and osteoarthritis (OA) progression. Design TSG-6 activity was determined in 132 synovial fluids from patients with OA of the knee, using a novel quantitative TSG-6 activity assay. The association between TSG-6 activities at baseline and four distinct disease progression states, determined at three-year follow-up, was analyzed using logistic regression. Results There was a statistically significant relationship between TSG-6 activity at baseline and all OA progression states over a three-year period. Patient knees with TSG-6 activities in the top 10th percentile, compared to the median activity, had an odds ratio (OR) of at least 7.86 (confidence interval (CI) [3.2, 20.5]) for total knee arthroplasty (TKA) within three years, and of at least 5.20 (CI [1.8, 13.9]) after adjustment for confounding factors. Receiver operating characteristic (ROC) analysis for knee arthroplasty yielded a cut-off point of 13.3 TSG-6 activity units/ml with the following parameters: area under the curve 0.90 (CI [0.804, 0.996]), sensitivity 0.91 (CI [0.59, 0.99]), specificity 0.82 (CI [0.74, 0.88]) and a negative predictive value (NPV) of 0.99 (CI [0.934, 0.994]). Conclusion The TSG-6 activity is a promising independent biomarker for OA progression. Given the high NPV, this assay may be particularly suitable for identifying patients at low risk of rapid disease progression and to assist in the timing of arthroplasty. PMID:24333293

  4. Image-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Unberath, Mathias; Choi, Jang-Hwan; Berger, Martin; Maier, Andreas; Fahrig, Rebecca

    2015-03-01

    We previously introduced four fiducial marker-based strategies to compensate for involuntary knee-joint motion during weight-bearing C-arm CT scanning of the lower body. 2D methods showed significant reduction of motion- related artifacts, but 3D methods worked best. However, previous methods led to increased examination times and patient discomfort caused by the marker attachment process. Moreover, sub-optimal marker placement may lead to decreased marker detectability and therefore unstable motion estimates. In order to reduce overall patient discomfort, we developed a new image-based 2D projection shifting method. A C-arm cone-beam CT system was used to acquire projection images of five healthy volunteers at various flexion angles. Projection matrices for the horizontal scanning trajectory were calibrated using the Siemens standard PDS-2 phantom. The initial reconstruction was forward projected using maximum-intensity projections (MIP), yielding an estimate of a static scan. This estimate was then used to obtain the 2D projection shifts via registration. For the scan with the most motion, the proposed method reproduced the marker-based results with a mean error of 2.90 mm +/- 1.43 mm (compared to a mean error of 4.10 mm +/- 3.03 mm in the uncorrected case). Bone contour surrounding modeling clay layer was improved. The proposed method is a first step towards automatic image-based, marker-free motion-compensation.

  5. Knee Dislocations

    PubMed Central

    Schenck, Robert C.; Richter, Dustin L.; Wascher, Daniel C.

    2014-01-01

    Background: Traumatic knee dislocation is becoming more prevalent because of improved recognition and increased exposure to high-energy trauma, but long-term results are lacking. Purpose: To present 2 cases with minimum 20-year follow-up and a review of the literature to illustrate some of the fundamental principles in the management of the dislocated knee. Study Design: Review and case reports. Methods: Two patients with knee dislocations who underwent multiligamentous knee reconstruction were reviewed, with a minimum 20-year follow-up. These patients were brought back for a clinical evaluation using both subjective and objective measures. Subjective measures include the following scales: Lysholm, Tegner activity, visual analog scale (VAS), Short Form–36 (SF-36), International Knee Documentation Committee (IKDC), and a psychosocial questionnaire. Objective measures included ligamentous examination, radiographic evaluation (including Telos stress radiographs), and physical therapy assessment of function and stability. Results: The mean follow-up was 22 years. One patient had a vascular injury requiring repair prior to ligament reconstruction. The average assessment scores were as follows: SF-36 physical health, 52; SF-36 mental health, 59; Lysholm, 92; IKDC, 86.5; VAS involved, 10.5 mm; and VAS uninvolved, 2.5 mm. Both patients had excellent stability and were functioning at high levels of activity for their age (eg, hiking, skydiving). Both patients had radiographic signs of arthritis, which lowered 1 subject’s IKDC score to “C.” Conclusion: Knee dislocations have rare long-term excellent results, and most intermediate-term studies show fair to good functional results. By following fundamental principles in the management of a dislocated knee, patients can be given the opportunity to function at high levels. Hopefully, continued advances in the evaluation and treatment of knee dislocations will improve the long-term outcomes for these patients in the

  6. Effects of Therapeutic Exercise and Hydrotherapy on Pain Severity and Knee Range of Motion in Patients with Hemophilia: A Randomized Controlled Trial

    PubMed Central

    Mazloum, Vahid; Rahnama, Nader; Khayambashi, Khalil

    2014-01-01

    Background: Pain and limited range of motion (ROM) are the crucial subsequent results of joint hemorrhages in individuals with bleeding disorders and hemophilia. Exercise interventions are particularly recommended in treatment of such patients. The purpose of this study was to detect the influences of conventional exercise therapy and hydrotherapy on the knee joint complications in patients with hemophilia. Methods: A total of 40 patients engaging hemophilia A were randomized into one of three groups: Therapeutic exercise (N = 13), hydrotherapy (N = 14) or control (N = 13). While the first two groups followed their specific programs for 4 weeks, routine life-style was maintained by subjects in the control group in this period. To evaluate the pain level and knee ROM the visual analog scale and standard goniometer were utilized, respectively. The outcome was measured at baseline and after completing the prescribed protocols. Data analysis was performed using one-way analysis of variance and Scheffe statistical tests (P < 0.05). Results: Both experimental groups experienced more significant decreasing in pain level (P < 0.001) and knee flexion and extension ROM (P < 0.001) in comparison to the control group. Although the pain was significantly (P < 0.01) more alleviated in participants treated through hydrotherapy in comparison to exercise therapy, the difference in ROM improvement was not statistically significant (P > 0.05). Conclusions: Using hydrotherapy in addition to usual rehabilitation training can result in beneficial effect in terms of pain and knee joint ROM. However, it appears that hydrotherapy is more effective in reducing pain. PMID:24554996

  7. Image based weighted center of proximity versus directly measured knee contact location during simulated gait

    PubMed Central

    Wang, Hongsheng; Chen, Tony; Koff, Matthew F.; Hutchinson, Ian D.; Gilbert, Susannah; Choi, Dan; Warren, Russell F.; Rodeo, Scott A.; Maher, Suzanne A.

    2014-01-01

    To understand the mechanical consequences of knee injury requires a detailed analysis of the effect of that injury on joint contact mechanics during activities of daily living. Three-dimensional (3D) knee joint geometric models have been combined with knee joint kinematics to dynamically estimate the location of joint contact during physiological activities – using a weighted center of proximity (WCoP) method. However, the relationship between the estimated WCoP and the actual location of contact has not been defined. The objective of this study was to assess the relationship between knee joint contact location as estimated using the image-based WCoP method, and a directly measured weighted center of contact (WCoC) method during simulated walking. To achieve this goal, we created knee specific models of six human cadaveric knees from magnetic resonance imaging. All knees were then subjected to physiological loads on a knee simulator intended to mimic gait. Knee joint motion was captured using a motion capture system. Knee joint contact stresses were synchronously recorded using a thin electronic sensor throughout gait, and used to compute WCoC for the medial and lateral plateaus of each knee. WCoP was calculated by combining knee kinematics with the MRI-based knee specific model. Both metrics were compared throughout gait using linear regression. The anteroposterior (AP) location of WCoP was significantly correlated with that of WCoC on both tibial plateaus in all specimens (P < 0.01, 95% confidence interval of Person’s coefficient r > 0), but the correlation was not significant in the mediolateral (ML) direction for 4/6 knees (P > 0.05). Our study demonstrates that while the location of joint contact obtained from 3D knee joint contact model, using the WCoP method, is significantly correlated with the location of actual contact stresses in the AP direction, that relationship is less certain in the ML direction. PMID:24837219

  8. Knee and Hip Joint Kinematics Predict Quadriceps and Hamstrings Neuromuscular Activation Patterns in Drop Jump Landings

    PubMed Central

    Malfait, Bart; Dingenen, Bart; Smeets, Annemie; Staes, Filip; Pataky, Todd; Robinson, Mark A.; Vanrenterghem, Jos; Verschueren, Sabine

    2016-01-01

    Purpose The purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ). Methods Fifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping. Results The peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001). Conclusion This study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an

  9. Gait patterns during different walking conditions in older adults with and without knee osteoarthritis--results from the Baltimore Longitudinal Study of Aging.

    PubMed

    Ko, Seung-uk; Ling, Shari M; Schreiber, Catherine; Nesbitt, Mark; Ferrucci, Luigi

    2011-02-01

    Biomechanical analysis of lower extremity activities while walking at different speeds and in challenging conditions may help to identify specific gait patterns associated with knee osteoarthritis (knee-OA). We hypothesized that individuals with asymptomatic knee-OA have lower ankle activity, while individuals with symptomatic knee-OA have similar or higher ankle activity compared to individuals without knee-OA, and that such differences are enhanced during challenging gait tasks. We tested this hypothesis by examining gait characteristics in multiple gait tasks using data from 153 Baltimore Longitudinal Study of Aging (BLSA) participants (112 without knee-OA, 41 with knee-OA; 53-87 years, 52% women). All participants who could walk unassisted were evaluated in the BLSA gait lab while walking at self-selected speed (usual-walking), at maximum speed (fast-walking) and again at self-selected speed after 30-min of walking activities (usual-walking-after-30 min). Knee range of motion was lower for knee-OA participants in the fast-walking and usual-walking-after-30 min tasks (p<0.030). Ankle range of motion for symptomatic knee-OA was greater compared to asymptomatic knee-OA for all walking tasks (p<0.050). Symptomatic knee-OA had greater generative MWE of the ankle compared to asymptomatic knee-OA (p=0.034), while keeping similar absorptive MWE of the knee when compared to no-OA controls (p=0.151). Symptomatic knee-OA individuals seem to adapt an ankle kinematic gait pattern aimed at avoiding knee pain, by enhancing forward propulsion so to minimize knee joint load. Whether these conditions represent subsequent steps in the causal pathway from knee-OA to changes in gait is still not clear.

  10. Is high flexion following total knee arthroplasty safe?: evaluation of knee joint loads in the patients during maximal flexion.

    PubMed

    Nagura, Takeo; Otani, Toshiro; Suda, Yasunori; Matsumoto, Hideo; Toyama, Yoshiaki

    2005-08-01

    The purpose of this study was to indicate the mechanical loads and the flexion angle at the knee during rise from maximal flexion following total knee arthroplasty (TKA). Twenty three knees were evaluated using skin marker-based motion analysis system during four different activities of daily living. The average maximum flexion was 90 degrees (34 degrees less than passive flexion) and all subjects required support for their weight to rise from maximal flexion. The external moments and the external forces at the knee during the maximal flexion were smaller than those during the stair descending activity. The results indicate that capable flexion angle for the patients following TKA is approximately 90 degrees which has smaller mechanical loads at the knee than the stair descending activity.

  11. Knee Conditioning Program

    MedlinePlus

    ... muscles help your knee joint absorb shock. Flexibility: Stretching the muscles that you strengthen is important for restoring range of motion and preventing injury. Gently stretching after strengthening exercises can help reduce muscle soreness ...

  12. Assessment of Knee Cartilage Stress Distribution and Deformation Using Motion Capture System and Wearable Sensors for Force Ratio Detection.

    PubMed

    Mijailovic, N; Vulovic, R; Milankovic, I; Radakovic, R; Filipovic, N; Peulic, A

    2015-01-01

    Knowledge about the knee cartilage deformation ratio as well as the knee cartilage stress distribution is of particular importance in clinical studies due to the fact that these represent some of the basic indicators of cartilage state and that they also provide information about joint cartilage wear so medical doctors can predict when it is necessary to perform surgery on a patient. In this research, we apply various kinds of sensors such as a system of infrared cameras and reflective markers, three-axis accelerometer, and force plate. The fluorescent marker and accelerometers are placed on the patient's hip, knee, and ankle, respectively. During a normal walk we are recording the space position of markers, acceleration, and ground reaction force by force plate. Measured data are included in the biomechanical model of the knee joint. Geometry for this model is defined from CT images. This model includes the impact of ground reaction forces, contact force between femur and tibia, patient body weight, ligaments, and muscle forces. The boundary conditions are created for the finite element method in order to noninvasively determine the cartilage stress distribution.

  13. Design and control of an active 1-DoF mechanism for knee rehabilitation.

    PubMed

    Naghavi, Nader; Mahjoob, Mohammad J

    2016-10-01

    A 1-DoF robot is designed and fabricated to be used for knee rehabilitation training. The mechanism (robot) is designed to perform specific set of exercises while the patient is sitting on a chair. The therapy process for patients has different stages; each stage consists of specific exercises to recover the knee to its condition before injury. The maximum torque of healthy joint during the extension/flexion exercise is evaluated by simulation and suitable actuator is selected based on the results. A prototype is then fabricated as a platform to evaluate the design and control concepts. The experiment procedure consisting of three stages of therapy indicates good tracking performance and safe operation of the system. Implication for Rehabilitation A 1-DoF mechanism for knee rehabilitation has been designed to perform three stages of therapy: passive, active assist and active resist. The assistive and resistive torque, during active assist and active resist stages, can be set according to the progress in therapy. The results of this study suggest the system has the potential to result in various benefits including reduction of physical workload of physiotherapists and improved repeatability.

  14. Technology Efficacy in Active Prosthetic Knees for Transfemoral Amputees: A Quantitative Evaluation

    PubMed Central

    El-Sayed, Amr M.; Abu Osman, Noor Azuan

    2014-01-01

    Several studies have presented technological ensembles of active knee systems for transfemoral prosthesis. Other studies have examined the amputees' gait performance while wearing a specific active prosthesis. This paper combined both insights, that is, a technical examination of the components used, with an evaluation of how these improved the gait of respective users. This study aims to offer a quantitative understanding of the potential enhancement derived from strategic integration of core elements in developing an effective device. The study systematically discussed the current technology in active transfemoral prosthesis with respect to its functional walking performance amongst above-knee amputee users, to evaluate the system's efficacy in producing close-to-normal user performance. The performances of its actuator, sensory system, and control technique that are incorporated in each reported system were evaluated separately and numerical comparisons were conducted based on the percentage of amputees' gait deviation from normal gait profile points. The results identified particular components that contributed closest to normal gait parameters. However, the conclusion is limitedly extendable due to the small number of studies. Thus, more clinical validation of the active prosthetic knee technology is needed to better understand the extent of contribution of each component to the most functional development. PMID:25110727

  15. Effects of activity modification on the patients with osteoarthritis of the knee.

    PubMed

    Shakoor, M A; Taslim, Md Abu; Hossain, Md Shahadat

    2007-08-01

    A prospective randomized clinical trial was conducted on 162 patients of osteoarthritis of knee were included in the study. The patients were divided into two groups- Group A and Group B. The Group A was treated with shortwave diathermy, exercise, naproxen and activity modification and the Group B was treated with shortwave diathermy, exercise and naproxen. Improvement was found more in Group A than Group B after 4th week (95% CI was -2.59 to 6.56). Then it was found that the improvement was gradually increased in Group A than Group B and finally, it was found that there was highly significant improvement in Group A than Group B after 6th week (95% CI was -3.45 to -0.70). This study suggests that activity modification play an important role for the treatment of the patients with osteoarthritis of knee.

  16. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs.

    PubMed

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-08-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles.

  17. A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

    PubMed Central

    Logerstedt, David; Arundale, Amelia; Lynch, Andrew; Snyder-Mackler, Lynn

    2015-01-01

    Injuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health. PMID:26537805

  18. Patterns of knee osteoarthritis in Arabian and American knees.

    PubMed

    Hodge, W Andrew; Harman, Melinda K; Banks, Scott A

    2009-04-01

    This study illustrates differences in the cartilage degeneration in osteoarthritic knees in patients with more frequent hyperflexion activities of daily living compared with Western patients. Proximal tibial articular cartilage wear and cruciate ligament condition were assessed in Saudi Arabian and North American patients with varus osteoarthritis undergoing total knee arthroplasty. In anterior cruciate ligament (ACL) intact knees, there were significant differences in wear location, with a clearly more anterior pattern in Saudi Arabian knees. Complete ACL deficiency occurred in 25% of North American knees but only 14% of Saudi Arabian knees. These ACL-deficient knees showed the most severe cartilage wear in both groups and posterior medial wear patterns. Biomechanical descriptions of knee flexion and axial rotation during kneeling or squatting are consistent with the more pronounced anteromedial and posterolateral cartilage wear patterns observed on the Saudi Arabian knees. These observations provide insight into altered knee mechanics in 2 culturally different populations with different demands on knee flexion.

  19. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    PubMed Central

    Choi, Jang-Hwan; Maier, Andreas; Keil, Andreas; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Gold, Garry E.; Fahrig, Rebecca

    2014-01-01

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjects in vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D

  20. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    SciTech Connect

    Choi, Jang-Hwan; Maier, Andreas; Keil, Andreas; McWalter, Emily J.; Gold, Garry E.; Fahrig, Rebecca; Pal, Saikat; Beaupré, Gary S.

    2014-06-15

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjectsin vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D

  1. Quantifying knee mechanics during balance training exercises.

    PubMed

    Benson, Lauren C; Almonroeder, Thomas G; O'Connor, Kristian M

    2017-01-01

    Patellofemoral pain (PFP) is common among runners and those recovering from anterior cruciate ligament reconstruction. Training programs designed to prevent or treat injuries often include balance training, although balance interventions have been reported to coincide with more knee injuries. Knowledge of the effect of balance exercises on knee mechanics may be useful when designing training programs. High knee abduction moment has been implicated in the development of PFP, and imbalance between vastus lateralis (VL) and vastus medialis oblique (VMO) may contribute to patellofemoral stress. The purpose was to quantify knee abduction moment and vasti muscle activity during balance exercises. Muscle activity of VMO and VL, three-dimensional lower-extremity kinematics, and ground reaction forces of healthy recreational athletes (12M, 13F) were recorded during five exercises. Peak knee abduction moment, ratio of VMO:VL activity, and delay in onset of VMO relative to VL were quantified for each exercise. The influence of sex and exercise on each variable was determined using a mixed-model ANOVA. All analyses indicated a significant main effect of exercise, p<0.05. Follow-up comparisons showed low peak knee abduction moment and high VMO:VL ratio for the task with anterior-posterior motion. Delay of VMO relative to VL was similar among balance board tasks.

  2. Symptom Assessment in Knee Osteoarthritis Needs to Account for Physical Activity Level

    PubMed Central

    Lo, Grace H.; McAlindon, Timothy E.; Hawker, Gillian A.; Driban, Jeffrey B.; Price, Lori Lyn; Song, Jing; Eaton, Charles B.; Hochberg, Marc C.; Jackson, Rebecca D.; Kwoh, C. Kent; Nevitt, Michael C.; Dunlop, Dorothy D.

    2015-01-01

    Objective Pain is not always correlated with radiographic osteoarthritis (OA) severity possibly because people modify activities to manage symptoms. Measures of symptoms that consider pain in the context of activity level may therefore provide greater discrimination than pain alone. Our objective was to compare discrimination of a measure of pain alone with combined measures of pain relative to physical activity across radiographic OA levels. Methods This is a cross-sectional study of the Osteoarthritis Initiative accelerometer substudy, including those with and without knee OA. Two composite pain and activity knee symptom (PAKS) scores were calculated as Western Ontario and McMaster (WOMAC) Universities Osteoarthritis Pain Scale plus one divided by physical activity measures (step and activity counts). Symptom score discrimination across Kellgren and Lawrence (KL) grades were evaluated using histograms and quantile regression. Results 1806 participants, mean age 65.1 (9.1) years, mean BMI 28.4 (4.8) kg/m2, and 55.6% female, were included. WOMAC, but not PAKS scores, exhibited a floor effect. Adjusted median WOMAC by KL grades 0 – 4 were 0, 0, 1, 1, and 3 respectively. Median PAKS1 and PAKS2 were 24.9, 26.0, 32.4, 46.1, 97.9, and 7.2, 7.2, 9.2, 12.9, 23.8, respectively. PAKS scores had more statistically significant comparisons between KL grades compared with WOMAC. Conclusions Symptom assessments incorporating pain and physical activity did not exhibit a floor effect and were better able to discriminate radiographic severity than pain alone, particularly in milder disease. Pain in the context of physical activity level should be used to assess knee OA symptoms. PMID:26407008

  3. Wear Testing of Moderate Activities of Daily Living Using In Vivo Measured Knee Joint Loading

    PubMed Central

    Reinders, Jörn; Sonntag, Robert; Vot, Leo; Gibney, Christian; Nowack, Moritz; Kretzer, Jan Philippe

    2015-01-01

    Resumption of daily living activities is a basic expectation for patients provided with total knee replacements. However, there is a lack of knowledge regarding the impact of different activities on the wear performance. In this study the wear performance under application of different daily activities has been analyzed. In vivo load data for walking, walking downstairs/upstairs, sitting down/standing up, and cycling (50 W & 120 W) has been standardized for wear testing. Wear testing of each activity was carried out on a knee wear simulator. Additionally, ISO walking was tested for reasons of comparison. Wear was assessed gravimetrically and wear particles were analyzed. In vivo walking produced the highest overall wear rates, which were determined to be three times higher than ISO walking. Moderate wear rates were determined for walking upstairs and downstairs. Low wear rates were determined for standing up/sitting down and cycling at power levels of 50 W and 120 W. The largest wear particles were observed for cycling. Walking based on in vivo data has been shown to be the most wear-relevant activity. Highly demanding activities (stair climbing) produced considerably less wear. Taking into account the expected number of loads, low-impact activities like cycling may have a greater impact on articular wear than highly demanding activities. PMID:25811996

  4. Predictors of Facility Discharge, Range of Motion, and Patient-Reported Physical Function Improvement Following Primary Total Knee Arthroplasty: A Prospective CohortAnalysis

    PubMed Central

    M.Rissman, Cody; Keeney, Benjamin J.; Ercolano, Ellyn M.; Koenig, Karl M.

    2015-01-01

    Patients are discharged to home or inpatient settings following primary unilateral total knee arthroplasty (TKA). We identified predictors of inpatient discharge and 3-month postoperative range of motion (ROM) and patient-reported physical function improvement (VR12 PCS) between these discharge settings. We studied prospectively collected cohortdata for 738 TKAs between April 2011 and April 2013. Significant adjusted predictors of inpatient discharge included older age, female gender, surgeon, comorbidity, lower PCS, and BMI >40. Only lower preoperative ROM predicted postoperative ROM. Inpatient discharge and higher preoperative PCS predicted lower PCS improvement. Home-based rehabilitation was associated with greater 3-month PCS improvement and showed no difference with 3-month ROM. TKA inpatient discharge should be based on patient care requirements rather than perceived benefit of improved ROM and physical function. PMID:26483260

  5. Cooling Does Not Affect Knee Proprioception

    PubMed Central

    Ozmun, John C.; Thieme, Heather A.; Ingersoll, Christopher D.; Knight, Kenneth L.

    1996-01-01

    The effect of cooling on proprioception of the knee has not been studied extensively. In this study, we investigated the movement reproduction (timing and accuracy) aspect of proprioception. Subjects were tested under two conditions: a 20-minute application of ice and control. Proprioceptive accuracy and timing were measured by passively moving the knee, then comparing the subject's active reproduction of the passive movement. Subjects were blindfolded, then tested in three sectors of the knee's range of motion: 90° to 60°, 60° to 30°, and 30° to full extension. Ice application had no apparent effect on the subject's ability to perform accurate movement reproductions in the sectors tested. However, accuracy of the subject's final angle reproduction varied between the sectors as did the total time of the movement. One possible explanation for the difference between sectors is that different receptors are active at different points in the knee's range of motion. We conclude that cooling the knee joint for 20 minutes does not have an adverse effect on proprioception. PMID:16558379

  6. Cooling does not affect knee proprioception.

    PubMed

    Ozmun, J C; Thieme, H A; Ingersoll, C D; Knight, K L

    1996-01-01

    The effect of cooling on proprioception of the knee has not been studied extensively. In this study, we investigated the movement reproduction (timing and accuracy) aspect of proprioception. Subjects were tested under two conditions: a 20-minute application of ice and control. Proprioceptive accuracy and timing were measured by passively moving the knee, then comparing the subject's active reproduction of the passive movement. Subjects were blindfolded, then tested in three sectors of the knee's range of motion: 90 degrees to 60 degrees , 60 degrees to 30 degrees , and 30 degrees to full extension. Ice application had no apparent effect on the subject's ability to perform accurate movement reproductions in the sectors tested. However, accuracy of the subject's final angle reproduction varied between the sectors as did the total time of the movement. One possible explanation for the difference between sectors is that different receptors are active at different points in the knee's range of motion. We conclude that cooling the knee joint for 20 minutes does not have an adverse effect on proprioception.

  7. Effect of ACL graft material on anterior knee force during simulated in vivo ovine motion applied to the porcine knee: An in vitro examination of force during 2000 cycles.

    PubMed

    Boguszewski, Daniel V; Wagner, Christopher T; Butler, David L; Shearn, Jason T

    2015-12-01

    This study determined how anterior cruciate ligament (ACL) reconstruction affected the magnitude and temporal patterns of anterior knee force and internal knee moment during 2000 cycles of simulated gait. Porcine knees were tested using a six degree-of-freedom robot, examining three porcine allograft materials compared with the native ACL. Reconstructions were performed using: (1) bone-patellar tendon-bone allograft (BPTB), (2) reconstructive porcine tissue matrix (RTM), or (3) an RTM-polymer hybrid construct (Hybrid). Forces and moments were measured over the entire gait cycle and contrasted at heel strike, mid stance, toe off, and peak flexion. The Hybrid construct performed the best, as magnitude and temporal changes in both anterior knee force and internal knee moment were not different from the native ACL knee. Conversely, the RTM knees showed greater loss in anterior knee force during 2000 cycles than the native ACL knee at heel strike and toe off, with an average force loss of 46%. BPTB knees performed the least favorably, with significant loss in anterior knee force at all key points and an average force loss of 61%. This is clinically relevant, as increases in post-operative knee laxity are believed to play a role in graft failure and early onset osteoarthritis.

  8. Simulation of the active Brownian motion of a microswimmer

    NASA Astrophysics Data System (ADS)

    Volpe, Giorgio; Gigan, Sylvain; Volpe, Giovanni

    2014-07-01

    Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution—a clear signature of their out-of-equilibrium nature—and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted.

  9. In vivo prompt gamma neutron activation analysis for the screening of boron-10 distribution in a rabbit knee: a simulation study

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Clackdoyle, R.; Shortkroff, S.; Yanch, J.

    2008-05-01

    Boron neutron capture synovectomy (BNCS) is under development as a potential treatment modality for rheumatoid arthritis (RA). RA is characterized by the inflammation of the synovium (the membrane lining articular joints), which leads to pain and a restricted range of motion. BNCS is a two-part procedure involving the injection of a boronated compound directly into the diseased joint followed by irradiation with a low-energy neutron beam. The neutron capture reactions taking place in the synovium deliver a local, high-linear energy transfer (LET) dose aimed at destroying the inflamed synovial membrane. For successful treatment via BNCS, a boron-labeled compound exhibiting both high synovial uptake and long retention time is necessary. Currently, the in vivo uptake behavior of potentially useful boronated compounds is evaluated in the knee joints of rabbits in which arthritis has been induced. This strategy involves the sacrifice and dissection of a large number of animals. An in vivo 10B screening approach is therefore under investigation with the goal of significantly reducing the number of animals needed for compound evaluation via dissection studies. The 'in vivo prompt gamma neutron activation analysis' (IVPGNAA) approach uses a narrow neutron beam to irradiate the knee from several angular positions following the intra-articular injection of a boronated compound whose uptake characteristics are unknown. A high-purity germanium detector collects the 478 keV gamma photons produced by the 10B capture reactions. The 10B distribution in the knee is then reconstructed by solving a system of simultaneous equations using a weighted least squares algorithm. To study the practical feasibility of IVPGNAA, simulation data were generated with the Monte Carlo N-particle transport code. The boron-containing region of a rabbit knee was partitioned into 8 compartments, and the 10B prompt gamma signals were tallied from 16 angular positions. Results demonstrate that for this

  10. Muscle motion and EMG activity in vibration treatment.

    PubMed

    Fratini, Antonio; La Gatta, Antonio; Bifulco, Paolo; Romano, Maria; Cesarelli, Mario

    2009-11-01

    The aim of this study is to highlight the relationship between muscle motion, generated by whole body vibration, and the correspondent electromyographic (EMG) activity and to suggest a new method to customize the stimulation frequency. Simultaneous recordings of EMG and tri-axial accelerations of quadriceps rectus femoris from fifteen subjects undergoing vibration treatments were collected. Vibrations were delivered via a sinusoidal oscillating platform at different frequencies (10-45 Hz). Muscle motion was estimated by processing the accelerometer data. Large EMG motion artifacts were removed using sharp notch filters centred at the vibration frequency and its superior harmonics. EMG-RMS values were computed and analyzed before and after artifact suppression to assess muscular activity. Muscles acceleration amplitude increased with frequency. Muscle displacements revealed a mechanical resonant-like behaviour of the muscle. Resonance frequencies and dumping factors depended on subject. Moreover, RMS of artifact-free EMG was found well correlated (R(2)=0.82) to the actual muscle displacement, while the maximum of the EMG response was found related to the mechanical resonance frequency of muscle. Results showed that maximum muscular activity was found in correspondence to the mechanical resonance of the muscle itself. Assuming the hypothesis that muscle activation is proportional to muscle displacement, treatment optimization (i.e. to choose the best stimulation frequency) could be obtained by simply monitoring local acceleration (resonance), leading to a more effective muscle stimulation. Motion artifact produced an overestimation of muscle activity, therefore its removal was essential.

  11. A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise

    PubMed Central

    Kang, Jeong-Il; Park, Joon-Su; Choi, Hyun; Jeong, Dae-Keun; Kwon, Hye-Min; Moon, Young-Jun

    2017-01-01

    [Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome. PMID:28210036

  12. A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise.

    PubMed

    Kang, Jeong-Il; Park, Joon-Su; Choi, Hyun; Jeong, Dae-Keun; Kwon, Hye-Min; Moon, Young-Jun

    2017-01-01

    [Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome.

  13. Cortical activity differs between position- and force-control knee extension tasks.

    PubMed

    Poortvliet, Peter C; Tucker, Kylie J; Finnigan, Simon; Scott, Dion; Sowman, Paul; Hodges, Paul W

    2015-12-01

    Neural control differs between position- and force-control tasks as evident from divergent effects of fatigue and pain. Unlike force-control tasks, position-control tasks focus on a postural goal to maintain a joint angle. Cortical involvement is suggested to be less during postural control, but whether this differs between position- and force-control paradigms remains unclear. Coherence estimates the functional communication between spatially distinct active regions within the cortex (cortico-cortical coherence; CCC) and between the cortex and muscles (corticomuscular coherence; CMC). We investigated whether cortical involvement differed between force-control and more posturally focused, position-control tasks. Seventeen adults performed position- and force-control knee extensor efforts at a submaximal load (10 % maximum voluntary contraction). Surface electromyography was recorded from the right knee extensor and flexor muscles and brain activity using electroencephalography (EEG). CCC and CMC in the beta (13-30 Hz) and gamma (30-45 Hz) frequency bands were calculated between combinations of intra- and inter-hemispheric pairs of electrodes, and between four EEG electrodes that approximated the left motor cortical area, and right knee extensor EMG, respectively. Differences in EEG power and muscle activity were also calculated. CCC was greater across distributed regions in the force-control task. Beta EEG power in the left hemisphere was higher for the position-control task. Although averaged CMC data differed between tasks, there was no task difference for individual CMC data. Muscle activity and force did not differ between tasks. The results demonstrate differential cortical contributions to control force- versus position-control tasks. This might contribute to differences in performance outcomes of these tasks that have been shown previously.

  14. Stance controlled knee flexion improves stimulation driven walking after spinal cord injury

    PubMed Central

    2013-01-01

    Background Functional neuromuscular stimulation (FNS) restores walking function after paralysis from spinal cord injury via electrical activation of muscles in a coordinated fashion. Combining FNS with a controllable orthosis to create a hybrid neuroprosthesis (HNP) has the potential to extend walking distance and time by mechanically locking the knee joint during stance to allow knee extensor muscle to rest with stimulation turned off. Recent efforts have focused on creating advanced HNPs which couple joint motion (e.g., hip and knee or knee and ankle) to improve joint coordination during swing phase while maintaining a stiff-leg during stance phase. Methods The goal of this study was to investigate the effects of incorporating stance controlled knee flexion during loading response and pre-swing phases on restored gait. Knee control in the HNP was achieved by a specially designed variable impedance knee mechanism (VIKM). One subject with a T7 level spinal cord injury was enrolled and served as his own control in examining two techniques to restore level over-ground walking: FNS-only (which retained a stiff knee during stance) and VIKM-HNP (which allowed controlled knee motion during stance). The stimulation pattern driving the walking motion remained the same for both techniques; the only difference was that knee extensor stimulation was constant during stance with FNS-only and modulated together with the VIKM to control knee motion during stance with VIKM-HNP. Results Stance phase knee angle was more natural during VIKM-HNP gait while knee hyperextension persisted during stiff-legged FNS-only walking. During loading response phase, vertical ground reaction force was less impulsive and instantaneous gait speed was increased with VIKM-HNP, suggesting that knee flexion assisted in weight transfer to the leading limb. Enhanced knee flexion during pre-swing phase also aided flexion during swing, especially when response to stimulation was compromised. Conclusions

  15. Statistics of Superluminal Motion in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Wei; Fan, Jun-Hui

    2008-08-01

    We have collected an up-to-date sample of 123 superluminal sources (84 quasars, 27 BL Lac objects and 12 galaxies) and calculated the apparent velocities (βapp) for 224 components in the sources with the Λ-CDM model. We checked the relationships between their proper motions, redshifts, βapp and 5 GHz flux densities. Our analysis shows that the radio emission is strongly boosted by the Doppler effect. The superluminal motion and the relativistic beaming boosting effect are, to some extent, the same in active galactic nuclei.

  16. Influence of knee flexion angle and age on triceps surae muscle activity during heel raises.

    PubMed

    Hébert-Losier, Kim; Schneiders, Anthony G; García, José A; Sullivan, S John; Simoneau, Guy G

    2012-11-01

    Triceps surae and Achilles tendon injuries are frequent in sports medicine, particularly in middle-aged adults. Muscle imbalances and weakness are suggested to be involved in the etiology of these conditions, with heel-raise testing often used to assess and treat triceps surae (TS) injuries. Although heel raises are recommended with the knee straight for gastrocnemius and bent for soleus (SOL), the extent of muscle selectivity in these positions is not clear. This study aimed to determine the influence of knee angle and age on TS muscle activity during heel raises. Forty-eight healthy men and women were recruited from a younger-aged (18-25 years) and middle-aged (35-45 years) population. All the subjects performed unilateral heel raises in 0° and 45° knee flexion (KF). Soleus, gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) surface electromyography signals were processed to compute root-mean-square amplitudes, and data were analyzed using mixed-effects models and stepwise regression. The mean TS activity during heel raises was 23% of maximum voluntary isometric contraction when performed in 0° KF and 21% when in 45°. Amplitudes were significantly different between TS muscles (p < 0.001) and KF angles (p < 0.001), with a significant interaction (p < 0.001). However, the age of the population did not influence the results (p = 0.193). The findings demonstrate that SOL activity was 4% greater when tested in 45° compared with 0° KF and 5% lower in the GM and GL. The results are consistent with the recommended use of heel raises in select knee positions for assessing, training, and rehabilitating the SOL and gastrocnemius muscles; however, the 4-5% documented change in activity might not be enough to significantly influence clinical outcome measures or muscle-specific benefits. Contrary to expectations, TS activity did not distinguish between middle-aged and younger-aged adults, despite the higher injury prevalence in middle age.

  17. An acute bout of self-myofascial release increases range of motion without a subsequent decrease in muscle activation or force.

    PubMed

    MacDonald, Graham Z; Penney, Michael D H; Mullaley, Michelle E; Cuconato, Amanda L; Drake, Corey D J; Behm, David G; Button, Duane C

    2013-03-01

    Foam rolling is thought to improve muscular function, performance, overuse, and joint range of motion (ROM); however, there is no empirical evidence demonstrating this. Thus, the objective of the study was to determine the effect of self-myofascial release (SMR) via foam roller application on knee extensor force and activation and knee joint ROM. Eleven healthy male (height 178.9 ± 3.5 cm, mass 86.3 ± 7.4 kg, age 22.3 ± 3.8 years) subjects who were physically active participated. Subjects' quadriceps maximum voluntary contraction force, evoked force and activation, and knee joint ROM were measured before, 2 minutes, and 10 minutes after 2 conditions: (a) 2, 1-minute trials of SMR of the quadriceps via a foam roller and (b) no SMR (Control). A 2-way analysis of variance (condition × time) with repeated measures was performed on all dependent variables recorded in the precondition and postcondition tests. There were no significant differences between conditions for any of the neuromuscular dependent variables. However, after foam rolling, subjects' ROM significantly (p < 0.001) increased by 10° and 8° at 2 and 10 minutes, respectively. There was a significant (p < 0.01) negative correlation between subjects' force and ROM before foam rolling, which no longer existed after foam rolling. In conclusion, an acute bout of SMR of the quadriceps was an effective treatment to acutely enhance knee joint ROM without a concomitant deficit in muscle performance.

  18. Activation to self-management and exercise in overweight and obese older women with knee osteoarthritis.

    PubMed

    Kawi, Jennifer; Schuerman, Sue; Alpert, Patricia T; Young, Daniel

    2015-12-01

    Knee osteoarthritis (OA) affects approximately 1 in 10 adults in the United States, with higher prevalence in women, aggravated by increased weight. This quasi-experimental pilot study implemented an online self-management (SM) program for older overweight and obese women with knee OA combined with a two-arm progressive exercise trial (walking and stepping groups). After the 10-week intervention using an interprofessional approach, activation to SM scores were significantly higher in all participants (N = 16) and between groups, with a higher increase in the stepping group. Those with higher activation scores pre-intervention obtained higher scores post-intervention. Activation levels also increased significantly among all participants with majority at the highest activation level. Follow-up data at 6 weeks and 6 months showed sustained SM and health-directed behaviors. These findings, although preliminary, highlight the value of combined SM and progressive exercise intervention using an interprofessional approach. Further investigations are essential toward potential practice and policy changes.

  19. A comparison of lower-body flexibility, strength, and knee stability between karate athletes and active controls.

    PubMed

    Probst, Manuel M; Fletcher, Richard; Seelig, Dayna S

    2007-05-01

    The purposes of this study were to compare the lower-body flexibility, strength, and knee stability of karate athletes against that of non-karate controls and to determine whether regular karate training results in adaptations that may result in an increased risk for knee injury. Flexibility measurements included knee flexion and extension, hip flexion and extension, hip internal and external rotation, and foot inversion and eversion. Nine karate athletes (4 women and 5 men, age = 24.3 +/- 6.7 years) and 15 active, non-karate controls (7 women and 8 men, age = 22.1 +/- 3.2 years) participated. No subjects reported recent knee surgery or chronic or acute knee pain. Concentric quadriceps and hamstrings strength and endurance were measured using a Biodex II isokinetic dynamometer at 60 degrees .s(-1) and 180 degrees .s(-1). Eccentric strength was measured at 150 degrees .s(-1) and 250 ft-lb (339 N.m). Knee stability was measured via varus and valgus stress and anterior drawer testing. Karate athletes demonstrated a significantly greater right hip flexion (p knees between the karate and control groups. The results indicate that this group of karate athletes may have demonstrated sport-specific adaptations in certain flexibility and strength measurements, but they showed no increased risk for knee injury.

  20. Intraoperative passive kinematics of osteoarthritic knees before and after total knee arthroplasty.

    PubMed

    Siston, Robert A; Giori, Nicholas J; Goodman, Stuart B; Delp, Scott L

    2006-08-01

    Total knee arthroplasty is a successful procedure to treat pain and functional disability due to osteoarthritis. However, precisely how a total knee arthroplasty changes the kinematics of an osteoarthritic knee is unknown. We used a surgical navigation system to measure normal passive kinematics from 7 embalmed cadaver lower extremities and in vivo intraoperative passive kinematics on 17 patients undergoing primary total knee arthroplasty to address two questions: How do the kinematics of knees with advanced osteoarthritis differ from normal knees?; and, Does posterior substituting total knee arthroplasty restore kinematics towards normal? Osteoarthritic knees displayed a decreased screw-home motion and abnormal varus/valgus rotations between 10 degrees and 90 degrees of knee flexion when compared to normal knees. The anterior-posterior motion of the femur in osteoarthritic knees was not different than in normal knees. Following total knee arthroplasty, we found abnormal varus/valgus rotations in early flexion, a reduced screw-home motion when compared to the osteoarthritic knees, and an abnormal anterior translation of the femur during the first 60 degrees of flexion. Posterior substituting total knee arthroplasty does not appear to restore normal passive varus/valgus rotations or the screw motion and introduces an abnormal anterior translation of the femur during intraoperative evaluation.

  1. Observing shadow motions: resonant activity within the observer's motor system?

    PubMed

    Alaerts, Kaat; Van Aggelpoel, Tinne; Swinnen, Stephan P; Wenderoth, Nicole

    2009-09-25

    Several studies have demonstrated that the human motor cortex is activated by the mere observation of actions performed by others. In the present study, we explored whether the perception of 'impoverished motion stimuli', such as shadow animations, is sufficient to activate motor areas. To do so, transcranial magnetic stimulation (TMS) was applied over the hand area of the primary motor cortex (M1) while subjects observed shadow animations depicting finger motions. Data showed that resonant motor responses in M1 were only found when a biological effector was recognized from the observed shadow animation. Interestingly, M1 responses were similar for observing shadow or real motions. Therefore, the loss of 'pictorial' movement features in a shadow animation appeared to have no effect on motor resonance in M1. In summary, these findings suggest that the 'recognition' of biological motion from sparse visual input is both necessary and sufficient to recruit motor areas. This supports the hypothesis that the motor system is involved in recognizing the actions performed by others.

  2. The Importance of Spatiotemporal Information in Biological Motion Perception: White Noise Presented with a Step-like Motion Activates the Biological Motion Area.

    PubMed

    Callan, Akiko; Callan, Daniel; Ando, Hiroshi

    2017-02-01

    Humans can easily recognize the motion of living creatures using only a handful of point-lights that describe the motion of the main joints (biological motion perception). This special ability to perceive the motion of animate objects signifies the importance of the spatiotemporal information in perceiving biological motion. The posterior STS (pSTS) and posterior middle temporal gyrus (pMTG) region have been established by many functional neuroimaging studies as a locus for biological motion perception. Because listening to a walking human also activates the pSTS/pMTG region, the region has been proposed to be supramodal in nature. In this study, we investigated whether the spatiotemporal information from simple auditory stimuli is sufficient to activate this biological motion area. We compared spatially moving white noise, having a running-like tempo that was consistent with biological motion, with stationary white noise. The moving-minus-stationary contrast showed significant differences in activation of the pSTS/pMTG region. Our results suggest that the spatiotemporal information of the auditory stimuli is sufficient to activate the biological motion area.

  3. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  4. Motion.

    ERIC Educational Resources Information Center

    Gerhart, James B.; Nussbaum, Rudi H.

    This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

  5. Sports activity following total knee arthroplasty in patients older than 60 years.

    PubMed

    Mayr, Hermann O; Reinhold, Maik; Bernstein, Anke; Suedkamp, Norbert P; Stoehr, Amelie

    2015-01-01

    In a retrospective study with a population over 65 years, sports activity was conducted 6 years after cruciate retaining (CR) total condylar knee arthroplasty (TKA) with rotating platform (RP). Eighty-one Patients (71.8±5.4years) were examined at follow-up 6.4±0.9 years postoperative. Sport was practiced 5.3 hours every week in mean. Patients were active in sports 3.5times per week. Twenty-five percent performed high impact sports, 47% medium impact sports and 52% low impact sports at follow-up. In KOOS sports 60±28 was reached, in WOMAC 12.1±15.1. It can be concluded that in this population 50% of patients were active in medium and low impact sport 6 years after surgery. However, a quarter of patients were also active in high impact sports.

  6. The effect of ankle bracing on knee kinetics and kinematics during volleyball-specific tasks.

    PubMed

    West, T; Ng, L; Campbell, A

    2014-12-01

    The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P < 0.05). The results revealed no significant effect of bracing on knee kinematics or ground reaction forces during any task or on knee kinetics during the straight-line movement volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players.

  7. Physical Activity Levels in Early Knee Osteoarthritis Patients Measured by Accelerometry

    PubMed Central

    Farr, Joshua N.; Going, Scott B.; Lohman, Timothy G.; Rankin, Lucinda; Kasle, Shelley; Cornett, Michelle; Cussler, Ellen

    2008-01-01

    Objective: Physical activity (PA) is recommended for osteoarthritis (OA) management to reduce pain and improve function. The purpose of this study was to objectively assess the level and pattern of PA in male and female knee OA patients to determine adherence to CDC/ACSM and EPAC recommendations for PA. Methods: Early OA patients (n = 255, 76% women, 54.6 ± 7.1 years, body mass index (BMI) 27.8 ± 4.3 kg/m2) having radiographic status of Kellgren and Lawrence-defined grade II OA (and no higher) in at least one knee wore an accelerometer (Actigraph MTI) for 6-7 contiguous days. Light (LPA), moderate (MPA) and vigorous (VPA) PA intensities were defined as accelerometer recordings of 100 to 2,224, 2,225 to 5,950, and > 5,950 counts per minute, respectively. Results: Subjects wore accelerometers for 6.8 ± 0.3 days and 13.8 ± 2.2 hours per day (hr/day) and spent much more (P < 0.001) time in MPA (23.6 ± 17.2 min/day) compared to VPA (0.95 ± 3.5 min/day). Males spent significantly (P < 0.05) more time in all PA intensities than females. Only 30% of subjects achieved recommended PA levels. The proportion of males (47%) achieving the recommendation was significantly (P = 0.04) higher than females (24%). Conclusion: Knee OA patients accumulate little vigorous PA and most (70%) do not achieve recommended levels for moderate or greater intensity PA. New strategies to increase levels of PA in this population are needed. PMID:18759320

  8. Age-related changes in kinematics of the knee joint during deep squat.

    PubMed

    Fukagawa, Shingo; Leardini, Alberto; Callewaert, Barbara; Wong, Pius D; Labey, Luc; Desloovere, Kaat; Matsuda, Shuichi; Bellemans, Johan

    2012-06-01

    Researchers frequently use the deep knee squat as a motor task in order to evaluate the kinematic performance after total knee arthroplasty. Many authors reported about the kinematics of a normal squatting motion, however, little is known on what the influence of aging is. Twenty-two healthy volunteers in various age groups (range 21-75 years) performed a deep knee squat activity while undergoing motion analysis using an optical tracking system. The influence of aging was evaluated with respect to kinematics of the trunk, hip, knee and ankle joints. Older subjects required significantly more time to perform a deep squat, especially during the descending phase. They also had more knee abduction and delayed peak knee flexion. Older subjects were slower in descend than ascend during the squat. Although older subjects had a trend towards less maximal flexion and less internal rotation of the knee compared to younger subjects, this difference was not significant. Older subjects also showed a trend towards more forward leaning of the trunk, resulting in increased hip flexion and anterior thoracic tilt. This study confirmed that some aspects of squat kinematics vary significantly with age, and that the basic methodology employed here can successfully detect these age-related trends. Older subjects had more abduction of the knee joint, and this may indicate the load distribution of the medial and lateral condyles could be different amongst ages. Age-matched control data are therefore required whenever the performance of an implant is evaluated during a deep knee squat.

  9. Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments.

    PubMed

    Kumar, Deepak; Swanik, Charles Buz; Reisman, Darcy S; Rudolph, Katherine S

    2014-01-01

    Neuromuscular control relies on sensory feedback that influences responses to changing external demands, and the normal response is for movement and muscle activation patterns to adapt to repeated perturbations. People with knee osteoarthritis (OA) are known to have pain, quadriceps weakness, and neuromotor deficits that could affect adaption to external perturbations. The aim of this study was to analyze neuromotor adaptation during walking in people with knee OA (n = 38) and controls (n = 23). Disability, quadriceps strength, joint space width, malalignment, and proprioception were assessed. Kinematic and EMG data were collected during undisturbed walking and during perturbations that caused lateral translation of the foot at initial contact. Knee excursions and EMG magnitudes were analyzed. Subjects with OA walked with less knee motion and higher muscle activation and had greater pain, limitations in function, quadriceps weakness, and malalignment, but no difference was observed in proprioception. Both groups showed increased EMG and decreased knee motion in response to the first perturbation, followed by progressively decreased EMG activity and increased knee motion during midstance over the first five perturbations, but no group differences were observed. Over 30 trials, EMG levels returned to those of normal walking. The results illustrate that people with knee OA respond similarly to healthy individuals when exposed to challenging perturbations during functional weight-bearing activities despite structural, functional, and neuromotor impairments. Mechanisms underlying the adaptive response in people with knee OA need further study.

  10. Thermally activated depinning motion of contact lines in pseudopartial wetting.

    PubMed

    Du, Lingguo; Bodiguel, Hugues; Colin, Annie

    2014-07-01

    We investigate pressure-driven motion of liquid-liquid menisci in circular tubes, for systems in pseudopartial wetting conditions. The originality of this type of wetting lies in the coexistence of a macroscopic contact angle with a wetting liquid film covering the solid surface. Focusing on small capillary numbers, we report observations of an apparent contact angle hysteresis at first sight similar to the standard partial wetting case. However, this apparent hysteresis exhibits original features. We observe very long transient regimes before steady state, up to several hundreds of seconds. Furthermore, in steady state, the velocities are nonzero, meaning that the contact line is not strongly pinned to the surface defects, but are very small. The velocity of the contact line tends to vanish near the equilibrium contact angle. These observations are consistent with the thermally activated depinning theory that has been proposed to describe partial wetting systems on disordered substrates and suggest that a single physical mechanism controls both the hysteresis (or the pinning) and the motion of the contact line. The proposed analysis leads to the conclusion that the depinning activated energy is lower with pseudopartial wetting systems than with partial wetting ones, allowing the direct observation of the thermally activated motion of the contact line.

  11. Motion Sensor Use for Physical Activity Data: Methodological Considerations

    PubMed Central

    McCarthy, Margaret; Grey, Margaret

    2015-01-01

    Background Physical inactivity continues to be a major risk factor for cardiovascular disease, and only one half of adults in the United States meet physical activity (PA) goals. PA data are often collected for surveillance or for measuring change after an intervention. One of the challenges in PA research is quantifying exactly how much and what type of PA is taking place—especially because self-report instruments have inconsistent validity. Objective The purpose is to review the elements to consider when collecting PA data via motion sensors, including the difference between PA and exercise; type of data to collect; choosing the device; length of time to monitor PA; instructions to the participants; and interpretation of the data. Methods The current literature on motion sensor research was reviewed and synthesized to summarize relevant considerations when using a motion sensor to collect PA data. Results Exercise is a division of PA that is structured, planned, and repetitive. Pedometer data includes steps taken, and calculated distance and energy expenditure. Accelerometer data includes activity counts and intensity. The device chosen depends on desired data, cost, validity, and ease of use. Reactivity to the device may influence the duration of data collection. Instructions to participants may vary depending on purpose of the study. Experts suggest pedometer data be reported as steps—since that is the direct output—and distance traveled and energy expenditure are estimated values. Accelerometer count data may be analyzed to provide information on time spent in moderate or vigorous activity. Discussion Thoughtful decision making about PA data collection using motion sensor devices is needed to advance nursing science. PMID:26126065

  12. Knee Proprioception and Strength and Landing Kinematics During a Single-Leg Stop-Jump Task

    PubMed Central

    Nagai, Takashi; Sell, Timothy C; House, Anthony J; Abt, John P; Lephart, Scott M

    2013-01-01

    Context The importance of the sensorimotor system in maintaining a stable knee joint has been recognized. As individual entities, knee-joint proprioception, landing kinematics, and knee muscles play important roles in functional joint stability. Preventing knee injuries during dynamic tasks requires accurate proprioceptive information and adequate muscular strength. Few investigators have evaluated the relationship between knee proprioception and strength and landing kinematics. Objective To examine the relationship between knee proprioception and strength and landing kinematics. Design Cross-sectional study. Setting University research laboratory. Patients or Other Participants Fifty physically active men (age = 26.4 ± 5.8 years, height = 176.5 ± 8.0 cm, mass = 79.8 ± 16.6 kg). Intervention(s) Three tests were performed. Knee conscious proprioception was evaluated via threshold to detect passive motion (TTDPM). Knee strength was evaluated with a dynamometer. A 3-dimensional biomechanical analysis of a single-legged stop-jump task was used to calculate initial contact (IC) knee-flexion angle and knee-flexion excursion. Main Outcome Measure(s) The TTDPM toward knee flexion and extension, peak knee flexion and extension torque, and IC knee-flexion angle and knee flexion excursion. Linear correlation and stepwise multiple linear regression analyses were used to evaluate the relationships of both proprioception and strength against landing kinematics. The α level was set a priori at .05. Results Enhanced TTDPM and greater knee strength were positively correlated with greater IC knee-flexion angle (r range = 0.281–0.479, P range = .001–.048). The regression analysis revealed that 27.4% of the variance in IC knee-flexion angle could be accounted for by knee-flexion peak torque and TTDPM toward flexion (P = .001). Conclusions The current research highlighted the relationship between knee proprioception and strength and landing kinematics. Individuals with enhanced

  13. Quadriceps Strength Asymmetry Following ACL Reconstruction Alters Knee Joint Biomechanics and Functional Performance at Time of Return to Activity

    PubMed Central

    Palmieri-Smith, RM; Lepley, LK

    2016-01-01

    Background Quadriceps strength deficits are observed clinically following anterior cruciate injury and reconstruction and are often not overcome despite rehabilitation. Given that quadriceps strength may be important for achieving symmetrical joint biomechanics and promoting long-term joint health, determining the magnitude of strength deficits that lead to altered mechanics is critical. Purpose To determine if the magnitude of quadriceps strength asymmetry alters knee and hip biomechanical symmetry, as well as functional performance and self-reported function. Study Design Cross-Sectional study. Methods Seventy-three patients were tested at the time they were cleared for return to activity following ACL reconstruction. Quadriceps strength and activation, scores on the International Knee Documentation Committee form, the hop for distance test, and sagittal plane lower extremity biomechanics were recorded while patients completed a single-legged hop. Results Patients with high and moderate quadriceps strength symmetry had larger central activation ratios as well as greater limb symmetry indices on the hop for distance compared to patients with low quadriceps strength symmetry (P<0.05). Similarly, knee flexion angle and external moment symmetry was higher in the patients with high and moderate quadriceps symmetry compared to those with low symmetry (P<0.05). Quadriceps strength was found to be associated with sagittal plane knee angle and moment symmetry (P<0.05). Conclusion Patients with low quadriceps strength displayed greater movement asymmetries at the knee in the sagittal plane. Quadriceps strength was related to movement asymmetries and functional performance. Rehabilitation following ACL reconstruction needs to focus on maximizing quadriceps strength, which likely will lead to more symmetrical knee biomechanics. PMID:25883169

  14. Collective motion in an active suspension of Escherichia coli bacteria

    NASA Astrophysics Data System (ADS)

    Gachelin, J.; Rousselet, A.; Lindner, A.; Clement, E.

    2014-02-01

    We investigate experimentally the emergence of collective motion in the bulk of an active suspension of Escherichia coli bacteria. When increasing the concentration from a dilute to a semi-dilute regime, we observe a continuous crossover from a dynamical cluster regime to a regime of ‘bio-turbulence’ convection patterns. We measure a length scale characterizing the collective motion as a function of the bacteria concentration. For bacteria fully supplied with oxygen, the increase of the correlation length is almost linear with concentration and at the largest concentrations tested, the correlation length could be as large as 24 bacterial body sizes (or 7-8 when including the flagella bundle). In contrast, under conditions of oxygen shortage the correlation length saturates at a value of around 7 body lengths.

  15. Can a finite set of knee extension in supine position be used for a knee functional examination?

    PubMed

    Marin, F; Sangeux, M; Charleux, F; Ho Ba Tho, M-C; Dürselen, L

    2006-01-01

    The kinematic magnetic resonance imaging technique has been developed to provide a functional examination of the knee. Technical limitations require this examination to be performed in supine position, and the knee motion is represented by an assembly of static positions at different knee angles. However, the main knee function is to support the body weight and perform continuous motion, e.g. parallel squat. Our study quantified the knee kinematics of 20 healthy subjects in different motion conditions (finite and continuous) and in different mechanical conditions (continuous unloaded and continuous loaded). We evaluated the angular and localisation difference of a finite helical axis of the knee motion for parallel squat, continuous knee extension in supine position and the finite set of knee extension in supine position. We found large inter-individual dispersion. The majority of subjects had equivalent knee kinematics between continuous knee extension and the finite set of knee extension in supine position, but not between continuous knee extension in supine position and the parallel squat. Therefore, results from a functional examination of a finite set of knee extensions in supine position do not represent the knee motion in a parallel squat. Our results suggest that functional examination of the knee from magnetic resonance imaging do not necessarily reflect the physiological kinematics of the knee. Further investigation should focus on a new magnetic resonance imaging acquisition protocol that allows image acquisition during weight bearing or includes a special device which reproduces the loaded condition.

  16. Motion of Euglena gracilis: Active fluctuations and velocity distribution

    NASA Astrophysics Data System (ADS)

    Romanczuk, P.; Romensky, M.; Scholz, D.; Lobaskin, V.; Schimansky-Geier, L.

    2015-07-01

    We study the velocity distribution of unicellular swimming algae Euglena gracilis using optical microscopy and active Brownian particle theory. To characterize a peculiar feature of the experimentally observed distribution at small velocities we use the concept of active fluctuations, which was recently proposed for the description of stochastically self-propelled particles [Romanczuk, P. and Schimansky-Geier, L., Phys. Rev. Lett. 106, 230601 (2011)]. In this concept, the fluctuating forces arise due to internal random performance of the propulsive motor. The fluctuating forces are directed in parallel to the heading direction, in which the propulsion acts. In the theory, we introduce the active motion via the depot model [Schweitzer, et al., Phys. Rev. Lett. 80(23), 5044 (1998)]. We demonstrate that the theoretical predictions based on the depot model with active fluctuations are consistent with the experimentally observed velocity distributions. In addition to the model with additive active noise, we obtain theoretical results for a constant propulsion with multiplicative noise.

  17. Modulation of Physical Activity to Optimize Pain Sensation following an Intra-Articular Corticosteroid Injection in Patients with Knee Osteoarthritis

    PubMed Central

    Dessery, Yoann; Belzile, Étienne L.; Turmel, Sylvie; Doré, Jean; Diallo, Binta

    2014-01-01

    Background. Intra-articular corticosteroid injection is often used to relieve pain caused by knee osteoarthritis. This study aims to assess the impact after an intra-articular corticosteroid injection treatment on objective and subjective measurement of physical function in knee osteoarthritis patients. Methods. Fourteen patients with unilateral knee osteoarthritis participated in this open-label uncontrolled trial. The intra-articular corticosteroid injection was given at the end of the second week. Physical activity was objectively measured by an accelerometer worn by the participants for eight weeks. Symptoms, quality of life and spatiotemporal parameters of gait were assessed every two weeks. Results. From the injection until six weeks later, pain and stiffness were reduced by approximately 60%. Patients' daily physical activity time was significantly improved after injection: participation in light and moderate physical activities increased during four and two weeks, respectively. Conclusions. The beneficial effects after the intra-articular corticosteroid injection are visible in the duration and intensity of the knee osteoarthritis patients' daily physical activity. However, these effects declined gradually two weeks after injection. Modulating the intensity and duration of physical activity would allow patients to optimize pain sensation over a longer period following an intra-articular corticosteroid injection. Trial Registration. This trial was registered with ClinicalTrials: NCT02049879. PMID:25478585

  18. Knee Bursitis

    MedlinePlus

    ... make a diagnosis of knee bursitis during a physical exam. Your doctor will inspect your knee by: Comparing the condition of both knees, particularly if only one is painful Gently pressing on different areas of your knee to detect warmth, swelling and the source of pain Carefully moving ...

  19. Improvement of the knee center of rotation during walking after opening wedge high tibial osteotomy.

    PubMed

    Kim, Kyungsoo; Feng, Jun; Nha, Kyung Wook; Park, Won Man; Kim, Yoon Hyuk

    2015-06-01

    Accurate measurement of the center of rotation of the knee joint is indispensable for prediction of joint kinematics and kinetics in musculoskeletal models. However, no study has yet identified the knee center of rotations during several daily activities before and after high tibial osteotomy surgery, which is one surgical option for treating knee osteoarthritis. In this study, an estimation method for determining the knee joint center of rotation was developed by applying the optimal common shape technique and symmetrical axis of rotation approach techniques to motion-capture data and validated for typical activities (walking, squatting, climbing up stairs, walking down stairs) of 10 normal subjects. The locations of knee joint center of rotations for injured and contralateral knees of eight subjects with osteoarthritis, both before and after high tibial osteotomy surgery, were then calculated during walking. It was shown that high tibial osteotomy surgery improved the knee joint center of rotation since the center of rotations for the injured knee after high tibial osteotomy surgery were significantly closer to those of the normal healthy population. The difference between the injured and contralateral knees was also generally reduced after surgery, demonstrating increased symmetry. These results indicate that symmetry in both knees can be recovered in many cases after high tibial osteotomy surgery. Moreover, the recovery of center of rotation in the injured knee was prior to that of symmetry. This study has the potential to provide fundamental information that can be applied to understand abnormal kinematics in patients, diagnose knee joint disease, and design a novel implants for knee joint surgeries.

  20. Knee kinematics during walking at different speeds in people who have undergone total knee replacement.

    PubMed

    McClelland, Jodie A; Webster, Kate E; Feller, Julian A; Menz, Hylton B

    2011-06-01

    People who have undergone total knee replacement (TKR) experience difficulties in some daily activities including walking. Walking at faster speeds requires more knee flexion and may therefore present a greater challenge following TKR. The aim of this study was to compare the knee kinematics of patients following TKR and unimpaired controls during comfortable and fast walking speeds. Forty patients (22 women, 18 men) 12 months following TKR and 40 control participants (matched for age and sex) were assessed during walking at self-selected comfortable and fast speeds using three dimensional motion analysis. The group averages of spatiotemporal and peak kinematic characteristics in the sagittal, coronal and transverse movement planes were compared using univariate analysis of variance with walking speed as a co-variate. The TKR group walked with significantly reduced cadence (p < 0.001 at both speeds) and reduced stride length (p < 0.001 at both speeds), less knee flexion during stance and swing phases (p < 0.001 for both speeds) and less knee extension during stance phase (p < 0.024 for comfortable speed; p < 0.042 for fast speed). The TKR group also walked with less peak knee external rotation than controls at both speeds (p < 0.001 for both speeds). Both groups increased their velocity, cadence and stride length by a similar proportion when walking at fast speed. When walking at a faster speed, spatiotemporal gait parameters and knee motion are altered in a similar manner for both TKR patients and controls. However, at both walking speeds, TKR patients exhibit residual deficits 12 months following surgery.

  1. Do radiographic disease and pain account for why people with or at high risk of knee osteoarthritis do not meet Physical Activity Guidelines?

    PubMed Central

    White, Daniel K.; Tudor-Locke, Catrine; Felson, David T.; Gross, K. Doug; Niu, Jingbo; Nevitt, Michael; Lewis, Cora E.; Torner, James; Neogi, Tuhina

    2012-01-01

    OBJECTIVE Knee Osteoarthritis (OA) and pain are assumed to be barriers for meeting physical activity guidelines, but this has not been formally evaluated. The purpose of this study was to determine the proportion of people with and without knee OA and knee pain who met recommended physical activity levels through walking. METHODS Cross-sectional analysis of community dwelling adults who have or who are at high risk of knee OA from The Multicenter Osteoarthritis Study. Participants wore a StepWatch activity monitor to record steps/day over 7 days. The proportion that met the recommended physical activity levels was determined as those accumulating ≥150 minutes/week at ≥100 steps/minute in bouts lasting ≥10 minutes. These proportions were also determined for those with and without knee OA, as classified by radiograph, and by severity of knee pain. RESULTS Of the 1788 study participants (age 67 sd 8 yrs, BMI 31 sd 6 kg/m2, 60% female), lower overall percentages of participants with radiographic knee OA and knee pain met recommended physical activity levels. However, these differences were not statistically significant between those with and without knee OA; 7.3% and 10.1% of men (p=0.34), and 6.3% and 7.8% of women (p=0.51), respectively, met recommended physical activity levels. Similarly, for those with moderate/severe pain versus no pain, 12.9% and 10.9% of men (p=0.74) and 6.7% and 11.0% (p=0.40) of women met recommended physical activity levels. CONCLUSIONS Disease and pain have little impact on achieving recommended physical activity levels among people with or at high risk of knee OA. PMID:23124774

  2. Fusion of smartphone motion sensors for physical activity recognition.

    PubMed

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

    2014-06-10

    For physical activity recognition, smartphone sensors, such as an accelerometer and a gyroscope, are being utilized in many research studies. So far, particularly, the accelerometer has been extensively studied. In a few recent studies, a combination of a gyroscope, a magnetometer (in a supporting role) and an accelerometer (in a lead role) has been used with the aim to improve the recognition performance. How and when are various motion sensors, which are available on a smartphone, best used for better recognition performance, either individually or in combination? This is yet to be explored. In order to investigate this question, in this paper, we explore how these various motion sensors behave in different situations in the activity recognition process. For this purpose, we designed a data collection experiment where ten participants performed seven different activities carrying smart phones at different positions. Based on the analysis of this data set, we show that these sensors, except the magnetometer, are each capable of taking the lead roles individually, depending on the type of activity being recognized, the body position, the used data features and the classification method employed (personalized or generalized). We also show that their combination only improves the overall recognition performance when their individual performances are not very high, so that there is room for performance improvement. We have made our data set and our data collection application publicly available, thereby making our experiments reproducible.

  3. Fusion of Smartphone Motion Sensors for Physical Activity Recognition

    PubMed Central

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J. M.

    2014-01-01

    For physical activity recognition, smartphone sensors, such as an accelerometer and a gyroscope, are being utilized in many research studies. So far, particularly, the accelerometer has been extensively studied. In a few recent studies, a combination of a gyroscope, a magnetometer (in a supporting role) and an accelerometer (in a lead role) has been used with the aim to improve the recognition performance. How and when are various motion sensors, which are available on a smartphone, best used for better recognition performance, either individually or in combination? This is yet to be explored. In order to investigate this question, in this paper, we explore how these various motion sensors behave in different situations in the activity recognition process. For this purpose, we designed a data collection experiment where ten participants performed seven different activities carrying smart phones at different positions. Based on the analysis of this data set, we show that these sensors, except the magnetometer, are each capable of taking the lead roles individually, depending on the type of activity being recognized, the body position, the used data features and the classification method employed (personalized or generalized). We also show that their combination only improves the overall recognition performance when their individual performances are not very high, so that there is room for performance improvement. We have made our data set and our data collection application publicly available, thereby making our experiments reproducible. PMID:24919015

  4. In vivo healthy knee kinematics during dynamic full flexion.

    PubMed

    Hamai, Satoshi; Moro-oka, Taka-aki; Dunbar, Nicholas J; Miura, Hiromasa; Iwamoto, Yukihide; Banks, Scott A

    2013-01-01

    Healthy knee kinematics during dynamic full flexion were evaluated using 3D-to-2D model registration techniques. Continuous knee motions were recorded during full flexion in a lunge from 85° to 150°. Medial and lateral tibiofemoral contacts and femoral internal-external and varus-valgus rotations were analyzed as a function of knee flexion angle. The medial tibiofemoral contact translated anteroposteriorly, but remained on the center of the medial compartment. On the other hand, the lateral tibiofemoral contact translated posteriorly to the edge of the tibial surface at 150° flexion. The femur exhibited external and valgus rotation relative to the tibia over the entire activity and reached 30° external and 5° valgus rotations at 150° flexion. Kinematics' data during dynamic full flexion may provide important insight as to the designing of high-flexion total knee prostheses.

  5. Reduced Maximal Force during Acute Anterior Knee Pain Is Associated with Deficits in Voluntary Muscle Activation

    PubMed Central

    Salomoni, Sauro; Tucker, Kylie; Hug, François; McPhee, Megan; Hodges, Paul

    2016-01-01

    Although maximal voluntary contraction (MVC) force is reduced during pain, studies using interpolated twitch show no consistent reduction of voluntary muscle drive. The present study aimed to test if the reduction in MVC force during acute experimental pain could be explained by increased activation of antagonist muscles, weak voluntary activation at baseline, or changes in force direction. Twenty-two healthy volunteers performed maximal voluntary isometric knee extensions before, during, and after the effects of hypertonic (pain) and isotonic (control) saline injections into the infrapatellar fat pad. The MVC force, voluntary activation, electromyographic (EMG) activity of agonist, antagonist, and auxiliary (hip) muscles, and pain cognition and anxiety scores were recorded. MVC force was 9.3% lower during pain than baseline (p < 0.001), but there was no systematic change in voluntary activation. Reduced MVC force during pain was variable between participants (SD: 14%), and was correlated with reduced voluntary activation (r = 0.90), baseline voluntary activation (r = − 0.62), and reduced EMG amplitude of agonist and antagonist muscles (all r > 0.52), but not with changes in force direction, pain or anxiety scores. Hence, reduced MVC force during acute pain was mainly explained by deficits in maximal voluntary drive. PMID:27559737

  6. Peak triceps surae muscle activity is not specific to knee flexion angles during MVIC.

    PubMed

    Hébert-Losier, Kim; Schneiders, Anthony G; García, José A; Sullivan, S John; Simoneau, Guy G

    2011-10-01

    There is limited research on peak activity of the separate triceps surae muscles in select knee flexion (KF) positions during a maximum voluntary isometric contraction (MVIC) used to normalize EMG signals. The aim of this study was to determine how frequent peak activity occurred during an MVIC for soleus (SOL), gastrocnemius medialis (GM), and gastrocnemius lateralis (GL) in select KF positions, and if these peaks were recorded in similar KF positions. Forty-eight healthy individuals performed unilateral plantar-flexion MVIC in standing with 0°KF and 45°KF, and in sitting with 90°KF. Surface EMG of SOL, GM, and GL were collected and processed in 250 ms epochs to determine peak root-mean-square amplitude. Peak activity was most frequently captured in standing and rarely in sitting, with no position selective to SOL, GM or GL activity. Peak GM and GL activity was more frequent in 0°KF than 45°KF, and more often in similar KF positions than not. Peak SOL activity was just as likely in 45°KF as 0°KF, and more in positions similar to GM, but not GL. The EMG amplitudes were at least 20% greater in positions that captured peak activity over those that did not. The overall findings support performing an MVIC in more than one KF position to normalize triceps surae EMG. It is emphasized that no KF position is selective to SOL, GM, or GL alone.

  7. Knee cartilage segmentation using active shape models and local binary patterns

    NASA Astrophysics Data System (ADS)

    González, Germán.; Escalante-Ramírez, Boris

    2014-05-01

    Segmentation of knee cartilage has been useful for opportune diagnosis and treatment of osteoarthritis (OA). This paper presents a semiautomatic segmentation technique based on Active Shape Models (ASM) combined with Local Binary Patterns (LBP) and its approaches to describe the surrounding texture of femoral cartilage. The proposed technique is tested on a 16-image database of different patients and it is validated through Leave- One-Out method. We compare different segmentation techniques: ASM-LBP, ASM-medianLBP, and ASM proposed by Cootes. The ASM-LBP approaches are tested with different ratios to decide which of them describes the cartilage texture better. The results show that ASM-medianLBP has better performance than ASM-LBP and ASM. Furthermore, we add a routine which improves the robustness versus two principal problems: oversegmentation and initialization.

  8. Differential brain activity states during the perception and nonperception of illusory motion as revealed by magnetoencephalography.

    PubMed

    Crowe, David A; Leuthold, Arthur C; Georgopoulos, Apostolos P

    2010-12-28

    We studied visual perception using an annular random-dot motion stimulus called the racetrack. We recorded neural activity using magnetoencephalography while subjects viewed variants of this stimulus that contained no inherent motion or various degrees of embedded motion. Subjects reported seeing rotary motion during viewing of all stimuli. We found that, in the absence of any motion signals, patterns of brain activity differed between states of motion perception and nonperception. Furthermore, when subjects perceived motion, activity states within the brain did not differ across stimuli of different amounts of embedded motion. In contrast, we found that during periods of nonperception brain-activity states varied with the amount of motion signal embedded in the stimulus. Taken together, these results suggest that during perception the brain may lock into a stable state in which lower-level signals are suppressed.

  9. Character, Incidence, and Predictors of Knee Pain and Activity after Infrapatellar Intramedullary Nailing of an Isolated Tibia Fracture

    PubMed Central

    Obremskey, William; Agel, Julie; Archer, Kristin; To, Philip; Tornetta, Paul

    2015-01-01

    Objective To study the activity and incidence of knee pain after sustaining a isolated tibia fracture treated with an infrapatellar intramedullary nail at one year. Design Retrospective review of prospective cohort Setting Multicenter Academic and Community hospitals Patients 437 patients with an isolated tibia fracture completed a 12 month assessment on pain and self-reported activity. Intervention Infrapatellar Intramedullary Nail Outcomes Demographic information co-morbid conditions, injury characteristics, and surgical technique were recorded. Knee pain was defined on a 1-7 scale with 1 being “no pain” and 7 being a “very great deal of pain.” Knee pain > 4 was considered clinically significant. Patients reported if they were “able”, “able with difficulty” or “unable” to perform the following activities: kneel, run, climb stairs, and walk prolonged. Variables were tested in multilevel multivariable regression analyses. Results Knee Pain: 11% percent of patients reported a “good deal” to a “very great deal” of pain (> 4). 52% of patients reported “no” or “very little” pain at 12 months. Activity at 12 months: 26% and 29% of patients were unable to kneel or run, respectively. 31% and 35% of patients respectively stated they were able with difficulty or unable to use stairs or walk. Conclusion Clinically significant knee pain (>4/7) was present in 11% of patients one year after a tibia fracture. 31%-71% of patients had difficulty performing or were unable to perform routine daily activities of kneeling, running, and stair climbing or walking prolonged distances. PMID:26496180

  10. Acute effects of blood flow restriction on muscle activity and endurance during fatiguing dynamic knee extensions at low load.

    PubMed

    Wernbom, Mathias; Järrebring, Rickard; Andreasson, Mikael A; Augustsson, Jesper

    2009-11-01

    The purpose of this study was to investigate muscle activity and endurance during fatiguing low-intensity dynamic knee extension exercise with and without blood flow restriction. Eleven healthy subjects with strength training experience performed 3 sets of unilateral knee extensions with no relaxation between repetitions to concentric torque failure at 30% of the 1 repetition maximum. One leg was randomized to exercise with cuff occlusion and the other leg to exercise without occlusion. The muscle activity in the quadriceps was recorded with electromyography (EMG). Ratings of perceived exertion (RPE) and acute pain were collected immediately, and delayed onset muscle soreness (DOMS) was rated before and at 24, 48, and 72 hours after exercise. The results demonstrated high EMG levels in both experimental conditions, but there were no significant differences regarding maximal muscle activity, except for a higher EMG in the eccentric phase in set 3 for the nonoccluded condition (p = 0.005). Significantly more repetitions were performed with the nonoccluded leg in every set (p < 0.05). The RPE and acute pain ratings were similar, but DOMS was higher in the nonoccluded leg (p < 0.05). We conclude that blood flow restriction during low-intensity dynamic knee extension decreases the endurance but does not increase the maximum muscle activity compared with training without restriction when both regimes are performed to failure. The high levels of muscle activity suggest that performing low-load dynamic knee extensions in a no-relaxation manner may be a useful method in knee rehabilitation settings when large forces are contraindicated. However, similarly to fatiguing blood flow restricted exercise, this method is associated with ischemic muscle pain, and thus its applications may be limited to highly motivated individuals.

  11. Knee angular displacement and extensor muscle activity in telemark skiing and in ski-specific strength exercises.

    PubMed

    Nilsson, Johnny; Haugen, Per

    2004-04-01

    Much of the training of competitive telemark skiers is performed as dry-land exercises. The specificity of these exercises is important for optimizing the training effect. Our aim here was to study the activation of the knee extensor musculature and knee angular displacement during competitive telemark skiing and during dry-land strength training exercises to determine the specificity of the latter. Specificity was analysed with respect to angular amplitude, angular velocity, muscle action and electromyographic (EMG) activity. Five male telemark skiers of national and international standard volunteered to participate in the study, which consisted of two parts: (1) skiing a telemark ski course and (2) specific dry-land strength training exercises for telemark skiing (telemark jumps and barbell squats). The angular displacement of the right knee joint was recorded with an electrogoniometer. A tape pressure sensor was used to measure pressure between the sole of the foot and the bottom of the right ski boot. Electromyographic activity in the right vastus lateralis was recorded with surface electrodes. The EMG activity recorded during maximum countermovement jumps was used to normalize the EMG activity during telemark skiing, telemark jumps and barbell squats. The results showed that knee angular displacement during telemark skiing and dry-land telemark jumps had four distinct phases: a flexion (F1) and extension (E1) phase during the thrust phase of the outside ski/leg in the turn/jump and a flexion (F2) and extension (E2) phase when the leg was on the inside of the turn/jump. The vastus lateralis muscle was activated during F1 and E1 in the thrust phase during telemark skiing and telemark jumps. The overall net knee angular amplitude was significantly greater (P < 0.05) for telemark jumps than for telemark skiing. Barbell squats showed a knee angular amplitude significantly greater than that in telemark skiing (P < 0.05). The mean knee angular velocity of the F1 and

  12. Crew activity and motion effects on the space station

    NASA Technical Reports Server (NTRS)

    Rochon, Brian V.; Scheer, Steven A.

    1987-01-01

    Among the significant sources of internal disturbances that must be considered in the design of space station vibration control systems are the loads induced on the structure from various crew activities. Flight experiment T013, flown on the second manned mission of Skylab, measured force and moment time histories for a range of preplanned crew motions and activities. This experiment has proved itself invaluable as a source of on-orbit crew induced loads that has allowed a space station forcing function data base to be built. This will enable forced response such as acceleration and deflections, attributable to crew activity, to be calculated. The flight experiment, resultant database and structural model pre-processor, analysis examples and areas of combined research shall be described.

  13. Evaluation of a variable resistance orthotic knee joint.

    PubMed

    Herbert-Copley, Andrew; Lemaire, Edward D; Baddour, Natalie

    2016-08-01

    Knee-ankle-foot orthoses (KAFOs) are full leg braces for individuals with knee extensor weakness, designed to support the person during weight bearing activities by preventing knee flexion. KAFOs typically result in an unnatural gait pattern and are primarily used for level ground walking. A novel variable resistance orthotic knee joint, the Ottawalk-Variable Speed (OWVS), was designed to address these limitations. This paper presents a pilot test to evaluate the OWVS functional performance during walking and stair descent. A carbon-fiber KAFO was adjusted for an able-bodied participant by a certified orthotist, with a standard orthotic single axis knee joint on the medial side and the OWVS on the lateral side. The participant performed level ground walking (stance-control, open, closed) and stair descent tests. The operator was able to manually switch between closed mode in terminal swing to open mode in terminal stance for stance-control walking. Knee angle kinematics were similar between open and stance control modes. For stair descent, resistance settings supported the participant as they lowered their body to the next step, but with smaller range of motion compared to the open setting. The Ottawalk-Variable Speed design successfully controls knee flexion during stance and stair descent, with one lateral control joint. Mode switching was fast and appropriate. This microprocessor controlled SCKAFO has a low profile that fits beneath clothing and the variable resistance design will allow people to negotiate different terrain types.

  14. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  15. A COMPARISON OF TWO TAPING TECHNIQUES (KINESIO AND MCCONNELL) AND THEIR EFFECT ON ANTERIOR KNEE PAIN DURING FUNCTIONAL ACTIVITIES

    PubMed Central

    Babu, Jenie; Dmochowska, Katarzyna; Scariah, Shiju; Varughese, Jincy

    2013-01-01

    Background: Anterior knee pain is a clinical syndrome characterized by pain experienced perceived over the anterior aspect of the knee that can be aggravated by functional activities such as stair climbing and squatting. Two taping techniques commonly used for anterior knee pain in the clinic include the McConnell Taping Technique (MT) and the Kinesio Taping® Method (KT®). Objective: The purpose of this study was to compare the effectiveness of KT® and the MT versus no tape in subjects with anterior knee pain during a squat lift and stair climbing. Design: Pretest‐ posttest design. Participants: A total of 20 subjects (15 female, 5 male) with unilateral anterior knee pain were recruited. The mean age of the subjects was 24 (+/–3) years, with a mean weight of 160 (+/–28) pounds. Methods: Each participant was tested during two functional activities; a squat lift with a weighted box (10% of his/her body weight, plus the weight [8.5 pounds] of the box) and stair climbing under three conditions: 1) no tape, 2) MT and 3) KT®. Pain levels were assessed (verbally) using the 0‐10 Numeric Pain Intensity Scale. Results: The median (interquartile range [IQR]) pain during squat lift was 2 (2.75) for no tape, 1 (1) for KT®, and 0.5 (2) for McConnell, with no significant differences between the groups. During the stair activity the median (IQR) pain was 1.5 (2.75) for no tape, 1 (1.75) for KT®, and 1 (1.75) for MT with a significant difference (p=0.024) between the groups. Further analysis determined that the only a significant difference was (p=0.034) between the no tape and the KT® conditions. Conclusion: The results of this study found that both the KT® and the MT may be effective in reducing pain during stair climbing activities. Level of Evidence: Level 2, Prospective Cohort study PMID:23593548

  16. In vivo kinematic comparison between mobile-bearing and fixed-bearing total knee arthroplasty during step-up activity.

    PubMed

    Okamoto, Nobukazu; Nakamura, Eiichi; Nishioka, Hiroaki; Karasugi, Tatsuki; Okada, Tatsuya; Mizuta, Hiroshi

    2014-12-01

    Mobile-bearing total knee arthroplasty (TKA) expects high conformity and low contact stress. It is designed to correct the rotational mismatch between femoral and tibial components. We examined the difference in weight-bearing knee kinematics in patients with mobile-bearing and fixed-bearing TKA performing step-up activities. We randomly assigned 40 knees (37 patients) to mobile-bearing TKA (n=20) or fixed-bearing TKA (n=20). Using fluoroscopic imaging we evaluated knee kinematics during step-up activity one year after surgery. The total extent of rotation was not different for the two TKAs. Due to the axial rotation of the polyethylene insert, patients with mobile-bearing TKA had a wider range of absolute axial rotation. The position of the medial and the lateral condyles was significantly more posterior in the fixed-bearing TKA. There were only minor kinematic differences between the two TKAs. The polyethylene insert in the mobile-bearing TKA moved as designed especially with respect to the self-alignment feature.

  17. Active motion and load control of floating offshore wind turbines

    NASA Astrophysics Data System (ADS)

    Jalili, Kaveh

    The research in this thesis is focused on stabilization and load reduction of floating offshore wind turbine (FOWT) structures for both the fore-aft (pitch) and side-to-side (roll) directions. Based on the Tuned Mass Damper (TMD) and Active Vane concepts recently proposed, two composite actuation schemes are investigated. The first scheme is to apply the horizontal vane and vertical vane to platform pitch and roll, respectively, resulting in the so-called Double Vane Actuation (DVA) scheme. The second scheme is the combination of the TMD based pitch control and active vertical vane based roll control, resulting in the so-called Hybrid Actuation (HA) scheme. Simulation results of DVA show great reductions of motions and loads in the fore-aft and side-to-side directions. Performance of HA is investigated by extensive simulations based on the IEC61400-3 standard and results show significant and consistent motions and loads reductions in both FA and SS directions.

  18. Active Motion Control of Tetrahymena pyriformis by Galvanotaxis and Geotaxis

    NASA Astrophysics Data System (ADS)

    Kim, Jihoon; Byun, Doyoung; Kim, Min Jun

    2013-11-01

    Recently, there has been increasing interest in the swimming behavior of microorganisms and biologically inspired micro-robots. These microorganisms naturally accompanied by complex motions. Therefore it is important to understand the flow characteristics as well as control mechanisms. One of eukaryotic cells, the protozoa are a diverse group of unicellular organisms, many of which are motile cilia. Motile cilia are cover on the surface of cell in large numbers and beat in oriented waves. Sequential beating motions of a single cilium form metachronal strokes, producing a propagation wave, and therefore the body is achieved propulsion force. So preliminary studies are achieved to understand the flow induced by swimming microorganisms. Based on hydrodynamic results, the follow study of a few micro-scale protozoa cell, such as the Tetrahymena pyriformis, has provided active or passive control into several external stimuli. In typical control methods, the galvanotaxis and geotaxis were adopted active and passive control, respectively. The validation of galvanotaxis is used DC and AC voltage. In terms of geotaxis, corrugated microstructures were used to control in the microchannel. This research was supported by the Ministry of Education, Science and Technology (MEST, 2011-0016461), National Science Foundation (NSF) CMMI Control Systems Program (#1000255) and Army Research Office (W911NF-11-1-0490).

  19. Flare Activity and Magnetic Helicity Injection By Photospheric Horizontal Motions

    NASA Astrophysics Data System (ADS)

    Moon, Y.-J.; Chae, J.; Choe, G.; Wang, H.; Park, Y. D.; Yun, H. S.; Yurchyshyn, V.; Goode, P. R.

    2002-05-01

    We present observational evidence that the occurrence of homologous flares in an active region is physically related to the injection of magnetic helicity by horizontal photospheric motions. We have analyzed a set of 1 minute cadence magnetograms of NOAA AR 8100 taken over a period of 6.5 hours by Michelson Doppler Imager (MDI) on board Solar and Heliospheric Observatory (SOHO). During this observing time span, seven homologous flares took place in the active region. We have computed the magnetic helicity injection rate into the solar atmosphere by photospheric shearing motions, and found that a significant amount of magnetic helicity was injected during the observing period. In a strong M4.1 flare, the magnetic helicity injection rate impulsively increased and peaked at the same time as the X-ray flux did. The flare X-ray flux integrated over the X-ray emission time strongly correlates with the magnetic helicity injected during the flaring interval. The integrated X-ray flux is found to be a logarithmically increasing function of the injected magnetic helicity. Our results suggest that injection of helicity and abrupt increase of helicity magnitude play a significant role in flare triggering. This work has been supported by NASA grants NAG5-10894 and NAG5-7837, by MURI grant of AFOSR, by the US-Korea Cooperative Science Program (NSF INT-98-16267), by NRL M10104000059-01J000002500 of the Korean government, and by the BK 21 project of the Korean government.

  20. Knee problems and its associated factors among active cyclists in Eastern Province, Saudi Arabia

    PubMed Central

    Althunyan, Abdullatif K.; Darwish, Magdy A.; Abdel Wahab, Moataza M.

    2017-01-01

    INTRODUCTION: Bicycling is one of the most enjoyable aerobic exercises recommended for the promotion of an individual's health. The Eastern Province of Saudi Arabia has seen a huge increase in the number of people who cycle. People have different goals for bicycling, but the injuries they sustain are common. Most of them relate to overuse, particularly of lower body joints. This study was conducted to determine the prevalence of knee problems and factors associated with knee pain in cyclists. MATERIALS AND METHODS: A cross-sectional study was conducted in October 2015, using an online self-administered questionnaire. The questionnaire was based on pertinent literature, was piloted, and validated. A web link was sent to 513 cyclists (professional and amateur) using E-mail, WhatsApp application, or SMS. Three hundred and eleven responses were received, 283 of which were included in the analysis. RESULTS: The overall prevalence of knee pain was 25.8%; 27.6% for amateur cyclists and 15.9% for professional cyclists. Only 17.2% knee pain was attributed to cycling, whereas in 32.8% it happened spontaneously and in 25% of cases it occurred while running. Majority of the cyclists reported pain as mild (61.6%) or moderate (28.7%); anterior knee pain accounted for 58.1% knee pain. Different goals of cycling and different bicycle types had statistically significant difference on the rate of knee pain. Of underweight cyclists, 62.2% reported knee pain. Cyclists who run more or participated in football had a higher rate of pain. CONCLUSION: Knee injuries are common with cyclists. Factors such as the type of the bicycle, the goal of bicycling, club type, body mass index, and participation in other sports play a significant role in the rate of knee pain. PMID:28163572

  1. Assessing the Relative Contributions of Active Ankle and Knee Assistance to the Walking Mechanics of Transfemoral Amputees Using a Powered Prosthesis

    PubMed Central

    Simon, Ann M.; Hargrove, Levi J.

    2016-01-01

    Powered knee-ankle prostheses are capable of providing net-positive mechanical energy to amputees. Yet, there are limitless ways to deliver this energy throughout the gait cycle. It remains largely unknown how different combinations of active knee and ankle assistance affect the walking mechanics of transfemoral amputees. This study assessed the relative contributions of stance phase knee swing initiation, increasing ankle stiffness and powered plantarflexion as three unilateral transfemoral amputees walked overground at their self-selected walking speed. Five combinations of knee and ankle conditions were evaluated regarding the kinematics and kinetics of the amputated and intact legs using repeated measures analyses of variance. We found eliminating active knee swing initiation or powered plantarflexion was linked to increased compensations of the ipsilateral hip joint during the subsequent swing phase. The elimination of knee swing initiation or powered plantarflexion also led to reduced braking ground reaction forces of the amputated and intact legs, and influenced both sagittal and frontal plane loading of the intact knee joint. Gradually increasing prosthetic ankle stiffness influenced the shape of the prosthetic ankle plantarflexion moment, more closely mirroring the intact ankle moment. Increasing ankle stiffness also corresponded to increased prosthetic ankle power generation (despite a similar maximum stiffness value across conditions) and increased braking ground reaction forces of the amputated leg. These findings further our understanding of how to deliver assistance with powered knee-ankle prostheses and the compensations that occur when specific aspects of assistance are added/removed. PMID:26807889

  2. Functional and morphological adaptations to aging in knee extensor muscles of physically active men.

    PubMed

    Baroni, Bruno Manfredini; Geremia, Jeam Marcel; Rodrigues, Rodrigo; Borges, Marcelo Krás; Jinha, Azim; Herzog, Walter; Vaz, Marco Aurélio

    2013-10-01

    It is not known if a physically active lifestyle, without systematic training, is sufficient to combat age-related muscle and strength loss. Therefore, the purpose of this study was to evaluate if the maintenance of a physically active lifestyle prevents muscle impairments due to aging. To address this issue, we evaluated 33 healthy men with similar physical activity levels (IPAQ = 2) across a large range of ages. Functional (torque-angle and torque-velocity relations) and morphological (vastus lateralis muscle architecture) properties of the knee extensor muscles were assessed and compared between three age groups: young adults (30 ± 6 y), middle-aged subjects (50 ± 7 y) and elderly subjects (69 ± 5 y). Isometric peak torques were significantly lower (30% to 36%) in elderly group subjects compared with the young adults. Concentric peak torques were significantly lower in the middle aged (18% to 32%) and elderly group (40% to 53%) compared with the young adults. Vastus lateralis thickness and fascicles lengths were significantly smaller in the elderly group subjects (15.8 ± 3.9 mm; 99.1 ± 25.8 mm) compared with the young adults (19.8 ± 3.6 mm; 152.1 ± 42.0 mm). These findings suggest that a physically active lifestyle, without systematic training, is not sufficient to avoid loss of strength and muscle mass with aging.

  3. Documenting Western Burrowing Owl Reproduction and Activity Patterns Using Motion-Activated Cameras

    SciTech Connect

    Hall, Derek B.; Greger, Paul D.

    2014-08-01

    We used motion-activated cameras to monitor the reproduction and patterns of activity of the Burrowing Owl (Athene cunicularia) above ground at 45 burrows in south-central Nevada during the breeding seasons of 1999, 2000, 2001, and 2005. The 37 broods, encompassing 180 young, raised over the four years represented an average of 4.9 young per successful breeding pair. Young and adult owls were detected at the burrow entrance at all times of the day and night, but adults were detected more frequently during afternoon/early evening than were young. Motion-activated cameras require less effort to implement than other techniques. Limitations include photographing only a small percentage of owl activity at the burrow; not detecting the actual number of eggs, young, or number fledged; and not being able to track individual owls over time. Further work is also necessary to compare the accuracy of productivity estimates generated from motion-activated cameras with other techniques.

  4. Knee Power Is an Important Parameter in Understanding Medial Knee Joint Load in Knee Osteoarthritis

    PubMed Central

    Calder, Kristina M; Acker, Stacey M; Arora, Neha; Beattie, Karen A; Callaghan, Jack P; Adachi, Jonathan D; Maly, Monica R

    2014-01-01

    Objective To determine the extent to which knee extensor strength and power explain variance in knee adduction moment (KAM) peak and impulse in clinical knee osteoarthritis (OA). Methods Fifty-three adults (mean ± SD age 61.6 ± 6.3 years, 11 men) with clinical knee OA participated. The KAM waveform was calculated from motion and force data and ensemble averaged from 5 walking trials. The KAM peak was normalized to body mass (Nm/kg). The mean KAM impulse reflected the mean total medial knee load during stride (Nm × seconds). For strength, the maximum knee extensor moment attained from maximal voluntary isometric contractions (MVIC) was normalized to body mass (Nm/kg). For power, the maximum knee extensor power during isotonic contractions, with the resistance set at 25% of MVIC, was normalized to body mass (W/kg). Covariates included age, sex, knee pain on the Knee Injury and Osteoarthritis Outcome Score, gait speed, and body mass index (BMI). Relationships of the KAM peak and impulse with strength and power were examined using sequential stepwise forward linear regressions. Results Covariates did not explain variance in the KAM peak. While extensor strength did not, peak knee extensor power explained 8% of the variance in the KAM peak (P = 0.02). Sex and BMI explained 24% of the variance in the KAM impulse (P < 0.05). Sex, BMI, and knee extensor power explained 31% of the variance in the KAM impulse (P = 0.02), with power contributing 7% (P < 0.05). Conclusion Knee extensor power was more important than isometric knee strength in understanding medial knee loads during gait. PMID:24920175

  5. Motion Analysis and the Anterior Cruciate Ligament: Classification of Injury Risk.

    PubMed

    Bates, Nathaniel A; Hewett, Timothy E

    2016-02-01

    Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expense and lead to degradation of the knee. As such, various motion capture techniques have been applied to identify athletes who are at increased risk for suffering ACL injuries. The objective of this clinical commentary was to synthesize information related to how motion capture analyses contribute to the identification of risk factors that may predict relative injury risk within a population. Individuals employ both active and passive mechanisms to constrain knee joint articulation during motion. There is strong evidence to indicate that athletes who consistently classify as high-risk loaders during landing suffer from combined joint stability deficits in both the active and passive knee restraints. Implementation of prophylactic neuromuscular interventions and biofeedback can effectively compensate for some of the deficiencies that result from poor control of the active knee stabilizers and reduce the incidence of ACL injuries.

  6. Biological activity and migration of wear particles in the knee joint: an in vivo comparison of six different polyethylene materials.

    PubMed

    Utzschneider, S; Lorber, V; Dedic, M; Paulus, A C; Schröder, C; Gottschalk, O; Schmitt-Sody, M; Jansson, V

    2014-06-01

    Wear of polyethylene causes loosening of joint prostheses because of the particle mediated activity of the host tissue. It was hypothesized that conventional and crosslinked polyethylene particles lead to similar biological effects around the knee joint in vivo as well as to a similar particle distribution in the surrounding tissues. To verify these hypotheses, particle suspensions of six different polyethylene materials were injected into knee joints of Balb/C mice and intravital microscopic, histological and immunohistochemical evaluations were done after 1 week. Whereas the biological effects on the synovial layer and the subchondral bone of femur and tibia were similar for all the polyethylenes, two crosslinked materials showed an elevated cytokine expression in the articular cartilage. Furthermore, the distribution of particles around the joint was dependent on the injected polyethylene material. Those crosslinked particles, which remained mainly in the joint space, showed an increased expression of TNF-alpha in articular cartilage. The data of this study support the use of crosslinked polyethylene in total knee arthroplasty. In contrast, the presence of certain crosslinked wear particles in the joint space can lead to an elevated inflammatory reaction in the remaining cartilage, which challenges the potential use of those crosslinked polyethylenes for unicondylar knee prostheses.

  7. Knee pain, knee injury, knee osteoarthritis & work.

    PubMed

    Dulay, Gurdeep S; Cooper, C; Dennison, E M

    2015-06-01

    Symptomatic knee osteoarthritis (OA) can be viewed as the end result of a molecular cascade which ensues after certain triggers occur and ultimately results in irreversible damage to the articular cartilage. The clinical phenotype that knee OA can produce is variable and often difficult to accurately predict. This is further complicated by the often poor relationship between radiographic OA and knee pain. As a consequence, it can be difficult to compare studies that use different definitions of OA. However, the literature suggests that while there are multiple causes of knee OA, two have attracted particular attention over recent years; occupation related knee OA and OA subsequent to previous knee injury. The evidence of a relationship, and the strength of this association, is discussed in this chapter.

  8. Involvement of the proximal tibiofibular joint in osteoarthritis of the knee.

    PubMed

    Oztuna, Volkan; Yildiz, Altan; Ozer, Caner; Milcan, Abtullah; Kuyurtar, Fehmi; Turgut, Akin

    2003-12-01

    This study was performed to evaluate the possible involvement of the proximal tibiofibular joint in primary osteoarthritis of the knee. A total of 40 patients with primary osteoarthritis of the knee who had magnetic resonance imaging scans were reexamined for proximal tibiofibular joint involvement. The patient was questioned if pain was present in the proximal tibiofibular joint while at rest, when walking and climbing stairs. Symptoms were evaluated by applying moderate compression over the proximal tibiofibular joint during active ankle and knee motions. Magnetic resonance imaging scans were reexamined by two radiologists. Three of the 40 patients had minimal or moderate pain in the proximal tibiofibular joint during stair-climbing and on clinical examination. Magnetic resonance imaging scans of these three patients revealed osteophyte or subchondral cyst formation, or both. Degenerative changes in the proximal tibiofibular joint may be evident in association with osteoarthritis of the knee and may result in lateral-sided pain at the knee.

  9. Non-Sagittal Knee Joint Kinematics and Kinetics during Gait on Level and Sloped Grounds with Unicompartmental and Total Knee Arthroplasty Patients.

    PubMed

    Komnik, Igor; Peters, Markus; Funken, Johannes; David, Sina; Weiss, Stefan; Potthast, Wolfgang

    2016-01-01

    After knee arthroplasty (KA) surgery, patients experience abnormal kinematics and kinetics during numerous activities of daily living. Biomechanical investigations have focused primarily on level walking, whereas walking on sloped surfaces, which is stated to affect knee kinematics and kinetics considerably, has been neglected to this day. This study aimed to analyze over-ground walking on level and sloped surfaces with a special focus on transverse and frontal plane knee kinematics and kinetics in patients with KA. A three-dimensional (3D) motion analysis was performed by means of optoelectronic stereophogrammetry 1.8 ± 0.4 years following total knee arthroplasty (TKA) and unicompartmental arthroplasty surgery (UKA). AnyBody™ Modeling System was used to conduct inverse dynamics. The TKA group negotiated the decline walking task with reduced peak knee internal rotation angles compared with a healthy control group (CG). First-peak knee adduction moments were diminished by 27% (TKA group) and 22% (UKA group) compared with the CG during decline walking. No significant differences were detected between the TKA and UKA groups, regardless of the locomotion task. Decline walking exposed apparently more abnormal knee frontal and transverse plane adjustments in KA patients than level walking compared with the CG. Hence, walking on sloped surfaces should be included in further motion analysis studies investigating KA patients in order to detect potential deficits that might be not obvious during level walking.

  10. Non-Sagittal Knee Joint Kinematics and Kinetics during Gait on Level and Sloped Grounds with Unicompartmental and Total Knee Arthroplasty Patients

    PubMed Central

    Komnik, Igor; David, Sina; Weiss, Stefan; Potthast, Wolfgang

    2016-01-01

    After knee arthroplasty (KA) surgery, patients experience abnormal kinematics and kinetics during numerous activities of daily living. Biomechanical investigations have focused primarily on level walking, whereas walking on sloped surfaces, which is stated to affect knee kinematics and kinetics considerably, has been neglected to this day. This study aimed to analyze over-ground walking on level and sloped surfaces with a special focus on transverse and frontal plane knee kinematics and kinetics in patients with KA. A three-dimensional (3D) motion analysis was performed by means of optoelectronic stereophogrammetry 1.8 ± 0.4 years following total knee arthroplasty (TKA) and unicompartmental arthroplasty surgery (UKA). AnyBody™ Modeling System was used to conduct inverse dynamics. The TKA group negotiated the decline walking task with reduced peak knee internal rotation angles compared with a healthy control group (CG). First-peak knee adduction moments were diminished by 27% (TKA group) and 22% (UKA group) compared with the CG during decline walking. No significant differences were detected between the TKA and UKA groups, regardless of the locomotion task. Decline walking exposed apparently more abnormal knee frontal and transverse plane adjustments in KA patients than level walking compared with the CG. Hence, walking on sloped surfaces should be included in further motion analysis studies investigating KA patients in order to detect potential deficits that might be not obvious during level walking. PMID:28002437

  11. Diffusion in different models of active Brownian motion

    NASA Astrophysics Data System (ADS)

    Lindner, B.; Nicola, E. M.

    2008-04-01

    Active Brownian particles (ABP) have served as phenomenological models of self-propelled motion in biology. We study the effective diffusion coefficient of two one-dimensional ABP models (simplified depot model and Rayleigh-Helmholtz model) differing in their nonlinear friction functions. Depending on the choice of the friction function the diffusion coefficient does or does not attain a minimum as a function of noise intensity. We furthermore discuss the case of an additional bias breaking the left-right symmetry of the system. We show that this bias induces a drift and that it generally reduces the diffusion coefficient. For a finite range of values of the bias, both models can exhibit a maximum in the diffusion coefficient vs. noise intensity.

  12. Unwinding motion of a twisted active region filament

    SciTech Connect

    Yan, X. L.; Xue, Z. K.; Kong, D. F.; Liu, J. H.; Xu, C. L.

    2014-12-10

    To better understand the structures of active region filaments and the eruption process, we study an active region filament eruption in active region NOAA 11082 in detail on 2010 June 22. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament consisted of twisted magnetic field lines. The total twist of the filament is at least 5π obtained by using a time slice method. According to the morphology change during the filament eruption, it is found that the active region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magnetic helicity injection before and during the filament eruption. It is confirmed that magnetic helicity can be transferred from the photosphere to the filament. Using the extrapolated potential fields, the average decay index of the background magnetic fields over the filament is 0.91. Consequently, these findings imply that the mechanism of solar filament eruption could be due to the kink instability and magnetic helicity accumulation.

  13. Tibiofemoral kinematics and condylar motion during the stance phase of gait.

    PubMed

    Kozanek, Michal; Hosseini, Ali; Liu, Fang; Van de Velde, Samuel K; Gill, Thomas J; Rubash, Harry E; Li, Guoan

    2009-08-25

    Accurate knowledge of the dynamic knee motion in-vivo is instrumental for understanding normal and pathological function of the knee joint. However, interpreting motion of the knee joint during gait in other than the sagittal plane remains controversial. In this study, we utilized the dual fluoroscopic imaging technique to investigate the six-degree-of-freedom kinematics and condylar motion of the knee during the stance phase of treadmill gait in eight healthy volunteers at a speed of 0.67 m/s. We hypothesized that the 6DOF knee kinematics measured during gait will be different from those reported for non-weightbearing activities, especially with regards to the phenomenon of femoral rollback. In addition, we hypothesized that motion of the medial femoral condyle in the transverse plane is greater than that of the lateral femoral condyle during the stance phase of treadmill gait. The rotational motion and the anterior-posterior translation of the femur with respect to the tibia showed a clear relationship with the flexion-extension path of the knee during the stance phase. Additionally, we observed that the phenomenon of femoral rollback was reversed, with the femur noted to move posteriorly with extension and anteriorly with flexion. Furthermore, we noted that motion of the medial femoral condyle in the transverse plane was greater than that of the lateral femoral condyle during the stance phase of gait (17.4+/-2.0mm vs. 7.4+/-6.1mm, respectively; p<0.01). The trend was opposite to what has been observed during non-weightbearing flexion or single-leg lunge in previous studies. These data provide baseline knowledge for the understanding of normal physiology and for the analysis of pathological function of the knee joint during walking. These findings further demonstrate that knee kinematics is activity-dependent and motion patterns of one activity (non-weightbearing flexion or lunge) cannot be generalized to interpret a different one (gait).

  14. Developing an estimate of daily cumulative loading for the knee: examining test-retest reliability.

    PubMed

    Robbins, Shawn M K; Birmingham, Trevor B; Jones, Gareth R; Callaghan, Jack P; Maly, Monica R

    2009-11-01

    Although the knee adduction moment during gait is a valid and reliable proxy for the dynamic load on the medial compartment of the knee, it represents exposure to loading during one stride only. In contrast, a measure that incorporates both the nature and frequency of loading throughout daily activities might provide additional insight into the effects of cumulative knee loading. The purpose of this study was to introduce a new representation of daily cumulative knee loading and examine its test-retest reliability. Thirty healthy adults participated. Cumulative knee loading was calculated on two testing periods from the mean external knee adduction moment stance phase impulse, measured with a three-dimensional motion capture system over five walking trials, and mean steps/day, measured with a unidimensional accelerometer over one week. Analysis for test-retest reliability included Bland-Altman graphs, intraclass correlation coefficients (ICC 2,1) and standard errors of measurements (SEM). The ICC values for cumulative knee loading, adduction impulse and steps/day ranged from 0.84 to 0.89. Bland-Altman plots suggested daily cumulative knee loading and steps/day measures were less reliable at higher values. The SEM values were 9.67 kNm s, 1.45 Nm s and 1043 steps/day for cumulative knee loading, adduction impulse and steps/day, respectively. Daily cumulative knee loading is reliable and provides a stable measure of the total exposure to knee loading. These findings support further study of cumulative knee loading to determine its potential clinical importance.

  15. Prosthetic knee design by simulation

    SciTech Connect

    Hollerbach, K; Hollister, A

    1999-07-30

    Although 150,000 total knee replacement surgeries are performed annually in North America, current designs of knee prostheses have mechanical problems that include a limited range of motion, abnormal gait patterns, patellofemoral joint dysfunction, implant loosening or subsidence, and excessive wear. These problems fall into three categories: failure to reproduce normal joint kinematics, which results in altered limb function; bone-implant interface failure; and material failure. Modern computer technology can be used to design, prototype, and test new total knee implants. The design team uses the full range of CAD-CAM to design and produce implant prototypes for mechanical and clinical testing. Closer approximation of natural knee kinematics and kinetics is essential for improved patient function and diminished implant loads. Current knee replacement designs are based on 19th Century theories that the knee moves about a variable axis of rotation. Recent research has shown, however, that knee motion occurs about two fixed, offset axes of rotation. These aces are not perpendicular to the long axes of the bones or to each other, and the axes do not intersect. Bearing surfaces of mechanisms that move about axes of rotation are surfaces of revolution of those axes which advanced CAD technology can produce. Solids with surfaces of revolution for the two axes of rotation for the knee have been made using an HP9000 workstation and Structural Ideas Master Series CAD software at ArthroMotion. The implant's CAD model should closely replicate movements of the normal knee. The knee model will have a range of flexion-extension (FE) from -5 to 120 degrees. Movements include varus, valgus, internal and external rotation, as well as flexion and extension. The patellofemoral joint is aligned perpendicular to the FE axis and replicates the natural joint more closely than those of existing prostheses. The bearing surfaces will be more congruent than current designs and should

  16. Effects of image noise, respiratory motion, and motion compensation on 3D activity quantification in count-limited PET images

    NASA Astrophysics Data System (ADS)

    Siman, W.; Mawlawi, O. R.; Mikell, J. K.; Mourtada, F.; Kappadath, S. C.

    2017-01-01

    The aims of this study were to evaluate the effects of noise, motion blur, and motion compensation using quiescent-period gating (QPG) on the activity concentration (AC) distribution—quantified using the cumulative AC volume histogram (ACVH)—in count-limited studies such as 90Y-PET/CT. An International Electrotechnical Commission phantom filled with low 18F activity was used to simulate clinical 90Y-PET images. PET data were acquired using a GE-D690 when the phantom was static and subject to 1-4 cm periodic 1D motion. The static data were down-sampled into shorter durations to determine the effect of noise on ACVH. Motion-degraded PET data were sorted into multiple gates to assess the effect of motion and QPG on ACVH. Errors in ACVH at AC90 (minimum AC that covers 90% of the volume of interest (VOI)), AC80, and ACmean (average AC in the VOI) were characterized as a function of noise and amplitude before and after QPG. Scan-time reduction increased the apparent non-uniformity of sphere doses and the dispersion of ACVH. These effects were more pronounced in smaller spheres. Noise-related errors in ACVH at AC20 to AC70 were smaller (<15%) compared to the errors between AC80 to AC90 (>15%). The accuracy of ACmean was largely independent of the total count. Motion decreased the observed AC and skewed the ACVH toward lower values; the severity of this effect depended on motion amplitude and tumor diameter. The errors in AC20 to AC80 for the 17 mm sphere were  -25% and  -55% for motion amplitudes of 2 cm and 4 cm, respectively. With QPG, the errors in AC20 to AC80 of the 17 mm sphere were reduced to  -15% for motion amplitudes  <4 cm. For spheres with motion amplitude to diameter ratio  >0.5, QPG was effective at reducing errors in ACVH despite increases in image non-uniformity due to increased noise. ACVH is believed to be more relevant than mean or maximum AC to calculate tumor control and normal tissue complication probability

  17. The use of the greater trochanter marker in the thigh segment model: implications for hip and knee frontal and transverse plane motion

    PubMed Central

    Graci, Valentina; Salsich, Gretchen

    2015-01-01

    Background The greater trochanter marker is commonly used in 3-dimensional models; however, its influence on hip and knee kinematics during gait is unclear. Understanding the influence of the greater trochanter marker is important when quantifying frontal and transverse plane hip and knee kinematics, parameters which are particularly relevant to investigate in individuals with conditions such as patellofemoral pain, knee osteoarthritis, ACL injury and hip pain. The aim of this study was to evaluate the effect of including the greater trochanter in the construction of the thigh segment on hip and knee kinematics during gait. Methods Three-dimensional kinematics were collected in 19 healthy subjects during walking using a surface marker system. Hip and knee angles were compared across two thigh segment definitions (with and without greater trochanter) at two time points during stance: peak knee flexion (PKF) and minimum knee flexion (MinKF). Results Hip and knee angles differed in magnitude and direction in the transverse plane at both time points. In the thigh model with the greater trochanter the hip was more externally rotated than in the thigh model without the greater trochanter, (PKF −9.34°±5.21° vs 1.40°±5.22°, MinKF −5.68°±4.24° vs 5.01°±4.86°, p<0.001). In the thigh model with the greater trochanter, the knee angle was more internally rotated compared to the knee angle calculated using the thigh definition without the greater trochanter (PKF 14.67°±6.78° vs 4.33°±4.18°, MinKF 10.54°±6.71° vs −0.01°±2.69°, p<.001). Small but significant differences were detected in the sagittal and frontal plane angles at both time points (p<.001). Conclusion Hip and knee kinematics differed across different segment definitions including or excluding the greater trochanter marker, especially in the transverse plane. Therefore when considering whether to include the greater trochanter in the thigh segment model when using a surface markers to

  18. Activation of PAR2 receptors sensitizes primary afferents and causes leukocyte rolling and adherence in the rat knee joint

    PubMed Central

    Russell, FA; Schuelert, N; Veldhoen, VE; Hollenberg, MD; McDougall, JJ

    2012-01-01

    Background and Purpose The PAR2 receptors are involved in chronic arthritis by mechanisms that are as yet unclear. Here, we examined PAR2 activation in the rat knee joint. Experimental Approach PAR2 in rat knee joint dorsal root ganglia (DRG) cells at L3-L5, retrogradely labelled with Fluoro-gold (FG) were demonstrated immunohistochemically. Electrophysiological recordings from knee joint nerve fibres in urethane anaesthetized Wistar rats assessed the effects of stimulating joint PAR2 with its activating peptide, 2-furoyl-LIGRLO-NH2 (1–100 nmol·100 μL−1, via close intra-arterial injection). Fibre firing rate was recorded during joint rotations before and 15 min after administration of PAR2 activating peptide or control peptide. Leukocyte kinetics in the synovial vasculature upon PAR2 activation were followed by intravital microscopy for 60 min after perfusion of 2-furoyl-LIGRLO-NH2 or control peptide. Roles for transient receptor potential vanilloid-1 (TRPV1) or neurokinin-1 (NK1) receptors in the PAR2 responses were assessed using the selective antagonists, SB366791 and RP67580 respectively. Key Results PAR2 were expressed in 59 ± 5% of FG-positive DRG cells; 100 nmol 2-furoyl-LIGRLO-NH2 increased joint fibre firing rate during normal and noxious rotation, maximal at 3 min (normal; 110 ± 43%, noxious; 90 ± 31%). 2-Furoyl-LIGRLO-NH2 also significantly increased leukocyte rolling and adhesion over 60 min. All these effects were blocked by pre-treatment with SB366791 and RP67580 (P < 0.05 compared with 2-furoyl-LIGRLO-NH2 alone). Conclusions and Implications PAR2 receptors play an acute inflammatory role in the knee joint via TRPV1- and NK1-dependent mechanisms involving both PAR2-mediated neuronal sensitization and leukocyte trafficking. PMID:22849826

  19. Effect of ACL graft material on joint forces during a simulated in vivo motion in the porcine knee: examining force during the initial cycles.

    PubMed

    Boguszewski, Daniel V; Wagner, Christopher T; Butler, David L; Shearn, Jason T

    2014-11-01

    This study compared three-dimensional forces in knees containing anterior cruciate ligament (ACL) graft materials versus the native porcine ACL. A six-degree-of-freedom (DOF) robot simulated gait while recording the joint forces and moments. Knees were subjected to 10 cycles of simulated gait in intact, ACL-deficient, and ACL-reconstructed knee states to examine time zero biomechanical performance. Reconstruction was performed using bone-patellar tendon-bone allograft (BPTB), reconstructive porcine tissue matrix (RTM), and an RTM-polymer hybrid (Hybrid). Forces and moments were examined about anatomic DOFs throughout the gait cycle and at three key points during gait: heel strike (HS), mid stance (MS), toe off (TO). Compared to native ACL, each graft restored antero-posterior (A-P) forces throughout gait. However, all failed to mimic normal joint forces in other DOFs. For example, each reconstructed knee showed greater compressive forces at HS and TO compared to the native ACL knee. Overall, the Hybrid graft restored more of the native ACL forces following reconstruction than did BPTB, while RTM grafts were the least successful. If early onset osteoarthritis is in part caused by altered knee kinematics, then understanding how reconstruction materials restore critical force generation during gait is an essential step in improving a patient's long-term prognosis.

  20. Viewing the motion of human body parts activates different regions of premotor, temporal, and parietal cortex.

    PubMed

    Wheaton, Kylie J; Thompson, James C; Syngeniotis, Ari; Abbott, David F; Puce, Aina

    2004-05-01

    Activation of premotor and temporoparietal cortex occurs when we observe others movements, particularly relating to objects. Viewing the motion of different body parts without the context of an object has not been systematically evaluated. During a 3T fMRI study, 12 healthy subjects viewed human face, hand, and leg motion, which was not directed at or did not involve an object. Activation was identified relative to static images of the same human face, hand, and leg in both individual subject and group average data. Four clear activation foci emerged: (1) right MT/V5 activated to all forms of viewed motion; (2) right STS activated to face and leg motion; (3) ventral premotor cortex activated to face, hand, and leg motion in the right hemisphere and to leg motion in the left hemisphere; and (4) anterior intraparietal cortex (aIP) was active bilaterally to viewing hand motion and in the right hemisphere leg motion. In addition, in the group data, a somatotopic activation pattern for viewing face, hand, and leg motion occurred in right ventral premotor cortex. Activation patterns in STS and aIP were more complex--typically activation foci to viewing two types of human motion showed some overlap. Activation in individual subjects was similar; however, activation to hand motion also occurred in the STS with a variable location across subjects--explaining the lack of a clear activation focus in the group data. The data indicate that there are selective responses to viewing motion of different body parts in the human brain that are independent of object or tool use.

  1. Within- and between-session reliability of the maximal voluntary knee extension torque and activation.

    PubMed

    Park, Jihong; Hopkins, J Ty

    2013-01-01

    A ratio between the torque generated by maximal voluntary isometric contraction (MVIC) and exogenous electrical stimulus, central activation ratio (CAR), has been widely used to assess quadriceps function. To date, no data exist regarding between-session reliability of this measurement. Thirteen neurologically sound volunteers underwent three testing sessions (three trials per session) with 48 hours between-session. Subjects performed MVICs of the quadriceps with the knee locked at 90° flexion and the hip at 85°. Once the MVIC reached a plateau, an electrical stimulation from superimposed burst technique (SIB: 125 V with peak output current 450 mA) was manually delivered and transmitted directly to the quadriceps via stimulating electrodes. CAR was calculated by using the following equation: CAR = MVIC torque/MVIC + SIB torque. Intraclass correlation coefficients (ICC) were calculated within- (ICC((2,1))) and between-session (ICC((2,k))) for MVIC torques and CAR values. Our data show that quadriceps MVIC and CAR are very reliable both within- (ICC((2,1)) = 0.99 for MVIC; 0.94 for CAR) and between-measurement sessions (ICC((2,k)) = 0.92 for MVIC; 0.86 for CAR) in healthy young adults. For clinical research, more data of the patients with pathological conditions are required to ensure reproducibility of calculation of CAR.

  2. Evaluation of (241)Am deposited in different parts of the leg bones and skeleton to justify in vivo measurements of the knee for estimating total skeletal activity.

    PubMed

    Khalaf, Majid; Brey, Richard R; Derryberry, DeWayne

    2013-01-01

    The percentage of Am deposited in different parts of leg bones relative to the total leg activity was calculated from radiochemical analysis results from six whole body donors participating in the U.S. Transuranium and Uranium Registries (USTUR). In five of these six USTUR cases, the percentage of Am deposited in the knee region as well as in the entire leg was separately calculated relative to total skeletal activity. The purpose of this study is to find a region in the leg that is both suitable for in vivo measurement of Am deposited in the bones and has a good correlation with the total skeletal Am burden. In all analyzed cases, the femur was the bone with the highest percentage of Am deposited in the leg (48.8%). In the five cases that have complete whole skeletal analysis, the percentage of Am activity in the knee relative to entire skeletal activity was 4.8%, and the average value of its coefficient of variation was 10.6%. The percentage of Am in the leg relative to total skeletal activity was 20% with an average coefficient of variation of 13.63%. The Am activity in the knee as well as in the leg was strongly correlated (R = 99.5% and R = 99.1%, respectively) with the amount of Am activity in the entire skeleton using a simple linear relationship. The highest correlation was found between the amount of Am deposited in the knee and the amount of Am deposited in the entire skeleton. This correlation is important because it might enable an accurate assessment of the total skeletal Am burden to be performed from in vivo monitoring of the knee region. In all analyzed cases, an excellent correlation (R = 99.9%) was found between the amount of Am activity in the knee and the amount of Am activity in the entire leg. The results of this study suggest three simple models: two models to predict the total skeletal activity based on either leg or knee activity, and the third model to predict the total leg activity based on knee activity. The results also suggest that the

  3. Antiarthritic activity of a standardized, multiherbal, Ayurvedic formulation containing Boswellia serrata: in vitro studies on knee cartilage from osteoarthritis patients.

    PubMed

    Sumantran, V N; Joshi, A K; Boddul, S; Koppikar, S J; Warude, D; Patwardhan, B; Chopra, A; Chandwaskar, R; Wagh, U V

    2011-09-01

    A validated in vitro model of cartilage damage and published data were used showing that this model measures the chondroprotective and antiinflammatory effects of different antiarthritic drugs. In this report, this model was used to evaluate the effects of a new antiarthritic Ayurvedic formulation containing Zingiber officinale root, Tinospora cordifolia stem, Phyllanthus emblica fruit and oleoresin of Boswellia serrata. Glucosamine sulphate was used as a positive control in the study. Aqueous extracts of each drug were tested on explant cultures of knee cartilage obtained from osteoarthritis patients undergoing knee replacement surgery. The new formulation caused a sustained and statistically significant inhibition in the release of glycosaminoglycans and aggrecan by cartilage explants from these patients. This formulation also induced a transient antiinflammatory effect as measured by a reduction in the levels of nitric oxide released by explants. Furthermore, the data strongly suggest that oleoresin of B. serrata plays a crucial role in the chondroprotective and antiinflammatory activity of this formulation. In summary, this report provides the first, direct, in vitro biochemical evidence of anti-arthritic activity a new Ayurvedic formulation. This formulation significantly reduced damage of articular knee cartilage from chronic osteoarthritis patients.

  4. Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females.

    PubMed

    Guner, Senem; Alsancak, Serap; Koz, Mitat

    2015-10-01

    [Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio taping application on the knee. Sixteen healthy female college students (age, 19.7 ± 0.4 years; height, 1.64 ± 3.4 cm; body mass, 51.5 ± 4.8 kg) participated in the study. [Results] Spatiotemporal parameters (cadence, walking speed, stride length) were significantly different among the trials. Knee joint sagittal plane range of motion was not different with either kinesio taping application. Knee external flexion moment during the early stance phase decreased significantly with facilitation kinesio taping and increased with the inhibition kinesio taping. Knee external extension moment during the mid-stance phase increased with facilitation kinesio taping. Knee power parameters, eccentric activity in the rectus femoris during the pre-swing phase was significantly increased with inhibition kinesio taping application, while eccentric activity of the hamstrings during the terminal swing of gait was decreased. [Conclusion] These findings showed that facilitation kinesio taping application affected the terminal stance phase and that inhibition kinesio taping influenced the terminal swing phase compared with the no tape condition.

  5. Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females

    PubMed Central

    Guner, Senem; Alsancak, Serap; Koz, Mitat

    2015-01-01

    [Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio taping application on the knee. Sixteen healthy female college students (age, 19.7 ± 0.4 years; height, 1.64 ± 3.4 cm; body mass, 51.5 ± 4.8 kg) participated in the study. [Results] Spatiotemporal parameters (cadence, walking speed, stride length) were significantly different among the trials. Knee joint sagittal plane range of motion was not different with either kinesio taping application. Knee external flexion moment during the early stance phase decreased significantly with facilitation kinesio taping and increased with the inhibition kinesio taping. Knee external extension moment during the mid-stance phase increased with facilitation kinesio taping. Knee power parameters, eccentric activity in the rectus femoris during the pre-swing phase was significantly increased with inhibition kinesio taping application, while eccentric activity of the hamstrings during the terminal swing of gait was decreased. [Conclusion] These findings showed that facilitation kinesio taping application affected the terminal stance phase and that inhibition kinesio taping influenced the terminal swing phase compared with the no tape condition. PMID:26644651

  6. Combined in vivo/in vitro method to study anteriomedial bundle strain in the anterior cruciate ligament using a dynamic knee simulator.

    PubMed

    Cassidy, Karla; Hangalur, Gajendra; Sabharwal, Preet; Chandrashekar, Naveen

    2013-03-01

    The mechanism of noncontact anterior cruciate ligament (ACL) injury is not well understood. It is partly because previous studies have been unable to relate dynamic knee muscle forces during sports activities such as landing from a jump to the strain in the ACL. We present a combined in vivo/in vitro method to relate the muscle group forces to ACL strain during jump-landing using a newly developed dynamic knee simulator. A dynamic knee simulator system was designed and developed to study the sagittal plane biomechanics of the knee. The simulator is computer controlled and uses six powerful electromechanical actuators to move a cadaver knee in the sagittal plane and to apply dynamic muscle forces at the insertion sites of the quadriceps, hamstring, and gastrocnemius muscle groups and the net moment at the hip joint. In order to demonstrate the capability of the simulator to simulate dynamic sports activities on cadaver knees, motion capture of a live subject landing from a jump on a force plate was performed. The kinematics and ground reaction force data obtained from the motion capture were input into a computer based musculoskeletal lower extremity model. From the model, the force-time profile of each muscle group across the knee during the movement was extracted, along with the motion profiles of the hip and ankle joints. This data was then programmed into the dynamic knee simulator system. Jump-landing was simulated on a cadaver knee successfully. Resulting strain in the ACL was measured using a differential variable reluctance transducer (DVRT). Our results show that the simulator has the capability to accurately simulate the dynamic sagittal plane motion and the dynamic muscle forces during jump-landing. The simulator has high repeatability. The ACL strain values agreed with the values reported in the literature. This combined in vivo/in vitro approach using this dynamic knee simulator system can be effectively used to study the relationship between sagittal

  7. Investigation the efficacy of intra-articular prolotherapy with erythropoietin and dextrose and intra-articular pulsed radiofrequency on pain level reduction and range of motion improvement in primary osteoarthritis of knee

    PubMed Central

    Rahimzadeh, Poupak; Imani, Farnad; Faiz, Seyed Hamid Reza; Entezary, Saeed Reza; Nasiri, Ali Akbar; Ziaeefard, Mohsen

    2014-01-01

    Background: Osteoarthritis is one of the most common diseases and the knee is the most commonly affected joint. Intra-articular prolotherapy is being utilized in acute and chronic pain management setting. This study was designed to compare the efficacy of three methods of intra-articular knee joint therapies with erythropoietin, dextrose, and pulsed radiofrequency. Materials and Methods: After approval by the Ethics Committee and explaining the therapeutic method to volunteers, 70 patients who were suffering from primary knee osteoarthrosis went through one of the treatment methods (erythropoietin, dextrose, and pulsed radiofrequency). The study was double-blind randomized clinical trial performed from December 2012 to July 2013. Patients’ pain level was assessed through the visual analog pain scale (VAS), and range of motion (ROM) was measured by goniometric method. Furthermore, patients’ satisfaction was assessed before and after different treatment methods in weeks 2, 4, and 12. For analysis, Chi-square, one-way ANOVA, and repeated measured ANOVA were utilized. Results: The demographic results among the three groups did not indicate any statistical difference. The mean VAS in erythropoietin group in the 2nd, 4th, and 12th weeks was 3.15 ± 1.08, 3.15 ± 1.08, and 3.5 ± 1.23, respectively (P ≤ 0.005). Knee joint ROM in the erythropoietin group in the 2nd, 4th, and 12th weeks was 124 ± 1.50, 124 ± 1.4, and 123 ± 1.53 respectively (P ≤ 0.005). Satisfaction score in the 12th week in erythropoietin group was extremely satisfied 15%, satisfied 55%, and moderately satisfied 30%, (P = 0.005). No specific side-effects were observed. Conclusion: Intra-articular prolotherapy with erythropoietin was more effective in terms of pain level reduction and ROM improvement compared with dextrose and pulsed radiofrequency. PMID:25422652

  8. Immediate effect of Masai Barefoot Technology shoes on knee joint moments in women with knee osteoarthritis.

    PubMed

    Tateuchi, Hiroshige; Taniguchi, Masashi; Takagi, Yui; Goto, Yusuke; Otsuka, Naoki; Koyama, Yumiko; Kobayashi, Masashi; Ichihashi, Noriaki

    2014-01-01

    Footwear modification can beneficially alter knee loading in patients with knee osteoarthritis. This study evaluated the effect of Masai Barefoot Technology shoes on reductions in external knee moments in patients with knee osteoarthritis. Three-dimensional motion analysis was used to examine the effect of Masai Barefoot Technology versus control shoes on the knee adduction and flexion moments in 17 women (mean age, 63.6 years) with radiographically confirmed knee osteoarthritis. The lateral and anterior trunk lean values, knee flexion and adduction angles, and ground reaction force were also evaluated. The influence of the original walking pattern on the changes in knee moments with Masai Barefoot Technology shoes was evaluated. The knee flexion moment in early stance was significantly reduced while walking with the Masai Barefoot Technology shoes (0.25±0.14Nm/kgm) as compared with walking with control shoes (0.30±0.19 Nm/kgm); whereas the knee adduction moment showed no changes. Masai Barefoot Technology shoes did not increase compensatory lateral and anterior trunk lean. The degree of knee flexion moment in the original walking pattern with control shoes was correlated directly with its reduction when wearing Masai Barefoot Technology shoes by multiple linear regression analysis (adjusted R2=0.44, P<0.01). Masai Barefoot Technology shoes reduced the knee flexion moment during walking without increasing the compensatory trunk lean and may therefore reduce external knee loading in women with knee osteoarthritis.

  9. Knee joint kinematics, fixation and function related to joint area design in total knee arthroplasty.

    PubMed

    Uvehammer, J

    2001-02-01

    AP-translations in both studies. The clinical outcome in terms of HSS score did not differ between the flat versus the concave designs in study 1 and between the concave versus the PS implants in study 2. Up to two years the migration of the tibial component and the development of radiolucent lines were of the same magnitude for the flat versus the concave inserts in study 3 and the concave versus the PS design in study 4. Also did the positioning of the implant and the fulfillment of the patients expectations on the surgery preoperatively not differ. The AMK prosthesis migrated at about the same amount as have been reported for similar designs. In study 5 all implants showed a correlation between some of the inducible displacements (anterior-posterior tilting and maximum total point motion) and the corresponding migration 0-2 years. The more the anterior tilt the more the migration in the same direction. If the PCL was sacrificed during the knee replacement the change into increased anterior tilt occurred earlier (i.e. at more degree of flexion) if a concave insert was used compared to the PS design. When the active extension reached 25 degrees there were more anterior tilt of the tibial component in the concave design (p = 0.001) and if the tibial plateau centre had a medial position (p < 0.0005). Compared with normal knees all prosthetic designs showed abnormal pattern of motion. The extent of this abnormality was influenced by the design of the joint area. A corresponding influence on the fixation of the tibial component could not be verified. The choice of joint area and recorded kinematics had no or small influence on the clinical results. Feelings of instability could to some extent be related to the kinematics of the knee joint.

  10. Jumper's Knee (Patellar Tendonitis)

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Jumper's Knee KidsHealth > For Teens > Jumper's Knee A A A ... continued damage to the knee. How Does the Knee Work? To understand how jumper's knee happens, it ...

  11. Knee arthroscopy - series (image)

    MedlinePlus

    ... knee problems such as: a torn knee disc (meniscus) a damaged knee bone (patella) a damaged ligament ... surgeon can see the ligaments, the knee disc (meniscus), the knee bone (patella), the lining of the ...

  12. Comparison of knee gait kinematics of workers exposed to knee straining posture to those of non-knee straining workers.

    PubMed

    Gaudreault, Nathaly; Hagemeister, Nicola; Poitras, Stéphane; de Guise, Jacques A

    2013-06-01

    Workers exposed to knee straining postures, such as kneeling and squatting, may present modifications in knee gait kinematics that can make them vulnerable to osteoarthritis. In this study, knee kinematics of workers exposed to occupational knee straining postures (KS workers) were compared to those of non-knee straining (non-KS) workers. Eighteen KS workers and 20 non-KS workers participated in the study. Three-dimensional gait kinematic data were recorded at the knee using an electromagnetic motion tracking system. The following parameters were extracted from flexion/extension, adduction/abduction and internal/external rotation angle data and used for group comparisons: knee angle at initial foot contact, peak angles, minimal angles and angle range during the entire gait cycle. Group comparisons were performed with Student t-tests. In the sagittal plane, KS workers had a greater knee flexion angle at initial foot contact, a lower peak knee flexion angle during the swing phase and a lower angle range than non-KS workers (p<0.05). In the frontal plane, all parameters indicated that KS workers had their knees more adducted than non-KS workers. External/internal rotation range was greater for KS workers. This study provides new knowledge on work related to KS postures and knee kinematics. The results support the concept that KS workers might exhibit knee kinematics that are different from those of non-KS workers.

  13. A triboelectric motion sensor in wearable body sensor network for human activity recognition.

    PubMed

    Hui Huang; Xian Li; Ye Sun

    2016-08-01

    The goal of this study is to design a novel triboelectric motion sensor in wearable body sensor network for human activity recognition. Physical activity recognition is widely used in well-being management, medical diagnosis and rehabilitation. Other than traditional accelerometers, we design a novel wearable sensor system based on triboelectrification. The triboelectric motion sensor can be easily attached to human body and collect motion signals caused by physical activities. The experiments are conducted to collect five common activity data: sitting and standing, walking, climbing upstairs, downstairs, and running. The k-Nearest Neighbor (kNN) clustering algorithm is adopted to recognize these activities and validate the feasibility of this new approach. The results show that our system can perform physical activity recognition with a successful rate over 80% for walking, sitting and standing. The triboelectric structure can also be used as an energy harvester for motion harvesting due to its high output voltage in random low-frequency motion.

  14. Chirality in microswimmer motion: From circle swimmers to active turbulence

    NASA Astrophysics Data System (ADS)

    Löwen, Hartmut

    2016-11-01

    In this minireview, recent progress in our understanding of the basic physical principles of microswimmers which perform a motion characterized by chirality is summarized. We discuss both the chiral motion of a single circle swimmer and the occurrence of bacterial turbulence where swirls of different chirality are formed spontaneously in an interacting ensemble of linear microswimmers. Some recent highlights in this context as obtained by theory, simulation and experiment are summarized and briefly discussed.

  15. Unsteady aerodynamic modeling for arbitrary motions. [for active control techniques

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Results indicating that unsteady aerodynamic loads derived under the assumption of simple harmonic motions executed by airfoil or wing can be extended to arbitrary motions are summarized. The generalized Theodorsen (1953) function referable to loads due to simple harmonic oscillations of a wing section in incompressible flow, the Laplace inversion integral for unsteady aerodynamic loads, calculations of root loci of aeroelastic loads, and analysis of generalized compressible transient airloads are discussed.

  16. Knee-Extension Training with a Single-Joint Hybrid Assistive Limb during the Early Postoperative Period after Total Knee Arthroplasty in a Patient with Osteoarthritis

    PubMed Central

    Sugaya, Hisashi; Kubota, Shigeki; Onishi, Mio; Kanamori, Akihiro; Sankai, Yoshiyuki; Yamazaki, Masashi

    2016-01-01

    The knee range of motion is an important outcome of total knee arthroplasty (TKA). According to previous studies, the knee range of motion temporarily decreases for approximately 1 month after TKA due to postoperative pain and quadriceps dysfunction following surgical invasion into the knee extensor mechanism. We describe our experience with a knee-extension training program based on a single-joint hybrid assistive limb (HAL-SJ, Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after TKA. HAL-SJ is a wearable robot suit that facilitates the voluntary control of knee joint motion. A 76-year-old man underwent HAL-SJ-based knee-extension training, which enabled him to perform knee function training during the acute phase after TKA without causing increased pain. Thus, he regained the ability to fully extend his knee postoperatively. HAL-SJ-based knee-extension training can be used as a novel post-TKA rehabilitation modality. PMID:27774330

  17. Segmentation of knee cartilage by using a hierarchical active shape model based on multi-resolution transforms in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    León, Madeleine; Escalante-Ramirez, Boris

    2013-11-01

    Knee osteoarthritis (OA) is characterized by the morphological degeneration of cartilage. Efficient segmentation of cartilage is important for cartilage damage diagnosis and to support therapeutic responses. We present a method for knee cartilage segmentation in magnetic resonance images (MRI). Our method incorporates the Hermite Transform to obtain a hierarchical decomposition of contours which describe knee cartilage shapes. Then, we compute a statistical model of the contour of interest from a set of training images. Thereby, our Hierarchical Active Shape Model (HASM) captures a large range of shape variability even from a small group of training samples, improving segmentation accuracy. The method was trained with a training set of 16- MRI of knee and tested with leave-one-out method.

  18. Modulation of the Relationship Between External Knee Adduction Moments and Medial Joint Contact Forces Across Subjects and Activities

    PubMed Central

    Trepczynski, Adam; Kutzner, Ines; Bergmann, Georg; Taylor, William R; Heller, Markus O

    2014-01-01

    Objective The external knee adduction moment (EAM) is often considered a surrogate measure of the distribution of loads across the tibiofemoral joint during walking. This study was undertaken to quantify the relationship between the EAM and directly measured medial tibiofemoral contact forces (Fmed) in a sample of subjects across a spectrum of activities. Methods The EAM for 9 patients who underwent total knee replacement was calculated using inverse dynamics analysis, while telemetric implants provided Fmed for multiple repetitions of 10 activities, including walking, stair negotiation, sit-to-stand activities, and squatting. The effects of the factors “subject” and “activity” on the relationships between Fmed and EAM were quantified using mixed-effects regression analyses in terms of the root mean square error (RMSE) and the slope of the regression. Results Across subjects and activities a good correlation between peak EAM and Fmed values was observed, with an overall R2 value of 0.88. However, the slope of the linear regressions varied between subjects by up to a factor of 2. At peak EAM and Fmed, the RMSE of the regression across all subjects was 35% body weight (%BW), while the maximum error was 127 %BW. Conclusion The relationship between EAM and Fmed is generally good but varies considerably across subjects and activities. These findings emphasize the limitation of relying solely on the EAM to infer medial joint loading when excessive directed cocontraction of muscles exists and call for further investigations into the soft tissue–related mechanisms that modulate the internal forces at the knee. PMID:24470261

  19. New Generation Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    1996-01-01

    A knee brace that uses Space Shuttle propulsion technology has moved a step closer to being available to help knee injury and stroke patients and may possibly benefit patients with birth defects, spinal cord injuries, and post-polio conditions. After years of hard work, inventors at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have turned over the final design and prototype to industry partners at Horton's Orthotic Lab in Little Rock, Arkansas for further clinical testing. The device, called the Selectively Lockable Knee Brace, may mean faster, less painful rehabilitation for patients by allowing the knee to move when weight is not on the heel. Devices currently on the market lock the knee in a rigid, straight-leg position, or allow continuous free motion. Pictured here is a knee brace prototype being tested and fitted at Horton's Orthotic Lab. The knee brace is just one example of how space technology is being used to improve the lives of people on Earth. NASA's MSFC inventors Michael Shadoan and Neill Myers are space propulsion engineers who use the same mechanisms and materials to build systems for rockets that they used to design and develop the knee brace.

  20. The effects of a single game of rugby on active cervical range of motion.

    PubMed

    Lark, Sally D; McCarthy, Peter W

    2009-03-01

    The cumulative effect of playing rugby over many years decreases active cervical range of motion, especially in the forwards. This in itself should influence long-term neck care; however, it leaves the important question of how noticeable the acute effects of active cervical range of motion are following a single game. The active cervical range of motion was measured in 21 elite rugby players (mean age 24.4 +/- 4.3 years; average professional career of 7 +/- 3.4 years) before and after a single game of rugby at the start of the season. The active cervical range of motion was recorded in flexion, extension, left and right side flexion, plus left and right rotation using a cervical range of motion device. The results show generally decreased active cervical range of motion from before to after a game independent of position played. Rugby backs had significantly (P < 0.05) reduced active cervical range of motion in flexion, while forwards were affected in extension and left lateral flexion (P < 0.05). These results highlight that a single game of rugby can reduce functional capacity of the neck (active cervical range of motion), and the affected neck movement appears to be related to the role of positional play. The authors suggest that neck training and muscle damage repair should be an important part of a rugby player's post-game recovery to limit the reduction in functional capacity.

  1. Support of Joint Function, Range of Motion, and Physical Activity Levels by Consumption of a Water-Soluble Egg Membrane Hydrolyzate

    PubMed Central

    Jensen, Gitte S.; Lenninger, Miki R.; Beaman, Joni L.; Taylor, Robert; Benson, Kathleen F.

    2015-01-01

    Abstract This study evaluated the effects of consumption of hydrolyzed water-soluble egg membrane (WSEM) on joint function in an otherwise healthy population experiencing chronic pain. A randomized, double-blind, placebo-controlled crossover study included two 4-week periods of placebo and WSEM consumption, separated by a 4-week washout period. Twenty-five study participants were randomized to either the “placebo-first” or “WSEM first” sequence in the crossover trial, and 22 participants completed the study requirements. Range of motion (ROM) was assessed using digital inclinometry for joints associated with vertical weight bearing from neck to knees and for shoulders. Pain at rest and when physically active was scored for the same anatomical areas using visual analog scales (VAS). Physical functioning was tracked using questionnaires with VAS. Consumption of WSEM was associated with improved ROM for neck, spine, hips, and knees, with ROM for the neck and right knee being significantly improved during WSEM consumption compared to placebo (P < .05). ROM improvement for the dominant shoulder was highly significant during WSEM consumption (P < .01). Physical activity levels were significantly higher after WSEM than after placebo consumption (P < .05). Many aspects of physical functioning as part of daily living improved. Subgroup analysis showed rapid improvement of lower back pain after 5 days of WSEM consumption compared to placebo consumption (P < .05) in subjects who participated in the study during the winter season. Daily consumption of 450 mg WSEM was associated with improved joint function, comfort during daily activities, and increased physical activity. PMID:26355952

  2. Postural activity and motion sickness during video game play in children and adults.

    PubMed

    Chang, Chih-Hui; Pan, Wu-Wen; Tseng, Li-Ya; Stoffregen, Thomas A

    2012-03-01

    Research has confirmed that console video games give rise to motion sickness in many adults. During exposure to console video games, there are differences in postural activity (movement of the head and torso) between participants who later experience motion sickness and those who do not, confirming a prediction of the postural instability theory of motion sickness. Previous research has not addressed relations between video games, movement and motion sickness in children. We evaluated the nauseogenic properties of a commercially available console video game in both adults and 10-year-old children. Individuals played the game for up to 50 min and were instructed to discontinue immediately if they experienced any symptoms of motion sickness, however mild. During game play, we monitored movement of the head and torso. Motion sickness was reported by 67% of adults and by 56% of children; these rates did not differ. As a group, children moved more than adults. Across age groups, the positional variability of the head and torso increased over time during game play. In addition, we found differences in movement between participants who later reported motion sickness and those who did not. Some of these differences were general across age groups but we also found significant differences between the movement of adults and children who later reported motion sickness. The results confirm that console video games can induce motion sickness in children and demonstrate that changes in postural activity precede the onset of subjective symptoms of motion sickness in children.

  3. Effective temperature and spontaneous collective motion of active matter

    NASA Astrophysics Data System (ADS)

    Wang, Shenshen; Wolynes, Peter

    2012-02-01

    Spontaneous directed motion, a hallmark of cell biology, is unusual in classical statistical physics. Here we study, using both numerical and analytical methods, organized motion in models of the cytoskeleton in which constituents are driven by energy-consuming motors. Although systems driven by small-step motors are described by an effective temperature and are thus quiescent, at higher order in step size, both homogeneous and inhomogeneous, flowing and oscillating behavior emerges. Motors that respond with a negative susceptibility to imposed forces lead to an apparent negative temperature system in which beautiful structures form resembling the asters seen in cell division.

  4. Sports Activity after Low-contact-stress Total Knee Arthroplasty – A long term follow-up study

    PubMed Central

    Vielgut, Ines; Leitner, Lukas; Kastner, Norbert; Radl, Roman; Leithner, Andreas; Sadoghi, Patrick

    2016-01-01

    The purpose of this study was to provide comprehensive long-term data about sports activity levels in patients following total knee arthroplasty (TKA) and to determine the impact of pre-operative function, pain and specific performed sports on the results. 236 patients who have undergone TKA for severe osteoarthritis of the knee were asked to provide specific information regarding exercised types of sports before surgery and after at least 10 years following TKA. Pre- and postoperative function and pain were evaluated by the use of Tegner-, WOMAC- and VAS Score. After a mean of 14.9 years, a significant improvement regarding pain and function was observed. Pre-operative Tegner- and WOMAC scores revealed significant positive correlations with the post-operative Tegner-Score. Accordingly, a high percentage of patients (70.9%) stayed actively involved in sports. Nevertheless, the number of performing patients has decreased according to the sports impact. 71.3% continued practising low-impact-, 43.7% intermediate-impact sports whereas only 16.4% kept performing high impact sports. We conclude that TKA is highly effective in long-time pain reduction as well as improvement of function. Additionally, we found considerable sports activities preserved in the investigated series. However, sports activities in particular, seem to decrease according to the impact of sports. PMID:27090945

  5. Focusing on Increasing Velocity during Heavy Resistance Knee Flexion Exercise Boosts Hamstring Muscle Activity in Chronic Stroke Patients

    PubMed Central

    Jakobsen, Markus D.

    2016-01-01

    Background. Muscle strength is markedly reduced in stroke patients, which has negative implications for functional capacity and work ability. Different types of feedback during strength training exercises may alter neuromuscular activity and functional gains. Objective. To compare levels of muscle activity during conditions of blindfolding and intended high contraction speed with a normal condition of high-intensity knee flexions. Methods. Eighteen patients performed unilateral machine knee flexions with a 10-repetition maximum load. Surface electromyography (EMG) was recorded from the quadrics and hamstring muscles and normalized to maximal EMG (nEMG) of the nonparetic limb. Results. For the paretic leg, the speed condition showed higher values of muscle activity compared with the normal and blindfolded conditions for both biceps femoris and semitendinosus. Likewise, the speed condition showed higher co-contraction values compared with the normal and blindfolded conditions for the vastus lateralis. No differences were observed between exercise conditions for the nonparetic leg. Conclusion. Chronic stroke patients are capable of performing heavy resistance training with intended high speed of contraction. Focusing on speed during the concentric phase elicited higher levels of muscle activity of the hamstrings compared to normal and blindfolded conditions, which may have implications for regaining fast muscle strength in stroke survivors. PMID:27525118

  6. Kettlebell swing, snatch, and bottoms-up carry: back and hip muscle activation, motion, and low back loads.

    PubMed

    McGill, Stuart M; Marshall, Leigh W

    2012-01-01

    The intent of this study was to quantify spine loading during different kettlebell swings and carries. No previously published studies of tissue loads during kettlebell exercises could be found. Given the popularity of kettlebells, this study was designed to provide an insight into the resulting joint loads. Seven male subjects participated in this investigation. In addition, a single case study of the kettlebell swing was performed on an accomplished kettlebell master. Electromyography, ground reaction forces (GRFs), and 3D kinematic data were recorded during exercises using a 16-kg kettlebell. These variables were input into an anatomically detailed biomechanical model that used normalized muscle activation; GRF; and spine, hip, and knee motion to calculate spine compression and shear loads. It was found that kettlebell swings create a hip-hinge squat pattern characterized by rapid muscle activation-relaxation cycles of substantial magnitudes (∼50% of a maximal voluntary contraction [MVC] for the low back extensors and 80% MVC for the gluteal muscles with a 16-kg kettlebell) resulting in about 3,200 N of low back compression. Abdominal muscular pulses together with the muscle bracing associated with carries create kettlebell-specific training opportunities. Some unique loading patterns discovered during the kettlebell swing included the posterior shear of the L4 vertebra on L5, which is opposite in polarity to a traditional lift. Thus, quantitative analysis provides an insight into why many individuals credit kettlebell swings with restoring and enhancing back health and function, although a few find that they irritate tissues.

  7. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles.

    PubMed

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-09-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles.

  8. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles

    PubMed Central

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-01-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles. PMID:26504295

  9. Design and Control of an Active Electrical Knee and Ankle Prosthesis

    PubMed Central

    Sup, Frank; Varol, Huseyin Atakan; Mitchell, Jason; Withrow, Thomas; Goldfarb, Michael

    2010-01-01

    This paper presents an overview of the design and control of an electrically powered knee and ankle prosthesis. The prosthesis design incorporates two motor-driven ball screw units to drive the knee and ankle joints. A spring in parallel with the ankle motor unit is employed to decrease the power consumption and increase the torque output for a given motor size. The device’s sensor package includes a custom load cell to measure the sagittal socket interface moment above the knee joint, a custom sensorized foot to measure the ground reaction force at the heel and ball of the foot, and commercial potentiometers and load cells to measure joint positions and torques. A finite-state based impedance control approach, previously developed by the authors, is used and experimental results on level treadmill walking are presented that demonstrate the potential of the device to restore normal gait. The experimental power consumption of the device projects a walking distance of 5.0 km at a speed of 2.8 km/hr with a lithium polymer battery pack. PMID:20648239

  10. Marker-less reconstruction of dense 4-D surface motion fields using active laser triangulation for respiratory motion management.

    PubMed

    Bauer, Sebastian; Berkels, Benjamin; Ettl, Svenja; Arold, Oliver; Hornegger, Joachim; Rumpf, Martin

    2012-01-01

    To manage respiratory motion in image-guided interventions a novel sparse-to-dense registration approach is presented. We apply an emerging laser-based active triangulation (AT) sensor that delivers sparse but highly accurate 3-D measurements in real-time. These sparse position measurements are registered with a dense reference surface extracted from planning data. Thereby a dense displacement field is reconstructed which describes the 4-D deformation of the complete patient body surface and recovers a multi-dimensional respiratory signal for application in respiratory motion management. The method is validated on real data from an AT prototype and synthetic data sampled from dense surface scans acquired with a structured light scanner. In a study on 16 subjects, the proposed algorithm achieved a mean reconstruction accuracy of +/- 0.22 mm w.r.t. ground truth data.

  11. Application of computational lower extremity model to investigate different muscle activities and joint force patterns in knee osteoarthritis patients during walking.

    PubMed

    Nha, Kyung Wook; Dorj, Ariunzaya; Feng, Jun; Shin, Jun Ho; Kim, Jong In; Kwon, Jae Ho; Kim, Kyungsoo; Kim, Yoon Hyuk

    2013-01-01

    Many experimental and computational studies have reported that osteoarthritis in the knee joint affects knee biomechanics, including joint kinematics, joint contact forces, and muscle activities, due to functional restriction and disability. In this study, differences in muscle activities and joint force patterns between knee osteoarthritis (OA) patients and normal subjects during walking were investigated using the inverse dynamic analysis with a lower extremity musculoskeletal model. Extensor/flexor muscle activations and torque ratios and the joint contact forces were compared between the OA and normal groups. The OA patients had higher extensor muscle forces and lateral component of the knee joint force than normal subjects as well as force and torque ratios of extensor and flexor muscles, while the other parameters had little differences. The results explained that OA patients increased the level of antagonistic cocontraction and the adduction moment on the knee joint. The presented findings and technologies provide insight into biomechanical changes in OA patients and can also be used to evaluate the postoperative functional outcomes of the OA treatments.

  12. Knee joint forces: prediction, measurement, and significance

    PubMed Central

    D’Lima, Darryl D.; Fregly, Benjamin J.; Patil, Shantanu; Steklov, Nikolai; Colwell, Clifford W.

    2011-01-01

    Knee forces are highly significant in osteoarthritis and in the survival and function of knee arthroplasty. A large number of studies have attempted to estimate forces around the knee during various activities. Several approaches have been used to relate knee kinematics and external forces to internal joint contact forces, the most popular being inverse dynamics, forward dynamics, and static body analyses. Knee forces have also been measured in vivo after knee arthroplasty, which serves as valuable validation of computational predictions. This review summarizes the results of published studies that measured knee forces for various activities. The efficacy of various methods to alter knee force distribution, such as gait modification, orthotics, walking aids, and custom treadmills are analyzed. Current gaps in our knowledge are identified and directions for future research in this area are outlined. PMID:22468461

  13. In vivo knee laxity in flexion and extension: a radiographic study in 30 older healthy subjects.

    PubMed

    Heesterbeek, P J C; Verdonschot, N; Wymenga, A B

    2008-01-01

    In order to determine how "tight" a total knee prosthesis should be implanted, it is important to know the amount of laxity in a healthy knee. The objective of this study was to determine knee laxity in extension and flexion in healthy, non-arthritic knees of subjects similar in age to patients undergoing a total knee arthroplasty and to provide guidelines for the orthopaedic surgeon in his attempt to restore the stability of an osteoarthritic knee to normal. Thirty healthy subjects (15 male, 15 female), mean age 62 (SD 6.4) years, were included in the study. For each subject one, randomly selected, knee was stressed in extension and in 70 degrees flexion (15 Nm). Varus and valgus laxity were measured on radiographs. The passive range of motion and active flexion was assessed. Mean valgus laxity in extension was 2.3 degrees (SD 0.9, range 0.2 degrees -4.1 degrees ). In extension mean varus laxity was 2.8 degrees (SD 1.3, range 0.6 degrees -5.4 degrees ). In flexion, mean valgus laxity was 2.5 degrees (SD 1.5, range 0.0 degrees -6.0 degrees ) and mean varus laxity was 3.1 degrees (SD 2.0, range 0.1 degrees -7.0 degrees ). Varus and valgus knee laxity in extension and in flexion were comparable. This study shows that the normal knee in this age group has an inherent degree of varus-valgus laxity. Whether the results of the present study can be used to optimise the total knee arthroplasty implantation technique requires further investigation.

  14. Photothermally Activated Motion and Ignition Using Aluminum Nanoparticles

    DTIC Science & Technology

    2013-01-17

    In comparison with alternative sources such as spark ignition,19 laser igni- tion,20 plasma ignition,21 plasma -assisted combustion,22 and combustion...energy-dispersive X-ray spectroscopy measurements of motion-only and afterignition products confirm significant Al oxidation occurs through sintering ...significant Al oxidation occurs through sintering and bursting after the flash exposure. Simulations suggest local heat generation is enhanced by LSPR. The

  15. Sunspots motions in the 22^nd cycle of activity

    NASA Astrophysics Data System (ADS)

    Tomic, A. S.; Vince, I.

    2006-08-01

    We handled approximately 30 000 rows with data for 5744 sunspots, obtained on Debrecen Heliophysical Observatory, for years 1986-1989 and 1993-1995. By method of last squares we solved for each spot inverse relations between time of observation, angular distance from central meridian and latitude. On this way were obtained mean equatorial and mean meridional motion, giving parameters of rotation for 90 latitude zones width of one degree. The averaged sideral equatorial angular speed of rotation: omega = 2.91+/-0.01[micro rad/ day], and: A = -0.65+/-0/01 [micro rad/day] were obtained. Solving second inverse problem - Busso's equation, were derived characteristic equatorial periods for different latitudes, from sunspots meridional motion. We obtained values between 32 day on the pole, and 400 years for latitude 2.5 degree. Also, covariance of spot motions along equator and meridian is calculated for all 5744 spots in 90 degree of latitude, which fully confirmed Ward's model of angular moment transport.

  16. Localized, Non-Harmonic Active Flap Motions for Low Frequency In-Plane Rotor Noise Reduction

    NASA Technical Reports Server (NTRS)

    Sim, Ben W.; Potsdam, Mark; Kitaplioglu, Cahit; LeMasurier, Philip; Lorber, Peter; Andrews, Joseph

    2012-01-01

    A first-of-its-kind demonstration of the use of localized, non-harmonic active flap motions, for suppressing low frequency, in-plane rotor noise, is reported in this paper. Operational feasibility is verified via testing of the full-scale AATD/Sikorsky/UTRC active flap demonstration rotor in the NFAC's 40- by 80-Foot anechoic wind tunnel. Effectiveness of using localized, non-harmonic active flap motions are compared to conventional four-per-rev harmonic flap motions, and also active flap motions derived from closed-loop acoustics implementations. All three approaches resulted in approximately the same noise reductions over an in-plane three-by-three microphone array installed forward and near in-plane of the rotor in the nearfield. It is also reported that using an active flap in this localized, non-harmonic manner, resulted in no more that 2% rotor performance penalty, but had the tendency to incur higher hub vibration levels.

  17. New Generation Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A knee brace that uses Space Shuttle propulsion technology has moved a step closer to being available to help knee injury and stroke patients and may possibly benefit patients with birth defects, spinal cord injuries, and post-polio conditions. After years of hard work, inventors at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have turned over the final design and prototype to industry partners at Horton's Orthotic Lab in Little Rock, Arkansas for further clinical testing. The device, called the Selectively Lockable Knee Brace, may mean faster, less painful rehabilitation for patients by allowing the knee to move when weight is not on the heel. Devices currently on the market lock the knee in a rigid, straight-leg position, or allow continuous free motion. The knee brace is just one example of how space technology is being used to improve the lives of people on Earth. NASA's MSFC inventors Michael Shadoan and Neill Myers are space propulsion engineers who use the same mechanisms and materials to build systems for rockets that they used to design and develop the knee brace.

  18. Modified gap-balancing technique in total knee arthroplasty: evaluation of the post-operative coronal laxity.

    PubMed

    Moro-oka, Taka-aki; Shiraishi, Hirokazu; Iwamoto, Yukihide; Banks, Scott A

    2010-03-01

    It is unknown how intra-operative soft-tissue balance affects post-operative knee kinematics during different functional tasks. In order to clarify this relationship, the intra-operative varus-valgus balance and post-operative knee kinematics were compared for 17 patients who underwent total knee arthroplasty using a modified gap technique. The intra-operative balance was recorded with a tensor device, and in vivo knee kinematics of lunging, kneeling and non-weight-bearing knee extension were analyzed with 3D-to-2D model registration techniques. Femoral condylar separation from the tibial articular surface also was investigated. The post-operative varus-valgus angle in 90 degrees kneeling had a strong relationship with the intra-operative varus-valgus angle, while there was a weak relationship for the non-weight-bearing motion at 0 degrees and 90 degrees flexion. Articular surface separation was an uncommon observation, seen in 2.2% of images during non-weight-bearing motion and in none of the lunging or kneeling images. The modified gap technique appears effective providing stable knee arthroplasty kinematics during in vivo activities with minimal articular separation in non-weight-bearing motion.

  19. Femoral quadriceps neuromuscular electrical stimulation after total knee arthroplasty: a systematic review

    PubMed Central

    Volpato, Helena Bruna Bettoni; Szego, Paulo; Lenza, Mario; Milan, Silvia Lefone; Talerman, Claudia; Ferretti, Mario

    2016-01-01

    ABSTRACT The purpose of this study was to evaluate the effects of neuromuscular electrical stimulation in patients submitted to total knee arthroplasty. This was a systematic review with no language or publication status restriction. Our search was made in Cochrane Library, MEDLINE, Embase and LILACS. Randomized or quasi-randomized clinical trials evaluating neuromuscular electrical stimulation after total knee arthroplasty were included. Four studies with moderate risk of bias and low statistical power were included, totalizing 376 participants. There was no statistically significant difference in knee function, pain and range of motion during 12 month follow-up. This review concluded that neuromuscular electrical stimulation was less effective than traditional rehabilitation in function, muscular strength and range of motion. However, this technique was useful for quadriceps activation during the first days after surgery. PMID:26537511

  20. Knee Injuries

    MedlinePlus

    ... keeping it from bending outward. anterior cruciate ligament (ACL): The ACL connects your femur to your tibia at the ... Common knee sprains usually involve damage to the ACL and/or MCL. The most serious sprains involve ...

  1. Knee MRI

    MedlinePlus

    ... of the knee uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  2. Total Knee Arthroplasty for Severe Flexion Contracture in Rheumatoid Arthritis Knees

    PubMed Central

    Hwang, Youn Soo; Moon, Kyu Pill; Kim, Kyung Taek; Kim, Jin Wan; Park, Won Seok

    2016-01-01

    Flexion contracture deformities, as well as severe varus and valgus deformities of the knee joint, accompany osteoarthritis or rheumatoid arthritis (RA). In particular, severe flexion contracture deformity of the knee joint is often found in patients with RA, which renders them nonambulatory. This report describes a 26-year-old female patient diagnosed with RA 10 years ago. She had chronic joint pain, severe flexion contracture, valgus deformity in both knees, and limited range of motion in both knees and became nonambulatory. She underwent a total knee arthroplasty (TKA) and serial casting and physical therapy to restore stable joint movement and correct knee joint deformity. Her pain was successfully relieved, and she was able to walk after surgery. Here, we report the excellent results of TKA in this RA patient with severe flexion contracture of both knees. PMID:27894181

  3. High Knee Valgus in Female Subjects Does Not Yield Higher Knee Translations During Drop Landings: A Biplane Fluoroscopic Study

    PubMed Central

    Torry, Michael R.; Shelburne, Kevin B.; Myers, Casey; Giphart, J. Erik; Pennington, W. Wesley; Krong, Jacob P.; Peterson, Daniel S.; Steadman, J. Richard; Woo, Savio L-Y.

    2012-01-01

    The goal of this study was to determine the effects of peak knee valgus angle and peak knee abductor moment on the anterior, medial, and lateral tibial translations (ATT, MTT, LTT) in the ‘at risk’ female knee during drop landing. Fifteen female subjects performed drop landings from 40 cm. 3D knee motion was simultaneously recorded using a high speed, biplane fluoroscopy system and a video-based motion analysis system. Valgus knee angles and knee abduction moments were stratified into low, intermediate and high groups and peak ATT, MTT and LTT were compared between these groups with ANOVA (α = .05). Significant differences were observed between stratified groups in peak knee valgus angle (p < .0001) and peak knee abduction moment (p < .0001). However, no corresponding differences in peak ATT, LTT and MTT between groups exhibiting low to high peak knee valgus angles (ATT: p = .80; LTT: p = .25; MTT: p = .72); or, in peak ATT (p = .61), LTT (p = .26) and MTT (p = .96) translations when stratified according to low to high knee abduction moments, were found. We conclude that the healthy female knee is tightly regulated with regard to translations even when motion analysis derived knee valgus angles and abduction moments are high. PMID:22968826

  4. High knee valgus in female subjects does not yield higher knee translations during drop landings: a biplane fluoroscopic study.

    PubMed

    Torry, Michael R; Shelburne, Kevin B; Myers, Casey; Giphart, J Erik; Pennington, W Wesley; Krong, Jacob P; Peterson, Daniel S; Steadman, J Richard; Woo, Savio L-Y

    2013-02-01

    The goal of this study was to determine the effects of peak knee valgus angle and peak knee abductor moment on the anterior, medial, and lateral tibial translations (ATT, MTT, LTT) in the "at risk" female knee during drop landing. Fifteen female subjects performed drop landings from 40 cm. Three-dimension knee motion was simultaneously recorded using a high speed, biplane fluoroscopy system, and a video-based motion analysis system. Valgus knee angles and knee abduction moments were stratified into low, intermediate, and high groups and peak ATT, MTT, and LTT were compared between these groups with ANOVA (α = 0.05). Significant differences were observed between stratified groups in peak knee valgus angle (p < 0.0001) and peak knee abduction moment (p < 0.0001). However, no corresponding differences in peak ATT, LTT, and MTT between groups exhibiting low to high-peak knee valgus angles (ATT: p = 0.80; LTT: p = 0.25; MTT: p = 0.72); or, in peak ATT (p = 0.61), LTT (p = 0.26) and MTT (p = 0.96) translations when stratified according to low to high knee abduction moments, were found. We conclude that the healthy female knee is tightly regulated with regard to translations even when motion analysis derived knee valgus angles and abduction moments are high.

  5. Motion sickness susceptibility in parabolic flight and velocity storage activity

    NASA Technical Reports Server (NTRS)

    Dizio, Paul; Lackner, James R.

    1991-01-01

    In parabolic flight experiments, postrotary nystagmus is as found to be differentially suppressed in free fall (G) and in a high gravitoinertial force (1.8 G) background relative to 1 G. In addition, the influence of postrotary head movements on nystagmus suppression was found to be contingent on G-dependency of the velocity storage and dumping mechanisms. Here, susceptibility to motion sickness during head movements in 0 G and 1.8 G was rank-correlated with the following: (1) the decay time constant of the slow phase velocity of postrotary nystagmus under 1 G, no head movement, baseline conditions, (2) the extent of time constant reduction elicited in 0 G and 1.8 G; (3) the extent of time constant reduction elicited by head tilts in 1 G; and (4) changes in the extent of time constants reduction in 0 G and 1.8 G over repeated tests. Susceptibility was significantly correlated with the extent to which a head movement reduced the time constant in 1 G, was weakly correlated with the baseline time constant, but was not correlated with the extent of reduction in 0 G or 1.8 G. This pattern suggests a link between mechanisms evoking symptoms of space motion sickness and the mechanisms of velocity storage and dumping. Experimental means of evaluating this link are described.

  6. Altered Tibiofemoral Joint Contact Mechanics and Kinematics in Patients with Knee Osteoarthritis and Episodic Complaints of Joint Instability

    PubMed Central

    Farrokhi, Shawn; Voycheck, Carrie A.; Klatt, Brian A.; Gustafson, Jonathan A.; Tashman, Scott; Fitzgerald, G. Kelley

    2014-01-01

    Background To evaluate knee joint contact mechanics and kinematics during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. Methods Forty-three subjects, 11 with medial compartment knee osteoarthritis and self-reported instability (unstable), 7 with medial compartment knee osteoarthritis but no reports of instability (stable), and 25 without knee osteoarthritis or instability (control) underwent Dynamic Stereo X-ray analysis during a downhill gait task on a treadmill. Findings The medial compartment contact point excursions were longer in the unstable group compared to the stable (p=0.046) and the control groups (p=0.016). The peak medial compartment contact point velocity was also greater for the unstable group compared to the stable (p=0.047) and control groups (p=0.022). Additionally, the unstable group demonstrated a coupled movement pattern of knee extension and external rotation after heel contact which was different than the coupled motion of knee flexion and internal rotation demonstrated by stable and control groups. Interpretation Our findings suggest that knee joint contact mechanics and kinematics are altered during the loading response phase of downhill gait in knee osteoarthritis patients with self-reported instability. The observed longer medial compartment contact point excursions and higher velocities represent objective signs of mechanical instability that may place the arthritic knee joint at increased risk for disease progression. Further research is indicated to explore the clinical relevance of altered contact mechanics and kinematics during other common daily activities and to assess the efficacy of rehabilitation programs to improve altered joint biomechanics in knee osteoarthritis patients with self-reported instability. PMID:24856791

  7. Evaluation of an intact, an ACL-deficient, and a reconstructed human knee joint finite element model.

    PubMed

    Vairis, Achilles; Stefanoudakis, George; Petousis, Markos; Vidakis, Nectarios; Tsainis, Andreas-Marios; Kandyla, Betina

    2016-02-01

    The human knee joint has a three-dimensional geometry with multiple body articulations that produce complex mechanical responses under loads that occur in everyday life and sports activities. Understanding the complex mechanical interactions of these load-bearing structures is of use when the treatment of relevant diseases is evaluated and assisting devices are designed. The anterior cruciate ligament (ACL) in the knee is one of four main ligaments that connects the femur to the tibia and is often torn during sudden twisting motions, resulting in knee instability. The objective of this work is to study the mechanical behavior of the human knee joint and evaluate the differences in its response for three different states, i.e., intact, ACL-deficient, and surgically treated (reconstructed) knee. The finite element models corresponding to these states were developed. For the reconstructed model, a novel repair device was developed and patented by the author in previous work. Static load cases were applied, as have already been presented in a previous work, in order to compare the calculated results produced by the two models the ACL-deficient and the surgically reconstructed knee joint, under the exact same loading conditions. Displacements were calculated in different directions for the load cases studied and were found to be very close to those from previous modeling work and were in good agreement with experimental data presented in literature. The developed finite element model for both the intact and the ACL-deficient human knee joint is a reliable tool to study the kinematics of the human knee, as results of this study show. In addition, the reconstructed human knee joint model had kinematic behavior similar to the intact knee joint, showing that such reconstruction devices can restore human knee stability to an adequate extent.

  8. The Effect of Increasing Volume of Exercise on Activation Pattern of Vastus Medialis and Lateralis and its Correlation With Anterior Knee Pain in Karate Elites

    PubMed Central

    Safar Cherati, Afsaneh; Lotfian, Sara; Jamshidi, Aliashraf; Sanjari, Mohammad Ali; Razi, Mohammad

    2016-01-01

    Background The effects of exercise volume on the pattern of muscle activity is one of the most important factors in training management and injury risk reduction. In the lower limb, the quadriceps muscle which plays a determining role in performing the stance and other karate techniques could be injured in intensive exercise and may induce anterior knee pain in athletes. Objectives The aim of this study was to determine the relationship between training volume and muscle activity of vastus medialis and vastus lateralis and its association with anterior knee pain in karate elites. Patients and Methods Male and female athletes from national junior and cadet karate team (14 to 18 years) were invited to participate in the study at the beginning and the end of the training camps. Studies involved measurement of electromyographic muscle activity of vastus medialis and vastus lateralis in both lower extremities with surface electromyography device and assessment of movement by electrogoniometery. Muscle activity was recorded in three tests of dachi, walking up and walking down stairs. Simultaneously, anterior knee pain was evaluated using visual analogue scale and anterior knee pain scale questionnaire. Results Eight athletes of a total number of 23 reported increased ratings of pain in their right knees. No differences in muscle activity were observed in tests of Dachi and stairs between the groups with and without pain. Comparing Dachi task pattern at the beginning and end of training camps, there was no significant difference in pattern of biomechanical movement; however, reducing the amount of muscle activity in early and late phases of tasks was observed in electromyographic assessment. Conclusions The results showed that performing the same task after a six-week training period, less muscle activity was required in all phases in two groups of tasks, including karate-specific movement (dachi) and activities of daily living (up or down stairs). PMID:27826403

  9. Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players.

    PubMed

    Rozzi, S L; Lephart, S M; Gear, W S; Fu, F H

    1999-01-01

    Anterior cruciate ligament injuries are occurring at a higher rate in female athletes compared with their male counterparts. Research in the area of anterior cruciate ligament injury has increasingly focused on the role of joint proprioception and muscle activity in promoting knee joint stability. We measured knee joint laxity, joint kinesthesia, lower extremity balance, the amount of time required to generate peak torque of the knee flexor and extensor musculature, and electromyographically assessed muscle activity in 34 healthy, collegiate-level athletes (average age, 19.6 +/- 1.5 years) who played soccer or basketball or both. Independent t-tests were used to determine significant sex differences. Results revealed that women inherently possess significantly greater knee joint laxity values, demonstrate a significantly longer time to detect the knee joint motion moving into extension, possess significantly superior single-legged balance ability, and produce significantly greater electromyographic peak amplitude and area of the lateral hamstring muscle subsequent to landing a jump. The excessive joint laxity of women appears to contribute to diminished joint proprioception, rendering the knee less sensitive to potentially damaging forces and possibly at risk for injury. Unable to rely on ligamentous structures, healthy female athletes appear to have adopted compensatory mechanisms of increased hamstring activity to achieve functional joint stabilization.

  10. Tracking of EEG activity using motion estimation to understand brain wiring.

    PubMed

    Nisar, Humaira; Malik, Aamir Saeed; Ullah, Rafi; Shim, Seong-O; Bawakid, Abdullah; Khan, Muhammad Burhan; Subhani, Ahmad Rauf

    2015-01-01

    The fundamental step in brain research deals with recording electroencephalogram (EEG) signals and then investigating the recorded signals quantitatively. Topographic EEG (visual spatial representation of EEG signal) is commonly referred to as brain topomaps or brain EEG maps. In this chapter, full search full search block motion estimation algorithm has been employed to track the brain activity in brain topomaps to understand the mechanism of brain wiring. The behavior of EEG topomaps is examined throughout a particular brain activation with respect to time. Motion vectors are used to track the brain activation over the scalp during the activation period. Using motion estimation it is possible to track the path from the starting point of activation to the final point of activation. Thus it is possible to track the path of a signal across various lobes.

  11. Ankle motion influences the external knee adduction moment and may predict who will respond to lateral wedge insoles?: an ancillary analysis from the SILK trial

    PubMed Central

    Chapman, G.J.; Parkes, M.J.; Forsythe, L.; Felson, D.T.; Jones, R.K.

    2015-01-01

    Summary Objective Lateral wedge insoles are a potential simple treatment for medial knee osteoarthritis (OA) patients by reducing the external knee adduction moment (EKAM). However in some patients, an increase in their EKAM is seen. Understanding the role of the ankle joint complex in the response to lateral wedge insoles is critical in understanding and potentially identifying why some patients respond differently to lateral wedge insoles. Method Participants with medial tibiofemoral OA underwent gait analysis whilst walking in a control shoe and a lateral wedge insole. We evaluated if dynamic ankle joint complex coronal plane biomechanical measures could explain and identify those participants that increased (biomechanical non-responder) or decreased (biomechanical responder) EKAM under lateral wedge conditions compared to the control shoe. Results Of the 70 participants studied (43 male), 33% increased their EKAM and 67% decreased their EKAM. Overall, lateral wedge insoles shifted the centre of foot pressure laterally, increased eversion of the ankle/subtalar joint complex (STJ) and the eversion moment compared to the control condition. Ankle angle at peak EKAM and peak eversion ankle/STJ complex angle in the control condition predicted if individuals were likely to decrease EKAM under lateral wedge conditions. Conclusions Coronal plane ankle/STJ complex biomechanical measures play a key role in reducing EKAM when wearing lateral wedge insoles. These findings may assist in the identification of those individuals that could benefit more from wearing lateral wedge insoles. PMID:25749010

  12. Move with Science: Energy, Force, & Motion. An Activities-Based Teacher's Guide.

    ERIC Educational Resources Information Center

    Beven, Roy Q.

    The secondary school level activities contained in this book use the subject of transportation to teach the basic concepts of physics and several areas of human biology. The material is organized into sections including curriculum design, activities, background readings, and resources. Activities focus on such topics as notions of motion stability…

  13. Is the Modified Tardieu Scale in Semi-Standing Position Better Associated with Knee Extension and Hamstring Activity in Terminal Swing than the Supine Tardieu?

    ERIC Educational Resources Information Center

    Faber, Irene R.; Nienhuis, Bart; Rijs, Nique P. A. M.; Geurts, Alexander C. H.; Duysens, Jacques

    2008-01-01

    The aim of this study was to investigate whether the modified Tardieu scale (MTS) in a semi-standing position, used for the assessment of hamstrings spasticity, was better associated with knee extension and hamstrings activity in terminal swing than the MTS in a supine position in children with cerebral palsy (CP). Seven children diagnosed with…

  14. Adaptations in muscular activation of the knee extensor muscles with strength training in young and older adults.

    PubMed

    Knight, C A; Kamen, G

    2001-12-01

    The purpose of this study was to compare the extent of muscular activation during maximal voluntary knee extension contractions in old and young individuals and to examine the effects of resistance training on muscular activation in each group. The interpolated twitch technique was used to estimate muscular activation during two pre-training baseline tests, and after two and six weeks of resistance training. Throughout the study, the older group was 30% less strong than the young group (p=0.02). The training protocol was effective in both groups with overall isometric strength gains of 30 and 36% in the older (p=0.01) and young (p<0.01) groups, respectively. 10-RM training loads increased by 66% in the old group (p<0.01) and by 77% in the young group (p<0.01) throughout training. At the first baseline test, a 2% difference in muscular activation between groups (p=0.3) did not explain the large disparity in strength. Muscular activation increased by 2% in both groups throughout training (p<0.01). Despite considerably less muscular strength in the older group, muscular activation was greater than 95% of maximum and appears to be equal in both young and older individuals. Both groups demonstrated similar but small increases in muscular activation throughout training.

  15. Activation of fibrinolysis by reinfusion of unwashed salvaged blood after total knee arthroplasty.

    PubMed

    Matsuda, Keiji; Nozawa, Masahiko; Katsube, Sadanobu; Maezawa, Katsuhiko; Kurosawa, Hisashi

    2010-02-01

    In 19 patients with RA and 20 with OA who underwent autotransfusion with unwashed salvaged blood (USB) after total knee arthroplasty, we performed serial measurement of D-dimer, FgDP, t-PA, and PIC in the plasma and salvaged blood. The PIC level at the completion of salvaged blood transfusion was closely correlated with the volume of USB reinfused in the RA group (p<0.001). The t-PA level of salvaged blood showed a significant positive correlation with the total volume of postoperative drainage in both the RA and OA groups (p<0.05). The increase of total postoperative drainage associated with reinfusion of USB is largely caused by an increase of t-PA in the salvaged blood.

  16. Student expectations in a group learning activity on harmonic motion

    NASA Astrophysics Data System (ADS)

    Kaczynski, Adam; Wittmann, Michael C.

    2013-01-01

    Students in a sophomore-level mechanics course participated in a new group learning activity that was intended to support model-building and finding coherence between multiple representations in the context of an underdamped harmonic system. Not all of the student groups framed the activity in the same way, and many attempted tasks that existed outside of the prompts of the activity. For one group, this meant that instead of providing a rich verbal description, they framed the activity as finding a mathematical expression.

  17. Blocking of tumor necrosis factor activity promotes natural repair of osteochondral defects in rabbit knee

    PubMed Central

    2009-01-01

    Background and purpose Osteochondral defects have a limited capacity for repair. We therefore investigated the effects of tumor necrosis factor (TNF) signal blockade by etanercept (human recombinant soluble TNF receptor) on the repair of osteochondral defects in rabbit knees. Material and methods Osteochondral defects (5 mm in diameter) were created in the femoral patellar groove in rabbits. Soon after the procedure, a first subcutaneous injection of etanercept was performed. This single injection or, alternatively, 4 injections in total (twice a week for 2 weeks) were given. Each of these 2 groups was divided further into 3 subgroups: a low-dose group (0.05 μg/kg), an intermediate-dose group (0.4 μ g/kg), and a high-dose group (1.6 μ g /kg) with 19 rabbits in each. As a control, 19 rabbits were injected with water alone. The rabbits in each subgroup were killed 4 weeks (6 rabbits), 8 weeks (6 rabbits), or 24 weeks (7 rabbits) after surgery and repair was assessed histologically. Results Histological examination revealed that the natural process of repair of the osteochondral defects was promoted by 4 subcutaneous injections of intermediate-dose etanercept and by 1 or 4 injections of high-dose etanercept at the various time points examined postoperatively (4, 8, and 24 weeks). Western blot showed that rabbit TNFα had a high affinity for etanercept. Interpretation Blocking of TNF by etanercept enabled repair of osteochondral defects in rabbit knee. Anti-TNF therapy could be a strategy for the use of tissue engineering for bone and cartilage repair. PMID:19916697

  18. The biomechanics and energetics of human running using an elastic knee exoskeleton.

    PubMed

    Elliott, Grant; Sawicki, Gregory S; Marecki, Andrew; Herr, Hugh

    2013-06-01

    While the effects of series compliance on running biomechanics are well documented, the effects of parallel compliance are known only for the simpler case of hopping. As many practical exoskeletal and orthotic designs act in parallel with the leg, it is desirable to understand the effects of such an intervention. Spring-like forces offer a natural choice of perturbation for running, as they are both biologically motivated and energetically inexpensive to implement. To this end, we investigate the hypothesis that the addition of an external elastic element at the knee during the stance phase of running results in a reduction in knee extensor activation so that total joint quasi-stiffness is maintained. An exoskeletal knee brace consisting of an elastic element engaged by a clutch is used to provide this stance phase extensor torque. Motion capture of five subjects is used to investigate the consequences of running with this device. No significant change in leg stiffness or total knee stiffness is observed due to the activation of the clutched parallel knee spring. However, this pilot data suggests differing responses between casual runners and competitive long-distance runners, whose total knee torque is increased by the device. Such a relationship between past training and effective utilization of an external force is suggestive of limitations on the applicability of assistive devices.

  19. Six degree-of-freedom knee joint kinematics in obese individuals with knee pain during gait

    PubMed Central

    Li, Jing-Sheng; Tsai, Tsung-Yuan; Felson, David T.; Li, Guoan; Lewis, Cara L.

    2017-01-01

    Knee joint pain is a common symptom in obese individuals and walking is often prescribed as part of management programs. Past studies in obese individuals have focused on standing alignment and kinematics in the sagittal and coronal planes. Investigation of 6 degree-of-freedom (6DOF) knee joint kinematics during standing and gait is important to thoroughly understand knee function in obese individuals with knee pain. This study aimed to investigate the 6DOF knee joint kinematics in standing and during gait in obese patients using a validated fluoroscopic imaging system. Ten individuals with obesity and knee pain were recruited. While standing, the knee was in 7.4±6.3°of hyperextension, 2.8±3.3° of abduction and 5.6±7.3° of external rotation. The femoral center was located 0.7±3.1mm anterior and 5.1±1.5mm medial to the tibial center. During treadmill gait, the sagittal plane motion, i.e., flexion/extension and anterior-posterior translation, showed a clear pattern. Specifically, obese individuals with knee pain maintained the knee in more flexion and more anterior tibial translation during most of the stance phase of the gait cycle and had a reduced total range of knee flexion when compared to a healthy non-obese group. In conclusion, obese individuals with knee pain used hyperextension knee posture while standing, but maintained the knee in more flexion during gait with reduced overall range of motion in the 6DOF analysis. PMID:28339477

  20. The visual perception of natural motion: abnormal task-related neural activity in DYT1 dystonia.

    PubMed

    Sako, Wataru; Fujita, Koji; Vo, An; Rucker, Janet C; Rizzo, John-Ross; Niethammer, Martin; Carbon, Maren; Bressman, Susan B; Uluğ, Aziz M; Eidelberg, David

    2015-12-01

    Although primary dystonia is defined by its characteristic motor manifestations, non-motor signs and symptoms have increasingly been recognized in this disorder. Recent neuroimaging studies have related the motor features of primary dystonia to connectivity changes in cerebello-thalamo-cortical pathways. It is not known, however, whether the non-motor manifestations of the disorder are associated with similar circuit abnormalities. To explore this possibility, we used functional magnetic resonance imaging to study primary dystonia and healthy volunteer subjects while they performed a motion perception task in which elliptical target trajectories were visually tracked on a computer screen. Prior functional magnetic resonance imaging studies of healthy subjects performing this task have revealed selective activation of motor regions during the perception of 'natural' versus 'unnatural' motion (defined respectively as trajectories with kinematic properties that either comply with or violate the two-thirds power law of motion). Several regions with significant connectivity changes in primary dystonia were situated in proximity to normal motion perception pathways, suggesting that abnormalities of these circuits may also be present in this disorder. To determine whether activation responses to natural versus unnatural motion in primary dystonia differ from normal, we used functional magnetic resonance imaging to study 10 DYT1 dystonia and 10 healthy control subjects at rest and during the perception of 'natural' and 'unnatural' motion. Both groups exhibited significant activation changes across perceptual conditions in the cerebellum, pons, and subthalamic nucleus. The two groups differed, however, in their responses to 'natural' versus 'unnatural' motion in these regions. In healthy subjects, regional activation was greater during the perception of natural (versus unnatural) motion (P < 0.05). By contrast, in DYT1 dystonia subjects, activation was relatively greater

  1. Classification of upper limb motions from around-shoulder muscle activities: hand biofeedback.

    PubMed

    González, Jose; Horiuchi, Yuse; Yu, Wenwei

    2010-05-28

    Mining information from EMG signals to detect complex motion intention has attracted growing research attention, especially for upper-limb prosthetic hand applications. In most of the studies, recordings of forearm muscle activities were used as the signal sources, from which the intention of wrist and hand motions were detected using pattern recognition technology. However, most daily-life upper limb activities need coordination of the shoulder-arm-hand complex, therefore, relying only on the local information to recognize the body coordinated motion has many disadvantages because natural continuous arm-hand motions can't be realized. Also, achieving a dynamical coupling between the user and the prosthesis will not be possible. This study objective was to investigate whether it is possible to associate the around-shoulder muscles' Electromyogram (EMG) activities with the different hand grips and arm directions movements. Experiments were conducted to record the EMG of different arm and hand motions and the data were analyzed to decide the contribution of each sensor, in order to distinguish the arm-hand motions as a function of the reaching time. Results showed that it is possible to differentiate hand grips and arm position while doing a reaching and grasping task. Also, these results are of great importance as one step to achieve a close loop dynamical coupling between the user and the prosthesis.

  2. The Effects of Continued Rehabilitation After Primary Knee Replacement

    PubMed Central

    Radulovic, Tatjana Nozica; Lazovic, Milica; Jandric, Slavica; Bucma, Tatjana; Cvjetkovic, Dragana Dragicevic; Manojlovic, Slavko

    2016-01-01

    Introduction: Tasks of rehabilitation after arthroplasty are to provide painless joint movements, to improve the range of motion, to establish a scheme of walking, to achieve independence in activities of daily living. The aim: of the study is to determine the effects of continued rehabilitation on the range of the knee motion and reducing the swelling after total knee replacement. Methods: The study was conducted from 2011 to 2013 and included 140 patients of both sexes, aged 45 to 85 with implanted endoprosthesis based on primary osteoarthritis. They were divided into two groups, experimental, which after early rehabilitation continued ongoing rehabilitation for a period of three weeks, while the control group after completion of early rehabilitation began rehabilitation two months from the surgery for a period of three weeks. The range of motion in the knee joint and the extent of the knee joint in the medium of patella were measured in both groups during the admission and discharge from rehabilitation. In the experimental group, control measurements were carried out three months after surgery. Results: In both groups, there was a significant reduction of the swelling at the discharge in relation to the admission while in the experimental group there was no change on the control of the joint swelling after three months in relation to the release from rehabilitation. In the experimental group, the range of motion of flexion and extension was improved at the discharge in relation to the admission as well as the flexion during the control while the range of motion of extension wasn’t significantly changing during the control examination. In the control group, the extension and flexion were significantly improved at the discharge compared to the admission. Comparing both groups, the results showed that there was a significant improvement in flexion movements in the experimental group during rehabilitation in comparison to the control group, while the range of

  3. Design of a continuous passive and active motion device for hand rehabilitation.

    PubMed

    Birch, B; Haslam, E; Heerah, I; Dechev, N; Park, E J

    2008-01-01

    This paper presents the design of a novel, portable device for hand rehabilitation. The device provides for CPM (continuous passive motion) and CAM (continuous active motion) hand rehabilitation for patients recovering from damage such as flexor tendon repair and strokes. The device is capable of flexing/extending the MCP (metacarpophalangeal) and PIP (proximal interphalangeal) joints through a range of motion of 0 degrees to 90 degrees for both the joints independently. In this way, typical hand rehabilitation motions such as intrinsic plus, intrinsic minus, and a fist can be achieved without the need of any splints or attachments. The CPM mode is broken into two subgroups. The first mode is the use of preset waypoints for the device to cycle through. The second mode involves motion from a starting position to a final position, but senses the torque from the user during the cycle. Therefore the user can control the ROM by resisting when they are at the end of the desired motion. During the CPM modes the device utilizes a minimum jerk trajectory model under PD control, moving smoothly and accurately between preselected positions. CAM is the final mode where the device will actively resist the movement of the user. The user moves from a start to end position while the device produces a torque to resist the motion. This active resistance motion is a unique ability designed to mimic the benefits of a human therapist. Another unique feature of the device is its ability to independently act on both the MCP and PIP joints. The feedback sensing built into the device makes it capable of offering a wide and flexible range of rehabilitation programs for the hand.

  4. Unicondylar knee arthroplasty: a cementless perspective

    PubMed Central

    Forsythe, Michael E.; Englund, Roy E.; Leighton, Ross K.

    2000-01-01

    Objective To compare the results of cementless unicondylar knee arthroplasty (UKA) with those already reported in a similar study on cemented UKA. Design A case-series cross-sectional study. Setting The Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax. Patients Fifty-one patients who underwent a total of 57 UKAs between May 1989 and May 1997. Inclusion criteria were osteoarthritis involving the predominantly the medial compartment of the knee, relative sparing of the other compartments, less than 15° of varus, minimal knee instability, and attendance at the postoperative clinical visit. Intervention Cementless UKA. Main outcome measures Clinical parameters that included pain, range of motion and the Knee Society Clinical Knee Score. Roentgenographic parameters that included α, β, γ and σ angles and the presence of periprosthetic radiolucency or loose beads. Results Age, weight, gender and follow-up interval did not significantly affect the clinical results in terms of pain, range of motion or knee score. Knees with more than 1 mm of radiolucency had significantly lower knee scores than those with no radiolucency. Knees that radiologically had loose beads also had significantly lower knee scores. The clinical outcomes of cementless UKA were comparable to those already reported on cemented UKA. Cementless femurs had less radiolucency than the cemented femurs, whereas cementless tibias had more radiolucency than their cemented counterparts. Conclusions Cementless UKA seems to be as efficacious as cemented UKA. However, there is some concern about the amount of radiolucency in the cementless tibial components. A randomized clinical trial comparing both cementless and cemented tibial components with a cementless femur (hybrid knee) is needed to further assess this controversial issue in UKA. PMID:11129829

  5. Effects of eating on vection-induced motion sickness, cardiac vagal tone, and gastric myoelectric activity

    NASA Technical Reports Server (NTRS)

    Uijtdehaage, S. H.; Stern, R. M.; Koch, K. L.

    1992-01-01

    This study investigated the effect of food ingestion on motion sickness severity and its physiological mechanisms. Forty-six fasted subjects were assigned either to a meal group or to a no-meal group. Electrogastrographic (EGG) indices (normal 3 cpm activity and abnormal 4-9 cpm tachyarrhythmia) and respiratory sinus arrhythmia (RSA) were measured before and after a meal and during a subsequent exposure to a rotating drum in which illusory self-motion was induced. The results indicated that food intake enhanced cardiac parasympathetic tone (RSA) and increased gastric 3 cpm activity. Postprandial effects on motion sickness severity remain equivocal due to group differences in RSA baseline levels. During drum rotation, dysrhythmic activity of the stomach (tachyarrhythmia) and vagal withdrawal were observed. Furthermore, high levels of vagal tone prior to drum rotation predicted a low incidence of motion sickness symptoms, and were associated positively with gastric 3 cpm activity and negatively with tachyarrhythmia. These data suggest that enhanced levels of parasympathetic activity can alleviate motion sickness symptoms by suppressing, in part, its dysrhythmic gastric underpinnings.

  6. Anterior Knee Pain (Chondromalacia Patellae).

    ERIC Educational Resources Information Center

    Garrick, James G.

    1989-01-01

    This article presents a pragmatic approach to the definition, diagnosis, and management of anterior knee pain. Symptoms and treatment are described. Emphasis is on active involvement of the patient in the rehabilitation exercise program. (IAH)

  7. Your Students Can Be Rocket Scientists! A Galaxy of Great Activities about Astronauts, Gravity, and Motion.

    ERIC Educational Resources Information Center

    Kepler, Lynne

    1994-01-01

    Presents activities for a springtime Space Day that can teach students about astronauts, gravity, and motion. Activities include creating a paper bag spacecraft to study liftoff and having students simulate gravity's effects by walking in various manners and recording pulse rates. A list of resources is included. (SM)

  8. Activation of nanoscale allosteric protein domain motion revealed by neutron spin echo spectroscopy

    NASA Astrophysics Data System (ADS)

    Bu, Zimei; Farago, Bela; Callaway, David

    2012-02-01

    NHERF1 is a multi-domain scaffolding protein that assembles the signaling complexes, and regulates the cell surface expression and endocytic recycling of a variety of membrane proteins. The ability of the two PDZ domains in NHERF1 to assemble protein complexes is allosterically modulated by a membrane-cytoskeleton linker protein ezrin, whose binding site is located as far as 110 angstroms away from the PDZ domains. Here, using neutron spin echo (NSE) spectroscopy, selective deuterium labeling, and theoretical analyses, we reveal the activation of interdomain motion in NHERF1 on nanometer length scales and on sub-microsecond time scales upon forming a complex with ezrin. We show that a much simplified coarse-grained model is sufficient to describe inter-domain motion of a multi-domain protein or protein complex. We expect that future NSE experiments will benefit by exploiting our approach of selective deuteration to resolve the specific domain motions of interest from a plethora of global translational and rotational motions. The results demonstrate that propagation of allosteric signals to distal sites involves the activation of long-range coupled domain motions on submicrosecond time scales, and that these coupled motions can be distinguished and characterized by NSE.

  9. Use of Low Level of Continuous Heat as an Adjunct to Physical Therapy Improves Knee Pain Recovery and the Compliance for Home Exercise in Patients With Chronic Knee Pain: A Randomized Controlled Trial.

    PubMed

    Petrofsky, Jerrold S; Laymon, Michael S; Alshammari, Faris S; Lee, Haneul

    2016-11-01

    Petrofsky, JS, Laymon, MS, Alshammari, FS, and Lee, H. Use of low level of continuous heat as an adjunct to physical therapy improves knee pain recovery and the compliance for home exercise in patients with chronic knee pain: a randomized controlled trial. J Strength Cond Res 30(11): 3107-3115, 2016-This study examined if the use of low level continuous heat (LLCH) wraps at home between physical therapy sessions at a clinic resulted in better therapy outcomes in patients with chronic knee pain. Fifty individuals with chronic nonspecific knee pain was randomly allocated to 2 groups: the LLCH group and the placebo group. All subjects underwent 1 hour of conventional physical therapy twice per week for 2 weeks at the outpatient clinic and they were asked to accomplish 1 hour of therapeutic exercise at home each day between sessions. The LLCH group applied LLCH knee wraps for 6 hours at home before home exercise while placebo group took a placebo ibuprofen. (This was done since placebo heat is impossible to use since subjects would notice that the wraps were cold) Before, during, and after intervention, pain intensity, active range of motion of the knee (AROM), knee strength, and home exercise compliance were measured. The LLCH group showed pain attenuation after 2 weeks of therapy sessions (p ≤ 0.05). AROM and strength of the knee significantly improved over time compared to the placebo group. Home exercise compliance was significantly higher in the LLCH group than placebo group (p ≤ 0.05). These results indicated that the use of LLCH as an adjunct to conventional physical therapy for chronic knee pain significantly improved pain attenuation and recovery of strength and movement in patients with chronic knee pain.

  10. Morphometrical investigations on the reproductive activity of the ovaries in rats subjected to immobilization and to motion activity

    NASA Technical Reports Server (NTRS)

    Konstantinov, N.; Cheresharov, L.; Toshkova, S.

    1982-01-01

    Wistar-strain white female rats were divided into three groups, with the first group subjected to motion loading, the second used as control, and the third group was immobilized. A considerable reduction in numbers of corpora lutea was observed in the immobilized group, together with smaller numbers of embryos, high percent of embryo mortality, fetal growth retardation, and endometrium disorders. The control group showed no deviation from normal conditions, and there was slight improvement in reproductive activity of animals under motion loading.

  11. Spontaneous Motion in Hierarchically Assembled Active Cellular Materials

    NASA Astrophysics Data System (ADS)

    Chen, Daniel

    2013-03-01

    With exquisite precision and reproducibility, cells orchestrate the cooperative action of thousands of nanometer-sized molecular motors to carry out mechanical tasks at much larger length scales, such as cell motility, division and replication. Besides their biological importance, such inherently far-from-equilibrium processes are an inspiration for the development of soft materials with highly sought after biomimetic properties such as autonomous motility and self-healing. I will describe our exploration of such a class of biologically inspired soft active materials. Starting from extensile bundles comprised of microtubules and kinesin, we hierarchically assemble active analogs of polymeric gels, liquid crystals and emulsions. At high enough concentration, microtubule bundles form an active gel network capable of generating internally driven chaotic flows that enhance transport and fluid mixing. When confined to emulsion droplets, these 3D networks buckle onto the water-oil interface forming a dense thin film of bundles exhibiting cascades of collective buckling, fracture, and self-healing driven by internally generated stresses from the kinesin clusters. When compressed against surfaces, this active nematic cortex exerts traction stresses that propel the locomotion of the droplet. Taken together, these observations exemplify how assemblies of animate microscopic objects exhibit collective biomimetic properties that are fundamentally distinct from those found in materials assembled from inanimate building blocks. These assemblies, in turn, enable the generation of a new class of materials that exhibit macroscale flow phenomena emerging from nanoscale components.

  12. Monte Carlo Simulation of In-vivo Measurement of the Most Suitable Knee Position for the Most Optimal Measurement of the Activity

    NASA Astrophysics Data System (ADS)

    Khalaf, Majid

    Internal contamination of 241Am is commonly detected and assessed by direct counting of gamma emissions in the region of the body that has high bone content and low surrounding tissue masses; for examples the skull or the knee. To assess the amount of activity in the knee, and then to calculate it in the skeleton, a suitable position of the leg by which all the knee bones contribute to detectable activity should be found. The aim of this study is to create a new and valid model for Monte Carlo simulation of in-vivo measurements of the knee, a model can be used to determine a position that optimizes conventional measurements. The United States Transuranium and Uranium Registries (USTUR) case 0846 is a whole-body donation; its body size is very close to reference man body dimensions. It may provide a unique opportunity to determine the full-lifetime biokinetics of 241Am Oxide chronic inhalation. A new leg voxel model in two different positions (straight and bent) was constructed based on CT images of the USTUR case 0846 leg and detailed radiochemical analysis of small bone sections from the same leg. In-vivo measurements were performed on the USTUR case 0846 leg. Front and lateral measurements of the knee of the USTUR case 0846 leg in a bent position and the same measurements with the leg in a straight position using a HP(Ge) detector were obtained. The experimental measurements showed that the front measurement of the knee in a bent leg position gave the highest counts rate and therefore the highest detection efficiency. Therefore, this geometry and the knee-detector position may be considered as the most appropriate position for knee monitoring. A computational model using the Monte Carlo (MC) code, namely MCNPX was created to simulate the experimental measurements by utilizing a leg voxel phantom. It was observed that there is no difference at the 0.1 significance level between the simulated and measured detection efficiencies in the assessment of 241Am within the

  13. Knee Menisci.

    PubMed

    Bryceland, James Kevin; Powell, Andrew John; Nunn, Thomas

    2017-04-01

    The menisci of the knees are semicircular fibrocartilaginous structures consisting of a hydrophilic extracellular matrix containing a network of collagen fibers, glycoproteins, and proteoglycans maintained by a cellular component. The menisci are responsible for more than 50% of load transmission across the knee and increase joint congruity thereby also aiding in fluid film lubrication of the joint. In the United Kingdom, meniscal tears are the most common form of intra-articular knee injury and one of the commonest indications for orthopedic intervention. The management of these injuries is dependent on the location within the meniscus (relative to peripheral blood supply) and the pattern of tear. Removal of meniscus is known to place the knee at increased risk of osteoarthritis; therefore repair of meniscal tears is preferable. However, a significant proportion of tears are irreparable and can only be treated by partial or even complete meniscectomy. More recent studies have shown encouraging results with meniscal replacement in this situation, though further work is required in this area.

  14. The Effects of a Lateral Wedge Insole on Knee and Ankle Joints During Slope Walking.

    PubMed

    Uto, Yuki; Maeda, Tetsuo; Kiyama, Ryoji; Kawada, Masayuki; Tokunaga, Ken; Ohwatashi, Akihiko; Fukudome, Kiyohiro; Ohshige, Tadasu; Yoshimoto, Yoichi; Yone, Kazunori

    2015-12-01

    The purpose of this study was to determine whether a lateral wedge insole reduces the external knee adduction moment during slope walking. Twenty young, healthy subjects participated in this study. Subjects walked up and down a slope using 2 different insoles: a control flat insole and a 7° lateral wedge insole. A three-dimensional motion analysis system and force plate were used to examine the knee adduction moment, the ankle valgus moment, and the moment arm of the ground reaction force to the knee joint center in the frontal plane. The lateral wedge insole significantly decreased the moment arm of the ground reaction force, resulting in a reduction of the knee adduction moment during slope walking, similar to level walking. The reduction ratio of knee adduction moment by the lateral wedge insole during the early stance of up-slope walking was larger than that of level walking. Conversely, the lateral wedge insole increased the ankle valgus moment during slope walking, especially during the early stance phase of up-slope walking. Clinicians should examine the utilization of a lateral wedge insole for knee osteoarthritis patients who perform inclined walking during daily activity, in consideration of the load on the ankle joint.

  15. Intra-articular pressures and joint mechanics: should we pay attention to effusion in knee osteoarthritis?

    PubMed

    Rutherford, Derek James

    2014-09-01

    What factors play a role to ensure a knee joint does what it should given the demands of moving through the physical environment? This paper aims to probe the hypothesis that intra-articular joint pressures, once a topic of interest, have been left aside in contemporary frameworks in which we now view knee joint function. The focus on ligamentous deficiencies and the chondrocentric view of osteoarthritis, while important, have left little attention to the consideration of other factors that can impair joint function across the lifespan. Dynamic knee stability is required during every step we take. While there is much known about the role that passive structures and muscular activation play in maintaining a healthy knee joint, this framework does not account for the role that intra-articular joint pressures may have in providing joint stability during motion and how these factors interact. Joint injuries invariably result in some form of intra-articular fluid accumulation. Ultimately, it may be how the knee mechanically responds to this fluid, of which pressure plays a significant role that provides the mechanisms for continued function. Do joint pressures provide an important foundation for maintaining knee function? This hypothesis is unique and argues that we are missing an important piece of the puzzle when attempting to understand implications that joint injury and disease have for joint function.

  16. Arthroscopic knee debridement can delay total knee replacement in painful moderate haemophilic arthropathy of the knee in adult patients.

    PubMed

    Rodriguez-Merchan, E Carlos; Gomez-Cardero, Primitivo

    2016-09-01

    The role of arthroscopic debridement of the knee in haemophilia is controversial in the literature. The purpose of this study is to describe the results of arthroscopic knee debridement (AKD), with the aim of determining whether it is possible to delay total knee replacement (TKR) for painful moderate haemophilic arthropathy of the knee in adult patients. In a 14-year period (1998-2011), AKD was performed for moderate haemophilic arthropathy of the knee in 27 patients with haemophilia A. Their average age at operation was 28.6 years (range 26-39 years). Indications for surgery were as follows: more than 90° of knee flexion, flexion deformity less than 30°, good axial alignment of the knee, good patellar alignment, and pain above >60 points in a visual analogue scale [0 (no pain) to 100 points]. Secondary haematological prophylaxis and rehabilitation (physiotherapy) was given for at least 3 months after surgery. Follow-up was for an average of 7.5 years (range 2-14 years). We assessed the clinical outcome before surgery and at the time of latest follow-up using the Knee Society pain and function scores, the range of motion, and the radiological score of the World Federation of Haemophilia. Knee Society pain scores improved from 39 preoperatively to 66 postoperatively, and function scores improved from 36 to 52. Range of motion improved on an average from -15° of extension and 90° of flexion before surgery, to -5° of extension and 110° of flexion at the last follow-up. A radiological deterioration of 2.8 points on average was found. There were two (7.4%) postoperative complications (haemarthroses resolved by joint aspiration). One patient (3.7%) required a TKR 12.5 years later. AKD should be considered in painful moderate haemophilic arthropathy of the knee in adult patients to delay TKR.

  17. The effect of prosthetic ankle energy storage and return properties on muscle activity in below-knee amputee walking.

    PubMed

    Ventura, Jessica D; Klute, Glenn K; Neptune, Richard R

    2011-02-01

    In an effort to improve amputee gait, energy storage and return (ESAR) prosthetic feet have been developed to provide enhanced function by storing and returning mechanical energy through elastic structures. However, the effect of ESAR feet on muscle activity in amputee walking is not well understood. Previous studies have analyzed commercial prosthetic feet with a wide range of material properties and geometries, making it difficult to associate specific ESAR properties with changes in muscle activity. In contrast, prosthetic ankles offer a systematic way to manipulate ESAR properties while keeping the prosthetic heel and keel geometry intact. In the present study, ESAR ankles were added to a Seattle Lightfoot2 to carefully control the energy storage and return by altering the ankle stiffness and orientation in order to identify its effect on lower extremity muscle activity during below-knee amputee walking. A total of five foot conditions were analyzed: solid ankle (SA), stiff forward-facing ankle (FA), compliant FA, stiff reverse-facing ankle (RA) and compliant RA. The ESAR ankles decreased the activity of muscles that contribute to body forward propulsion and increased the activity of muscles that provide body support. The compliant ankles generally caused a greater change in muscle activity than the stiff ankles, but without a corresponding increase in energy return. Ankle orientation also had an effect, with RA generally causing a lower change in muscle activity than FA. These results highlight the influence of ESAR stiffness on muscle activity and the importance of prescribing appropriate prosthetic foot stiffness to improve rehabilitation outcomes.

  18. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

    PubMed Central

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  19. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity.

  20. In vivo knee kinematics in patients with bilateral total knee arthroplasty of 2 designs.

    PubMed

    Okamoto, Nobukazu; Breslauer, Leigh; Hedley, Anthony K; Mizuta, Hiroshi; Banks, Scott A

    2011-09-01

    Many younger and highly active patients desire to achieve high flexion after total knee arthroplasty. This study's purpose was to determine if a contemporary total knee arthroplasty design improved functional knee flexion compared with a traditional total knee arthroplasty in patients living a Western lifestyle. Ten patients with bilateral total knee arthroplasty of 2 types were studied during weight-bearing lunge, kneeling, and stair activities using fluoroscopic imaging. There were no differences in maximum knee flexion during lunging or kneeling. Statistically significant differences in tibial rotation and condylar translation were observed during the 3 activities. Although several joint kinematic differences were observed, no important functional differences were observed in clinically excellent, high performing subjects with bilateral total knee arthroplasty of 2 types.

  1. Addition of telephone coaching to a physiotherapist-delivered physical activity program in people with knee osteoarthritis: A randomised controlled trial protocol

    PubMed Central

    2012-01-01

    Background Knee osteoarthritis (OA) is one of the most common and costly chronic musculoskeletal conditions world-wide and is associated with substantial pain and disability. Many people with knee OA also experience co-morbidities that further add to the OA burden. Uptake of and adherence to physical activity recommendations is suboptimal in this patient population, leading to poorer OA outcomes and greater impact of associated co-morbidities. This pragmatic randomised controlled trial will investigate the clinical- and cost-effectiveness of adding telephone coaching to a physiotherapist-delivered physical activity intervention for people with knee OA. Methods/Design 168 people with clinically diagnosed knee OA will be recruited from the community in metropolitan and regional areas and randomly allocated to physiotherapy only, or physiotherapy plus nurse-delivered telephone coaching. Physiotherapy involves five treatment sessions over 6 months, incorporating a home exercise program of 4–6 exercises (targeting knee extensor and hip abductor strength) and advice to increase daily physical activity. Telephone coaching comprises 6–12 telephone calls over 6 months by health practitioners trained in applying the Health Change Australia (HCA) Model of Health Change to provide behaviour change support. The telephone coaching intervention aims to maximise adherence to the physiotherapy program, as well as facilitate increased levels of participation in general physical activity. The primary outcomes are pain measured by an 11-point numeric rating scale and self-reported physical function measured by the Western Ontario and McMaster Universities Osteoarthritis Index subscale after 6 months. Secondary outcomes include physical activity levels, quality-of-life, and potential moderators and mediators of outcomes including self-efficacy, pain coping and depression. Relative cost-effectiveness will be determined from health service usage and outcome data. Follow

  2. The effect of preoperative exercise on total knee replacement outcomes.

    PubMed

    D'Lima, D D; Colwell, C W; Morris, B A; Hardwick, M E; Kozin, F

    1996-05-01

    This study compared the effects of preoperative physical therapy of general cardiovascular conditioning exercises with the routine procedure of no preoperative physical therapy on patients undergoing primary total knee replacement. Thirty patients were randomly assigned to 1 of 3 groups. Group 1 was the control group. Group 2 participated in a physical therapy program designed to strengthen the upper and lower limbs and improve knee range of motion. Group 3 participated in a cardiovascular conditioning program, consisting of arm ergometry, cycle ergometry, aquatic exercises, and aerobic activity. All patients were evaluated preoperatively and postoperatively using the Hospital for Special Surgery Knee Rating, the Arthritis Impact Measurement Scale, and the Quality of Well Being instrument. Both experimental groups tolerated their respective exercise protocols extremely well. All 3 groups showed significant improvement postoperatively as measured by the Hospital for Special Surgery Knee Rating, the Arthritis Impact Measurement Scale and the Quality of Well Being measurement scales. However, neither type of preoperative exercise added to the degree of improvement after surgery at any of the postoperative evaluations.

  3. Active experiments and single ion motion in the magnetotail

    NASA Astrophysics Data System (ADS)

    Rothwell, P. L.; Yates, G. K.

    1983-07-01

    Analytic solutions to the Lorentz equation which indicate that the magnetic field in the plasma sheet focuses selected ions from the plasma sheet boundaries on the neutral sheet are obtained. The kinetic energy of these ions usually exceeds the threshold energy required for the ion tearing mode instability. Two active experiments based on this effect are proposed. Heavy ions injected towards dusk on the plasma sheet boundary would become focused on the neutral sheet and perhaps trigger the ion tearing mode. A boundary perturbation, such as a thermal chemical release, that locally enhances the boundary turbulence level could be introduced, causing sufficient ksq = 1 ions to be focused on the neutral sheet to trigger the ion tearing mode.

  4. Aerobic training modulates T cell activation in elderly women with knee osteoarthritis.

    PubMed

    Gomes, W F; Lacerda, A C R; Brito-Melo, G E A; Fonseca, S F; Rocha-Vieira, E; Leopoldino, A A O; Amorim, M R; Mendonça, V A

    2016-01-01

    Osteoarthritis of the knee (kOA) is a disease that mainly affects the elderly and can lead to major physical and functional limitations. However, the specific effects of walking, particularly on the immune system, are unknown. Therefore, this study aimed to analyze the effect of 12 weeks of walking (3×/week) on the leukocyte profile and quality of life (QL) of elderly women with kOA. Sixteen women (age: 67±4 years, body mass index: 28.07±4.16 kg/m2) participated in a walking program. The variables were assessed before and after 12 weeks of training with a progressively longer duration (30-55 min) and higher intensity (72-82% of HRmax determined using a graded incremental treadmill test). The QL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), and blood samples were collected for analysis with a cell counter and the San Fac flow cytometer. Walking training resulted in a 47% enhancement of the self-reported QL (P<0.05) and a 21% increase in the VO2max (P<0.0001) in elderly women with kOA. Furthermore, there was a reduction in CD4+ cells (pre=46.59±7%, post=44.58±9%, P=0.0189) and a higher fluorescence intensity for CD18+CD4+ (pre=45.30±10, post=64.27±33, P=0.0256) and CD18+CD8+ (pre=64.2±27, post=85.02±35, P=0.0130). In conclusion, the walking program stimulated leukocyte production, which may be related to the immunomodulatory effect of exercise. Walking also led to improvements in the QL and physical performance in elderly women with kOA.

  5. Aerobic training modulates T cell activation in elderly women with knee osteoarthritis

    PubMed Central

    Gomes, W.F.; Lacerda, A.C.R.; Brito-Melo, G.E.A.; Fonseca, S.F.; Rocha-Vieira, E.; Leopoldino, A.A.O.; Amorim, M.R.; Mendonça, V.A.

    2016-01-01

    Osteoarthritis of the knee (kOA) is a disease that mainly affects the elderly and can lead to major physical and functional limitations. However, the specific effects of walking, particularly on the immune system, are unknown. Therefore, this study aimed to analyze the effect of 12 weeks of walking (3×/week) on the leukocyte profile and quality of life (QL) of elderly women with kOA. Sixteen women (age: 67±4 years, body mass index: 28.07±4.16 kg/m2) participated in a walking program. The variables were assessed before and after 12 weeks of training with a progressively longer duration (30–55 min) and higher intensity (72–82% of HRmax determined using a graded incremental treadmill test). The QL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), and blood samples were collected for analysis with a cell counter and the San Fac flow cytometer. Walking training resulted in a 47% enhancement of the self-reported QL (P<0.05) and a 21% increase in the VO2max (P<0.0001) in elderly women with kOA. Furthermore, there was a reduction in CD4+ cells (pre=46.59±7%, post=44.58±9%, P=0.0189) and a higher fluorescence intensity for CD18+CD4+ (pre=45.30±10, post=64.27±33, P=0.0256) and CD18+CD8+ (pre=64.2±27, post=85.02±35, P=0.0130). In conclusion, the walking program stimulated leukocyte production, which may be related to the immunomodulatory effect of exercise. Walking also led to improvements in the QL and physical performance in elderly women with kOA. PMID:27828665

  6. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... scanners can perform the exam without stopping.) A computer makes several images of the body area. These ...

  7. Knee pain (image)

    MedlinePlus

    ... front of the knee can be due to bursitis, arthritis, or softening of the patella cartilage as ... knee. Overall knee pain can be due to bursitis, arthritis, tears in the ligaments, osteoarthritis of the ...

  8. Knee joint replacement

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002974.htm Knee joint replacement To use the sharing features on this page, please enable JavaScript. Knee joint replacement is a surgery to replace a knee ...

  9. Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors.

    PubMed

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

    2016-03-24

    The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2-30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available.

  10. Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors

    PubMed Central

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J. M.

    2016-01-01

    The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2–30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available. PMID:27023543

  11. Parkinson-Related Changes of Activation in Visuomotor Brain Regions during Perceived Forward Self-Motion

    PubMed Central

    van der Hoorn, Anouk; Renken, Remco J.; Leenders, Klaus L.; de Jong, Bauke M.

    2014-01-01

    Radial expanding optic flow is a visual consequence of forward locomotion. Presented on screen, it generates illusionary forward self-motion, pointing at a close vision-gait interrelation. As particularly parkinsonian gait is vulnerable to external stimuli, effects of optic flow on motor-related cerebral circuitry were explored with functional magnetic resonance imaging in healthy controls (HC) and patients with Parkinson’s disease (PD). Fifteen HC and 22 PD patients, of which 7 experienced freezing of gait (FOG), watched wide-field flow, interruptions by narrowing or deceleration and equivalent control conditions with static dots. Statistical parametric mapping revealed that wide-field flow interruption evoked activation of the (pre-)supplementary motor area (SMA) in HC, which was decreased in PD. During wide-field flow, dorsal occipito-parietal activations were reduced in PD relative to HC, with stronger functional connectivity between right visual motion area V5, pre-SMA and cerebellum (in PD without FOG). Non-specific ‘changes’ in stimulus patterns activated dorsolateral fronto-parietal regions and the fusiform gyrus. This attention-associated network was stronger activated in HC than in PD. PD patients thus appeared compromised in recruiting medial frontal regions facilitating internally generated virtual locomotion when visual motion support falls away. Reduced dorsal visual and parietal activations during wide-field optic flow in PD were explained by impaired feedforward visual and visuomotor processing within a magnocellular (visual motion) functional chain. Compensation of impaired feedforward processing by distant fronto-cerebellar circuitry in PD is consistent with motor responses to visual motion stimuli being either too strong or too weak. The ‘change’-related activations pointed at covert (stimulus-driven) attention. PMID:24755754

  12. Generalized analysis of thermally activated domain-wall motion in Co/Pt multilayers

    NASA Astrophysics Data System (ADS)

    Emori, Satoru; Umachi, Chinedum K.; Bono, David C.; Beach, Geoffrey S. D.

    2015-03-01

    Thermally activated domain-wall (DW) motion driven by magnetic field and electric current is investigated experimentally in out-of-plane magnetized Pt(Co/Pt)3 multilayers. We directly extract the thermal activation energy barrier for DW motion and observe the dynamic regimes of creep, depinning, and viscous flow. Further analysis reveals that the activation energy must be corrected with a factor dependent on the Curie temperature, and we derive a generalized Arrhenius-like equation governing thermally activated motion. By using this generalized equation, we quantify the efficiency of current-induced spin torque in assisting DW motion. Current produces no effect aside from Joule heating in the multilayer with 7-Å thick Co layers, whereas it generates a finite spin torque on DWs in the multilayer with atomically thin 3-Å Co layers. These findings suggest that conventional spin-transfer torques from in-plane spin-polarized current do not drive DWs in ultrathin Co/Pt multilayers.

  13. Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Choi, Jang-Hwan; Maier, Andreas; Berger, Martin; Fahrig, Rebecca

    2014-03-01

    We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

  14. Soft tissue artifact compensation in knee kinematics by multi-body optimization: Performance of subject-specific knee joint models.

    PubMed

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2015-11-05

    Soft tissue artifact (STA) distort marker-based knee kinematics measures and make them difficult to use in clinical practice. None of the current methods designed to compensate for STA is suitable, but multi-body optimization (MBO) has demonstrated encouraging results and can be improved. The goal of this study was to develop and validate the performance of knee joint models, with anatomical and subject-specific kinematic constraints, used in MBO to reduce STA errors. Twenty subjects were recruited: 10 healthy and 10 osteoarthritis (OA) subjects. Subject-specific knee joint models were evaluated by comparing dynamic knee kinematics recorded by a motion capture system (KneeKG™) and optimized with MBO to quasi-static knee kinematics measured by a low-dose, upright, biplanar radiographic imaging system (EOS(®)). Errors due to STA ranged from 1.6° to 22.4° for knee rotations and from 0.8 mm to 14.9 mm for knee displacements in healthy and OA subjects. Subject-specific knee joint models were most effective in compensating for STA in terms of abduction-adduction, inter-external rotation and antero-posterior displacement. Root mean square errors with subject-specific knee joint models ranged from 2.2±1.2° to 6.0±3.9° for knee rotations and from 2.4±1.1 mm to 4.3±2.4 mm for knee displacements in healthy and OA subjects, respectively. Our study shows that MBO can be improved with subject-specific knee joint models, and that the quality of the motion capture calibration is critical. Future investigations should focus on more refined knee joint models to reproduce specific OA knee geometry and physiology.

  15. Clinical evaluation of a mobile sensor-based gait analysis method for outcome measurement after knee arthroplasty.

    PubMed

    Calliess, Tilman; Bocklage, Raphael; Karkosch, Roman; Marschollek, Michael; Windhagen, Henning; Schulze, Mareike

    2014-08-28

    Clinical scores and motion-capturing gait analysis are today's gold standard for outcome measurement after knee arthroplasty, although they are criticized for bias and their ability to reflect patients' actual quality of life has been questioned. In this context, mobile gait analysis systems have been introduced to overcome some of these limitations. This study used a previously developed mobile gait analysis system comprising three inertial sensor units to evaluate daily activities and sports. The sensors were taped to the lumbosacral junction and the thigh and shank of the affected limb. The annotated raw data was evaluated using our validated proprietary software. Six patients undergoing knee arthroplasty were examined the day before and 12 months after surgery. All patients reported a satisfactory outcome, although four patients still had limitations in their desired activities. In this context, feasible running speed demonstrated a good correlation with reported impairments in sports-related activities. Notably, knee flexion angle while descending stairs and the ability to stop abruptly when running exhibited good correlation with the clinical stability and proprioception of the knee. Moreover, fatigue effects were displayed in some patients. The introduced system appears to be suitable for outcome measurement after knee arthroplasty and has the potential to overcome some of the limitations of stationary gait labs while gathering additional meaningful parameters regarding the force limits of the knee.

  16. The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing.

    PubMed

    Zorko, Martin; Nemec, Bojan; Babič, Jan; Lešnik, Blaz; Supej, Matej

    2015-09-01

    Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers' trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries. Key pointsThe change in the skis' waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions.The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries.The overall results of the abduction and internal

  17. The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing

    PubMed Central

    Zorko, Martin; Nemec, Bojan; Babič, Jan; Lešnik, Blaz; Supej, Matej

    2015-01-01

    Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers’ trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries. Key points The change in the skis’ waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions. The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries. The overall results of the abduction and

  18. Preclinical computational models: predictors of tibial insert damage patterns in total knee arthroplasty: AAOS exhibit selection.

    PubMed

    Morra, Edward A; Heim, Christine S; Greenwald, A Seth

    2012-09-19

    Computational models that predict clinical surface damage of the tibial insert during activities of daily living are emerging as powerful tools to assess the safety and efficacy of contemporary total knee arthroplasty designs. These models have the advantage of quickly determining the performance of new designs at low cost, and they allow direct comparison with the performance of classic, clinically successful designs. This study validated finite element and kinematic modeling predictions through comparison with preclinical physical testing results, damage patterns on retrieved tibial inserts, and clinically measured knee motion. There is a mounting body of evidence to support the role of computational modeling as a preclinical tool that enables the optimization of total knee arthroplasty designs and the auditing of component quality control before large-scale manufacturing is undertaken.

  19. Reverse Engineering Nature to Design Biomimetic Total Knee Implants.

    PubMed

    Varadarajan, Kartik Mangudi; Zumbrunn, Thomas; Rubash, Harry E; Malchau, Henrik; Muratoglu, Orhun K; Li, Guoan

    2015-10-01

    While contemporary total knee arthroplasty (TKA) provides tremendous clinical benefits, the normal feel and function of the knee is not fully restored. To address this, a novel design process was developed to reverse engineer "biomimetic" articular surfaces that are compatible with normal soft-tissue envelope and kinematics of the knee. The biomimetic articular surface is created by moving the TKA femoral component along in vivo kinematics of normal knees and carving out the tibial articular surface from a rectangular tibial block. Here, we describe the biomimetic design process. In addition, we utilize geometric comparisons and kinematic simulations to show that; (1) tibial articular surfaces of conventional implants are fundamentally incompatible with normal knee motion, and (2) the anatomic geometry of the biomimetic surface contributes directly to restoration of normal knee kinematics. Such biomimetic implants may enable us to achieve the long sought after goal of a "normal" knee post-TKA surgery.

  20. Prospective Real-Time Correction for Arbitrary Head Motion Using Active Markers

    PubMed Central

    Ooi, Melvyn B.; Krueger, Sascha; Thomas, William J.; Swaminathan, Srirama V.; Brown, Truman R.

    2011-01-01

    Patient motion during an MRI exam can result in major degradation of image quality, and is of increasing concern due to the aging population and its associated diseases. This work presents a general strategy for real-time, intra-image compensation of rigid-body motion that is compatible with multiple imaging sequences. Image quality improvements are established for structural brain MRI acquired during volunteer motion. A headband integrated with three active markers is secured to the forehead. Prospective correction is achieved by interleaving a rapid track-and-update module into the imaging sequence. For every repetition of this module, a short tracking pulse-sequence re-measures the marker positions; during head motion, the rigid-body transformation that realigns the markers to their initial positions is fed back to adaptively update the image-plane – maintaining it at a fixed orientation relative to the head – before the next imaging segment of k-space is acquired. In cases of extreme motion, corrupted lines of k-space are rejected and re-acquired with the updated geometry. High precision tracking measurements (0.01 mm) and corrections are accomplished in a temporal resolution (37 ms) suitable for real-time application. The correction package requires minimal additional hardware and is fully integrated into the standard user interface, promoting transferability to clinical practice. PMID:19488989

  1. Population variability in the Active Brownian Particle model of Daphnia motions

    NASA Astrophysics Data System (ADS)

    Moss, Frank; Erdmann, Udo; Schimansky-Geier, Lutz; Ordmann, Anke

    2004-03-01

    Three characteristic motions of foraging biological agents are predicted by the Active Brownian Particle model [1]. These are random motions about the minimum of a central attracting potential, a bifurcation to bidirectional circular motions about the axis of symmetry of the potential, and a transition to vortex motion. All three can be observed in swarms of the zooplankton Daphnia swimming in light fields. Here we focus on the bidirectional circular motions in 2-D space [1]. The mean radii, as well as other characteristics of the paths, are determined by three strength parameters appropriate to individual Daphnia: energy uptake from the medium, metabolistic drain, and dissipation due to movement. It is shown that individual variability can be represented by distributions of these strength parameters. Conditions for which the experimental data are best described by the model are discussed. [1] U. Erdmann, W. Ebeling and V. S. Anishchenko, Excitation of rotational modes in two-dimensional systems of driven Brownian particles. Phys. Rev. E 65, 061106 (2002)

  2. Active contour-based visual tracking by integrating colors, shapes, and motions.

    PubMed

    Hu, Weiming; Zhou, Xue; Li, Wei; Luo, Wenhan; Zhang, Xiaoqin; Maybank, Stephen

    2013-05-01

    In this paper, we present a framework for active contour-based visual tracking using level sets. The main components of our framework include contour-based tracking initialization, color-based contour evolution, adaptive shape-based contour evolution for non-periodic motions, dynamic shape-based contour evolution for periodic motions, and the handling of abrupt motions. For the initialization of contour-based tracking, we develop an optical flow-based algorithm for automatically initializing contours at the first frame. For the color-based contour evolution, Markov random field theory is used to measure correlations between values of neighboring pixels for posterior probability estimation. For adaptive shape-based contour evolution, the global shape information and the local color information are combined to hierarchically evolve the contour, and a flexible shape updating model is constructed. For the dynamic shape-based contour evolution, a shape mode transition matrix is learnt to characterize the temporal correlations of object shapes. For the handling of abrupt motions, particle swarm optimization is adopted to capture the global motion which is applied to the contour in the current frame to produce an initial contour in the next frame.

  3. On the relationship between photospheric footpoint motions and coronal heating in solar active regions

    SciTech Connect

    Van Ballegooijen, A. A.; Asgari-Targhi, M.; Berger, M. A.

    2014-05-20

    Coronal heating theories can be classified as either direct current (DC) or alternating current (AC) mechanisms, depending on whether the coronal magnetic field responds quasi-statically or dynamically to the photospheric footpoint motions. In this paper we investigate whether photospheric footpoint motions with velocities of 1-2 km s{sup –1} can heat the corona in active regions, and whether the corona responds quasi-statically or dynamically to such motions (DC versus AC heating). We construct three-dimensional magnetohydrodynamic models for the Alfvén waves and quasi-static perturbations generated within a coronal loop. We find that in models where the effects of the lower atmosphere are neglected, the corona responds quasi-statically to the footpoint motions (DC heating), but the energy flux into the corona is too low compared to observational requirements. In more realistic models that include the lower atmosphere, the corona responds more dynamically to the footpoint motions (AC heating) and the predicted heating rates due to Alfvén wave turbulence are sufficient to explain the observed hot loops. The higher heating rates are due to the amplification of Alfvén waves in the lower atmosphere. We conclude that magnetic braiding is a highly dynamic process.

  4. Analysis of in vitro and in vivo function of total knee replacements using dynamic contact models

    NASA Astrophysics Data System (ADS)

    Zhao, Dong

    Despite the high incidence of osteoarthritis in human knee joint, its causes remain unknown. Total knee replacement (TKR) has been shown clinically to be effective in restoring the knee function. However, wear of ultra-high molecular weight polyethylene has limited the longevity of TKRs. To address these important issues, it is necessary to investigate the in vitro and in vivo function of total knee replacements using dynamic contact models. A multibody dynamic model of an AMTI knee simulator was developed. Incorporating a wear prediction model into the contact model based on elastic foundation theory enables the contact surface to take into account creep and wear during the dynamic simulation. Comparisons of the predicted damage depth, area, and volume lost with worn retrievals from a physical machine were made to validate the model. In vivo tibial force distributions during dynamic and high flexion activities were investigated using the dynamic contact model. In vivo medial and lateral contact forces experienced by a well-aligned instrumented knee implant, as well as upper and lower bounds on contact pressures for a variety of activities were studied. For all activities, the predicted medial and lateral contact forces were insensitive to the selected material model. For this patient, the load split during the mid-stance phase of gait and during stair is more equal than anticipated. The external knee adduction torque has been proposed as a surrogate measure for medial compartment load during gait. However, a direct link between these two quantities has not been demonstrated using in vivo measurement of medial compartment load. In vivo data collected from a subject with an instrumented knee implant were analyzed to evaluate this link. The subject performed five different overground gait motions (normal, fast, slow, wide, and toe out) while instrumented implant, video motion, and ground reaction data were simultaneously collected. The high correlation coefficient

  5. EFFECTS OF THE GENIUM MICROPROCESSOR KNEE SYSTEM ON KNEE MOMENT SYMMETRY DURING HILL WALKING

    PubMed Central

    Highsmith, M. Jason; Klenow, Tyler D.; Kahle, Jason T.; Wernke, Matthew M.; Carey, Stephanie L.; Miro, Rebecca M.; Lura, Derek J.

    2016-01-01

    Use of the Genium microprocessor knee (MPK) system reportedly improves knee kinematics during walking and other functional tasks compared to other MPK systems. This improved kinematic pattern was observed when walking on different hill conditions and at different speeds. Given the improved kinematics associated with hill walking while using the Genium, a similar improvement in the symmetry of knee kinetics is also feasible. The purpose of this study was to determine if Genium MPK use would reduce the degree of asymmetry (DoA) of peak stance knee flexion moment compared to the C-Leg MPK in transfemoral amputation (TFA) patients. This study used a randomized experimental crossover of TFA patients using Genium and C-Leg MPKs (n = 20). Biomechanical gait analysis by 3D motion tracking with floor mounted force plates of TFA patients ambulating at different speeds on 5° ramps was completed. Knee moment DoA was significantly different between MPK conditions in the slow and fast uphill as well as the slow and self-selected downhill conditions. In a sample of high-functioning TFA patients, Genium knee system accommodation and use improved knee moment symmetry in slow speed walking up and down a five degree ramp compared with C-Leg. Additionally, the Genium improved knee moment symmetry when walking downhill at comfortable speed. These results likely have application in other patients who could benefit from more consistent knee function, such as older patients and others who have slower walking speeds. PMID:28066523

  6. EFFECTS OF THE GENIUM MICROPROCESSOR KNEE SYSTEM ON KNEE MOMENT SYMMETRY DURING HILL WALKING.

    PubMed

    Highsmith, M Jason; Klenow, Tyler D; Kahle, Jason T; Wernke, Matthew M; Carey, Stephanie L; Miro, Rebecca M; Lura, Derek J

    2016-09-01

    Use of the Genium microprocessor knee (MPK) system reportedly improves knee kinematics during walking and other functional tasks compared to other MPK systems. This improved kinematic pattern was observed when walking on different hill conditions and at different speeds. Given the improved kinematics associated with hill walking while using the Genium, a similar improvement in the symmetry of knee kinetics is also feasible. The purpose of this study was to determine if Genium MPK use would reduce the degree of asymmetry (DoA) of peak stance knee flexion moment compared to the C-Leg MPK in transfemoral amputation (TFA) patients. This study used a randomized experimental crossover of TFA patients using Genium and C-Leg MPKs (n = 20). Biomechanical gait analysis by 3D motion tracking with floor mounted force plates of TFA patients ambulating at different speeds on 5° ramps was completed. Knee moment DoA was significantly different between MPK conditions in the slow and fast uphill as well as the slow and self-selected downhill conditions. In a sample of high-functioning TFA patients, Genium knee system accommodation and use improved knee moment symmetry in slow speed walking up and down a five degree ramp compared with C-Leg. Additionally, the Genium improved knee moment symmetry when walking downhill at comfortable speed. These results likely have application in other patients who could benefit from more consistent knee function, such as older patients and others who have slower walking speeds.

  7. MR-based motion correction for PET imaging using wired active MR microcoils in simultaneous PET-MR: Phantom study

    SciTech Connect

    Huang, Chuan; Brady, Thomas J.; El Fakhri, Georges; Ouyang, Jinsong; Ackerman, Jerome L.; Petibon, Yoann

    2014-04-15

    Purpose: Artifacts caused by head motion present a major challenge in brain positron emission tomography (PET) imaging. The authors investigated the feasibility of using wired active MR microcoils to track head motion and incorporate the measured rigid motion fields into iterative PET reconstruction. Methods: Several wired active MR microcoils and a dedicated MR coil-tracking sequence were developed. The microcoils were attached to the outer surface of an anthropomorphic{sup 18}F-filled Hoffman phantom to mimic a brain PET scan. Complex rotation/translation motion of the phantom was induced by a balloon, which was connected to a ventilator. PET list-mode and MR tracking data were acquired simultaneously on a PET-MR scanner. The acquired dynamic PET data were reconstructed iteratively with and without motion correction. Additionally, static phantom data were acquired and used as the gold standard. Results: Motion artifacts in PET images were effectively removed by wired active MR microcoil based motion correction. Motion correction yielded an activity concentration bias ranging from −0.6% to 3.4% as compared to a bias ranging from −25.0% to 16.6% if no motion correction was applied. The contrast recovery values were improved by 37%–156% with motion correction as compared to no motion correction. The image correlation (mean ± standard deviation) between the motion corrected (uncorrected) images of 20 independent noise realizations and static reference was R{sup 2} = 0.978 ± 0.007 (0.588 ± 0.010, respectively). Conclusions: Wired active MR microcoil based motion correction significantly improves brain PET quantitative accuracy and image contrast.

  8. Active vibration isolation of macro-micro motion stage disturbances using a floating stator platform

    NASA Astrophysics Data System (ADS)

    Zhang, Lufan; Long, Zhili; Cai, Jiandong; Liu, Yang; Fang, Jiwen; Wang, Michael Yu

    2015-10-01

    Macro-micro motion stage is mainly applied in microelectronics manufacturing to realize a high-acceleration, high-speed and nano-positioning motion. The high acceleration and nano-positioning accuracy would be influenced by the vibration of the motion stage. In the paper, a concept of floating stage is introduced in the macro-micro motion for isolating vibration disturbances. The design model of the floating stage is established and its theoretical analyses including natural frequency, transient and frequency response analyses are investigated, in order to demonstrate the feasibility of the floating stator platform as a vibration isolator for the macro-micro motion stage. Moreover, an optimal design of the floating stator is conducted and then verified by experiments. In order to characterize and quantify the performance of isolation obtained from the traditional fixed stator and the floating stator, the acceleration responses at different accelerations, speeds and displacements are measured in x, y and z directions. The theoretical and experimental analyses in time and frequency domains indicate that the floating stator platform is effective to actively isolate the vibration in the macro-micro motion stage. In macro-micro motion stage, high acceleration motion is provided by VCM. Vibration is induced from VCM, that is, VCM is a source system, the vibration response or force is felt by a receiver system. Generally, VCM is fixed on the base, which means that the base is the receiver system which absorbs or transfers the vibration. However, the vibration cannot completely disappear and the base vibration is inevitable. In the paper, a floated stator platform as isolation system is developed to decrease or isolate vibration between VCM and base. The floated stator platform consists of damper, stopper, floated lock, spring, limiter, sub base, etc. Unlike the traditional stator of VCM fixed on the base, the floated stator can be moved on the linear guide under vibration

  9. Biomechanical Analysis of the Effects of Bilateral Hinged Knee Bracing.

    PubMed

    Lee, Hangil; Ha, Dokyeong; Kang, Yeoun-Seung; Park, Hyung-Soon

    2016-01-01

    This research analyzed the effect of bilateral hinged knee braces on a healthy knee from a biomechanical frame in vivo. This was accomplished by fitting a knee brace with two customized wireless force/torque (F/T) sensors that could readily record force and torque during live motion, while the kinetics at the knee were computed using the inverse dynamics of the motion capture and force plate data. Four tasks to test the brace's effects were drop vertical jumping, pivoting, stop vertical jumping, and cutting. The results showed that the hinges in the knee brace can absorb up to 18% of the force and 2.7% of the torque at the knee during various athletic motions. Thus, the hinges demonstrated minimal effect in reducing the mechanical load on the knee. There were limitations concerning the consistency of the motions performed by the subjects during the trials and the influence of the other portions of the brace to evaluate the overall effectiveness of the brace as a whole. Future works may incorporate a fatigue protocol and injured subjects to better determine the effects of the brace. There is still a need for more research on the biomechanical influence of knee braces to develop safer and more effective products.

  10. Biomechanical Analysis of the Effects of Bilateral Hinged Knee Bracing

    PubMed Central

    Lee, Hangil; Ha, Dokyeong; Kang, Yeoun-Seung; Park, Hyung-Soon

    2016-01-01

    This research analyzed the effect of bilateral hinged knee braces on a healthy knee from a biomechanical frame in vivo. This was accomplished by fitting a knee brace with two customized wireless force/torque (F/T) sensors that could readily record force and torque during live motion, while the kinetics at the knee were computed using the inverse dynamics of the motion capture and force plate data. Four tasks to test the brace’s effects were drop vertical jumping, pivoting, stop vertical jumping, and cutting. The results showed that the hinges in the knee brace can absorb up to 18% of the force and 2.7% of the torque at the knee during various athletic motions. Thus, the hinges demonstrated minimal effect in reducing the mechanical load on the knee. There were limitations concerning the consistency of the motions performed by the subjects during the trials and the influence of the other portions of the brace to evaluate the overall effectiveness of the brace as a whole. Future works may incorporate a fatigue protocol and injured subjects to better determine the effects of the brace. There is still a need for more research on the biomechanical influence of knee braces to develop safer and more effective products. PMID:27379233

  11. Range of Motion Requirements for Upper-Limb Activities of Daily Living

    PubMed Central

    Walters, Lisa Smurr; Cowley, Jeffrey; Wilken, Jason M.; Resnik, Linda

    2016-01-01

    OBJECTIVE. We quantified the range of motion (ROM) required for eight upper-extremity activities of daily living (ADLs) in healthy participants. METHOD. Fifteen right-handed participants completed several bimanual and unilateral basic ADLs while joint kinematics were monitored using a motion capture system. Peak motions of the pelvis, trunk, shoulder, elbow, and wrist were quantified for each task. RESULTS. To complete all activities tested, participants needed a minimum ROM of −65°/0°/105° for humeral plane angle (horizontal abduction–adduction), 0°–108° for humeral elevation, −55°/0°/79° for humeral rotation, 0°–121° for elbow flexion, −53°/0°/13° for forearm rotation, −40°/0°/38° for wrist flexion–extension, and −28°/0°/38° for wrist ulnar–radial deviation. Peak trunk ROM was 23° lean, 32° axial rotation, and 59° flexion–extension. CONCLUSION. Full upper-limb kinematics were calculated for several ADLs. This methodology can be used in future studies as a basis for developing normative databases of upper-extremity motions and evaluating pathology in populations. PMID:26709433

  12. Examining the Magnetic Field Strength and the Horizontal and Vertical Motions in an Emerging Active Region

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Hsien; Chen, Yu-Che

    2016-03-01

    Earlier observational studies have used the time evolution of emerging magnetic flux regions at the photosphere to infer their subsurface structures, assuming that the flux structure does not change significantly over the near-surface layer. In this study, we test the validity of this assumption by comparing the horizontal and vertical motions of an emerging active region. The two motions would be correlated if the emerging structure is rigid. The selected active region (AR) NOAA 11645 is not embedded in detectable preexisting magnetic field. The observed horizontal motion is quantified by the separation of the two AR polarities and the width of the region. The vertical motion is derived from the magnetic buoyancy theory. Our results show that the separation of the polarities is fastest at the beginning with a velocity of {≈ }4 Mm hr^{-1} and decreases to ≤ 1 Mm hr^{-1} after the main growing phase of flux emergence. The derived thick flux-tube buoyant velocity is between 1 and 3 Mm hr^{-1}, while the thin flux-tube approximation results in an unreasonably high buoyant velocity, consistent with the expectation that the approximation is inappropriate at the surface layer. The observed horizontal motion is not found to directly correlate with either the magnetic field strength or the derived buoyant velocities. However, the percentage of the horizontally oriented fields and the temporal derivatives of the field strength and the buoyant velocity show some positive correlations with the separation velocity. The results of this study imply that the assumption that the emerging active region is the cross section of a rising flux tube whose structure can be considered rigid as it rises through the near-surface layer should be taken with caution.

  13. Predicting the effects of muscle activation on knee, thigh, and hip injuries in frontal crashes using a finite-element model with muscle forces from subject testing and musculoskeletal modeling.

    PubMed

    Chang, Chia-Yuan; Rupp, Jonathan D; Reed, Matthew P; Hughes, Richard E; Schneider, Lawrence W

    2009-11-01

    In a previous study, the authors reported on the development of a finite-element model of the midsize male pelvis and lower extremities with lower-extremity musculature that was validated using PMHS knee-impact response data. Knee-impact simulations with this model were performed using forces from four muscles in the lower extremities associated with two-foot bracing reported in the literature to provide preliminary estimates of the effects of lower-extremity muscle activation on knee-thigh-hip injury potential in frontal impacts. The current study addresses a major limitation of these preliminary simulations by using the AnyBody three-dimensional musculoskeletal model to estimate muscle forces produced in 35 muscles in each lower extremity during emergency one-foot braking. To check the predictions of the AnyBody Model, activation levels of twelve major muscles in the hip and lower extremities were measured using surface EMG electrodes on 12 midsize-male subjects performing simulated maximum and 50% of maximum braking in a laboratory seating buck. Comparisons between test results and the predictions of the AnyBody Model when it was used to simulate these same braking tests suggest that the AnyBody model appropriately predicts agonistic muscle activations but under predicts antagonistic muscle activations. Simulations of knee-to-knee-bolster impacts were performed by impacting the knees of the lower-extremity finite element model with and without the muscle forces predicted by the validated AnyBody Model. Results of these simulations confirm previous findings that muscle tension increases knee-impact force by increasing the effective mass of the KTH complex due to tighter coupling of muscle mass to bone. They also indicate that muscle activation preferentially couples mass distal to the hip, thereby accentuating the decrease in femur force from the knee to the hip. However, the reduction in force transmitted from the knee to the hip is offset by the increased force

  14. Surgery for osteoarthritis of the knee.

    PubMed

    Richmond, John C

    2013-02-01

    Although total knee replacement is an excellent treatment of end-stage osteoarthritis of the knee in the older (>65 years) population, many patients with less severe disease are significantly impacted by their symptoms and have failed to respond to less invasive treatment alternatives. For this group, there are several less invasive surgical alternatives, including arthroscopic meniscectomy, grafting of symptomatic areas of bone marrow lesions, unloading osteotomy, and unicompartmental knee replacement. Current total knee arthroplasty designs can be expected to survive 20 years or more in the older, less active population. New materials may extend that survivorship.

  15. Knee Injuries and Disorders

    MedlinePlus

    Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt ... your life. The most common disease affecting the knee is osteoarthritis. The cartilage in the knee gradually wears away, ...

  16. Direction of Biological Motion Affects Early Brain Activation: A Link with Social Cognition

    PubMed Central

    Pegna, Alan John; Gehring, Elise; Meyer, Georg; Del Zotto, Marzia

    2015-01-01

    A number of EEG studies have investigated the time course of brain activation for biological movement over this last decade, however the temporal dynamics of processing are still debated. Moreover, the role of direction of movement has not received much attention even though it is an essential component allowing us to determine the intentions of the moving agent, and thus permitting the anticipation of potential social interactions. In this study, we examined event-related responses (ERPs) in 15 healthy human participants to light point walkers and their scrambled counterparts, whose movements occurred either in the radial or in the lateral plane. Compared to scrambled motion (SM), biological motion (BM) showed an enhanced negativity between 210 and 360ms. A source localization algorithm (sLORETA) revealed that this was due to an increase in superior and middle temporal lobe activity. Regarding direction, we found that radial BM produced an enhanced P1 compared to lateral BM, lateral SM and radial SM. This heightened P1 was due to an increase in activity in extrastriate regions, as well as in superior temporal, medial parietal and medial prefrontal areas. This network is known to be involved in decoding the underlying intentionality of the movement and in the attribution of mental states. The social meaning signaled by the direction of biological motion therefore appears to trigger an early response in brain activity. PMID:26121591

  17. Coupling of postural activity with motion of a ship at sea.

    PubMed

    Varlet, Manuel; Bardy, Benoît G; Chen, Fu-Chen; Alcantara, Cristina; Stoffregen, Thomas A

    2015-05-01

    On land, body sway during stance becomes coupled with imposed oscillations of the illuminated environment or of the support surface. This coupling appears to have the function of stabilizing the body relative to the illuminated or inertial environment. In previous research, the stimulus has been limited to motion in a single axis. Little is known about our ability to couple postural activity with complex, multi-axis oscillations. On a ship at sea, we evaluated postural activity using measures of body movement, as such, and we separately evaluated a direct measure of coupling between body movement and ship motion. Participants were tested while facing fore-aft and athwartship. We compared postural activity between participants who had been seasick at the beginning of the voyage and those who had not. Coupling of postural activity with ship motion differed between body axes as a function of body orientation relative to the ship. In addition, coupling differed between participants who had been seasick at the beginning of the voyage and those who had not. We discuss the results in terms of implications for general theories of postural control, and for prediction of susceptibility to seasickness in individuals.

  18. Knee injuries account for the sports-related increased risk of knee osteoarthritis.

    PubMed

    Thelin, N; Holmberg, S; Thelin, A

    2006-10-01

    Increased risk of osteoarthritis has been found among athletes active in different kinds of sports. Knee injury is an established risk factor for knee osteoarthritis. In this population-based case-control study we investigated the risk of knee osteoarthritis with respect to sports activity and previous knee injuries. A total of 825 cases with x-ray-verified femorotibial osteoarthritis were identified at six hospitals in southern Sweden. The cases were matched (age, sex and residential area) with 825 controls from the general population. Mailed questionnaire data on sports activity for more than 1 year after the age of 16, knee injuries and confounding variables (weight, height, heredity, smoking and occupation) were collected and analyzed using logistic regression models. The response frequency was 89%. Among men knee osteoarthritis was related to soccer (odds ratio (OR) 1.6, 95% confidence interval (CI) 1.1-2.2), ice hockey (OR 1.9, 95% CI 1.2-3.0) and tennis (OR 2.0, 95% CI 1.1-3.8) but not to track and field sports, cross-country skiing, and orienteering. After adjustment for confounding variables soccer and ice hockey remained significantly related to knee osteoarthritis, but after adjustment for knee injuries no significant relation remained. The sports-related increased risk for knee osteoarthritis was explained by knee injuries.

  19. Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome

    PubMed Central

    Casabona, Antonino; Valle, Maria Stella; Pisasale, Mariangela; Pantò, Maria Rosita

    2012-01-01

    In this study, we assessed kinematics and viscoelastic features of knee joint in adults with Down syndrome (DS) by means of the Wartenberg pendulum test. This test allows the measuring of the kinematics of the knee joint during passive pendular motion of leg under the influence of gravity. In addition, by a combination of kinematic and anthropometric data, pendulum test provides estimates of joint viscoelastic properties by computing damping and stiffness coefficients. To monitor the occurrences of muscle activation, the surface electromyogram (EMG) of muscle rectus femoris was recorded. The experimental protocol was performed in a group of 10 adults with DS compared with 10 control adults without DS. Joint motion amplitude, velocity, and acceleration of the leg during the first knee flexion significantly decreased in persons with DS with respect to those without DS. This behavior was associated with the activation of rectus femoris in subjects with DS that resulted in increasing of joint resistance shortly after the onset of the first leg flexion. The EMG bursts mostly occurred between 50 and 150 ms from the leg flexion onset. During the remaining cycles of pendular motion, persons with DS exhibited passive leg oscillations with low tonic EMG activity and reduced damping coefficient compared with control subjects. These results suggest that adults with DS might perform preprogrammed contractions to increase joint resistance and compensate for inherent joint instability occurring for quick and unpredictable perturbations. The reduction of damping coefficients observed during passive oscillations could be a predictor of muscle hypotonia. PMID:22995394

  20. [Chronic knee joint discomfort].

    PubMed

    Wittke, R

    2005-06-23

    Chronic pain in the knee joint is frequently a sign of arthrosis in adults. This must be clearly differentiated from other knee problems. Patellofemoral stress syndrome (occurs mostly in young people) and arthritis with effusion in the knee joint after long and mostly unusual stress also allow only a reduced function of the knee joint. However, even when the knee joint is still fully functional, chronic problems could already exist: For example, for joggers, iliotibial band friction syndrome (runner's knee) or after high unphysiological stress, patellar tendinopathy (jumper's knee). These must be differentiated from pes anserinus syndrome and a plica mediopatellaris.

  1. Activity-Modifying Behaviour Mediates the Relationship between Pain Severity and Activity Limitations among Adults with Emergent Knee Pain.

    PubMed

    Hamilton, Clayon B; Maly, Monica R; Clark, Jessica M; Speechley, Mark; Petrella, Robert J; Chesworth, Bert M

    2013-01-01

    Objectif : Déterminer si un comportement modifiant les activités peut influer sur la relation entre la sévérité d'une douleur au genou et chacune des fonctions physiques et la qualité de vie associée au genou. Méthode : Au total, 105 participants avec douleur au genou interne et aucun diagnostic d'arthrose du genou (âge moyen de 52,2 ans; écart type de 6,7 ans) ont rempli deux questionnaires d'auto-évaluation. Le questionnaire pour déterminer les symptômes au genou (Questionnaire to Identify Knee Symptoms, QuIKS) visait à évaluer les comportements qui modifient les activités; le pointage obtenu au questionnaire sur les blessures au genou et l'arthrose (Knee injury and Osteoarthritis Outcome Score, KOOS) permettait d'évaluer la sévérité de la douleur, la fonction physique et la qualité de vie associée au genou. Une analyse de médiation simple a été réalisée à l'aide d'un modèle de régression linéaire. Résultats : Le coefficient de régression non normalisé (±erreur type) du comportement modifiant l'activité a révélé une réduction partielle de l'effet de la sévérité de la douleur sur la fonction physique (0,31±0,09, p<0,001) et sur la qualité de vie associée au genou (0,24±0,07, p<0,001). Après la mise en place d'un comportement modifiant l'activité, la variation de la fonction physique causée par la douleur est passée de 45 % à 15 %, et la variation dans la qualité de vie associée au genou provoquée par la douleur est passée de 64 % à 25 %. Conclusion : Un comportement qui modifie l'activité réduit partiellement la relation entre la sévérité de la douleur et la fonction physique et entre la sévérité de la douleur et la qualité de vie associée au genou. On a donc recours à une modification de l'activité chez les personnes aux prises avec une douleur émergente au genou, et cette modification pourrait contrer les effets de la douleur au genou sur la fonction physique et sur la qualité de

  2. The cerebral activity related to the visual perception of forward motion in depth.

    PubMed

    de Jong, B M; Shipp, S; Skidmore, B; Frackowiak, R S; Zeki, S

    1994-10-01

    We have used the technique of PET to chart the areas of human cerebral cortex specifically responsive to an optical flow stimulus simulating forward motion in depth over a flat horizontal surface. The optical flow display contained about 2000 dots accelerating in radial directions away from the focus of expansion, which subjects fixated at the centre of the display monitor. Dots remained of constant size, but their density decreased from the horizon, lying across the middle of the screen, to the foreground at the lower screen margin; the top half of the display was void. For the control stimulus the dot motions were randomized, removing any sensation of motion in depth and diminishing the impression of a flat terrain. Comparison of the regional cerebral blood flow (rCBF) elicited by the optical flow and control stimuli was thus intended to reveal any area selectively responsive to the radial velocity field that is characteristic of optical flow in its simplest natural form. Six subjects were scanned, and analysed as a group. Four subjects were analysed as individuals, their PET data being co-registered with MRIs of the cerebrum to localize rCBF changes to individual gyri and sulci. There were three main areas of activation associated with optical flow: the dorsal cuneus (area V3) and the latero-posterior precuneus (or superior parietal lobe) in the right hemisphere, and the occipito-temporal ventral surface, in the region of the fusiform gyrus, in both hemispheres. There was no significant activation of V1/V2, nor of V5. These results show that higher stages of motion take place in both the 'dorsal' and 'ventral' visual pathways, as these are commonly conceived, and that both may be fed by area V3. The information potentially derivable from optical flow concerns the direction of heading, and the layout of the visual environment, a form of three-dimensional structure-from-motion. The perceptual division of labour between the various activated areas cannot be

  3. Automatic active space selection for the similarity transformed equations of motion coupled cluster method

    NASA Astrophysics Data System (ADS)

    Dutta, Achintya Kumar; Nooijen, Marcel; Neese, Frank; Izsák, Róbert

    2017-02-01

    An efficient scheme for the automatic selection of an active space for similarity transformed equations of motion (STEOM) coupled cluster method is proposed. It relies on state averaged configuration interaction singles (CIS) natural orbitals and makes it possible to use STEOM as a black box method. The performance of the new scheme is tested for singlet and triplet valence, charge transfer, and Rydberg excited states.

  4. Biomechanics of hyperflexion and kneeling before and after total knee arthroplasty.

    PubMed

    Lee, Thay Q

    2014-06-01

    The capacity to perform certain activities is frequently compromised after total knee arthroplasty (TKA) due to a functional decline resulting from decreased range of motion and a diminished ability to kneel. In this manuscript, the current biomechanical understanding of hyperflexion and kneeling before and after TKA will be discussed. Patellofemoral and tibiofemoral joint contact area, contact pressure, and kinematics were evaluated in cadaveric studies using a Tekscan pressure measuring system and Microscribe. Testing was performed on intact knees and following cruciate retaining and posterior stabilized TKA at knee flexion angles of 90°, 105°, 120°, and 135°. Three loading conditions were used to simulate squatting, double stance kneeling, and single stance kneeling. Following TKA with double stance kneeling, patellofemoral contact areas did not increase significantly at high knee flexion angle (135°). Kneeling resulted in tibial posterior translation and external rotation at all flexion angles. Moving from double to single stance kneeling tended to increase pressures in the cruciate retaining group, but decreased pressures in the posterior stabilized group. The cruciate retaining group had significantly larger contact areas than the posterior stabilized group, although no significant differences in pressures were observed comparing the two TKA designs (p < 0.05). If greater than 120° of postoperative knee range of motion can be achieved following TKA, then kneeling may be performed with less risk in the patellofemoral joint than was previously believed to be the case. However, kneeling may increase the likelihood of damage to cartilage and menisci in intact knees and after TKA increases in tibiofemoral contact area and pressures may lead to polyethyelene wear if performed on a chronic, repetitive basis.

  5. Antibacterial activity of joint fluid in cemented total-knee arthroplasty: an in vivo comparative study of polymethylmethacrylate with and without antibiotic loading.

    PubMed

    Ueng, Steve W N; Hsieh, Pang-Hsin; Shih, Hsin-Nung; Chan, Yi-Shan; Lee, Mel S; Chang, Yuhan

    2012-11-01

    The objective of this study was to evaluate the antibacterial activities of joint fluids of patients undergoing total-knee arthroplasty (TKA). Thirty patients who were scheduled for primary cemented TKA were enrolled in the study. The patients were grouped on the basis of whether the cement was without antibiotic loading (control group) or loaded with oxacillin (oxacillin group) or vancomycin (vancomycin group). Cefazolin was administered to every patient as the perioperative prophylactic antibiotic. Samples of joint fluids were collected from the knee joints at 8, 16, 24, 32, 40, and 48 h after prosthesis implantation. We assessed the bioactivities of the joint fluids against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The antibiotic contents of the joint fluid samples were further evaluated by using high-performance liquid chromatography. Against MSSA, all joint fluid samples exhibited at least 24 h of bacterial inhibition activity. The oxacillin (43.2 h ± 2 h) and vancomycin (40.8 h ± 1.8 h) groups exhibited significantly longer durations of antibacterial activities than the control group (28 h ± 1.3 h; P < 0.05). However, antibacterial activity against MRSA was observed only in the vancomycin group. In conclusion, cefazolin, which was administered as a prophylactic antibiotic in TKA, exhibited good ability for knee joint penetration and was sufficient to inhibit MSSA during its administration. The use of antibiotic-loaded cement can prolong the antibacterial activity of joint fluid in TKA. Further, vancomycin-loaded cement had antibacterial activity against MRSA superior to that of cement loaded with oxacillin or without antibiotic loading.

  6. Low contact stress (LCS) complete knee system in revision surgery.

    PubMed

    Lippe, Craig N; Crossett, Lawrence S

    2006-09-01

    Revision total knee arthroplasty (TKA) should offer the same benefits to patients as primary TKA. As in primary TKA, a main objective of revision TKA is to reduce pain and restore functional range of motion. There are several potential causes of total knee failure, but the principles of repairing each of them is similar. The long-term success of the low contact stress knee system in primary TKA is well established, and clinical evidence for revision TKA with the low contact stress knee is promising.

  7. Assessment of Knee Proprioception in the Anterior Cruciate Ligament Injury Risk Position in Healthy Subjects: A Cross-sectional Study.

    PubMed

    Mir, Seyed Mohsen; Talebian, Saeed; Naseri, Nasrin; Hadian, Mohammad-Reza

    2014-10-01

    [Purpose] Knee joint proprioception combines sensory input from a variety of afferent receptors that encompasses the sensations of joint position and motion. Poor proprioception is one of the risk factors of anterior cruciate ligament injury. Most studies have favored testing knee joint position sense in the sagittal plane and non-weight-bearing position. One of the most common mechanisms of noncontact anterior cruciate ligament injury is dynamic knee valgus. No study has measured joint position sense in a manner relevant to the mechanism of injury. Therefore, the aim of this study was to measure knee joint position sense in the noncontact anterior cruciate ligament injury risk position and normal condition. [Subjects and Methods] Thirty healthy male athletes participated in the study. Joint position sense was evaluated by active reproduction of the anterior cruciate ligament injury risk position and normal condition. The dominant knees of subjects were tested. [Results] The results showed less accurate knee joint position sense in the noncontact anterior cruciate ligament injury risk position rather than the normal condition. [Conclusion] The poorer joint position sense in non-contact anterior cruciate ligament injury risk position compared with the normal condition may contribute to the increased incidence of anterior cruciate ligament injury.

  8. Trunk biomechanics and its association with hip and knee kinematics in patients with and without patellofemoral pain.

    PubMed

    Nakagawa, Theresa Helissa; Maciel, Carlos Dias; Serrão, Fábio Viadanna

    2015-02-01

    Patellofemoral pain (PFP) is a common lower extremity condition observed in sports clinics. Recently, it has been suggested that trunk motion could affect hip and knee biomechanics in the frontal plane. Thus, the purpose of the study was compare trunk kinematics, strength and muscle activation between people with PFP and healthy participants. In addition, the associations among trunk biomechanics, hip and knee kinematics were analysed. Thirty people with PFP and thirty pain-free individuals participated. The peak ipsilateral trunk lean, hip adduction, and knee abduction were evaluated with an electromagnetic tracking system, and the surface electromyographic signals of the iliocostalis and external oblique muscle were recorded during single-leg squats. Trunk extension and trunk flexion with rotation isometric strength and side bridge tests were quantified using a handheld dynamometer. Compared with the control group, the PFP group demonstrated increased ipsilateral trunk lean, hip adduction and knee abduction (p = 0.02-0.04) during single-leg squat accompanied with decreased trunk isometric strength (p = < 0.001-0.009). There was no between-group difference in trunk muscle activation. Only in the control group, ipsilateral trunk lean was significantly correlated with hip adduction (r = -0.66) and knee abduction (r = 0.49); also, the side bridge test correlated with knee abduction (r = -0.51). Differences in trunk, hip and knee biomechanics were found in people with PFP. No relationship among trunk, hip and knee biomechanics was found in the PFP group, suggesting that people with PFP show different movement patterns compared to the control group.

  9. Metal hypersensitivity in total knee arthroplasty: revision surgery using a ceramic femoral component - a case report.

    PubMed

    Bergschmidt, Philipp; Bader, Rainer; Mittelmeier, Wolfram

    2012-03-01

    We present a case involving the revision of a total knee arthroplasty with a metal femoral component using a ceramic implant due to metal hypersensitivity. A 58-year-old female patient underwent total knee arthroplasty (TKA) with a standard metal bicondylar knee system. She suffered from persistent pain and strong limitations in her range of motion (ROM) associated with flexion during the early postoperative period. Arthroscopic arthrolysis of the knee joint and intensive active and passive physical treatment, in combination with a cortisone regime, temporarily increased the ROM and reduced pain. No signs of low grade infection or other causes of implant failure were evident. Histology of synovial tissue revealed lymphoplasmacellular fibrinous tissue, consistent with a type IV allergic reaction. Allergometry (skin reaction) revealed type IV hypersensitivity against nickel-II-sulfate and palladium chloride. Revision surgery of the metal components was performed with a cemented ceramic femoral component (same bicondylar design) and a cemented titanium alloy tibial component. Postoperative evaluations were performed 10days, and 3 and 12months after the revision surgery. There was an increased ROM in flexion to 90° at the 12month follow-up. No swelling or effusion was observed at all clinical examinations after the revision surgery. No pain at rest and moderate walking pain were evident. The presented case demonstrates that ceramic implants are a promising solution for patients suffering from hypersensitivity to metal ions in total knee arthroplasty.

  10. A comparison between dynamic implicit and explicit finite element simulations of the native knee joint.

    PubMed

    Naghibi Beidokhti, Hamid; Janssen, Dennis; Khoshgoftar, Mehdi; Sprengers, Andre; Perdahcioglu, Emin Semih; Van den Boogaard, Ton; Verdonschot, Nico

    2016-10-01

    The finite element (FE) method has been widely used to investigate knee biomechanics. Time integration algorithms for dynamic problems in finite element analysis can be classified as either implicit or explicit. Although previously both static/dynamic implicit and dynamic explicit method have been used, a comparative study on the outcomes of both methods is of high interest for the knee modeling community. The aim of this study is to compare static, dynamic implicit and dynamic explicit solutions in analyses of the knee joint to assess the prediction of dynamic effects, potential convergence problems, the accuracy and stability of the calculations, the difference in computational time, and the influence of mass-scaling in the explicit formulation. The heel-strike phase of fast, normal and slow gait was simulated for two different body masses in a model of the native knee. Our results indicate that ignoring the dynamic effect can alter joint motion. Explicit analyses are suitable to simulate dynamic loading of the knee joint in high-speed simulations, as this method offers a substantial reduction of the computational time with a similar prediction of cartilage stresses and meniscus strains. Although mass-scaling can provide even more gain in computational time, it is not recommended for high-speed activities, in which inertial forces play a significant role.

  11. Conical Euler simulation and active suppression of delta wing rocking motion

    NASA Technical Reports Server (NTRS)

    Lee, Elizabeth M.; Batina, John T.

    1990-01-01

    A conical Euler code was developed to study unsteady vortex-dominated flows about rolling highly-swept delta wings, undergoing either forced or free-to-roll motions including active roll suppression. The flow solver of the code involves a multistage Runge-Kutta time-stepping scheme which uses a finite volume spatial discretization of the Euler equations on an unstructured grid of triangles. The code allows for the additional analysis of the free-to-roll case, by including the rigid-body equation of motion for its simultaneous time integration with the governing flow equations. Results are presented for a 75 deg swept sharp leading edge delta wing at a freestream Mach number of 1.2 and at alpha equal to 10 and 30 deg angle of attack. A forced harmonic analysis indicates that the rolling moment coefficient provides: (1) a positive damping at the lower angle of attack equal to 10 deg, which is verified in a free-to-roll calculation; (2) a negative damping at the higher angle of attack equal to 30 deg at the small roll amplitudes. A free-to-roll calculation for the latter case produces an initially divergent response, but as the amplitude of motion grows with time, the response transitions to a wing-rock type of limit cycle oscillation. The wing rocking motion may be actively suppressed, however, through the use of a rate-feedback control law and antisymmetrically deflected leading edge flaps. The descriptions of the conical Euler flow solver and the free-to-roll analysis are presented. Results are also presented which give insight into the flow physics associated with unsteady vortical flows about forced and free-to-roll delta wings, including the active roll suppression of this wing-rock phenomenon.

  12. Cryotherapy impairs knee joint position sense.

    PubMed

    Oliveira, R; Ribeiro, F; Oliveira, J

    2010-03-01

    The effects of cryotherapy on joint position sense are not clearly established; however it is paramount to understand its impact on peripheral feedback to ascertain the safety of using ice therapy before resuming exercise on sports or rehabilitation settings. Thus, the aim of the present study was to determine the effects of cryotherapy, when applied over the quadriceps and over the knee joint, on knee position sense. This within-subjects repeated-measures study encompassed fifteen subjects. Knee position sense was measured by open kinetic chain technique and active positioning at baseline and after cryotherapy application. Knee angles were determined by computer analysis of the videotape images. Twenty-minute ice bag application was applied randomly, in two sessions 48 h apart, over the quadriceps and the knee joint. The main effect for cryotherapy application was significant (F (1.14)=7.7, p=0.015) indicating an increase in both absolute and relative angular errors after the application. There was no significant main effect for the location of cryotherapy application, indicating no differences between the application over the quadriceps and the knee joint. In conclusion, cryotherapy impairs knee joint position sense in normal knees. This deleterious effect is similar when cryotherapy is applied over the quadriceps or the knee joint.

  13. Sagittal knee joint kinematics and energetics in response to different landing heights and techniques.

    PubMed

    Yeow, C H; Lee, P V S; Goh, J C H

    2010-03-01

    Single-leg and double-leg landing techniques are common athletic maneuvers typically performed from various landing heights during intensive sports activities. However, it is still unclear how the knee joint responds in terms of kinematics and energetics to the combined effects of different landing heights and techniques. We hypothesized that the knee displays greater flexion angles and angular velocities, joint power and work in response to the larger peak ground reaction force from 0.6-m height, compared to 0.3-m height. We further hypothesized that the knee exhibits elevated flexion angles and angular velocities, joint power and work during double-leg landing, relative to single-leg landing. Ground reaction force, knee joint kinematics and energetics data were obtained from 10 subjects performing single-leg and double-leg landing from 0.3-m to 0.6-m heights, using motion-capture system and force-plates. Higher peak ground reaction force (p<0.05) was observed during single-leg landing and/or at greater landing height. We found greater knee flexion angles and angular velocities (p<0.05) during double-leg landing and/or at greater landing height. Elevated knee joint power and work were noted (p<0.05) during double-leg landing and/or at greater landing height. The knee joint is able to respond more effectively in terms of kinematics and energetics to a larger landing impact from an elevated height during double-leg landing, compared to single-leg landing. This allows better shock absorption and thus minimizes the risk of sustaining lower extremity injuries.

  14. Convergence in full motion video processing, exploitation, and dissemination and activity based intelligence

    NASA Astrophysics Data System (ADS)

    Phipps, Marja; Lewis, Gina

    2012-06-01

    Over the last decade, intelligence capabilities within the Department of Defense/Intelligence Community (DoD/IC) have evolved from ad hoc, single source, just-in-time, analog processing; to multi source, digitally integrated, real-time analytics; to multi-INT, predictive Processing, Exploitation and Dissemination (PED). Full Motion Video (FMV) technology and motion imagery tradecraft advancements have greatly contributed to Intelligence, Surveillance and Reconnaissance (ISR) capabilities during this timeframe. Imagery analysts have exploited events, missions and high value targets, generating and disseminating critical intelligence reports within seconds of occurrence across operationally significant PED cells. Now, we go beyond FMV, enabling All-Source Analysts to effectively deliver ISR information in a multi-INT sensor rich environment. In this paper, we explore the operational benefits and technical challenges of an Activity Based Intelligence (ABI) approach to FMV PED. Existing and emerging ABI features within FMV PED frameworks are discussed, to include refined motion imagery tools, additional intelligence sources, activity relevant content management techniques and automated analytics.

  15. A Novel Methodology for the Simulation of Athletic Tasks on Cadaveric Knee Joints with Respect to In Vivo Kinematics

    PubMed Central

    Bates, Nathaniel A.; Nesbitt, Rebecca J.; Shearn, Jason T.; Myer, Gregory D.; Hewett, Timothy E.

    2015-01-01

    Six degree of freedom (6-DOF) robotic manipulators have simulated clinical tests and gait on cadaveric knees to examine knee biomechanics. However, these activities do not necessarily emulate the kinematics and kinetics that lead to anterior cruciate ligament (ACL) rupture. The purpose of this study was to determine the techniques needed to derive reproducible, in vitro simulations from in vivo skin-marker kinematics recorded during simulated athletic tasks. Input of raw, in vivo, skin-marker-derived motion capture kinematics consistently resulted in specimen failure. The protocol described in this study developed an in-depth methodology to adapt in vivo kinematic recordings into 6-DOF knee motion simulations for drop vertical jumps and sidestep cutting. Our simulation method repeatably produced kinetics consistent with vertical ground reaction patterns while preserving specimen integrity. Athletic task simulation represents an advancement that allows investigators to examine ACL-intact and graft biomechanics during motions that generate greater kinetics, and the athletic tasks are more representative of documented cases of ligament rupture. Establishment of baseline functional mechanics within the knee joint during athletic tasks will serve to advance the prevention, repair and rehabilitation of ACL injuries. PMID:25869454

  16. Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements.

    PubMed

    Siu, Aaron; Schinkel-Ivy, Alison; Drake, Janessa Dm

    2016-10-01

    To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.

  17. Early active motion protocol following open reduction internal fixation of the scaphoid: A pilot study.

    PubMed

    Dunn, J-C; Kusnezov, N; Fares, A; Buccino, Z; Esquivel, D; Mitchell, J

    2017-02-01

    Scaphoid fractures are common injuries which traditionally have been treated with long periods of immobilization even after open reduction and internal fixation (ORIF). The purpose of this pilot investigation was two-fold: 1) describe a precise postoperative Early Active Motion (EAM) rehabilitation protocol following ORIF of scaphoid fractures and 2) record the outcomes of the EAM protocol. Eight consecutive patients having undergone ORIF of the scaphoid were enrolled in the EAM and followed for a minimum of 1 year. At 12 weeks, Disabilities of the Arm Shoulder and Hand (DASH) score, Mayo Wrist score, and range of motion values were obtained. At 1 year, a telephone survey was conducted and several data points were obtained including DASH and Mayo Wrist score, number of push-ups, satisfaction with surgery and ability to remain on active duty. All 8 patients were male, on active duty, with an average age of 26 years. Two patients used tobacco products and none had major health problems. All patients completed the EAM protocol and obtained CT; all CT exams demonstrated healing at 8 weeks. At 12 weeks postoperatively, the average DASH score was 8.8±16 (range: 0-47.5), Mayo wrist score was 88±10 (range: 75-100) and range of motion nearly symmetrical. At a mean final follow-up of 15.4 months postoperatively, the average DASH score was 1.1±1.7 (Range: 0-4.5), Mayo wrist score was 97.5±4 (range 90-100), average number of push-ups was 57 (40-70) at the prior Army Physical Fitness Test. All patients were satisfied with surgery and all remained on active duty at 1 year. There were no reported complications. The EAM protocol following scaphoid fracture ORIF is safe and effective. The EAM can reliably return patients back to high demand activity earlier than a traditional protocol.

  18. Anterior knee pain and cold knees: a possible association in women.

    PubMed

    Selfe, James; Sutton, Chris; Hardaker, Natalie J; Greenhalgh, Sue; Karki, Anne; Dey, Paola

    2010-10-01

    Abnormal reactions to environmental cold have been observed in some patients with Anterior Knee Pain (AKP). The aims of this study were to investigate whether palpation of the knee could classify patients into those with and those without cold knees; whether this classification could be objectively validated using thermal imaging; whether the cold and not cold knee groups varied in response to a cold stress test and in patient-reported measures. Fifty eight patients were recruited; palpation classified them into cold and not cold groups. Twenty-one (36%) patients were classified as having a cold knee by palpation: fourteen (36%) females and seven males (37%). Preliminary analysis suggested gender might be an effect modifier and the number of men was small, therefore the analysis focussed on females. Women with cold knees had a significantly smaller patellar skin fold, lower levels of activity and worse scores on the MFIQ, there also appeared to be an association with a traumatic onset. Women with cold knees were more likely to report cold weather affected their knees and they preferred a hot water bottle compared to an ice-pack on their knee; there was also a trend towards having to wear extra tights/long johns in the winter. This study has helped to define a clinical profile for a group of females with AKP and cold knees. This group appears to demonstrate a mild form of Reflex Sympathetic Dystrophy.

  19. Ice motion and seismic activity on a steep temporate glacier tongue

    NASA Astrophysics Data System (ADS)

    Dalban Canassy, Pierre; Faillettaz, Jerome; Funk, Martin

    2010-05-01

    Ice motion and seismic activity on a steep temporate glacier (Triftgletscher, Bernese Alps, Switzerland) Pierre Dalban Canassy*, Jerome Faillettaz* and Martin Funk* * Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, CH-8092 Zurich, Switzerland (dalban@vaw.baug.ethz.ch) In the last 15 years Triftgletscher (Bernese Alps, Switzerland) has substantially retreated (several hundreds of meters) from the riegel and a proglacial lake containing 6.106 m3 water has been formed in the glacier forefield. Because of the glacier retreat, especially the thinning of the lower flat tongue, the stability of the steep section behind it is affected. The consequence is that the likelihood of large ice avalanches starting from the steep section will increase. The recent intensive glacier thinning in the lower tongue area of 6-10 m.a-1 has even worsened the situation because the runout path of the ice avalanches has become steeper. Ice avalanches with several millions of m3 triggering impulse waves by plunguing into the lake can be the consequence. The aim of our study is to improve the understanding of the mechanisms leading to such instabilities and to develop a predictive method based on both seismic and photogrammetric surveys. The seismic recording is performed with help of 3 geophones installed on the rock on both sides of the serac fall allowing a continuous record. We are able to highlight seismic events by applying an automatic detection procedure, to locate their sources and also to evaluate the released energy of each detected icequake. The most part of these events are due to crack openings and falls of ice chunks, but we could also isolate specific events corresponding to stick-slip motions. The latter seem to play a significant role in the destabilization of the ice mass and represent valuable precursors to break-off episodes. The 2D picture analysis is achieved by analysing photographs taken every day at the same time by an automatic camera installed in

  20. Impact of Physical Activity in Cardiovascular and Musculoskeletal Health: Can Motion Be Medicine?

    PubMed Central

    Curtis, Gannon L.; Chughtai, Morad; Khlopas, Anton; Newman, Jared M.; Khan, Rafay; Shaffiy, Shervin; Nadhim, Ali; Bhave, Anil; Mont, Michael A.

    2017-01-01

    Physical activity is a well-known therapeutic tool for various types of medical conditions, including vasculopathic diseases such as coronary artery disease, stroke, type 2 diabetes, and obesity. Additionally, increased physical activity has been proposed as a therapy to improve musculoskeletal health; however, there are conflicting reports about physical activity potentially leading to degenerative musculoskeletal disease, especially osteoarthritis (OA). Additionally, although physical activity is known to have its benefits, it is unclear as to what amount of physical activity is the most advantageous. Too much, as well as not enough exercise can have negative consequences. This could impact how physicians advise their patients about exercise intensity. Multiple studies have evaluated the effect of physical activity on various aspects of health. However, there is a paucity of systematic studies which review cardiovascular and musculoskeletal health as outcomes. Therefore, the purpose of this review was to assess how physical activity impacts these aspects of health. Specifically, we evaluated the effect of various levels of physical activity on: 1) cardiovascular and 2) musculoskeletal health. The review revealed that physical activity may decrease cardiovascular disease and improve OA symptoms, and therefore, motion can be considered a “medicine”. However, because heavy activity can potentially lead to increased OA risk, physicians should advise their patients that excessive activity can also potentially impact their health negatively, and should be done in moderation, until further study. PMID:28392856

  1. Is Lifelong Knee Joint Force from Work, Home, and Sport Related to Knee Osteoarthritis?

    PubMed Central

    Ratzlaff, Charles R.; Koehoorn, Mieke; Cibere, Jolanda; Kopec, Jacek A.

    2012-01-01

    Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the “cumulative peak force index”, a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA. PMID:22848225

  2. Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

    NASA Astrophysics Data System (ADS)

    Marshall, Wallace F.; Fung, Jennifer C.

    2016-04-01

    The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by unattached chromosomes, but that randomly directed active forces applied to the telomeres speed up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions.

  3. Predicting muscle activation patterns from motion and anatomy: modelling the skull of Sphenodon (Diapsida: Rhynchocephalia)

    PubMed Central

    Curtis, Neil; Jones, Marc E. H.; Evans, Susan E.; Shi, JunFen; O'Higgins, Paul; Fagan, Michael J.

    2010-01-01

    The relationship between skull shape and the forces generated during feeding is currently under widespread scrutiny and increasingly involves the use of computer simulations such as finite element analysis. The computer models used to represent skulls are often based on computed tomography data and thus are structurally accurate; however, correctly representing muscular loading during food reduction remains a major problem. Here, we present a novel approach for predicting the forces and activation patterns of muscles and muscle groups based on their known anatomical orientation (line of action). The work was carried out for the lizard-like reptile Sphenodon (Rhynchocephalia) using a sophisticated computer-based model and multi-body dynamics analysis. The model suggests that specific muscle groups control specific motions, and that during certain times in the bite cycle some muscles are highly active whereas others are inactive. The predictions of muscle activity closely correspond to data previously recorded from live Sphenodon using electromyography. Apparent exceptions can be explained by variations in food resistance, food size, food position and lower jaw motions. This approach shows considerable promise in advancing detailed functional models of food acquisition and reduction, and for use in other musculoskeletal systems where no experimental determination of muscle activity is possible, such as in rare, endangered or extinct species. PMID:19474084

  4. Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

    PubMed Central

    Marshall, Wallace F.; Fung, Jennifer C.

    2016-01-01

    The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by un-attached chromosomes, but that randomly-directed active forces applied to the telomeres speeds up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions. PMID:27046097

  5. Active breathing control (ABC): Determination and reduction of breathing-induced organ motion in the chest

    SciTech Connect

    Gagel, Bernd . E-mail: BGagel@UKAachen.de; Demirel, Cengiz M.P.; Kientopf, Aline; Pinkawa, Michael; Piroth, Marc; Stanzel, Sven; Breuer, Christian; Asadpour, Branka; Jansen, Thomas; Holy, Richard; Wildberger, Joachim E.; Eble, Michael J.

    2007-03-01

    Purpose: Extensive radiotherapy volumes for tumors of the chest are partly caused by interfractional organ motion. We evaluated the feasibility of respiratory observation tools using the active breathing control (ABC) system and the effect on breathing cycle regularity and reproducibility. Methods and Materials: Thirty-six patients with unresectable tumors of the chest were selected for evaluation of the ABC system. Computed tomography scans were performed at various respiratory phases starting at the same couch position without patient movement. Threshold levels were set at minimum and maximum volume during normal breathing cycles and at a volume defined as shallow breathing, reflecting the subjective maximal tolerable reduction of breath volume. To evaluate the extent of organ movement, 13 landmarks were considering using commercial software for image coregistration. In 4 patients, second examinations were performed during therapy. Results: Investigating the differences in a normal breathing cycle versus shallow breathing, a statistically significant reduction of respiratory motion in the upper, middle, and lower regions of the chest could be detected, representing potential movement reduction achieved through reduced breath volume. Evaluating interfraction reproducibility, the mean displacement ranged between 0.24 mm (chest wall/tracheal bifurcation) to 3.5 mm (diaphragm) for expiration and shallow breathing and 0.24 mm (chest wall) to 5.25 mm (diaphragm) for normal inspiration. Conclusions: By modifying regularity of the respiratory cycle through reduction of breath volume, a significant and reproducible reduction of chest and diaphragm motion is possible, enabling reduction of treatment planning margins.

  6. Respiratory Motion of The Heart and Positional Reproducibility Under Active Breathing Control

    SciTech Connect

    Jagsi, Reshma; Moran, Jean M.; Kessler, Marc L.; Marsh, Robin B. C; Balter, James M.; Pierce, Lori J. . E-mail: ljpierce@umich.edu

    2007-05-01

    Purpose: To reduce cardiotoxicity from breast radiotherapy (RT), innovative techniques are under investigation. Information about cardiac motion with respiration and positional reproducibility under active breathing control (ABC) is necessary to evaluate these techniques. Methods and Materials: Patients requiring loco-regional RT for breast cancer were scanned by computed tomography using an ABC device at various breath-hold states, before and during treatment. Ten patients were studied. For each patient, 12 datasets were analyzed. Mutual information-based regional rigid alignment was used to determine the magnitude and reproducibility of cardiac motion as a function of breathing state. For each scan session, motion was quantified by evaluating the displacement of a point along the left anterior descending artery (LAD) with respect to its position at end expiration. Long-term positional reproducibility was also assessed. Results: Displacement of the LAD was greatest in the inferior direction, moderate in the anterior direction, and lowest in the left-right direction. At shallow breathing states, the average displacement of LAD position was up to 6 mm in the inferior direction. The maximum displacement in any patient was 2.8 cm in the inferior direction, between expiration and deep-inspiration breath hold. At end expiration, the long-term reproducibility (SD) of the LAD position was 3 mm in the A-P, 6 mm in the S-I, and 4 mm in the L-R directions. At deep-inspiration breath hold, long-term reproducibility was 3 mm in the A-P, 7 mm in the S-I, and 3 mm in the L-R directions. Conclusions: These data demonstrate the extent of LAD displacement that occurs with shallow breathing and with deep-inspiration breath hold. This information may guide optimization studies considering the effects of respiratory motion and reproducibility of cardiac position on cardiac dose, both with and without ABC.

  7. Conceptualization of an exoskeleton Continuous Passive Motion(CPM) device using a link structure.

    PubMed

    Kim, Kyu-Jung; Kang, Min-Sung; Choi, Youn-Sung; Han, Jungsoo; Han, Changsoo

    2011-01-01

    This study is about developing an exoskeleton Continuous Passive Motion (CPM) with the same Range of Motion (ROM) and instant center of rotation as the human knee. The key feature in constructing a CPM is an accurate alignment with the human knee joint enabling it to deliver the same movements as the actual body on the CPM. In this research, we proposed an exoskeleton knee joint through kinematic interpretation, measured the knee joint torque generated while using a CPM and applied it to the device. Thus, this new exoskeleton type CPM will allow precise alignment with the human knee joint, and follow the same ROM as the human knee in any position.

  8. Extract the Relational Information of Static Features and Motion Features for Human Activities Recognition in Videos

    PubMed Central

    2016-01-01

    Both static features and motion features have shown promising performance in human activities recognition task. However, the information included in these features is insufficient for complex human activities. In this paper, we propose extracting relational information of static features and motion features for human activities recognition. The videos are represented by a classical Bag-of-Word (BoW) model which is useful in many works. To get a compact and discriminative codebook with small dimension, we employ the divisive algorithm based on KL-divergence to reconstruct the codebook. After that, to further capture strong relational information, we construct a bipartite graph to model the relationship between words of different feature set. Then we use a k-way partition to create a new codebook in which similar words are getting together. With this new codebook, videos can be represented by a new BoW vector with strong relational information. Moreover, we propose a method to compute new clusters from the divisive algorithm's projective function. We test our work on the several datasets and obtain very promising results. PMID:27656199

  9. Circular Motion.

    ERIC Educational Resources Information Center

    Lee, Paul D.

    1995-01-01

    Provides a period-long activity using battery powered cars rolling in a circular motion on a tile floor. Students measure the time and distance as the car moves to derive the equation for centripetal acceleration. (MVL)

  10. Knee Bracing: What Works?

    MedlinePlus

    ... that make knee braces claim that their products work well. Scientific studies have not completely agreed. It's not clear what the knee braces actually do. Braces often work better in the laboratory than they do in ...

  11. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  12. Knee arthroscopy - discharge

    MedlinePlus

    ... remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Inflamed or damaged ... surgery Knee pain Meniscal allograft transplantation Patient Instructions ACL reconstruction - discharge Getting your home ready - knee or ...

  13. Microprocessor prosthetic knees.

    PubMed

    Berry, Dale

    2006-02-01

    This article traces the development of microprocessor prosthetic knees from early research in the 1970s to the present. Read about how microprocessor knees work, functional options, patient selection, and the future of this prosthetic.

  14. Knee braces - unloading

    MedlinePlus

    ... in their knees, they are referring to a type of arthritis called osteoarthritis . Osteoarthritis is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions all of ...

  15. Post-traumatic knee stiffness: surgical techniques.

    PubMed

    Pujol, N; Boisrenoult, P; Beaufils, P

    2015-02-01

    Post-traumatic knee stiffness and loss of range of motion is a common complication of injuries to the knee area. The causes of post-traumatic knee stiffness can be divided into flexion contractures, extension contractures, and combined contractures. Post-traumatic stiffness can be due to the presence of dense intra-articular adhesions and/or fibrotic transformation of peri-articular structures. Various open and arthroscopic surgical treatments are possible. A precise diagnosis and understanding of the pathology is mandatory prior to any surgical treatment. Failure is imminent if all pathologies are not addressed correctly. From a general point of view, a flexion contracture is due to posterior adhesions and/or anterior impingement. On the other hand, extension contractures are due to anterior adhesions and/or posterior impingement. This overview will describe the different modern surgical techniques for treating post-traumatic knee stiffness. Any bony impingements must be treated before soft tissue release is performed. Intra-articular stiff knees with a loss of flexion can be treated by an anterior arthroscopic arthrolysis. Extra-articular pathology causing a flexion contracture can be treated by open or endoscopic quadriceps release. Extension contractures can be treated by arthroscopic or open posterior arthrolysis. Postoperative care (analgesia, rehabilitation) is essential to maintaining the range of motion obtained intra-operatively.

  16. Successful arthroscopic treatment of pigmented villonodular synovitis of the knee in a patient with congenital deficiency of plasminogen activator inhibitor-1 and recurrent haemarthrosis.

    PubMed

    Matsui, H; Takahashi, Y; Matsunaga, T; Tanaka-Horie, T; Minowa, H; Sugimoto, M; Tsukino, R; Mii, Y; Giddings, J; Yoshioka, A

    2001-01-01

    We report the arthroscopic treatment of pigmented villonodular synovitis (PVNS) in a 13-year-old Japanese boy with congenital partial deficiency of plasminogen activator inhibitor-1 (PAI-1). He was admitted to our hospital with recurrent haemarthrosis of his right knee. Characteristic abnormalities of fibrinolysis included shortened euglobulin lysis time, low PAI-1 activity and low PAI-1 antigen levels. In addition, levels of "active PAI" in the plasma, which is a measure of total PAI bound to exogenous plasminogen activator, were very low. These parameters remained low after venous occlusion. The diagnosis of PVNS was established by synovial membrane biopsy, and arthroscopic synovectomy was performed with adjuvant administration of intravenous tranexamic acid. Subsequent bleeding episodes have been well controlled by oral administration of tranexamic acid on demand.

  17. Examining the knee joint.

    PubMed

    Monk, Daniel

    2013-04-01

    Appropriate history taking and examination can ensure accurate diagnosis of common knee problems, and rapid and effective interventions or referral to orthopaedic specialists. This article describes the anatomy of the knee joint and discusses relevant history taking, the examination process, special tests and radiology, as well as common knee injuries and their management.

  18. Complicated Congenital Dislocation of the Knee: A Case Report

    PubMed Central

    Madadi, Firooz; Tahririan, Mohammad A.; Karami, Mohsen; Madadi, Firoozeh

    2016-01-01

    Congenital dislocation of the knee (CDK) is a rare disorder. We report the case of a 7-year-old girl with bilateral knee stiffness, marked anterior bowing of both legs, and inability to walk without aid. Radiologic investigation revealed bilateral knee joint dislocation accompanied by severe anterior bowing of both tibia proximally and posterior bowing of both femur distally, demonstrating a complicated congenital knee dislocation. Two-staged open reduction with proximal tibial osteotomy was performed to align the reduced knee joints. The patient was completely independent in her daily activities after surgical correction. PMID:27847857

  19. Knee disarticulation after total-knee replacement.

    PubMed

    Lambregts, S A M; Hitters, W M G C

    2002-12-01

    An 89-year-old woman who had a total-knee replacement in the past, underwent a knee disarticulation of the same leg because of an ischaemic foot. Eight (8) months postoperatively the stump is fully weight-bearing and the patient is able to walk safely, using a prosthesis and a walking frame.

  20. Knee Lymphocutaneous Fistula Secondary to Knee Arthroplasty

    PubMed Central

    Pérez-de la Fuente, T.; Sandoval, E.; Alonso-Burgos, A.; García-Pardo, L.; Cárcamo, C.; Caballero, O.

    2014-01-01

    Lower limb lymphorrhea secondary to a surgical procedure is a rare but difficult-to-solve complication. In lower limb, this entity is frequently associated with vascular procedures around the inguinal area. We report on a case of a knee lymphocutaneous fistula secondary to a knee revision arthroplasty. To our knowledge, no previous reports regarding this complication have been published. PMID:25580333

  1. Primary Total Knee Arthroplasty for Simple Distal Femoral Fractures in Elderly Patients with Knee Osteoarthritis

    PubMed Central

    Choi, Nam-Yong; Sohn, Jong-Min; Cho, Sung-Gil; Kim, Seung-Chan

    2013-01-01

    Purpose Primary total knee arthroplasty (TKA) can be an alternative method for treating distal femoral fractures in elderly patients with knee osteoarthritis. The purpose of this study was to evaluate the clinical and radiographic results in patients with knee osteoarthritis who underwent TKA with the Medial Pivot prosthesis for distal femoral fractures. Materials and Methods Eight displaced distal femoral fractures in 8 patients were treated with TKA using the Medial Pivot prosthesis and internal fixation. The radiographic and clinical evaluations were performed using simple radiographs and Hospital for Special Surgery (HSS) knee scores during a mean follow-up period of 49 months. Results All fractures united and the mean time to radiographic union was 15 weeks. The mean range of motion of the knee joint was 114.3° and the mean HSS knee score was 85.1 at the final follow-up. Conclusions Based on the radiographic and clinical results, TKA with internal fixation can be considered as an option for the treatment of simple distal femoral fractures in elderly patients who have advanced osteoarthritis of the knee with appropriate bone stock. PMID:24032103

  2. Increased sensitivity to physical activity among individuals with knee osteoarthritis: relation to pain outcomes, psychological factors, and responses to quantitative sensory testing.

    PubMed

    Wideman, Timothy H; Finan, Patrick H; Edwards, Robert R; Quartana, Phillip J; Buenaver, Luis F; Haythornthwaite, Jennifer A; Smith, Michael T

    2014-04-01

    Recent findings suggest that certain individuals with musculoskeletal pain conditions have increased sensitivity to physical activity (SPA) and respond to activities of stable intensity with increasingly severe pain. This study aimed to determine the degree to which individuals with knee osteoarthritis (OA) show heightened SPA in response to a standardized walking task and whether SPA cross-sectionally predicts psychological factors, responses to quantitative sensory testing (QST), and different OA-related outcomes. One hundred seven adults with chronic knee OA completed self-report measures of pain, function, and psychological factors, underwent QST, and performed a 6-min walk test. Participants rated their discomfort levels throughout the walking task; an index of SPA was created by subtracting first ratings from peak ratings. Repeated-measure analysis of variance revealed that levels of discomfort significantly increased throughout the walking task. A series of hierarchical regression analyses determined that after controlling for significant covariates, psychological factors, and measures of mechanical pain sensitivity, individual variance in SPA predicted self-report pain and function and performance on the walking task. Analyses also revealed that both pain catastrophizing and the temporal summation of mechanical pain were significant predictors of SPA and that SPA mediated the relationship between catastrophizing and self-reported pain and physical function. The discussion addresses the potential processes contributing to SPA and the role it may play in predicting responses to different interventions for musculoskeletal pain conditions.

  3. The elephant knee joint: morphological and biomechanical considerations

    PubMed Central

    Weissengruber, G E; Fuss, F K; Egger, G; Stanek, G; Hittmair, K M; Forstenpointner, G

    2006-01-01

    Elephant limbs display unique morphological features which are related mainly to supporting the enormous body weight of the animal. In elephants, the knee joint plays important roles in weight bearing and locomotion, but anatomical data are sparse and lacking in functional analyses. In addition, the knee joint is affected frequently by arthrosis. Here we examined structures of the knee joint by means of standard anatomical techniques in eight African (Loxodonta africana) and three Asian elephants (Elephas maximus). Furthermore, we performed radiography in five African and two Asian elephants and magnetic resonance imaging (MRI) in one African elephant. Macerated bones of 11 individuals (four African, seven Asian elephants) were measured with a pair of callipers to give standardized measurements of the articular parts. In one Asian and three African elephants, kinematic and functional analyses were carried out using a digitizer and according to the helical axis concept. Some peculiarities of healthy and arthrotic knee joints of elephants were compared with human knees. In contrast to those of other quadruped mammals, the knee joint of elephants displays an extended resting position. The femorotibial joint of elephants shows a high grade of congruency and the menisci are extremely narrow and thin. The four-bar mechanism of the cruciate ligaments exists also in the elephant. The main motion of the knee joint is extension–flexion with a range of motion of 142°. In elephants, arthrotic alterations of the knee joint can lead to injury or loss of the cranial (anterior) cruciate ligament. PMID:16420379

  4. Effect of motion on tracer activity determination in CT attenuation corrected PET images: A lung phantom study

    SciTech Connect

    Pevsner, Alex; Nehmeh, Sadek A.; Humm, John L.; Mageras, Gig S.; Erdi, Yusuf E.

    2005-07-15

    Respiratory motion is known to affect the quantitation of {sup 18}FDG uptake in lung lesions. The aim of the study was to investigate the magnitude of errors in tracer activity determination due to motion, and its dependence upon CT attenuation at different phases of the motion cycle. To estimate these errors we have compared maximum activity concentrations determined from PET/CT images of a lung phantom at rest and under simulated respiratory motion. The NEMA 2001 IEC body phantom, containing six hollow spheres with diameters 37, 28, 22, 17, 13, and 10 mm, was used in this study. To mimic lung tissue density, the phantom (excluding spheres) was filled with low density polystyrene beads and water. The phantom spheres were filled with {sup 18}FDG solution setting the target-to-background activity concentration ratio at 8:1. PET/CT data were acquired with the phantom at rest, and while it was undergoing periodic motion along the longitudinal axis of the scanner with a range of displacement being 2 cm, and a period of 5 s. The phantom at rest and in motion was scanned using manufacturer provided standard helical/clinical protocol, a helical CT scan followed by a PET emission scan. The moving phantom was also scanned using a 4D-CT protocol that provides volume image sets at different phases of the motion cycle. To estimate the effect of motion on quantitation of activities in six spheres, we have examined the activity concentration data for (a) the stationary phantom, (b) the phantom undergoing simulated respiratory motion, and (c) a moving phantom acquired with PET/4D-CT protocol in which attenuation correction was performed with CT images acquired at different phases of motion cycle. The data for the phantom at rest and in motion acquired with the standard helical/clinical protocol showed that the activity concentration in the spheres can be underestimated by as much as 75%, depending on the sphere diameter. We have also demonstrated that fluctuations in sphere

  5. Effect of knee sleeve on static and dynamic balance in patients with knee osteoarthritis.

    PubMed

    Chuang, Shih-Hung; Huang, Mao-Hsiung; Chen, Tien-Wen; Weng, Ming-Chang; Liu, Chin-Wei; Chen, Chia-Hsin

    2007-08-01

    Patients with knee osteoarthritis (OA) find that use of elastic knee sleeves gives them partial pain relief and a greater sense of joint stability. However, the scientific effects of knee OA patients wearing braces are unclear. The purpose of this study was to investigate the effects of knee sleeves on static and dynamic balance in knee OA patients. Fifty patients with knee OA were enrolled in the study and all subjects were randomly divided into two groups. Initially, subjects in group A did not wear a neoprene sleeve while receiving balance tests but then wore them to be re-tested. Subjects in group B did just the reverse procedure. In this investigation, an instrument (KAT 2000; Breg Inc., Vista, CA, USA), which quantified motor control performance of the lower extremities was used and balance scores from the KAT 2000 software were obtained. The results revealed that the scores of patients wearing braces were significantly lower than those of patients without braces (p < 0.05).The finding of this study demonstrated that knee OA patients wearing knee sleeves could experience increased balance ability in both static and dynamic conditions. The improvement might prevent knee OA patients from falling down and increase their sense of security during physical activities.

  6. Multibody dynamic simulation of knee contact mechanics

    PubMed Central

    Bei, Yanhong; Fregly, Benjamin J.

    2006-01-01

    Multibody dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to knee joint degeneration and restoration. Current three-dimensional multi-body knee models are either quasi-static with deformable contact or dynamic with rigid contact. This study proposes a computationally efficient methodology for combining multibody dynamic simulation methods with a deformable contact knee model. The methodology requires preparation of the articular surface geometry, development of efficient methods to calculate distances between contact surfaces, implementation of an efficient contact solver that accounts for the unique characteristics of human joints, and specification of an application programming interface for integration with any multibody dynamic simulation environment. The current implementation accommodates natural or artificial tibiofemoral joint models, small or large strain contact models, and linear or nonlinear material models. Applications are presented for static analysis (via dynamic simulation) of a natural knee model created from MRI and CT data and dynamic simulation of an artificial knee model produced from manufacturer’s CAD data. Small and large strain natural knee static analyses required 1 min of CPU time and predicted similar contact conditions except for peak pressure, which was higher for the large strain model. Linear and nonlinear artificial knee dynamic simulations required 10 min of CPU time and predicted similar contact force and torque but different contact pressures, which were lower for the nonlinear model due to increased contact area. This methodology provides an important step toward the realization of dynamic musculoskeletal models that can predict in vivo knee joint motion and loading simultaneously. PMID:15564115

  7. The infected total knee: management options.

    PubMed

    Cuckler, John M

    2005-06-01

    The management of infection after total knee arthroplasty depends on the chronicity of the infection, host factors, and sensitivity of the infecting bacteria. Two-stage salvage consisting of removal of implants and cement, placement of an antibiotic spacer, and appropriate intravenous antibiotic therapy followed by reimplantation with an antibiotic-impregnated cement appears to be the predominant approach to managing this complication. The use of articulated spacers consisting of the sterilized femoral and polyethylene components with antibiotic cement allows maintenance of motion and bone stock. This report details the author's experience with 44 infected knee arthroplasties.

  8. Submaximal fatigue of the hamstrings impairs specific reflex components and knee stability.

    PubMed

    Melnyk, Mark; Gollhofer, Albert

    2007-05-01

    Rupture of the anterior cruciate ligament (ACL) is one of the most serious sports-related injuries and requires long recovery time. The quadriceps and hamstring muscles are functionally important to control stability of the knee joint complex. Fatigue, however, is an important factor that may influence stabilizing control and thus cause ACL injuries. The objective of this study was therefore to assess how submaximal fatigue exercises of the hamstring muscles affect anterior tibial translation as a direct measure of knee joint stability. While 15 test participants were standing upright with the knees in 30 degrees of flexion, anterior tibial translation was induced by a force of 315 N. Two linear potentiometers placed on the tibial tuberosity and the patella recorded tibial motion relative to the femur. Reflex latencies and neuromuscular hamstring activity were determined using surface electromyography (EMG). Muscle fatigue produced a significant longer latency for the monosynaptic reflex latencies, whereas no differences in the latencies of the medium latency component were found. Fatigue significantly reduced EMG amplitudes of the short and medium latency components. These alterations were in line with significantly increased anterior tibial translation. Our results suggest that hamstring fatigue is effectively associated with mechanical loss of knee stability. This decrease in joint stability may at least in part explain higher risk of ACL injury, especially in fatigued muscles. Furthermore, we discuss why the present findings indicate that reduced motor activity rather than the extended latency of the first hamstring response is the reason for possible failure.

  9. Evaluating knee replacement mechanics during ADL with PID-controlled dynamic finite element analysis.

    PubMed

    Fitzpatrick, Clare K; Baldwin, Mark A; Clary, Chadd W; Maletsky, Lorin P; Rullkoetter, Paul J

    2014-01-01

    Validated computational knee simulations are valuable tools for design phase development of knee replacement devices. Recently, a dynamic finite element (FE) model of the Kansas knee simulator was kinematically validated during gait and deep flexion cycles. In order to operate the computational simulator in the same manner as the experiment, a proportional-integral-derivative (PID) controller was interfaced with the FE model to control the quadriceps actuator excursion and produce a target flexion profile regardless of implant geometry or alignment conditions. The controller was also expanded to operate multiple actuators simultaneously in order to produce in vivo loading conditions at the joint during dynamic activities. Subsequently, the fidelity of the computational model was improved through additional muscle representation and inclusion of relative hip-ankle anterior-posterior (A-P) motion. The PID-controlled model was able to successfully recreate in vivo loading conditions (flexion angle, compressive joint load, medial-lateral load distribution or varus-valgus torque, internal-external torque, A-P force) for deep knee bend, chair rise, stance-phase gait and step-down activities.

  10. Effect of motion smoothness on brain activity while observing a dance: An fMRI study using a humanoid robot.

    PubMed

    Miura, Naoki; Sugiura, Motoaki; Takahashi, Makoto; Sassa, Yuko; Miyamoto, Atsushi; Sato, Shigeru; Horie, Kaoru; Nakamura, Katsuki; Kawashima, Ryuta

    2010-01-01

    Motion smoothness is critical in transmitting implicit information of body action, such as aesthetic qualities in dance performances. We expected that the perception of motion smoothness would be characterized by great intersubject variability deriving from differences in personal backgrounds and attitudes toward expressive body actions. We used functional magnetic resonance imaging and a humanoid robot to investigate the effects of the motion smoothness of expressive body actions and the intersubject variability due to personal attitudes on perceptions during dance observation. The effect of motion smoothness was analyzed by both conventional subtraction analysis and functional connectivity analyses that detect cortical networks reflecting intersubject variability. The results showed that the cortical networks of motion- and body-sensitive visual areas showed increases in activity in areas corresponding with motion smoothness, but the intersubject variability of personal attitudes toward art did not influence these active areas. In contrast, activation of cortical networks, including the parieto-frontal network, has large intersubject variability, and this variability is associated with personal attitudes about the consciousness of art. Thus, our results suggest that activity in the cortical network involved in understanding action is influenced by personal attitudes about the consciousness of art during observations of expressive body actions.

  11. Anterior knee pain.

    PubMed

    LLopis, Eva; Padrón, Mario

    2007-04-01

    Anterior knee pain is a common complain in all ages athletes. It may be caused by a large variety of injuries. There is a continuum of diagnoses and most of the disorders are closely related. Repeated minor trauma and overuse play an important role for the development of lesions in Hoffa's pad, extensor mechanism, lateral and medial restrain structures or cartilage surface, however usually an increase or change of activity is referred. Although the direct relation of cartilage lesions, especially chondral, and pain is a subject of debate these lesions may be responsible of early osteoarthrosis and can determine athlete's prognosis. The anatomy and biomechanics of patellofemoral joint is complex and symptoms are often unspecific. Transient patellar dislocation has MR distinct features that provide evidence of prior dislocation and rules our complication. However, anterior knee pain more often is related to overuse and repeated minor trauma. Patella and quadriceps tendon have been also implicated in anterior knee pain, as well as lateral or medial restraint structures and Hoffa's pad. US and MR are excellent tools for the diagnosis of superficial tendons, the advantage of MR is that permits to rule out other sources of intraarticular derangements. Due to the complex anatomy and biomechanic of patellofemoral joint maltracking is not fully understood; plain films and CT allow the study of malalignment, new CT and MR kinematic studies have promising results but further studies are needed. Our purpose here is to describe how imaging techniques can be helpful in precisely defining the origin of the patient's complaint and thus improve understanding and management of these injuries.

  12. Effectiveness of a Web-Based Physical Activity Intervention in Patients With Knee and/or Hip Osteoarthritis: Randomized Controlled Trial

    PubMed Central

    Veenhof, Cindy; Van Beek, Karin EC; Spreeuwenberg, Peter MM; Dekker, Joost; De Bakker, Dinny H

    2013-01-01

    Background Patients with knee and/or hip osteoarthritis (OA) are less physically active than the general population, while the benefits of physical activity (PA) have been well documented. Based on the behavioral graded activity treatment, we developed a Web-based intervention to improve PA levels in patients with knee and/or hip OA, entitled “Join2move”. The Join2move intervention is a self-paced 9-week PA program in which the patient’s favorite recreational activity is gradually increased in a time-contingent way. Objective The aim of the study was to investigate whether a fully automated Web-based PA intervention in patients with knee and/or hip OA would result in improved levels of PA, physical function, and self-perceived effect compared with a waiting list control group. Methods The study design was a two-armed randomized controlled trial which was not blinded. Volunteers were recruited via articles in newspapers and health-related websites. Eligibility criteria for participants were: (1) aged 50-75 years, (2) self-reported knee and/or hip OA, (3) self-reported inactivity (30 minutes of moderate PA, 5 times or less per week), (4) no face-to-face consultation with a health care provider other than general practitioners, for OA in the last 6 months, (5) ability to access the Internet weekly, and (6) no contra-indications to exercise without supervision. Baseline, 3-month, and 12-month follow-up data were collected through online questionnaires. Primary outcomes were PA, physical function, and self-perceived effect. In a subgroup of participants, PA was measured objectively using accelerometers. Secondary outcomes were pain, fatigue, anxiety, depression, symptoms, quality of life, self-efficacy, pain coping, and locus of control. Results Of the 581 interested respondents, 199 eligible participants were randomly assigned to the intervention (n=100) or waiting list control group (n=99). Response rates of questionnaires were 84.4% (168/199) after 3 months and

  13. MIS unicondylar knee arthroplasty: surgical approach and early results.

    PubMed

    Gesell, Mark W; Tria, Alfred J

    2004-11-01

    Unicondylar arthroplasty of the knee has seen a resurgence of interest in the United States. The principles of unicondylar arthroplasty of the knee are different from those for total knee arthroplasty, allowing replacement of only the affected joint compartment with less bone loss. Minimally invasive surgery allows for less soft tissue dissection with the potential for less morbidity. The key question is: will the changes associated with the minimally invasive surgery procedure improve the clinical results of the standard unicondylar arthroplasty of the knee or will the changes make the procedure too difficult and lead to an increasing failure rate? This study reviews the surgical technique and presents the 2 to 4 year results of the minimally invasive unicondylar arthroplasty of the knee 47 knees in 41 patients. The average range of motion increased from 121 degrees -132 degrees . The Knee Society pain score improved from 45-80 and the function score improved from 47-78. Only one knee has been revised. With proper patient selection, minimally invasive unicondylar arthroplasty of the knee allows for results that are at least equal to those of the standard open procedure at 2 to 4 years after the surgery.

  14. Mobile Sensor Application for Kinematic Detection of the Knees

    PubMed Central

    Suputtitada, Areerat; Khovidhungij, Watcharapong

    2015-01-01

    Objective To correctly measure the knee joint angle, this study utilized a Qualisys motion capture system and also used it as the reference to assess the validity of the study's Inertial Measurement Unit (IMU) system that consisted of four IMU sensors and the Knee Angle Recorder software. The validity was evaluated by the root mean square (RMS) of different angles and the intraclass correlation coefficient (ICC) values between the Qualisys system and the IMU system. Methods Four functional knee movement tests for ten healthy participants were investigated, which were the knee flexion test, the hip and knee flexion test, the forward step test and the leg abduction test, and the walking test. Results The outcomes of the knee flexion test, the hip and knee flexion test, the forward step test, and the walking test showed that the RMS of different angles were less than 6°. The ICC values were in the range of 0.84 to 0.99. However, the leg abduction test showed a poor correlation in the measurement of the knee abduction-adduction movement. Conclusion The IMU system used in this study is a new good method to measure the knee flexion-extension movement. PMID:26361597

  15. Simple arthroscopic partial meniscectomy associated with anterior cruciate-deficient knees.

    PubMed

    Marshall, S; Levas, M G; Harrah, A

    1985-01-01

    Twenty-five patients with combined tears of the meniscus and anterior cruciate ligament in the same knee were evaluated for the results of a simple arthroscopic meniscectomy that preserved the meniscal rim. These patients, classified as "recreational athletes," were analyzed to determine their postoperative functional capabilities. Using the presence or absence of the pivot shift sign as the most important indicator of functional capability, we found that partial meniscectomy was effective in allowing patients to regain a high degree of normal functional ability and in permitting forward motion activities. However, all patients were left with an anterior cruciate-deficient knee that caused laxity in the anterior plane and frequently in the rotatory plane. Rotatory laxity markedly limits activities, and those patients unable to adjust to their instability are considering further surgery.

  16. Thermal and Kinetic Properties of Motions in a Prominence Activation and Nearby Loop

    NASA Technical Reports Server (NTRS)

    Kucera, Therese; Landi, E.

    2005-01-01

    We perform a quantitative analysis of the thermal properties of a prominence activation and motions in a nearby loop. In order to make measurements of the quickly moving features seen in prominences in the UV we use the SOHO/SUMER spectrograph to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The lines observed cover a broad range of temperatures from 80,000 - 1.6 million K. These measurements are combined with TRACE movies in transition region and coronal temperature bands to obtain more complete information concerning prominence structure and motions. The resulting observations allow us to analyze the thermal and kinetic energy of the moving sources as functions of time. The loop and prominence are most apparent in lines formed at temperatures below 250,000 K. We find that in most cases the temperature distribution of plasma in a moving feature changes relatively little over time periods of about 20 minutes.

  17. Understanding and Visualizing Multitasking and Task Switching Activities: A Time Motion Study to Capture Nursing Workflow.

    PubMed

    Yen, Po-Yin; Kelley, Marjorie; Lopetegui, Marcelo; Rosado, Amber L; Migliore, Elaina M; Chipps, Esther M; Buck, Jacalyn

    2016-01-01

    A fundamental understanding of multitasking within nursing workflow is important in today's dynamic and complex healthcare environment. We conducted a time motion study to understand nursing workflow, specifically multitasking and task switching activities. We used TimeCaT, a comprehensive electronic time capture tool, to capture observational data. We established inter-observer reliability prior to data collection. We completed 56 hours of observation of 10 registered nurses. We found, on average, nurses had 124 communications and 208 hands-on tasks per 4-hour block of time. They multitasked (having communication and hands-on tasks simultaneously) 131 times, representing 39.48% of all times; the total multitasking duration ranges from 14.6 minutes to 109 minutes, 44.98 minutes (18.63%) on average. We also reviewed workflow visualization to uncover the multitasking events. Our study design and methods provide a practical and reliable approach to conducting and analyzing time motion studies from both quantitative and qualitative perspectives.

  18. Understanding and Visualizing Multitasking and Task Switching Activities: A Time Motion Study to Capture Nursing Workflow

    PubMed Central

    Yen, Po-Yin; Kelley, Marjorie; Lopetegui, Marcelo; Rosado, Amber L.; Migliore, Elaina M.; Chipps, Esther M.; Buck, Jacalyn

    2016-01-01

    A fundamental understanding of multitasking within nursing workflow is important in today’s dynamic and complex healthcare environment. We conducted a time motion study to understand nursing workflow, specifically multitasking and task switching activities. We used TimeCaT, a comprehensive electronic time capture tool, to capture observational data. We established inter-observer reliability prior to data collection. We completed 56 hours of observation of 10 registered nurses. We found, on average, nurses had 124 communications and 208 hands-on tasks per 4-hour block of time. They multitasked (having communication and hands-on tasks simultaneously) 131 times, representing 39.48% of all times; the total multitasking duration ranges from 14.6 minutes to 109 minutes, 44.98 minutes (18.63%) on average. We also reviewed workflow visualization to uncover the multitasking events. Our study design and methods provide a practical and reliable approach to conducting and analyzing time motion studies from both quantitative and qualitative perspectives. PMID:28269924

  19. Vagal control of cardiac electrical activity and wall motion during ventricular fibrillation in large animals.

    PubMed

    Naggar, Isaac; Nakase, Ko; Lazar, Jason; Salciccioli, Louis; Selesnick, Ivan; Stewart, Mark

    2014-07-01

    Vagal inputs control pacemaking and conduction systems in the heart. Anatomical evidence suggests a direct ventricular action, but functional evidence that separates direct and indirect (via the conduction system) vagal actions is less well established. We studied vagus nerve stimulation (VNS) during sinus rhythm and ventricular fibrillation (VF) in pigs and sheep to determine: 1) the range of unilateral and bilateral actions (inotropic and chronotropic) and 2) whether VNS alters left ventricular motion and/or electrical activity during VF, a model of abnormal electrical conduction of the left ventricle that excludes sinus and atrioventricular nodal function. Adult pigs (N=8) and sheep (N=10) were anesthetized with urethane and mechanically ventilated. VNS was performed in animals at 1, 2, 5, 10, 20, 50, and 100Hz for 20s. VF was induced with direct current to the ventricles or occlusion of the left anterior descending coronary artery. In 4 pigs and 3 sheep, left ventricular wall motion was assessed from endocardial excursion in epicardial echocardiography. In sheep and pigs, the best frequency among those tested for VNS during sinus rhythm to produce sustained electrical and mechanical ventricular standstill was 50Hz for unilateral or bilateral stimulation. When applied during VF, bilateral VNS increased the variability of the dominant VF frequency, indicating a direct impact on the excitability of ventricular myocytes, and decreased endocardial excursion by more than 50% during VF. We conclude that the vagus nerve directly modulates left ventricular function independently from its effects on the conduction system.

  20. Development of magnetically preloaded air bearings for a linear slide: active compensation of three degrees of freedom motion errors.

    PubMed

    Ro, Seung-Kook; Kim, Soohyun; Kwak, Yoonkeun; Park, Chun-Hong

    2008-03-01

    This article describes a linear air-bearing stage that uses active control to compensate for its motion errors. The active control is based on preloads generated by magnetic actuators, which were designed to generate nominal preloads for the air bearings using permanent magnets to maintain the desired stiffness while changing the air-bearing clearance by varying the magnetic flux generated by the current in electromagnetic coils. A single-axis linear stage with a linear motor and 240 mm of travel range was built to verify this design concept and used to test its performance. The motion of the table in three directions was controlled with four magnetic actuators driven by current amplifiers and a DSP (Digital Signal Processor)-based digital controller. The motion errors were measured using a laser interferometer combined with a two-probe method, and had 0.085 microm of repeatability for the straightness error. As a result of feed-forward active compensation, the errors were reduced from 1.09 to 0.11 microm for the vertical motion, from 9.42 to 0.18 arcsec for the pitch motion, and from 2.42 to 0.18 arcsec for the roll motion.

  1. Control of a Virtual Vehicle Influences Postural Activity and Motion Sickness

    ERIC Educational Resources Information Center

    Dong, Xiao; Yoshida, Ken; Stoffregen, Thomas A.

    2011-01-01

    Everyday experience suggests that drivers are less susceptible to motion sickness than passengers. In the context of inertial motion (i.e., physical displacement), this effect has been confirmed in laboratory research using whole body motion devices. We asked whether a similar effect would occur in the context of simulated vehicles in a visual…

  2. Evaluation of total knee mechanics using a crouching simulator with a synthetic knee substitute.

    PubMed

    Lowry, Michael; Rosenbaum, Heather; Walker, Peter S

    2016-05-01

    Mechanical evaluation of total knees is frequently required for aspects such as wear, strength, kinematics, contact areas, and force transmission. In order to carry out such tests, we developed a crouching simulator, based on the Oxford-type machine, with novel features including a synthetic knee including ligaments. The instrumentation and data processing methods enabled the determination of contact area locations and interface forces and moments, for a full flexion-extension cycle. To demonstrate the use of the simulator, we carried out a comparison of two different total knee designs, cruciate retaining and substituting. The first part of the study describes the simulator design and the methodology for testing the knees without requiring cadaveric knee specimens. The degrees of freedom of the anatomic hip and ankle joints were reproduced. Flexion-extension was obtained by changing quadriceps length, while variable hamstring forces were applied using springs. The knee joint was represented by three-dimensional printed blocks on to which the total knee components were fixed. Pretensioned elastomeric bands of realistic stiffnesses passed through holes in the block at anatomical locations to represent ligaments. Motion capture of the knees during flexion, together with laser scanning and computer modeling, was used to reconstruct contact areas on the bearing surfaces. A method was also developed for measuring tibial component interface forces and moments as a comparative assessment of fixation. The method involved interposing Tekscan pads at locations on the interface. Overall, the crouching machine and the methodology could be used for many different mechanical measurements of total knee designs, adapted especially for comparative or parametric studies.

  3. OA Go Away: Development and Preliminary Validation of a Self-Management Tool to Promote Adherence to Exercise and Physical Activity for People with Osteoarthritis of the Hip or Knee.

    PubMed

    Paterson, Gail; Toupin April, Karine; Backman, Catherine; Tugwell, Peter

    2016-01-01

    Purpose: To determine the face and content validity, construct validity, and test-retest reliability of the OA Go Away (OGA), a personalized self-management tool to promote adherence to exercise and physical activity for people with osteoarthritis (OA) of the hip or knee. Methods: The face and content validity of OGA version 1.0 were determined via interviews with 10 people with OA of the hip or knee and 10 clinicians. A revised OGA version 2.0 was then tested for construct validity and test-retest reliability with a new sample of 50 people with OA of the hip or knee by comparing key items in the OGA journal with validated outcome measures assessing similar health outcomes and comparing scores on key items of the journal 4-7 days apart. Face and content validity were then confirmed with a new sample of 5 people with OA of the hip or knee and 5 clinicians. Results: Eighteen of 30 items from the OGA version 1.0 and 41 of 43 items from the OGA version 2.0 journal, goals and action plan, and exercise log had adequate content validity. Construct validity and test-retest reliability were acceptable for the main items of the OGA version 2.0 journal. The OGA underwent modifications based on results and participant feedback. Conclusion: The OGA is a novel self-management intervention and assessment tool for people with OA of the hip or knee that shows adequate preliminary measurement properties.

  4. Painful knee prosthesis: surgical approach

    PubMed Central

    Villano, Marco; Carulli, Christian; Puccini, Serena; Soderi, Stefano; Innocenti, Massimo

    2011-01-01

    Summary There are many conditions that may be responsible of a painful knee prosthesis. The possible causes are not always easily diagnosed. Common causes of prosthetic failure, such as aseptic loosening, infection, instability, progressive patellar arthropathy and recurrent synovitis are associated with clearly defined radiographic and/or clinical evidence. Prosthetic infection should always be considered first until any other cause has been demonstrated. In the presence of an infected prosthesis we carry out a two-step revision. Aseptic loosening needs implant revision more often with increasing prosthesis stability. Varus-valgus, anteroposterior, global and patello-femoral instability are failures often due to technical errors; superstabilized or constrained implants are needed depending on the instability entity. In presence of patello-femoral pain it is necessary to evaluate the stability of the patellar component and any alterations in its motion. Patellar progressive arthropathy can often cause late-onset knee pain; in this case patella resurfacing is needed. Altered patellar tracking, may need a lateral release but in some cases is related to misalignment of the components and the revision procedure is mandatory. Nevertheless, the diagnosis and treatment of a painful knee prosthesis can be extremely difficult if there is no clear evidence of any of the most common causes of failure. Referred pain, ligament and tendon dysfunction, cutaneous neuromas, synovitis, a patellar clunk have to be diagnosed and treated. A possible aetiological understimated factor is painful knee prosthesis due to metals sensibilization, in particular to nickel. In this event the quantity of nickel in the revision prosthesis must be minimal. PMID:22461812

  5. Osteotomies about the knee: AAOS exhibit selection.

    PubMed

    Uquillas, Carlos; Rossy, William; Nathasingh, Christopher K; Strauss, Eric; Jazrawi, Laith; Gonzalez-Lomas, Guillem

    2014-12-17

    Varus or valgus malalignment of the lower extremity can alter the load distribution across the knee and hasten the development of focal osteoarthritis. Although knee arthroplasty remains an effective option for end-stage arthritis, it is not typically recommended in the young, active patient. In the setting of painful unicompartmental cartilage injury in a mechanically malaligned limb, alignment correction by osteotomy has been shown to slow the progression of osteoarthritis and lessen pain. In this review, we will discuss the different options, indications, and techniques for osteotomies about the knee.

  6. Muscle metabolism and activation heterogeneity by combined 31P chemical shift and T2 imaging, and pulmonary O2 uptake during incremental knee-extensor exercise.

    PubMed

    Cannon, Daniel T; Howe, Franklyn A; Whipp, Brian J; Ward, Susan A; McIntyre, Dominick J; Ladroue, Christophe; Griffiths, John R; Kemp, Graham J; Rossiter, Harry B

    2013-09-01

    The integration of skeletal muscle substrate depletion, metabolite accumulation, and fatigue during large muscle-mass exercise is not well understood. Measurement of intramuscular energy store degradation and metabolite accumulation is confounded by muscle heterogeneity. Therefore, to characterize regional metabolic distribution in the locomotor muscles, we combined 31P magnetic resonance spectroscopy, chemical shift imaging, and T2-weighted imaging with pulmonary oxygen uptake during bilateral knee-extension exercise to intolerance. Six men completed incremental tests for the following: (1) unlocalized 31P magnetic resonance spectroscopy; and (2) spatial determination of 31P metabolism and activation. The relationship of pulmonary oxygen uptake to whole quadriceps phosphocreatine concentration ([PCr]) was inversely linear, and three of four knee-extensor muscles showed activation as assessed by change in T2. The largest changes in [PCr], [inorganic phosphate] ([Pi]) and pH occurred in rectus femoris, but no voxel (72 cm3) showed complete PCr depletion at exercise cessation. The most metabolically active voxel reached 11 ± 9 mM [PCr] (resting, 29 ± 1 mM), 23 ± 11 mM [Pi] (resting, 7 ± 1 mM), and a pH of 6.64 ± 0.29 (resting, 7.08 ± 0.03). However, the distribution of 31P metabolites and pH varied widely between voxels, and the intervoxel coefficient of variation increased between rest (∼10%) and exercise intolerance (∼30-60%). Therefore, the limit of tolerance was attained with wide heterogeneity in substrate depletion and fatigue-related metabolite accumulation, with extreme metabolic perturbation isolated to only a small volume of active muscle (<5%). Regional intramuscular disturbances are thus likely an important requisite for exercise intolerance. How these signals integrate to limit muscle power production, while regional "recruitable muscle" energy stores are presumably still available, remains uncertain.

  7. PHYSICAL ACTIVITY AND EXPERIENCE OF TOTAL KNEE REPLACEMENT IN PATIENTS 1-4 YEARS POST-SURGERY IN THE DOMINICAN REPUBLIC: A QUALITATIVE STUDY

    PubMed Central

    Stenquist, Derek S.; Elman, Scott A.; Davis, Aileen M.; Bogart, Laura M.; Brownlee, Sarah A.; Sanchez, Edward S.; Santiago, Adianez; Ghazinouri, Roya; Katz, Jeffrey N.

    2014-01-01

    Objective Musculoskeletal disorders are the second-leading cause of years lived with disability globally. Total Knee Replacement (TKR) offers patients with advanced arthritis relief from pain and the opportunity to return to physical activity. We investigated the impact of TKR on physical activity for patients in a developing nation. Methods We interviewed 18 Dominican patients (78% female) who received TKR as part of the Operation Walk Boston surgical mission program about their level of physical activity after surgery. Qualitative interviews were conducted in Spanish, and English transcripts were analyzed using content analysis. Results Most patients found that TKR increased their participation in physical activities in several life domains such as occupational or social pursuits. Some patients limited their own physical activities due to uncertainty about medically appropriate levels of joint use and post-operative physical activity. Many patients noted positive effects of TKR on mood and mental health. For most patients in the study, religion offered a framework for understanding their receipt of and experience with TKR. Conclusions Our findings underscore the potential of TKR to permit patients in the developing world to return to physical activities. This research also demonstrates the influence of patient education, culture, and religion on patients’ return to physical activity. As the global burden of musculoskeletal disease increases, it is important to characterize the impact of activity limitation on patients’ lives in diverse settings, and the potential for surgical intervention to ease the burden of chronic arthritis. PMID:24818572

  8. Relationship between active cervical range of motion and flexion-relaxation ratio in asymptomatic computer workers.

    PubMed

    Yoo, Won-Gyu; Park, Se-Yeon; Lee, Mi-Ra

    2011-01-01

    A high prevalence and incidence of neck and shoulder pain is present in the working population, especially sedentary workers. Recent findings have indicated that the flexion-relaxation (FR) ratio in the cervical erector spinae (CES) muscles might be a significant criteria of neuromuscular impairment and function. Additionally, the active cervical range of motion (ROM) is frequently used for discriminating between individuals with pain and those who are asymptomatic. The purpose of the present study was to examine the relationship between the active cervical ROM and the FR ratio in a sample of regular visual display terminal (VDT) workers. In total, 20 asymptomatic male VDT workers were recruited. Active cervical ROM was measured by a cervical ROM (CROM) instrument. Surface electromyography (EMG) was used to collect myoelectrical signals from the CES muscles, and the FR ratio was calculated for statistical analysis. Pearson correlation coefficients were used to quantify the linear relationship between the active cervical ROM and the FR ratio. The values obtained for the FR ratio in the right CES muscles correlated significantly with the active cervical ROM measured in flexion (r=0.73, p<0.01), left lateral flexion (r=0.64, p<0.01), and left rotation (r=0.60, p<0.01). Flexion (r=0.74, p<0.01) and right lateral flexion (r=0.61, p<0.01) positively correlated with the left FR ratio. Extension and right rotation showed either a very weak or no correlation with the mean value of the right and left FR ratio. Our findings suggested that the cervical FR ratio had a positive correlation with cervical movements, and that changes of the activation patterns in CES demonstrated as cervical FR ratio are associated with reduction of the cervical range of motion including flexion and lateral flexion. In addition, muscular dysfunction of the CES could occur in regular computer workers prior to occurrence of pain; this means that the FR ratio could be used to evaluate the potential

  9. Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

    PubMed Central

    Yousif, Nada; Fu, Richard Z.; Abou-El-Ela Bourquin, Bilal; Bhrugubanda, Vamsee; Schultz, Simon R.

    2016-01-01

    When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training. SIGNIFICANCE STATEMENT In this study, we address the issue of whether dopamine activation improves visual perception despite increasing sensory noise in the visual cortex

  10. Aftershock activity of the 2015 Gorkha, Nepal, earthquake determined using the Kathmandu strong motion seismographic array

    NASA Astrophysics Data System (ADS)

    Ichiyanagi, Masayoshi; Takai, Nobuo; Shigefuji, Michiko; Bijukchhen, Subeg; Sasatani, Tsutomu; Rajaure, Sudhir; Dhital, Megh Raj; Takahashi, Hiroaki

    2016-02-01

    The characteristics of aftershock activity of the 2015 Gorkha, Nepal, earthquake (Mw 7.8) were evaluated. The mainshock and aftershocks were recorded continuously by the international Kathmandu strong motion seismographic array operated by Hokkaido University and Tribhuvan University. Full waveform data without saturation for all events enabled us to clarify aftershock locations and decay characteristics. The aftershock distribution was determined using the estimated local velocity structure. The hypocenter distribution in the Kathmandu metropolitan region was well determined and indicated earthquakes located shallower than 12 km depth, suggesting that aftershocks occurred at depths shallower than the Himalayan main thrust fault. Although numerical investigation suggested less resolution for the depth component, the regional aftershock epicentral distribution of the entire focal region clearly indicated earthquakes concentrated in the eastern margin of the major slip region of the mainshock. The calculated modified Omori law's p value of 1.35 suggests rapid aftershock decay and a possible high temperature structure in the aftershock region.

  11. X-RAY ACTIVITY PHASED WITH PLANET MOTION IN HD 189733?

    SciTech Connect

    Pillitteri, I.; Guenther, H. M.; Wolk, S. J.; Kashyap, V. L.; Cohen, O.

    2011-11-01

    We report on the follow-up XMM-Newton observation of the planet-hosting star HD 189733 we obtained in 2011 April. We observe a flare just after the secondary transit of the hot Jupiter. This event shares the same phase and many of the characteristics of the flare we observed in 2009. We suggest that a systematic interaction between planet and stellar magnetic fields when the planet passes close to active regions on the star can lead to periodic variability phased with planetary motion. By means of high-resolution X-ray spectroscopy with the Reflection Grating Spectrometer on board XMM-Newton, we determine that the corona of this star is unusually dense.

  12. Recommended survey designs for occupancy modelling using motion-activated cameras: insights from empirical wildlife data.

    PubMed

    Shannon, Graeme; Lewis, Jesse S; Gerber, Brian D

    2014-01-01

    Motion-activated cameras are a versatile tool that wildlife biologists can use for sampling wild animal populations to estimate species occurrence. Occupancy modelling provides a flexible framework for the analysis of these data; explicitly recognizing that given a species occupies an area the probability of detecting it is often less than one. Despite the number of studies using camera data in an occupancy framework, there is only limited guidance from the scientific literature about survey design trade-offs when using motion-activated cameras. A fuller understanding of these trade-offs will allow researchers to maximise available resources and determine whether the objectives of a monitoring program or research study are achievable. We use an empirical dataset collected from 40 cameras deployed across 160 km(2) of the Western Slope of Colorado, USA to explore how survey effort (number of cameras deployed and the length of sampling period) affects the accuracy and precision (i.e., error) of the occupancy estimate for ten mammal and three virtual species. We do this using a simulation approach where species occupancy and detection parameters were informed by empirical data from motion-activated cameras. A total of 54 survey designs were considered by varying combinations of sites (10-120 cameras) and occasions (20-120 survey days). Our findings demonstrate that increasing total sampling effort generally decreases error associated with the occupancy estimate, but changing the number of sites or sampling duration can have very different results, depending on whether a species is spatially common or rare (occupancy = ψ) and easy or hard to detect when available (detection probability = p). For rare species with a low probability of detection (i.e., raccoon and spotted skunk) the required survey effort includes maximizing the number of sites and the number of survey days, often to a level that may be logistically unrealistic for many studies. For common species with

  13. Active range of motion outcomes after reconstruction of burned wrist and hand deformities.

    PubMed

    Afifi, Ahmed M; Mahboub, Tarek A; Ibrahim Fouad, Amr; Azari, Kodi; Khalil, Haitham H; McCarthy, James E

    2016-06-01

    This works aim is to evaluate the efficacy of skin grafts and flaps in reconstruction of post-burn hand and wrist deformities. A prospective study of 57 burn contractures of the wrist and dorsum of the hand was performed. Flaps were used only if there was a non-vascularized structure after contracture release, otherwise a skin graft was used. Active range of motion (ROM) was used to assess hand function. The extension deformity cohort uniformly underwent skin graft following contracture release with a mean improvement of 71 degrees (p<0.0001). The flexion deformity cohort was treated with either skin grafts (8 patients) or flaps (9 patients) with a mean improvement of 44 degrees (p<0.0001). Skin grafts suffice for dorsal hand contractures to restore functional wrist ROM. For flexion contractures, flaps were more likely for contractures >6 months. Early release of burn contracture is advisable to avoid deep structure contracture.

  14. Interpolation function for approximating knee joint behavior in human gait

    NASA Astrophysics Data System (ADS)

    Toth-Taşcǎu, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

  15. Thermal activation of 'allosteric-like' large-scale motions in a eukaryotic Lactate Dehydrogenase.

    PubMed

    Katava, Marina; Maccarini, Marco; Villain, Guillaume; Paciaroni, Alessandro; Sztucki, Michael; Ivanova, Oxana; Madern, Dominique; Sterpone, Fabio

    2017-01-23

    Conformational changes occurring during the enzymatic turnover are essential for the regulation of protein functionality. Individuating the protein regions involved in these changes and the associated mechanical modes is still a challenge at both experimental and theoretical levels. We present here a detailed investigation of the thermal activation of the functional modes and conformational changes in a eukaryotic Lactate Dehydrogenase enzyme (LDH). Neutron Spin Echo spectroscopy and Molecular Dynamics simulations were used to uncover the characteristic length- and timescales of the LDH nanoscale motions in the apo state. The modes involving the catalytic loop and the mobile region around the binding site are activated at room temperature, and match the allosteric reorganisation of bacterial LDHs. In a temperature window of about 15 degrees, these modes render the protein flexible enough and capable of reorganising the active site toward reactive configurations. On the other hand an excess of thermal excitation leads to the distortion of the protein matrix with a possible anti-catalytic effect. Thus, the temperature activates eukaryotic LDHs via the same conformational changes observed in the allosteric bacterial LDHs. Our investigation provides an extended molecular picture of eukaryotic LDH's conformational landscape that enriches the static view based on crystallographic studies alone.

  16. Thermal activation of ‘allosteric-like’ large-scale motions in a eukaryotic Lactate Dehydrogenase

    PubMed Central

    Katava, Marina; Maccarini, Marco; Villain, Guillaume; Paciaroni, Alessandro; Sztucki, Michael; Ivanova, Oxana; Madern, Dominique; Sterpone, Fabio

    2017-01-01

    Conformational changes occurring during the enzymatic turnover are essential for the regulation of protein functionality. Individuating the protein regions involved in these changes and the associated mechanical modes is still a challenge at both experimental and theoretical levels. We present here a detailed investigation of the thermal activation of the functional modes and conformational changes in a eukaryotic Lactate Dehydrogenase enzyme (LDH). Neutron Spin Echo spectroscopy and Molecular Dynamics simulations were used to uncover the characteristic length- and timescales of the LDH nanoscale motions in the apo state. The modes involving the catalytic loop and the mobile region around the binding site are activated at room temperature, and match the allosteric reorganisation of bacterial LDHs. In a temperature window of about 15 degrees, these modes render the protein flexible enough and capable of reorganising the active site toward reactive configurations. On the other hand an excess of thermal excitation leads to the distortion of the protein matrix with a possible anti-catalytic effect. Thus, the temperature activates eukaryotic LDHs via the same conformational changes observed in the allosteric bacterial LDHs. Our investigation provides an extended molecular picture of eukaryotic LDH’s conformational landscape that enriches the static view based on crystallographic studies alone. PMID:28112231

  17. Spinal Motion and Muscle Activity during Active Trunk Movements – Comparing Sheep and Humans Adopting Upright and Quadrupedal Postures

    PubMed Central

    Valentin, Stephanie; Licka, Theresia F.

    2016-01-01

    Sheep are used as models for the human spine, yet comparative in vivo data necessary for validation is limited. The purpose of this study was therefore to compare spinal motion and trunk muscle activity during active trunk movements in sheep and humans. Three-dimensional kinematic data as well as surface electromyography (sEMG) of spinal flexion and extension was compared in twenty-four humans in upright (UR) and 4-point kneeling (KN) postures and in 17 Austrian mountain sheep. Kinematic markers were attached over the sacrum, posterior iliac spines, and spinous and transverse processes of T5, T8, T11, L2 and L5 in humans and over the sacrum, tuber sacrale, T5, T8, T12, L3 and L7 in sheep. The activity of erector spinae (ES), rectus abdominis (RA), obliquus externus (OE), and obliquus internus (OI) were collected. Maximum sEMG (MOE) was identified for each muscle and trial, and reported as a percentage (MOE%) of the overall maximally observed sEMG from all trials. Spinal range of motion was significantly smaller in sheep compared to humans (UR / KN) during flexion (sheep: 6–11°; humans 12–34°) and extension (sheep: 4°; humans: 11–17°). During extension, MOE% of ES was greater in sheep (median: 77.37%) than UR humans (24.89%), and MOE% of OE and OI was greater in sheep (OE 76.20%; OI 67.31%) than KN humans (OE 21.45%; OI 19.34%), while MOE% of RA was lower in sheep (21.71%) than UR humans (82.69%). During flexion, MOE% of RA was greater in sheep (83.09%) than humans (KN 47.42%; UR 41.38%), and MOE% of ES in sheep (45.73%) was greater than KN humans (14.45%), but smaller than UR humans (72.36%). The differences in human and sheep spinal motion and muscle activity suggest that caution is warranted when ovine data are used to infer human spine biomechanics. PMID:26741136

  18. Knee joint loading during lineman-specific movements in American football players.

    PubMed

    Lambach, Rebecca L; Young, Jay W; Flanigan, David C; Siston, Robert A; Chaudhari, Ajit M

    2015-06-01

    Linemen are at high risk for knee cartilage injuries and osteoarthritis. High-intensity movements from squatting positions (eg, 3-point stance) may produce high joint loads, increasing the risk for cartilage damage. We hypothesized that knee moments and joint reaction forces during lineman-specific activities would be greater than during walking or jogging. Data were collected using standard motion analysis techniques. Fifteen NCAA linemen (mean ± SD: height = 1.86 ± 0.07 m, mass = 121.45 ± 12.78 kg) walked, jogged, and performed 3 unloaded lineman-specific blocking movements from a 3-point stance. External 3-dimensional knee moments and joint reaction forces were calculated using inverse dynamics equations. MANOVA with subsequent univariate ANOVA and post hoc Tukey comparisons were used to determine differences in peak kinetic variables and the flexion angles at which they occurred. All peak moments and joint reaction forces were significantly higher during jogging than during all blocking drills (all P < .001). Peak moments occurred at average knee flexion angles > 70° during blocking versus < 44° in walking or jogging. The magnitude of moments and joint reaction forces when initiating movement from a 3-point stance do not appear to increase risk for cartilage damage, but the high flexion angles at which they occur may increase risk on the posterior femoral condyles.

  19. A musculoskeletal modeling approach for estimating anterior cruciate ligament strains and knee anterior-posterior shear forces in stop-jumps performed by young recreational female athletes.

    PubMed

    Kar, Julia; Quesada, Peter M

    2013-02-01

    The central goal of this study was to contribute to the advancements being made in determining the underlying causes of anterior cruciate ligament (ACL) injuries. ACL injuries are frequently incurred by recreational and professional young female athletes during non-contact impact activities in sports like volleyball and basketball. This musculoskeletal-neuromuscular study investigated stop-jumps and factors related to ACL injury like knee valgus and internal-external moment loads, knee anterior-posterior (AP) shear forces, ACL strains and internal forces. Motion capture data was obtained from the landing phase of stop-jumps performed by eleven young recreational female athletes and electromyography (EMG) data collected from quadriceps, hamstring and gastrocnimius muscles which were then compared to numerically estimated activations. Numerical simulation tools used were Inverse Kinematics, Computed Muscle Control and Forward Dynamics and the knee modeled as a six degree of freedom joint. Results showed averaged peak strains of 12.2 ± 4.1% in the right and 11.9 ± 3.0% in the left ACL. Averaged peak knee AP shear forces were 482.3 ± 65.7 N for the right and 430.0 ± 52.4 N for the left knees, approximately equal to 0.7-0.8 times body weight across both knees. A lack of symmetry was observed between the knees for valgus angles (p < 0.04), valgus moments (p < 0.001) and muscle activations (p < 0.001), all of which can be detrimental to ACL stability during impact activities. Comparisons between recorded EMG data and estimated muscle activations show the relation between electrical signal and muscle depolarization. In summary, this study outlines a musculoskeletal simulation approach that provides numerical estimations for a number of variables associated with ACL injuries in female athletes performing stop-jumps.

  20. Dynamic analysis of astronaut motions in microgravity: Applications for Extravehicular Activity (EVA)

    NASA Technical Reports Server (NTRS)

    Newman, Dava J.

    1995-01-01

    Simulations of astronaut motions during extravehicular activity (EVA) tasks were performed using computational multibody dynamics methods. The application of computational dynamic simulation to EVA was prompted by the realization that physical microgravity simulators have inherent limitations: viscosity in neutral buoyancy tanks; friction in air bearing floors; short duration for parabolic aircraft; and inertia and friction in suspension mechanisms. These limitations can mask critical dynamic effects that later cause problems during actual EVA's performed in space. Methods of formulating dynamic equations of motion for multibody systems are discussed with emphasis on Kane's method, which forms the basis of the simulations presented herein. Formulation of the equations of motion for a two degree of freedom arm is presented as an explicit example. The four basic steps in creating the computational simulations were: system description, in which the geometry, mass properties, and interconnection of system bodies are input to the computer; equation formulation based on the system description; inverse kinematics, in which the angles, velocities, and accelerations of joints are calculated for prescribed motion of the endpoint (hand) of the arm; and inverse dynamics, in which joint torques are calculated for a prescribed motion. A graphical animation and data plotting program, EVADS (EVA Dynamics Simulation), was developed and used to analyze the results of the simulations that were performed on a Silicon Graphics Indigo2 computer. EVA tasks involving manipulation of the Spartan 204 free flying astronomy payload, as performed during Space Shuttle mission STS-63 (February 1995), served as the subject for two dynamic simulations. An EVA crewmember was modeled as a seven segment system with an eighth segment representing the massive payload attached to the hand. For both simulations, the initial configuration of the lower body (trunk, upper leg, and lower leg) was a neutral

  1. Short-interval two-stage approach to primary total knee arthroplasty for acutely septic osteoarthritic knees.

    PubMed

    Hochreiter, Bettina; Strahm, Carol; Behrend, Henrik

    2016-10-01

    Treatment strategies for advanced knee osteoarthritis with coexistent joint infection are not well established. While in periprosthetic joint infection the two-stage approach has been studied extensively, only few case reports on two-stage total knee arthroplasty (TKA) for knee osteoarthritis with coexistent joint infection have been published. The purpose of this paper was to report on our method of implementing a two-stage TKA with intervening antibiotic-loaded articulating cement spacers and a short interval between first- and second-stage procedures to treat two patients with Staphylococcus aureus-infected end-stage knee osteoarthritis. Consistent infection eradication was found at a 1-year follow-up with postoperative range of motion and knee scores comparing favourably with those of other case series. Level of evidence V.

  2. Nociceptive nerve activity in an experimental model of knee joint osteoarthritis of the guinea pig: effect of intra-articular hyaluronan application.

    PubMed

    Gomis, Ana; Miralles, Ana; Schmidt, Robert F; Belmonte, Carlos

    2007-07-01

    Nociceptive impulse activity was recorded extracellularly from single A delta and C primary afferents of the guinea pig's medial articular nerve after induction of an experimental osteoarthritis in the knee joint by partial medial menisectomy and transection of the anterior cruciate ligament (PMM+TACL). Also, the analgesic effects of intra-articular hyaluronan solutions were evaluated. Healthy, PMM+TACL operated, sham-operated (opening of the joint capsule without PMM and TACL surgery) and acutely inflamed (intra-articular kaolin-carrageenan, K-C) animals were used. The stimulus protocol consisted of torque meter-controlled, standardized innocuous and noxious inward and outward rotations of the joint. This stimulus protocol of 50 s duration was repeated every 5 min for 70 min. One day, one week and three weeks after PMM+TACL, the movement-evoked discharges of A delta articular afferents were increased significantly over values found in sham-operated animals. The discharges of C fibers were significantly augmented only one week after PMM+TACL surgery. Filling of the joint cavity with a high viscosity hyaluronan solution (hylan G-F 20, Synvisc) immediately and three days after surgery reduced significantly the enhanced nerve activity observed in joint afferent fibers one day and one week after surgery. Augmentation of movement-evoked discharges in K-C acutely inflamed knee joints was similar to that observed one week after PMM+TACL. Our results indicate that in the PMM+TACL model of osteoarthritis in guinea pigs, enhancement of nociceptive responses to joint movement was primarily associated to post-surgical inflammation. Intra-articular injection of an elastoviscous hyaluronan solution reduced the augmented nerve activity.

  3. Comparison of electromyographic activity and range of neck motion in violin students with and without neck pain during playing.

    PubMed

    Park, Kyue-nam; Kwon, Oh-yun; Ha, Sung-min; Kim, Su-jung; Choi, Hyun-jung; Weon, Jong-hyuck

    2012-12-01

    Neck pain is common in violin students during a musical performance. The purpose of this study was to compare electromyographic (EMG) activity in superficial neck muscles with neck motion when playing the violin as well as neck range of motion (ROM) at rest, between violin students with and without neck pain. Nine violin students with neck pain and nine age- and gender-matched subjects without neck pain were recruited. Muscle activity of the bilateral upper trapezius, sternocleidomastoid, and superficial cervical extensor muscles was measured using surface EMG. Kinematic data on neck motion while playing and active neck ROM were also measured using a three-dimensional motion analysis system. Independent t-tests were used to compare EMG activity with kinematic data between groups. These analyses revealed that while playing, both the angle of left lateral bending and leftward rotation of the cervical spine were significantly greater in the neck pain group than among those without neck pain. Similarly, EMG activity of the left upper trapezius, both cervical extensors, and both sternocleidomastoid muscles were significantly greater in the neck pain group. The active ROM of left axial rotation was significantly lower in the neck pain group. These results suggest that an asymmetric playing posture and the associated increased muscle activity as well as decreased neck axial rotation may contribute to neck pain in violin students.

  4. Electromyographic Activity of Scapular Muscle Control in Free-Motion Exercise

    PubMed Central

    Nakamura, Yukiko; Tsuruike, Masaaki; Ellenbecker, Todd S.

    2016-01-01

    Context:  The appropriate resistance intensity to prescribe for shoulder rehabilitative exercise is not completely known. Excessive activation of the deltoid and upper trapezius muscles could be counterproductive for scapulohumeral rhythm during humeral elevation. Objective:  To identify the effects of different exercise intensities on the scapular muscles during a free-motion “robbery” exercise performed in different degrees of shoulder abduction in seated and standing positions. Design:  Descriptive laboratory study. Setting:  Kinesiology Adapted Physical Education Laboratory. Patients or Other Participants:  A total of 15 healthy male college students (age = 20.5 ± 2.2 years, height = 174.5 ± 5.3 cm, mass = 63.8 ± 6.0 kg). Intervention(s):  Participants performed 5 repetitions of a randomized exercise sequence of the robbery exercise in 2 body positions (seated, standing), 2 shoulder-abducted positions (W [20°], 90/90 [90°]) at 3 intensities (0%, 3%, and 7% body weight). Main Outcome Measure(s):  Electromyographic (EMG) activity of the upper trapezius, lower trapezius, serratus anterior, anterior deltoid, and infraspinatus muscles of the upper extremity was collected. All EMG activities were normalized by the maximal voluntary isometric contraction of each corresponding muscle (%). Results:  The serratus anterior, anterior deltoid, and infraspinatus EMG activities were greater at 7% body weight in the seated position compared with the standing position (P < .05). The EMG activities in all 5 muscles were greater in the 90/90 position than in the W position (P < .05). Conclusions:  Scapular muscle activity modulated relative to changes in body posture and resistance intensity. These findings will enable clinicians to prescribe the appropriate level of exercise intensity and positioning during shoulder rehabilitation. PMID:26986055

  5. Detection of (in)activity periods in human body motion using inertial sensors: a comparative study.

    PubMed

    Olivares, Alberto; Ramírez, Javier; Górriz, Juan M; Olivares, Gonzalo; Damas, Miguel

    2012-01-01

    Determination of (in)activity periods when monitoring human body motion is a mandatory preprocessing step in all human inertial navigation and position analysis applications. Distinction of (in)activity needs to be established in order to allow the system to recompute the calibration parameters of the inertial sensors as well as the Zero Velocity Updates (ZUPT) of inertial navigation. The periodical recomputation of these parameters allows the application to maintain a constant degree of precision. This work presents a comparative study among different well known inertial magnitude-based detectors and proposes a new approach by applying spectrum-based detectors and memory-based detectors. A robust statistical comparison is carried out by the use of an accelerometer and angular rate signal synthesizer that mimics the output of accelerometers and gyroscopes when subjects are performing basic activities of daily life. Theoretical results are verified by testing the algorithms over signals gathered using an Inertial Measurement Unit (IMU). Detection accuracy rates of up to 97% are achieved.

  6. Detection of (In)activity Periods in Human Body Motion Using Inertial Sensors: A Comparative Study

    PubMed Central

    Olivares, Alberto; Ramírez, Javier; Górriz, Juan M.; Olivares, Gonzalo; Damas, Miguel

    2012-01-01

    Determination of (in)activity periods when monitoring human body motion<