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Sample records for flexion knee deformity

  1. Flexion test in the coronal plane deformities of knee

    PubMed Central

    Gautam, V.K.; Maini, Lalit; Gupta, Rajat; Sabharwal, Akash; Arora, Sumit

    2013-01-01

    Background/aims A little information is available in the orthopaedic literature on the clinical bedside assessment of the coronal plane deformities of the knee. We aim to explain the ‘knee flexion test’ to make it useful for the clinicians and the students learning the art of orthopaedics. Methods and results We describe the principle, pre-requisites, fallacy, and modification of the ‘knee flexion test’ along with the illustrative case description that had genu valgum deformity of the left knee of tibial origin. Conclusion The ‘knee flexion test’ should be a part of clinical bedside assessment of the coronal plane deformities of the knee. PMID:26403549

  2. Successful Correction of Idiopathic Bilateral Flexion Deformity of Knee: A Rare Case Report

    PubMed Central

    Mugalur, Aakash; Pathak, Aditya C; Shahane, Sunil M; Samant, Ashwin

    2015-01-01

    Introduction: Bilateral Flexion Deformity commonly results secondary to cerebral palsy, poliomyelitis, haemophilia etc. It is accompanied by valgus deformity and external rotation at knee in long standing cases secondary to the contracture of the iliotibial tract. Flexion deformity at knees is an impediment to the normal ambulation and is difficult to address. Case Report: A 34 year old male presented with bilateral knee stiffness. He had multifocal tuberculosis and was bed ridden for almost a year and consequently developed bilateral knee flexion deformity of 60o with further flexion upto 120o. Patient was treated with gradual distraction using a modified external fixator and achieved full correction at the end of 6 weeks. At final followup patient was walking comfortably and was able to squat and sit crossed legged. Conclusion: Idiopathic isolated bilateral flexion deformity of knees is very rare and is an impediment to normal ambulation. Arthrodiastasis with indigenously designed fixator using the Ilizarov principle and modified fixator is a simple, efficient and cost effective treatment for flexion deformity of knee. PMID:27299020

  3. Deformation analysis of Hoffa's fat pad from CT images of knee flexion and extension

    NASA Astrophysics Data System (ADS)

    Hamarneh, Ghassan; Chu, Vincent; Bordalo-Rodrigues, Marcelo; Schweitzer, Mark

    2005-04-01

    Recent advances in medicine conjecture that certain body fat may have mechanical function in addition to its classical role of energy storage. In particular we aim to analyze if the intra-articular fat pad of Hoffa is merely a space holder or if it changes shape to provide cushioning for the knee bones. Towards this goal, 3D CT images of real knees, as well as a skeletal knee model with fat simulating Hoffa's pad, were acquired in both extension and flexion. Image segmentation was performed to automatically extract the real and simulated fat regions from the extension and flexion images. Utilizing the segmentation results as binary masks, we performed automatic multi-resolution image registration of the fat pad between flexed and extended knee positions. The resulting displacement fields from flexion-extension registration are examined and used to calculate local fat volume changes thus providing insight into shape changes that may have a mechanical component.

  4. 3D skin length deformation of lower body during knee joint flexion for the practical application of functional sportswear.

    PubMed

    Choi, Jiyoung; Hong, Kyunghi

    2015-05-01

    With the advent of 3D technology in the design process, a tremendous amount of scanned data is available. However, it is difficult to trace the quantitative skin deformation of a designated location on the 3D body surface data during movement. Without identical landmarks or reflective markers, tracing the same reference points on the different body postures is not easy because of the complex shape change of the body. To find the least deformed location on the body, which is regarded as the optimal position of seams for the various lengths of functional compression pants, landmarks were directly marked on the skin of six subjects and scanned during knee joint flexion. Lines of non-extension (LoNE) and maximum stretch (LoMS) were searched for, both by tracing landmarks and newly drawn guidelines based on ratio division in various directions. Considering the waist as the anchoring position of the pants, holistic changes were quantified and visualized from the waistline in lengthwise and curvilinear deformation along the dermatomes of the lower body for various lengths of pants. Widthwise and unit area skin deformation data of the skin were also provided as guidelines for further use such as streamlined pants or design of other local wearing devices. PMID:25683546

  5. Distal femoral cut perpendicular to the mechanical axis may induce varus instability in flexion in medial osteoarthritic knees with varus deformity in total knee arthroplasty: a pitfall of the navigation system.

    PubMed

    Nagamine, Ryuji; Kondo, Keiichi; Ikemura, Satoshi; Shiranita, Atsushi; Nakashima, Satoshi; Hara, Toshihiko; Ihara, Hidetoshi; Sugioka, Yoichi

    2004-01-01

    Two factors that influence the external rotation angle of the femoral rotational axis in total knee arthroplasty (TKA) were assessed in 40 medial osteoarthritic knees with varus deformity. First, the anatomic configuration of the femur was assessed using standardized radiographs of the patients' lower extremities before TKA. Second, the degree of medial soft tissue release was assessed during TKA. The radiographs showed that the characteristics of the femur were lateral bowing of the shaft and external rotation of the condyle in the coronal plane. Therefore, when the distal femur is cut perpendicular to the mechanical axis, the cut surface may be in too much of a valgus position. Furthermore, some degree of medial soft tissue release was necessary in all knees. Medial soft tissue release rotates the femur externally in extension in the coronal plane, and it rotates the femur externally around the femoral axis in flexion relative to the tibia. A distal femoral cut in too much of a valgus position and medial soft tissue release induces varus instability in flexion in knees with lateral bowing of the femoral shaft. Anatomic variation such as femoral bowing should be considered when a navigation system is used for TKA because the navigation system shows only the mechanical axis. PMID:16228670

  6. Use of embedded strain gages for the in-vitro study of proximal tibial cancellous bone deformation during knee flexion-extension movement: development, reproducibility and preliminary results of feasibility after frontal low femoral osteotomy

    PubMed Central

    2011-01-01

    Background This paper reports the development of an in-vitro technique allowing quantification of relative (not absolute) deformations measured at the level of the cancellous bone of the tibial proximal epiphysis (CBTPE) during knee flexion-extension. This method has been developed to allow a future study of the effects of low femoral osteotomies consequence on the CBTPE. Methods Six strain gages were encapsulated in an epoxy resin solution to form, after resin polymerisation, six measurement elements (ME). The latter were inserted into the CBTPE of six unembalmed specimens, just below the tibial plateau. Knee motion data were collected by three-dimensional (3D) electrogoniometry during several cycles of knee flexion-extension. Intra- and inter-observer reproducibility was estimated on one specimen for all MEs. Intra-specimen repeatability was calculated to determine specimen's variability and the error of measurement. A varum and valgum chirurgical procedure was realised on another specimen to observed CBTPE deformation after these kind of procedure. Results Average intra-observer variation of the deformation ranged from 8% to 9% (mean coefficient of variation, MCV) respectively for extension and flexion movement. The coefficient of multiple correlations (CMC) ranged from 0.93 to 0.96 for flexion and extension. No phase shift of maximum strain peaks was observed. Inter-observer MCV averaged 23% and 28% for flexion and extension. The CMC were 0.82 and 0.87 respectively for extension and flexion. For the intra-specimen repeatability, the average of mean RMS difference and the mean ICC were calculated only for flexion movement. The mean RMS variability ranged from 7 to 10% and the mean ICC was 0.98 (0.95 - 0.99). A Pearson's correlation coefficient was calculated showing that RMS was independent of signal intensity. For the chirurgical procedure, valgum and varum deviation seems be in agree with the frontal misalignment theory. Conclusions Results show that the

  7. [A man with a painful knee with restricted flexion].

    PubMed

    Valkering, Lucia J J; Zengerink, Maartje; van Kampen, Albert

    2015-01-01

    A 39-year-old man presented with knee pain and limited knee flexion. MRI showed a mucoid degeneration of the anterior cruciate ligament (celery stalk sign). This rare condition can be treated with arthroscopic debridement with volume reduction of the anterior cruciate ligament. In severe cases, anterior cruciate ligament resection could be considered. PMID:26395568

  8. 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

  9. Interrater Reliability of Isokinetic Measures of Knee Flexion and Extension

    PubMed Central

    Keskula, Douglas R.; Dowling, Jeffrey S.; Davis, Virginia L.; Finley, Paula W.; Dell'Omo, Daniel L.

    1995-01-01

    The purpose of this investigation was to determine the interrater reliability of peak torque and total work values obtained with isokinetic measures of knee flexion and extension. Eight male and eight female students were evaluated on four occasions by four different examiners (range of isokinetic test experience: 0 to 10 yrs) using a standardized isokinetic measurement protocol. Subjects were randomly assigned to participate in a test sequence determined by a 4 × 4 balanced Latin square. Peak torque and total work values at 60°/sec and 180°/sec were obtained for the concentric measures of knee extension and flexion. The measures of peak torque and total work were corrected for the effects of gravity. Intraclass correlation coefficients and standard error of measurement estimates were used to estimate the interrater reliability for each test condition (test speed × muscle group). Intraclass correlation coefficient values ranged from .90 to .96 for peak torque and .90 to .95 for total work. Standard error of measurement estimates ranged from 8.9 to 13.3 Nm for peak torque and 11.3 to 16.8 Nm for total work. The results of this investigation demonstrate that reliable measures of isokinetic muscle performance of knee extension and flexion may be obtained by four clinicians with varied experience when following a standardized measurement protocol. ImagesFig 1.Fig 2. PMID:16558330

  10. Relationship Between Force Production During Isometric Squats and Knee Flexion Angles During Landing.

    PubMed

    Fisher, Harry; Stephenson, Mitchell L; Graves, Kyle K; Hinshaw, Taylour J; Smith, Derek T; Zhu, Qin; Wilson, Margaret A; Dai, Boyi

    2016-06-01

    Fisher, H, Stephenson, ML, Graves, KK, Hinshaw, TJ, Smith, DT, Zhu, Q, Wilson, MA, and Dai, B. Relationship between force production during isometric squats and knee flexion angles during landing. J Strength Cond Res 30(6): 1670-1679, 2016-Decreased knee flexion angles during landing are associated with increased anterior cruciate ligament loading. The underlying mechanisms associated with decreased self-selected knee flexion angles during landing are still unclear. The purpose of this study was to establish the relationship between the peak force production at various knee flexion angles (35, 55, 70, and 90°) during isometric squats and the actual knee flexion angles that occur during landing in both men and women. A total of 18 men and 18 women recreational/collegiate athletes performed 4 isometric squats at various knee flexion angles while vertical ground reaction forces were recorded. Participants also performed a jump-landing-jump task while lower extremity kinematics were collected. For women, significant correlations were found between the peak force production at 55 and 70° of knee flexion during isometric squats and the knee flexion angle at initial contact of landing. There were also significant correlations between the peak force production at 55, 70, and 90° of knee flexion during isometric squats and the peak knee flexion angle during landing. These correlations tended to be stronger during isometric squats at greater knee flexion compared with smaller knee flexion. No significant correlations were found for men. Posture-specific strength may play an important role in determining self-selected knee flexion angles during landing for women. PMID:26566166

  11. Elongation of the collateral ligaments after cruciate retaining total knee arthroplasty and the maximum flexion of the knee.

    PubMed

    Park, Kwan Kyu; Hosseini, Ali; Tsai, Tsung-Yuan; Kwon, Young-Min; Li, Guoan

    2015-02-01

    The mechanisms that affect knee flexion after total knee arthroplasty (TKA) are still debatable. This study investigated the elongation of the superficial medial (sMCL) and lateral collateral ligaments (LCL) before and after a posterior cruciate retaining (CR) TKA. We hypothesized that overstretching of the collateral ligaments in high flexion after TKA could reduce maximal flexion of the knee. Three-dimensional models of 11 osteoarthritic knees of 11 patients including the insertions of the collateral ligaments were created using MR images. Each ligament was divided into three equal portions: anterior, middle and posterior portions. The shortest 3D wrapping length of each ligament portion was determined before and after the TKA surgery along a weight-bearing, single leg flexion path. The relationship between the changes of ligament elongation and the changes of the maximal knee flexion after TKAs was quantitatively analyzed. The sMCL showed significant increases in length only at low flexion after TKA; the LCL showed decreases in length at full extension, but increases with further flexion after TKA. The amount of increases of the maximum flexion angle after TKA was negatively correlated with the increases of the elongations of the anterior portion (p=0.010, r=0.733) and middle portion (p=0.049, r=0.604) of the sMCL as well as the anterior portion (p=0.010, r=0.733) of the LCL at maximal flexion of the knee. The results indicated that the increases of the length of the collateral ligaments at maximal flexion after TKA were associated with the decreases of the maximal flexion of the knee. Our data suggest that collateral ligament management should also be evaluated at higher knee flexion angles in order to optimize maximal flexion of the knee after TKAs. PMID:25555307

  12. Modelling and Analysis on Biomechanical Dynamic Characteristics of Knee Flexion Movement under Squatting

    PubMed Central

    Wang, Jianping; Tao, Kun; Li, Huanyi; Wang, Chengtao

    2014-01-01

    The model of three-dimensional (3D) geometric knee was built, which included femoral-tibial, patellofemoral articulations and the bone and soft tissues. Dynamic finite element (FE) model of knee was developed to simulate both the kinematics and the internal stresses during knee flexion. The biomechanical experimental system of knee was built to simulate knee squatting using cadaver knees. The flexion motion and dynamic contact characteristics of knee were analyzed, and verified by comparing with the data from in vitro experiment. The results showed that the established dynamic FE models of knee are capable of predicting kinematics and the contact stresses during flexion, and could be an efficient tool for the analysis of total knee replacement (TKR) and knee prosthesis design. PMID:25013852

  13. Is referencing the posterior condyles sufficient to achieve a rectangular flexion gap in total knee arthroplasty?

    PubMed

    Schnurr, Christoph; Nessler, Jochen; König, Dietmar Pierre

    2009-12-01

    Femoral malrotation in total knee arthroplasty causes flexion gap instability. Conventional instruments mostly reference the posterior condylar angle (PCA). The aim of this study was to verify whether the computer-navigated flexion gap (GAP) method produces a rectangular flexion gap and if a balanced flexion gap could also be achieved by referencing the PCA. A total of 100 knee prostheses were analysed using the navigated GAP method, and flexion gap symmetry along with femoral rotation were recorded. The GAP technique resulted in a rectangular flexion gap with adequate femoral rotational alignment. If the PCA technique had been used, only 51% of the femoral components would have been implanted in correct femoral rotation; the remaining 49% would have implanted with flexion gap instability. The GAP technique produces a rectangular flexion gap. The referencing of the PCA was shown to be less reliable. Thus, modern knee prosthesis instrumentation should not base femoral rotation solely on the PCA. PMID:18956189

  14. Knee extension and flexion: MR delineation of normal and torn anterior cruciate ligaments

    SciTech Connect

    Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru; Anno, Izumi; Itai, Yuji

    1996-03-01

    Our goal was to assess the effect of joint position of semiflexed and extended knees in MR delineation of the anterior cruciate ligament (ACL). With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semiflexed position (average 45{degrees} of flexion) within the magnet bore. Sets of oblique sagittal MR images were obtained for both extended and flexed knee positions. Thirty-two knees with intact ACLs and 43 knees with arthroscopically proven ACL tears were evaluated. Two observers compared paired MR images of both extended and flexed positions and rated them by a relative three point scale. Anatomic correlation in MR images was obtained by a cadaveric knee with incremental flexion. The MR images of flexed knees were more useful than of extended knees in 53% of the case reviews of femoral attachments and 36% of reviews of midportions of normal ACLs. Compared with knee extensions, the MR images for knee flexion provided better clarity in 48% of reviews of disrupted sites and 52% of residual bundles of torn ACLs. Normal ACL appeared taut in the knee extension and lax in semiflexion. Compared with MR images of knees in extension, MR images of knees in flexion more clearly delineate the femoral side of the ligament with wider space under the intercondylar roof and with decreased volume-averaging artifacts, providing superior visualization of normal and torn ACLs. 13 refs., 7 figs., 1 tab.

  15. Fixed Lunate Flexion Deformity in Distal Radius Fractures.

    PubMed

    Lee, Sanglim; Yu, Jae-Ha; Jeon, Suk Ha

    2016-06-01

    Carpal malalignments in malunion of distal radius fracture are considered as an adaptive response of the carpus to loss of normal architecture of the distal radius. This condition leads to mechanical overload, ligament attenuation and progressive dynamic instability around the wrist joint. Radial corrective osteotomy is suggested as a treatment option of carpal malalignment after distal radius malunion. In radiocarpal malalignment, the lunate is usually observed in flexion in contrast to its extension posture in the more common midcarpal malalignment. We report two cases of fixed lunate flexion deformity after a distal radius fracture, in which reduction and fixation of fresh fracture or corrective osteotomy of malunion were not successful. Arthritic changes were observed in the radiolunate joint on arthroscopy. Thus, fixed flexion deformity of the lunate might be associated with posttraumatic arthritic change in the radiolunate joint. PMID:27247752

  16. Fixed Lunate Flexion Deformity in Distal Radius Fractures

    PubMed Central

    Lee, Sanglim; Yu, Jae-Ha

    2016-01-01

    Carpal malalignments in malunion of distal radius fracture are considered as an adaptive response of the carpus to loss of normal architecture of the distal radius. This condition leads to mechanical overload, ligament attenuation and progressive dynamic instability around the wrist joint. Radial corrective osteotomy is suggested as a treatment option of carpal malalignment after distal radius malunion. In radiocarpal malalignment, the lunate is usually observed in flexion in contrast to its extension posture in the more common midcarpal malalignment. We report two cases of fixed lunate flexion deformity after a distal radius fracture, in which reduction and fixation of fresh fracture or corrective osteotomy of malunion were not successful. Arthritic changes were observed in the radiolunate joint on arthroscopy. Thus, fixed flexion deformity of the lunate might be associated with posttraumatic arthritic change in the radiolunate joint. PMID:27247752

  17. Mid-term outcomes of primary constrained condylar knee arthroplasty for severe knee deformity.

    PubMed

    Feng, Xiao-Bo; Yang, Cao; Fu, De-Hao; Ye, Shu-Nan; Liu, Xian-Zhe; Chen, Zhe; Rai, Saroj; Yang, Shu-Hua

    2016-04-01

    This study aimed to examine the clinical and radiographic outcomes of primary total knee arthroplasy (TKA) with use of NexGen® Legacy® Constrained Condylar Knee (CCK) prosthesis for severe knee deformity. Clinical data of 46 patients (48 knees in total, aged 61 years on average) with severe knee deformity who underwent TKA with NexGen® Legacy® CCK prosthesis between December 2007 and February 2012 were retrospectively analyzed. There were 34 knees with severe valgus with incompetent medial collateral ligament, 11 knees with severe flexion contracture with inability to achieve knee balancing in flexion and extension by posterior soft tissue release, 2 knees with Charcot arthritis with severe varus and bone loss, and 1 with traumatic osteoarthritis with severe varus and ligamentous instability. The mean duration of follow-up was 71 months (range 40-90 months). The New Knee Society scoring (NKSS) system and the Hospital for Special Surgery (HSS) score were used to evaluate the functional and clinical outcomes. Visual Analogue Scale (VAS) was used for pain measurement and Knee Society criteria for evaluation of radiological images. The results showed that, in the total 48 knees, 1 case of loosening due to short-stem tibial component at 3 months post-operatively underwent revision. The 6-year prosthesis survival rate in this cohort was 97.9%. There was no component infection occurring within 6 years. Significant post-operative improvements were found in NKSS and HSS scores. Patient satisfaction was significantly increased. Pain score was decreased significantly. Total functional score was improved from 31.46±11.43 to 86.42±8.87, range of motion (ROM) from 42.42°±23.57° to 95.31°±23.45° and the flexion contracture from 5.31°±7.87° to 0.92°±1.80°. Preoperative radiographic study showed excessive valgus (≥7°) in 37 knees, and varus deformity in 3 knees. Post-operative femorotibial alignment was valgus 3.88°±1.76° in 48 knees. Antero/posterior (A

  18. Biomechanical Considerations in the Design of High-Flexion Total Knee Replacements

    PubMed Central

    Cheng, Cheng-Kung; McClean, Colin J.; Lai, Yu-Shu; Chen, Wen-Chuan; Huang, Chang-Hung; Chang, Chia-Ming

    2014-01-01

    Typically, joint arthroplasty is performed to relieve pain and improve functionality in a diseased or damaged joint. Total knee arthroplasty (TKA) involves replacing the entire knee joint, both femoral and tibial surfaces, with anatomically shaped artificial components in the hope of regaining normal joint function and permitting a full range of knee flexion. In spite of the design of the prosthesis itself, the degree of flexion attainable following TKA depends on a variety of factors, such as the joint's preoperative condition/flexion, muscle strength, and surgical technique. High-flexion knee prostheses have been developed to accommodate movements that require greater flexion than typically achievable with conventional TKA; such high flexion is especially prevalent in Asian cultures. Recently, computational techniques have been widely used for evaluating the functionality of knee prostheses and for improving biomechanical performance. To offer a better understanding of the development and evaluation techniques currently available, this paper aims to review some of the latest trends in the simulation of high-flexion knee prostheses. PMID:24892040

  19. Knee Flexion and Daily Activities in Patients following Total Knee Replacement: A Comparison with ISO Standard 14243

    PubMed Central

    Wimmer, Markus A.; Nechtow, William; Schwenke, Thorsten; Moisio, Kirsten C.

    2015-01-01

    Walking is only one of many daily activities performed by patients following total knee replacement (TKR). The purpose of this study was to examine the hypotheses (a) that subject activity characteristics are correlated with knee flexion range of motion (ROM) and (b) that there is a significant difference between the subject's flexion/extension excursion throughout the day and the ISO specified input for knee wear testing. In order to characterize activity, the number of walking and stair stepping cycles, the time spent with dynamic and stationary activities, the number of activity sequences, and the knee flexion/extension excursion of 32 TKR subjects were collected during daily activity. Flexion/extension profiles were compared with the ISO 14243 simulator input profile using a level crossing classification algorithm. Subjects took an average of 3102 (range: 343–5857) walking cycles including 65 (range: 0–319) stair stepping cycles. Active and passive ROMs were positively correlated with stair walking time, stair step counts, and stair walking sequences. Simulated knee motion according to ISO showed significantly fewer level crossings at the flexion angles 20–40° and beyond 50° than those measured with the monitor. This suggests that implant wear testing protocols should contain more cycles and a variety of activities requiring higher knee flexion angles with incorporated resting/transition periods to account for the many activity sequences. PMID:26347875

  20. Arthrometric evaluation of stabilizing effect of knee functional bracing at different flexion angles.

    PubMed

    Seyed Mohseni, Saeedeh; Moss, Farzam; Karimi, Hossein; Kamali, Mohammad

    2009-01-01

    Previous in-vivo investigations on the stabilizing efficacy of knee bracing for ACL reconstructed patients have been often limited to 20-30 degrees of knee flexion. In this study, the effectiveness of a uniaxial hinged functional brace to improve the knee stability was assessed at 30, 60 and 90 degrees of knee flexion. Arthrometry tests were conducted on 15 healthy subjects before and following wearing the brace and the tibial displacements were measured at up to 150 N anterior forces. Results indicated that functional bracing has a significant stabilizing effect throughout the range of knee flexion examined (p < 0.05). The rate of effectiveness, however, was not consistent across the flexion range, e.g., 50% at 30 degrees and only 4% at 90 degrees. It was suggested that accurate sizing and fitting as well as attention to correct hinge placement relative to the femoral condyles can limit brace migration and improve its effectiveness in mid and deep knee flexion. With using adaptive limb fittings, through flexible pads, and a polycentric joint a more significant improvement of the overall brace performance and efficacy might be obtained. Key pointsFunctional bracing improves the knee joint stability mostly in extension posture.Unlike the non-braced condition, the least knee joint stability appears in mid and deep flexion angles when using a hinged brace.Accurate sizing and fitting and attention to correct hinge placement relative to the femoral condyles can limit brace migration and improve its effectiveness in mid and deep knee flexion.The overall brace performance and efficacy might be improved significantly using adaptive limb fittings through flexible pads and/or polycentric joints. PMID:24149533

  1. External Knee Adduction and Flexion Moments during Gait and Medial Tibiofemoral Disease Progression in Knee Osteoarthritis

    PubMed Central

    Chang, Alison H.; Moisio, Kirsten C.; Chmiel, Joan S.; Eckstein, Felix; Guermazi, Ali; Prasad, Pottumarthi V.; Zhang, Yunhui; Almagor, Orit; Belisle, Laura; Hayes, Karen; Sharma, Leena

    2015-01-01

    Objective Test the hypothesis that greater baseline peak external knee adduction moment (KAM), KAM impulse, and peak external knee flexion moment (KFM) during the stance phase of gait are associated with baseline-to-2-year medial tibiofemoral cartilage damage and bone marrow lesion progression, and cartilage thickness loss. Methods Participants all had knee OA in at least one knee. Baseline peak KAM, KAM impulse, and peak KFM (normalized to body weight and height) were captured and computed using a motion analysis system and 6 force plates. Participants underwent MRI of both knees at baseline and two years later. To assess the association between baseline moments and baseline-to-2-year semiquantitative cartilage damage and bone marrow lesion progression and quantitative cartilage thickness loss, we used logistic regression with generalized estimating equations (GEE), adjusting for gait speed, age, gender, disease severity, knee pain severity, and medication use. Results The sample consisted of 391 knees (204 persons): mean age 64.2 years (SD 10.0); BMI 28.4 kg/m2 (5.7); 156 (76.5%) women. Greater baseline peak KAM and KAM impulse were each associated with worsening of medial bone marrow lesions, but not cartilage damage. Higher baseline KAM impulse was associated with 2-year medial cartilage thickness loss assessed both as % loss and as a threshold of loss, whereas peak KAM was related only to % loss. There was no relationship between baseline peak KFM and any medial disease progression outcome measures. Conclusion Findings support targeting KAM parameters in an effort to delay medial OA disease progression. PMID:25677110

  2. The Effect of Stabilization on Isokinetic Knee Extension and Flexion Torque Production

    PubMed Central

    Magnusson, S. Peter; Geismar, Richard A.; Gleim, Gilbert W.; Nicholas, James A.

    1993-01-01

    The purpose of this study was to examine the effect of four methods of stabilization on maximal reciprocal isokinetic knee extension and flexion. Left knee extension/flexion was tested at 60°/s in 20 subjects. Warm-up consisted of five submaximal and one maximal effort followed by three maximal efforts in each of four randomized stabilization conditions: 1) Hands and back stabilization; the trunk was strapped to the back rest and the hands grasped the seat. 2) Back stabilization; the trunk was strapped to the back rest and the hands were folded across the chest. 3) Hand stabilization; the hands grasped the seat and the back rest was removed. 4) No stabilization; the hands were folded across the chest and the back rest was removed. One-way repeated measures ANOVA showed a significant effect of stabilization for knee extension (F(3,57)=17.44, p=.0001) and knee flexion (F(3,57)= 5.37, p=.002). Paired, two-tailed student's t-tests with Bonferroni correction showed that, in knee extension, no stabilization was significantly less than all others, p<.001. In addition, back stabilization was less than hands and back stabilization, p<.005. In knee flexion, no stabilization was significantly less than all others, p<.01. In conclusion, the method of trunk stabilization significantly affected maximal reciprocal isokinetic knee extension/flexion strength measurements. Maximal knee extension/flexion torque production was achieved when the trunk was strapped to the back support and when the hands grasped the seat. ImagesFig 1a.Fig 1b.Fig 1c.Fig 1d. PMID:16558235

  3. Thigh-calf contact: does it affect the loading of the knee in the high-flexion range?

    PubMed

    Zelle, J; Barink, M; De Waal Malefijt, M; Verdonschot, N

    2009-03-26

    Recently, high-flexion knee implants have been developed to provide for a large range of motion (ROM>120 degrees ) after total knee arthroplasty (TKA). Since knee forces typically increase with larger flexion angles, it is commonly assumed that high-flexion knee implants are subjected to larger loads than conventional knee implants. However, most high-flexion studies do not consider thigh-calf contact which occurs during high-flexion activities such as squatting and kneeling. In this study, we hypothesized that thigh-calf contact reduces the knee forces during deep knee flexion as the tibio-femoral load shifts from occurring inside the knee towards the thigh-calf contact interface. Hence, the effect of thigh-calf contact on the knee loading was evaluated using a free body diagram and a finite element model and both the knee forces and polyethylene stresses were analyzed. Thigh-calf contact force characteristics from an earlier study were included and a squatting movement was simulated. In general, we found thigh-calf contact considerably reduced both the knee forces and polyethylene stresses during deep knee flexion. At maximal flexion (155 degrees ), the compressive knee force decreased from 4.89 to 2.90 times the bodyweight (BW) in case thigh-calf contact was included and the polyethylene contact stress at the tibial post decreased from 49.3 to 28.1MPa. Additionally, there was a clear correlation between a subject's thigh and calf circumference and the force reduction at maximal flexion due to thigh-calf contact (R=0.89). The findings presented in this study can be used to optimize the mechanical behavior of high-flexion total knee arthroplasty designs. PMID:19200996

  4. DOES TOTAL KNEE REPLACEMENT MODIFY FLEXION AXIS OF THE KNEE ON FRONTAL AND AXIAL PLANE REGARDLESS FROM LIMB ALIGNMENT?

    PubMed

    Bruni, D; Bragonzoni, L; Bontempi, M; Iacono, F; Neri, M P; Bignozzi, S; Zaffagnini, S; Marcacci, M

    2015-01-01

    The optimal reference for rotational positioning of femoral component in total knee replacement (TKR) is debated. Navigation has been suggested for intra-op acquisition of patient’s specific kinematics and functional flexion axis (FFA). The main purpose of the present study is to prospectively investigate whether pre-operative FFA in patients with osteoarthritis (OA) and varus alignment changes after TKR and whether a correlation exists between post-op FFA and pre-op alignment. A navigated TKR was performed in 108 patients using a specific software to acquire passive joint kinematics before and after TKR. The knee was cycled through three passive range of motions (PROM), from 0° to 120°. FFA was computed using the mean helical axis algorithm. The angle between FFA and surgical TEA was determined on frontal (αf) and axial (αa) plane. The pre- and post-op hip-knee-ankle angle (HKA) was determined. Post-op FFA was different from pre-op FFA only on frontal plane. No significant difference was found on axial plane. No correlation was found between HKA-pre and αA-pre. A significant correlation was found between HKA-pre and αF–pre. The study concluded that TKR modifies FFA only on frontal plane. No difference was found on axial plane. Pre-op FFA is in a more varus position respect to TEA. The position of FFA on frontal plane is dependent on limb alignment. The present study has demonstrated TKR modifies the position of FFA only on frontal plane. The position of FFA on axial plane is not dependent on the amount of varus deformity and is not influenced by TKR. Level of evidence, IV, case series. PMID:26652498

  5. A principal component analysis approach to correcting the knee flexion axis during gait.

    PubMed

    Jensen, Elisabeth; Lugade, Vipul; Crenshaw, Jeremy; Miller, Emily; Kaufman, Kenton

    2016-06-14

    Accurate and precise knee flexion axis identification is critical for prescribing and assessing tibial and femoral derotation osteotomies, but is highly prone to marker misplacement-induced error. The purpose of this study was to develop an efficient algorithm for post-hoc correction of the knee flexion axis and test its efficacy relative to other established algorithms. Gait data were collected on twelve healthy subjects using standard marker placement as well as intentionally misplaced lateral knee markers. The efficacy of the algorithm was assessed by quantifying the reduction in knee angle errors. Crosstalk error was quantified from the coefficient of determination (r(2)) between knee flexion and adduction angles. Mean rotation offset error (αo) was quantified from the knee and hip rotation kinematics across the gait cycle. The principal component analysis (PCA)-based algorithm significantly reduced r(2) (p<0.001) and caused αo,knee to converge toward 11.9±8.0° of external rotation, demonstrating improved certainty of the knee kinematics. The within-subject standard deviation of αo,hip between marker placements was reduced from 13.5±1.5° to 0.7±0.2° (p<0.001), demonstrating improved precision of the knee kinematics. The PCA-based algorithm performed at levels comparable to a knee abduction-adduction minimization algorithm (Baker et al., 1999) and better than a null space algorithm (Schwartz and Rozumalski, 2005) for this healthy subject population. PMID:27079622

  6. Dynamic Finite Element Analysis of Mobile Bearing Type Knee Prosthesis under Deep Flexional Motion

    PubMed Central

    Mohd Anuar, Mohd Afzan; Todo, Mitsugu; Hirokawa, Shunji

    2014-01-01

    The primary objective of this study is to distinguish between mobile bearing and fixed bearing posterior stabilized knee prostheses in the mechanics performance using the finite element simulation. Quantifying the relative mechanics attributes and survivorship between the mobile bearing and the fixed bearing prosthesis remains in investigation among researchers. In the present study, 3-dimensional computational model of a clinically used mobile bearing PS type knee prosthesis was utilized to develop a finite element and dynamic simulation model. Combination of displacement and force driven knee motion was adapted to simulate a flexion motion from 0° to 135° with neutral, 10°, and 20° internal tibial rotation to represent deep knee bending. Introduction of the secondary moving articulation in the mobile bearing knee prosthesis has been found to maintain relatively low shear stress during deep knee motion with tibial rotation. PMID:25133247

  7. Quasi-stiffness of the knee joint in flexion and extension during the golf swing.

    PubMed

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2015-01-01

    Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment-angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment-angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery. PMID:25651162

  8. Orthopedic management of spina bifida. Part I: hip, knee, and rotational deformities.

    PubMed

    Swaroop, Vineeta T; Dias, Luciano

    2009-12-01

    Children with spina bifida develop a wide variety of congenital and acquired orthopedic deformities. Among these are hip deformities such as contracture, subluxation, or dislocation. Patients may also have problems with the knee joint, such as knee flexion or extension contracture, knee valgus deformity, or late knee instability and pain. In addition, rotational deformities of the lower extremities, either internal or external torsion, are common as well. This paper will review both the overall orthopedic care of a patient with spina bifida and provide a focused review of the diagnosis and management of the above deformities. In addition, this paper will review the incidence, etiology, classification, and prognosis of spina bifida. The use of gait analysis and orthoses will be covered as well. The forthcoming Part II will cover foot and ankle deformities in spina bifida. PMID:19856195

  9. Sex Differences in Knee Flexion Angle During a Rapid Change of Direction While Running

    PubMed Central

    Sheu, Christopher L.; Gray, Aaron M.; Brown, David; Smith, Brian A.

    2015-01-01

    Background: Females experience greater overall rates of athletic anterior cruciate ligament (ACL) injury than males. The specific mechanisms of the predisposition remain unclear. Hypothesis: Modeling of knee kinematics has shown that the more extended the knee joint, the greater the strain on the ACL. The authors hypothesized that female athletes would have a lesser degree of knee flexion than male athletes at initial ground contact while performing change-of-direction cutting maneuvers. Study Design: Controlled laboratory study. Methods: Twenty female and 20 male high school soccer athletes with at least 1 year of experience were recruited for the study. Athletes were excluded if they had a history of any major lower limb injury or current knee pain causing a reduction in training and/or competition. Reflective markers were attached at the greater trochanter of the femur, the lateral epicondyle of the knee, and the lateral malleolus of the ankle to enable motion capture. Each athlete performed 6 change-of-direction maneuvers in random order in front of 2 cameras. Multiple regression analysis was used to determine differences between the sexes from the motion data captured; P < .05 defined significance. Results: Statistically significant differences existed in knee flexion angles between male and female participants at the 90° and 135° cutting angles. At 90°, males and females showed initial contact knee flexion angles (mean ± SD) of 39.0° ± 6.8° and 29.3° ± 6.2°, respectively (P < .0001), and mean maximum flexion angles of 56.4° ± 6.9° and 49.7° ± 7.0°, respectively (P = .0036). At 135°, males and females showed mean initial contact knee flexion angles of 36.8° ± 7.9° and 29.7° ± 7.8°, respectively (P = .0053), and mean maximum flexion angles of 60.7° ± 8.1° and 51.6° ± 9.4°, respectively (P = .0017). Conclusion: The research conducted is intended to foster an awareness of injury disposition in female athletes and guide future

  10. Knee MRI under varying flexion angles utilizing a flexible flat cable antenna.

    PubMed

    Jia, Fan; Yuan, Hongyang; Zhou, Diange; Zhang, Jue; Wang, Xiaoying; Fang, Jing

    2015-04-01

    The aim of this study is to fabricate and test a novel flexible flat cable antenna (FFCA) for MRI of the knee at different flexion angles. The FFCA was made of a flat cable, a tuning/matching circuit and a signal transmission line. To test its feasibility and validity, in vitro and in vivo experiments were carried out on a 3.0 T MR scanner. The in vitro experiment suggested that the proposed FFCA could achieve a high signal-to-noise ratio (SNR) of 336, while the SNR of an eight-channel knee coil was 291, and phantom images from the FFCA are homogeneously distributed. In the in vivo experiment, the FFCA had a higher SNR of 169 in the region of interest and more than 48.5 cm of longitudinal coverage, while the corresponding values for the commercial coil were 153 and 22.5 cm. Finally, five sagittal knee images at different flexion angles were acquired. The FFCA could acquire satisfactory knee images at different flexion angles, with the advantages of simplicity, low cost, large field of view and high SNR. It may therefore be further used to improve MR image quality of the knee joint. PMID:25740180

  11. Investigating the Effects of Knee Flexion during the Eccentric Heel-Drop Exercise

    PubMed Central

    Weinert-Aplin, Robert A.; Bull, Anthony M.J.; McGregor, Alison H.

    2015-01-01

    This study aimed to characterise the biomechanics of the widely practiced eccentric heel-drop exercises used in the management of Achilles tendinosis. Specifically, the aim was to quantify changes in lower limb kinematics, muscle lengths and Achilles tendon force, when performing the exercise with a flexed knee instead of an extended knee. A musculoskeletal modelling approach was used to quantify any differences between these versions of the eccentric heel drop exercises used to treat Achilles tendinosis. 19 healthy volunteers provided a group from which optical motion, forceplate and plantar pressure data were recorded while performing both the extended and flexed knee eccentric heel-drop exercises over a wooden step when barefoot or wearing running shoes. This data was used as inputs into a scaled musculoskeletal model of the lower limb. Range of ankle motion was unaffected by knee flexion. However, knee flexion was found to significantly affect lower limb kinematics, inter-segmental loads and triceps muscle lengths. Peak Achilles load was not influenced despite significantly reduced peak ankle plantarflexion moments (p < 0.001). The combination of reduced triceps lengths and greater ankle dorsiflexion, coupled with reduced ankle plantarflexion moments were used to provide a basis for previously unexplained observations regarding the effect of knee flexion on the relative loading of the triceps muscles during the eccentric heel drop exercises. This finding questions the role of the flexed knee heel drop exercise when specifically treating Achilles tendinosis. Key points A more dorsiflexed ankle and a flexing knee are characteristics of performing the flexed knee heel-drop eccentric exercise. Peak ankle plantarflexion moments were reduced with knee flexion, but did not reduce peak Achilles tendon force. Kinematic changes at the knee and ankle affected the triceps muscle length and resulted in a reduction in the amount of Achilles tendon work performed. A version

  12. Effect of chronic knee osteoarthritis on flexion-relaxation phenomenon of the erector spinae in elderly females

    PubMed Central

    Jeong, Yeon-Gyu; Jeong, Yeon-Jae; Koo, Jung-Wan

    2016-01-01

    [Purpose] This study investigated the flexion-relaxation phenomenon of the erector spinae in elderly women with chronic knee osteoarthritis and determined whether the flexion-relaxation phenomenon can be used as a pain evaluation tool in such cases. [Subjects and Methods] Seventeen elderly females with chronic knee osteoarthritis and 13 healthy young females voluntarily participated in this study. They performed three postural positions in 15 s: trunk flexion, complete trunk flexion, and trunk extension, each for 5 s. While these positions were held, muscle activation of the thoracic and lumbar erector spinae were measured using surface electromyography. The flexion-relaxation rate was determined by dividing the values for trunk extension by those of complete trunk flexion and by dividing the values for trunk flexion by those of complete trunk flexion. [Results] According to our results, the flexion-relaxation phenomenon was different between healthy young and elderly females with chronic knee osteoarthritis. Specifically, there was a difference in the left thoracic erector spinae muscle, but not in the left and right lumbar erector spinae or right thoracic spinae muscle. [Conclusion] Our study demonstrated that the erector spinae muscle flexion-relaxation phenomenon can be used as a pain evaluation tool in elderly females with chronic knee osteoarthritis. PMID:27512244

  13. A Textile-Based Wearable Sensing Device Designed for Monitoring the Flexion Angle of Elbow and Knee Movements

    PubMed Central

    Shyr, Tien-Wei; Shie, Jing-Wen; Jiang, Chang-Han; Li, Jung-Jen

    2014-01-01

    In this work a wearable gesture sensing device consisting of a textile strain sensor, using elastic conductive webbing, was designed for monitoring the flexion angle of elbow and knee movements. The elastic conductive webbing shows a linear response of resistance to the flexion angle. The wearable gesture sensing device was calibrated and then the flexion angle-resistance equation was established using an assembled gesture sensing apparatus with a variable resistor and a protractor. The proposed device successfully monitored the flexion angle during elbow and knee movements. PMID:24577526

  14. DOES RECTUS FEMORIS TRANSFER INCREASE KNEE FLEXION DURING STANCE PHASE IN CEREBRAL PALSY?

    PubMed Central

    de Morais, Mauro César; Blumetti, Francesco Camara; Kawamura, Cátia Miyuki; Lopes, José Augusto Fernandes; Neves, Daniella Lins; Cardoso, Michelle de Oliveira

    2016-01-01

    ABSTRACT Objective: To evaluate whether distal rectus femoris transfer (DRFT) is related to postoperative increase of knee flexion during the stance phase in cerebral palsy (CP). Methods: The inclusion criteria were Gross Motor Function Classification System (GMFCS) levels I-III, kinematic criteria for stiff-knee gait at baseline, and individuals who underwent orthopaedic surgery and had gait analyses performed before and after intervention. The patients included were divided into the following two groups: NO-DRFT (133 patients), which included patients who underwent orthopaedic surgery without DRFT, and DRFT (83 patients), which included patients who underwent orthopaedic surgery that included DRFT. The primary outcome was to evaluate in each group if minimum knee flexion in stance phase (FMJFA) changed after treatment. Results: The mean FMJFA increased from 13.19° to 16.74° (p=0.003) and from 10.60° to 14.80° (p=0.001) in Groups NO-DRFT and DRFT, respectively. The post-operative FMJFA was similar between groups NO-DRFT and DRFT (p=0.534). The increase of FMJFA during the second exam (from 13.01° to 22.51°) was higher among the GMFCS III patients in the DRFT group (p<0.001). Conclusion: In this study, DRFT did not generate additional increase of knee flexion during stance phase when compared to the control group. Level of Evidence III, Retrospective Comparative Study. PMID:26997910

  15. Comparison of the thoracic flexion relaxation ratio and pressure pain threshold after overhead assembly work and below knee assembly work

    PubMed Central

    Yoo, Won-gyu

    2016-01-01

    [Purpose] The purpose of this study was to compare the thoracic flexion relaxation ratio following overhead work and below-knee work. [Subjects and Methods] Ten men (20–30 years) were recruited to this study. The thoracic flexion relaxation ratio and pressure pain threshold was measured after both overhead work and below-knee work. [Results] The pressure-pain thresholds of the thoracic erector spinae muscle decreased significantly from initial, to overhead, to below-knee work. Similarly, the thoracic flexion relaxation ratio decreased significantly from initial, to overhead, to below-knee work. [Conclusion] Below-knee work results in greater thoracic pain than overhead work. Future studies should investigate below-knee work in detail. This study confirmed the thoracic relaxation phenomenon in the mid-position of the thoracic erector spinae. PMID:26957744

  16. The use of navigation to obtain rectangular flexion and extension gaps during primary total knee arthroplasty and midterm clinical results.

    PubMed

    Seon, Jong-Keun; Song, Eun-Kyoo; Park, Sang-Jin; Lee, Dam-Seon

    2011-06-01

    The authors evaluated 112 knees treated by total knee arthroplasty (TKA) using a navigation-assisted modified gap balancing technique. Initial mediolateral gap differences in extension and in 90° of flexion were measured after proximal tibia bone cutting. Final flexion and extension gaps were measured by checking distances under equal tension before prosthesis insertion. Amount of femoral bone cutting and external rotations of femoral components were found to depend on initial gaps. Patients with a final rectangular gap had greater knee flexion angles preoperatively and at 1 year after TKA. However, no differences were observed between the clinical and radiologic outcomes of knees with rectangular and nonrectangular gaps at 1 or 4 years after TKA. The study shows that the navigation-assisted modified gap balancing technique provides an effective means of achieving rectangular flexion and extension gaps during TKA. PMID:20580194

  17. A model of human knee ligaments in the sagittal plane. Part 1: Response to passive flexion.

    PubMed

    Zavatsky, A B; O'Connor, J J

    1992-01-01

    The development of a mathematical model of the knee ligaments in the sagittal plane is presented. Essential features of the model are (a) the representation of selected cruciate ligament fibres as isometric links in a kinematic mechanism that controls passive knee flexion and (b) the mapping of all other ligament fibres between attachments on the tibia and femur. Fibres slacken and tighten as the ligament attachment areas on the bones move relative to each other. The model is used to study the shape and fibre length changes of the cruciate and collateral ligaments in response to passive flexion/extension of the knee. The model ligament shape and fibre length changes compare well qualitatively with experimental results reported in the literature. The results suggest that when designing and implanting a ligament replacement with the aim of reproducing the natural fibre strain patterns, the surgeon must not only implant through the natural attachment areas but must also maintain the natural fibre mapping and render all fibres just tight at the appropriate flexion angle. PMID:1482508

  18. Identifying the Functional Flexion-extension Axis of the Knee: An In-Vivo Kinematics Study

    PubMed Central

    Yin, Li; Chen, Kaining; Guo, Lin; Cheng, Liangjun; Wang, Fuyou; Yang, Liu

    2015-01-01

    Purpose This study aimed to calculate the flexion-extension axis (FEA) of the knee through in-vivo knee kinematics data, and then compare it with two major anatomical axes of the femoral condyles: the transepicondylar axis (TEA) defined by connecting the medial sulcus and lateral prominence, and the cylinder axis (CA) defined by connecting the centers of posterior condyles. Methods The knee kinematics data of 20 healthy subjects were acquired under weight-bearing condition using bi-planar x-ray imaging and 3D-2D registration techniques. By tracking the vertical coordinate change of all points on the surface of femur during knee flexion, the FEA was determined as the line connecting the points with the least vertical shift in the medial and lateral condyles respectively. Angular deviation and distance among the TEA, CA and FEA were measured. Results The TEA-FEA angular deviation was significantly larger than that of the CA-FEA in 3D and transverse plane (3.45° vs. 1.98°, p < 0.001; 2.72° vs. 1.19°, p = 0.002), but not in the coronal plane (1.61° vs. 0.83°, p = 0.076). The TEA-FEA distance was significantly greater than that of the CA-FEA in the medial side (6.7 mm vs. 1.9 mm, p < 0.001), but not in the lateral side (3.2 mm vs. 2.0 mm, p = 0.16). Conclusion The CA is closer to the FEA compared with the TEA; it can better serve as an anatomical surrogate for the functional knee axis. PMID:26039711

  19. Effect of Varying Hamstring Tension on Anterior Cruciate Ligament Strain During in Vitro Impulsive Knee Flexion and Compression Loading

    PubMed Central

    Withrow, Thomas J.; Huston, Laura J.; Wojtys, Edward M.; Ashton-Miller, James A.

    2008-01-01

    Background: The hamstring muscles are well positioned to limit both anterior tibial translation and anterior cruciate ligament strain during the knee flexion phase of a jump landing. We hypothesized that systematically increasing or decreasing hamstring tension during the knee flexion phase of a simulated jump landing would significantly affect peak relative strain in the anterior cruciate ligament. Methods: Ten cadaveric knees from four male and six female donors (mean age [and standard deviation] at the time of death, 60.3 ± 23.6 years) were mounted in a custom fixture to initially position the specimen in 25° of knee flexion and simulate axial impulsive loading averaging 1700 N to cause an increase in knee flexion. Quadriceps, hamstring, and gastrocnemius muscle forces were simulated with use of pretensioned linear springs, with the tension in the hamstrings arranged to be increased, held constant, decreased, at “baseline,” or absent during knee flexion. Impulsive loading applied along the tibia and femur was monitored with use of triaxial load transducers, while uniaxial load cells monitored quadriceps and medial and lateral hamstring forces. Relative strain in the anterior cruciate ligament was measured with use of a differential variable reluctance transducer, and tibiofemoral kinematics were measured optoelectronically. For each specimen, anterior cruciate ligament strains were recorded over eighty impact trials: ten preconditioning trials, ten “baseline” trials involving decreasing hamstring tension performed before and after three sets of ten trials conducted with increasing hamstring tension, constant hamstring tension, or no hamstring tension. Peak relative strains in the anterior cruciate ligament were normalized for comparison across specimens. Results: Increasing hamstring force during the knee flexion landing phase decreased the peak relative strain in the anterior cruciate ligament by >70% compared with the baseline condition (p = 0

  20. Correcting deformity in total knee arthroplasty: Techniques to avoid the release of collateral ligaments in severely deformed knees.

    PubMed

    Mullaji, A B; Shetty, G M

    2016-01-01

    Collateral ligament release is advocated in total knee arthroplasty (TKA) to deal with significant coronal plane deformities, but is also associated with significant disadvantages. We describe steps to avoid release of the collateral (superficial medial and lateral collateral) ligaments during TKA in severely deformed knees, while correcting deformity and balancing the knee. PMID:26733653

  1. In vivo kinematic analysis of a high-flexion posterior stabilized fixed-bearing knee prosthesis in deep knee-bending motion.

    PubMed

    Tamaki, Masashi; Tomita, Tetsuya; Yamazaki, Takaharu; Hozack, William J; Yoshikawa, Hideki; Sugamoto, Kazuomi

    2008-09-01

    The objective of this study was to evaluate in vivo kinematics of a high-flexion, posterior-stabilized fixed-bearing, total knee arthroplasty in weight-bearing deep knee-bending motion. A total of 20 knees implanted with the Scorpio Non-Restrictive Geometry knee system in 17 patients were assessed in this study. The Scorpio Non-Restrictive Geometry is a recent implant design with modifications made to accommodate a higher flexion range of motion and greater axial rotation, particularly during more functionally demanding activities. Patients were examined during a deep knee-bending motion using fluoroscopy, and femorotibial motion was determined using a 2-dimensional to 3-dimensional registration technique. The average flexion angle was 126.5 degrees (110 degrees -149 degrees ). The femoral component demonstrated a mean of 13.5 degrees (5.2 degrees -21 degrees ) external rotation. The external rotation increased up to maximum flexion. The pivot pattern was a medial pivot pattern similar to that reported in normal knee kinematics. PMID:18555651

  2. Effect of Posterior Tibial Slope on Flexion and Anterior-Posterior Tibial Translation in Posterior Cruciate-Retaining Total Knee Arthroplasty.

    PubMed

    Chambers, Andrew W; Wood, Addison R; Kosmopoulos, Victor; Sanchez, Hugo B; Wagner, Russell A

    2016-01-01

    Reduced posterior tibial slope (PTS) and posterior tibiofemoral translation (PTFT) in posterior cruciate-retaining (PCR) total knee arthroplasty (TKA) may result in suboptimal flexion. We evaluated the relationship between PTS, PTFT, and total knee flexion after PCR TKA in a cadaveric model. We performed a balanced PCR TKA using 9 transfemoral cadaver specimens and changed postoperative PTS in 1° increments. We measured maximal flexion and relative PTFT at maximal flexion. We determined significant changes in flexion and PTFT as a function of PTS. Findings showed an average increase in flexion of 2.3° and average PTFT increase of 1mm per degree of PTS increase when increasing PTS from 1° to 4° (P<.05). Small initial increases in PTS appear to significantly increase knee flexion and PTFT. PMID:26476469

  3. Two- to Four-Year Follow-up Results of Total Knee Arthroplasty Using a New High-Flexion Prosthesis

    PubMed Central

    Kim, Man Soo; Koh, In Jun; Jang, Sung Won; Jeon, Neung Han

    2016-01-01

    Purpose The purpose of this study was to evaluate minimum 2-year follow-up results of total knee arthroplasty (TKA) performed using a new high-flexion prosthesis design (LOSPA). Materials and Methods The 2- to 4-year results of 191 consecutive TKAs (177 patients) with the LOSPA posterior-stabilized prosthesis were evaluated. The patients were assessed clinically and radiographically using the Knee Society scoring system (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results The mean range of motion (ROM) increased significantly from 117.4° (range, 75° to 140°) preoperatively to 126.7° (range, 80° to 144°) postoperatively (p<0.001). The mean KSS and WOMAC scores improved significantly from 121.4 (range, 42 to 185) and 56.1 (range, 23 to 88) preoperatively to 174.0 (range, 130 to 200) and 16.4 (range, 0 to 85) postoperatively, respectively (both, p<0.001). One knee required revision for deep infection. No knee had aseptic loosening or osteolysis. Radiolucent lines were noted in 15 knees (7.9%). Conclusions The new high-flexion total knee prosthesis resulted in no early aseptic loosening of the component and improved postoperative ROM comparable to other high-flexion TKA prostheses at 2- to 4-year follow-ups. PMID:26955612

  4. A Multibody Knee Model Corroborates Subject-Specific Experimental Measurements of Low Ligament Forces and Kinematic Coupling During Passive Flexion.

    PubMed

    Kia, Mohammad; Schafer, Kevin; Lipman, Joseph; Cross, Michael; Mayman, David; Pearle, Andrew; Wickiewicz, Thomas; Imhauser, Carl

    2016-05-01

    A multibody model of the knee was developed and the predicted ligament forces and kinematics during passive flexion corroborated subject-specific measurements obtained from a human cadaveric knee that was tested using a robotic manipulator. The model incorporated a novel strategy to estimate the slack length of ligament fibers based on experimentally measured ligament forces at full extension and included multifiber representations for the cruciates. The model captured experimentally measured ligament forces (≤ 5.7 N root mean square (RMS) difference), coupled internal rotation (≤ 1.6 deg RMS difference), and coupled anterior translation (≤ 0.4 mm RMS difference) through 130 deg of passive flexion. This integrated framework of model and experiment improves our understanding of how passive structures, such as ligaments and articular geometries, interact to generate knee kinematics and ligament forces. PMID:26926010

  5. A Novel Device to Apply Controlled Flexion and Extension to the Rat Knee Following Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Eng, Mark Stasiak M.; Wiznia, Dan; Alzoobae, Saif; Ciccotti, Michael; Imhauser, Carl; Voigt, Clifford; Torzilli, Peter; Deng, Xenghua; Rodeo, Scott

    2013-01-01

    We designed and validated a novel device for applying flexion-extension cycles to a rat knee in an in-vivo model of anterior cruciate ligament reconstruction (ACL-R). Our device is intended to simulate rehabilitation motion and exercise post ACL-R to optimize physical rehabilitation treatments for the improved healing of tendon graft ligament reconstructions. The device was validated for repeatability of the knee kinematic motion by measuring the force versus angular rotation response from repeated trials using cadaver rats. The average maximum force required for rotating an ACL reconstructed rat knee through 100 degrees of flexion-extension was 0.4 N with 95 % variability for all trials within ±0.1 N PMID:22667683

  6. Obliteration of Intercondylar Notch Mimicking Flexion-Extension Gap Imbalance in a Cruciate Retaining Total Knee Arthroplasty

    PubMed Central

    Gungor, Harun Resit; Kiter, Esat; Akkaya, Semih; Ok, Nusret; Yorukoglu, Cagdas

    2015-01-01

    Following total knee arthroplasty (TKA), the most frequent cause of extension deficit and limitation of range of motion in early postoperative period is related to improper tensioning of soft tissues and failure to balance extension and flexion gaps. If a cruciate retaining (CR) prosthesis is the planned implant, then attention should be given to balancing the posterior cruciate ligament (PCL), and any factor that alters this balance may also cause deterioration of knee balance in postoperative period. Here, we report on an unusual case referred from another hospital because of continuous pain and restriction of knee motion in early postoperative period following CR-designed TKA that was initially thought to be due to flexion-extension imbalance. However, during the revision procedure, extruded cement to the intercondylar notch was found to be both mechanically blocking terminal extension and limiting flexion by possible mechanism of irritation of the synovial nerve endings around the stretched anterior fibers of PCL during flexion. This case was successfully treated by removal of extruded cement from intercondylar notch to decompress PCL, polyethylene exchange, and secondary patellar resurfacing. PMID:26185697

  7. Analysis of Impingement between Patella Bone and Bearing Post in Cruciate-Substituting High-Flexion Total Knee Arthroplasty

    PubMed Central

    Chon, Jegyun; Shin, Sangyeop; Jang, Gunil; Jeon, Taehyeon

    2016-01-01

    Background We investigated the causes of impingement between the patella bone and the bearing post during high flexion in cruciate-substituting total knee arthroplasty and proposed a treatment strategy. Methods This prospective cohort study included 218 cases that had undergone cruciate-substituting total knee arthroplasty from February 2014 to January 2015; a single surgeon performed the operation using the same method without patellar resurfacing in all patients. Results In these patients, the occurrence of impingement was determined by performing more than 120° high knee flexion after inserting a bearing perioperatively. The incidence of impingement was significantly associated with bearing design, femoral implant size, patella bone length, and patella inferior pole angle (p < 0.05). The impingement was resolved by resection of the lower articular side of the patella bone. Conclusions In the cruciate-substituting high-flexion total knee arthroplasty, impingement between the patella bone and bearing post was more common in patients with mobile bearing, small-size femoral component, and a long patella or a large inferior pole angle. In cases of intraoperative impingement between the patella bone and the bearing post, resection in the lower portion of the patella prevented impingement of the bearing with soft tissue or the patella by widening the space between the patella and the bearing post, which in turn prevented postoperative reduction in range of motion. PMID:27247740

  8. A low-riding patella in posterior stabilised total knee replacements alters quadriceps' mechanical advantage, resulting in reduced knee flexion moments.

    PubMed

    Ward, T R; Pandit, H; Hollinghurst, D; Zavatsky, A B; Gill, H S; Thomas, N P; Murray, D W

    2012-08-01

    Abnormal in vivo Total Knee Replacement (TKR) kinetics is influenced by a range of factors, particularly by changes to the knee's geometric parameters such as the patellar tendon moment arm (PTMA). In this study, ground reaction force (GRF) measurements were combined with simultaneous fluoroscopic image measurements to investigate the relationship between abnormal TKR kinetics and geometric parameters. Nine Scorpio Cruciate Retaining (CR) TKR (Stryker, Newbury, UK), nine Scorpio Posterior Stabilized (PS) TKR and seven normal subjects performed a step-up activity on a forceplate in view of a fluoroscope. The TKR subjects were part of a larger ongoing randomised controlled trial. The maximum external knee flexion moment was 22.0% lower in the Scorpio PS group compared to the Scorpio CR group. No significant differences in PTMA were found between the groups. The Scorpio PS had a low-riding patella, with a 30.7% reduction in patellar height compared to the Scorpio CR. This was probably due to using a thick tibial insert after PCL release in the PS, and led to an 8° increase in patellar flexion angle which altered the patellar mechanism and reduced quadriceps' mechanical advantage. Consequently, PS subjects stepped-up more cautiously with a reduced knee flexion moment. PMID:22015171

  9. Direct nerve suture and knee immobilization in 90° flexion as a technique for treatment of common peroneal, tibial and sural nerve injuries in complex knee trauma.

    PubMed

    Döring, Robert; Ciritsis, Bernhard; Giesen, Thomas; Simmen, Hans-Peter; Giovanoli, Pietro

    2012-01-01

    There are different ways to treat peripheral nerve injuries with concomitant defects in the lower extremity. One option is a direct nerve suture followed by immobilization of the knee in flexion as it is described for gunshot wounds that lead to lesions of the sciatic nerve and its terminal branches as well as isolated nerve lesions. We used this technique to treat a case of multiple nerve injuries of the lower extremity combined with a complex knee trauma including a lesion of both bones and the posterior capsule. To our knowledge, this technique has not yet been described for such a combined injury in literature. PMID:24968417

  10. Anterior tibial artery perforator plus flaps for reconstruction of post-burn flexion contractures of the knee joint

    PubMed Central

    Adhikari, S.; Bandyopadhyay, T.; Saha, J.K.

    2012-01-01

    Summary Background. Post-burn flexion contractures of the knee may arise even with adequate treatment of the burn injury. After release of the contracture, most of these defects require flap coverage. Here we describe the application of the perforator plus flap concept in the management of these contractures. Method. Between December 2010 and December 2011 five female and two male patients with knee contractures were operated on using a perforator plus flap from the anterior tibia artery perforator. In one patient both sides were operated on and the rest had unilateral surgeries. All patients had mature scars and the aetiology was thermal burn injury. All these contractures were categorized as Category 4 and Level 3 by the ICIDH guidelines with an average contracture angle of 87.5 degrees. The flap was raised after release of the defect and a Doppler study located the perforator below the fibular head. The base of the flap was kept intact at all times. The flap was then transposed towards the defect and inset in a tensionless manner. Results. All flaps survived well with marginal necrosis in only one flap, providing stable coverage to the knee joint. The average residual contracture was around 10 degrees and the average range of flexion was 10-120 degrees. Conclusion. The perforator plus flap can be an excellent choice in defects over the posterior aspect of the knee where important neurovascular structures and tendons are exposed. Level of evidence: Level IV. PMID:23233827

  11. Restoration of Stance Phase Knee Flexion during Walking after Spinal Cord Injury using a Variable Impedance Orthosis

    PubMed Central

    Bulea, Thomas C.; Kobetic, Rudi; Triolo, Ronald. J.

    2013-01-01

    A hybrid neuroprosthesis (HNP) combines lower extremity bracing with functional neuromuscular stimulation (FNS) to restore walking function and enhance the efficiency of ambulation. This report details the development of a novel HNP containing a variable impedance knee mechanism (VIKM) capable of supporting the knee against collapse while allowing controlled stance phase knee flexion. The design of a closed loop, finite state controller for coordination of VIKM activity with FNS-driven gait is presented. The controller is verified in testing during able bodied gait. The improved functionality provided by this system has the potential to delay the onset of fatigue and to expand FNS driven gait to allow walking over uneven terrains and down stairs. PMID:22254383

  12. Alignment Analyses in the Varus Osteoarthritic Knee Using Computer Navigation.

    PubMed

    Tan, Kelvin G; Sathappan, Sathappan S; Teo, Yee Hong; Low, Wilson C J

    2015-06-01

    Osteoarthritic (OA) knees with severe extension varus deformity seem to have correspondingly more severe flexion varus, especially beyond a certain tibiofemoral angle. Clinical measurement of flexion varus and fixed flexion deformity (FFD), which had been difficult to perform because of the spatial alignment of the knee in flexion, was recently made possible with computer navigation. We conducted a study to evaluate the relationship of extension and flexion varus in OA knees and to determine whether severity of FFD in the sagittal plane correlates with severity of coronal plane varus deformity. The study included 317 consecutive cases of computer-navigated total knee arthroplasty performed on OA knees with varus deformities. Three sets of values were extracted from the navigation data: varus angle at maximal knee extension, 90° knee flexion, and maximal knee extension. Correlation analyses were performed for extension and flexion varus, FFD, and coronal plane deformity. OA knees with extension varus of more than 10° had an incremental likelihood of more severe flexion varus. When the extension varus angle exceeded 20°, probability became almost certainty. There was no correlation between FFD and coronal plane varus deformity. PMID:26046998

  13. Double-concave deformity of the polyethylene tibial post in posterior stabilized total knee arthroplasty.

    PubMed

    Niki, Yasuo; Matsumoto, Hideo; Yoshimine, Fumihiro; Toyama, Yoshiaki; Suda, Yasunori; Banks, Scott A

    2010-04-01

    This report describes a unique case of bilateral total knee arthroplasty necessitating revision of the polyethylene insert, which showed prominent marks on the tibial post resulting from repeated seiza-style sitting. The patient presented 7 years postoperatively with knee pain and flexion disturbance due to continuous joint effusion persisting for more than 4 months. Proliferating synovia throughout the joint revealed reactive synovitis to polyethylene particles. The retrieved polyethylene inserts displayed double-concave deformity of the tibial post with burnishing and creep in tibiofemoral articulation. The damage pattern of retrieved polyethylene inserts reflected the data from tibiofemoral contact location obtained using a shape-matching technique in the early postoperative phase. This case provides an example of damage to the polyethylene tibial post caused by a floor-sitting lifestyle and the potential clinical sequelae. PMID:19261434

  14. Reliability of a simple fluoroscopic method to study sagittal plane femorotibial contact changes in total knee arthroplasties during flexion.

    PubMed

    Lacoste, C; Granizo, J J; Gómez-Barrena, E

    2007-08-01

    Clinical interest in sagittal plane kinematic analysis of the knee undergoing total knee replacement fosters the development of simple, reliable methods to estimate femorotibial contact in a regular clinical setting. In this study, the sagittal femorotibial contact was analysed in lateral X-rays and lateral fluoroscopic views, from extension to knee flexion. Quantitative and categorical data were obtained from these views by two different observers, and compared with data from direct views of the components. Interobserver and intermethod errors for quantitative and categorical data were evaluated based on correlation, kappa coefficient, and Bland-Altman graphs. Interobserver reproducibility of quantitative measurement from fluoroscopic views was r=0.96 while categorical assignment exhibited a kappa coefficient of 0.95. Reproducibility from plain radiographs was not so high, with a kappa coefficient of 0.64. High concordance was also obtained when the method was compared with the direct view of the implant, supporting these measurement techniques. Bland-Altman graphs confirmed the absence of bias in the intermethod comparison. Therefore, with the obvious limitation of rotational assessment, lateral fluoroscopic evaluation enhanced by a simple fitting technique can be used as a valuable tool for clinical evaluation of knee kinematics in the sagittal plane. PMID:17553683

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

    PubMed

    Vinstrup, Jonas; Calatayud, Joaquin; Jakobsen, Markus D; Sundstrup, Emil; Andersen, Lars L

    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

  16. 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

  17. Noninvasive determination of knee cartilage deformation during jumping.

    PubMed

    Filipovic, Nenad; Vulovic, Radun; Peulic, Aleksandar; Radakovic, Radivoje; Kosanic, Djordje; Ristic, Branko

    2009-01-01

    The purpose of this investigation was to use a combination of image processing, force measurements and finite element modeling to calculate deformation of the knee cartilage during jumping. Professional athletes performed jumps analyzed using a force plate and high-speed video camera system. Image processing was performed on each frame of video using a color recognition algorithm. A simplified mass-spring-damper model was utilized for determination of global force and moment on the knee. Custom software for fitting the coupling characteristics was created. Simulated results were used as input data for the finite element calculation of cartilage deformation in the athlete's knee. Computer simulation data was compared with the average experimental ground reaction forces. The results show the three-dimensional mechanical deformation distribution inside the cartilage volume. A combination of the image recognition technology, force plate measurements and the finite element cartilage deformation in the knee may be used in the future as an effective noninvasive tool for prediction of injury during jumping. Key pointsEven there are many existing mathematical models of force distribution during running or jumping (Liu et al, 1998), to our knowledge there is no interdisciplinary approach where imaging processing, finite element modeling and experimental force plate system are employed.The aim is to explore noninvasive deformation in the knee cartilage during athlete's jumping on the force plate.An original image algorithms and software were developed as well as complex mathematical models using high-performance computational power of finite element modeling together with one-dimensional dynamics model.The initial results showed cartilage deformation in the knee and future research will be focused on the methodology and more precisely determination of the stress and strain distribution in the knee cartilage during training phase of sportsman. PMID:24149600

  18. Longitudinal and transverse deformation of human Achilles tendon induced by isometric plantar flexion at different intensities.

    PubMed

    Iwanuma, Soichiro; Akagi, Ryota; Kurihara, Toshiyuki; Ikegawa, Shigeki; Kanehisa, Hiroaki; Fukunaga, Tetsuo; Kawakami, Yasuo

    2011-06-01

    The present study determined in vivo deformation of the entire Achilles tendon in the longitudinal and transverse directions during isometric plantar flexions. Twelve young women and men performed isometric plantar flexions at 0% (rest), 30%, and 60% of the maximal voluntary contraction (MVC) while a series of oblique longitudinal and cross-sectional magnetic resonance (MR) images of the Achilles tendon were taken. At the distal end of the soleus muscle belly, the Achilles tendon was divided into the aponeurotic (ATapo) and the tendinous (ATten) components. The length of each component was measured in the MR images. The widths of the Achilles tendon were determined at 10 regions along ATapo and at four regions along ATten. Longitudinal and transverse strains were calculated as changes in relative length and width compared with those at rest. The ATapo deformed in both longitudinal and transverse directions at 30%MVC and 60%MVC. There was no difference between the strains of the ATapo at 30%MVC and 60%MVC either in the longitudinal (1.1 and 1.6%) or transverse (5.0∼11.4 and 5.0∼13.9%) direction. The ATten was elongated longitudinally (3.3%) to a greater amount than ATapo, while narrowing transversely in the most distal region (-4.6%). The current results show that the magnitude and the direction of contraction-induced deformation of Achilles tendon are different for the proximal and distal components. This may be related to the different functions of Achilles tendon, i.e., force transmission or elastic energy storage during muscle contractions. PMID:21415176

  19. Robust 2D/3D registration for fast-flexion motion of the knee joint using hybrid optimization.

    PubMed

    Ohnishi, Takashi; Suzuki, Masahiko; Kobayashi, Tatsuya; Naomoto, Shinji; Sukegawa, Tomoyuki; Nawata, Atsushi; Haneishi, Hideaki

    2013-01-01

    Previously, we proposed a 2D/3D registration method that uses Powell's algorithm to obtain 3D motion of a knee joint by 3D computed-tomography and bi-plane fluoroscopic images. The 2D/3D registration is performed consecutively and automatically for each frame of the fluoroscopic images. This method starts from the optimum parameters of the previous frame for each frame except for the first one, and it searches for the next set of optimum parameters using Powell's algorithm. However, if the flexion motion of the knee joint is fast, it is likely that Powell's algorithm will provide a mismatch because the initial parameters are far from the correct ones. In this study, we applied a hybrid optimization algorithm (HPS) combining Powell's algorithm with the Nelder-Mead simplex (NM-simplex) algorithm to overcome this problem. The performance of the HPS was compared with the separate performances of Powell's algorithm and the NM-simplex algorithm, the Quasi-Newton algorithm and hybrid optimization algorithm with the Quasi-Newton and NM-simplex algorithms with five patient data sets in terms of the root-mean-square error (RMSE), target registration error (TRE), success rate, and processing time. The RMSE, TRE, and the success rate of the HPS were better than those of the other optimization algorithms, and the processing time was similar to that of Powell's algorithm alone. PMID:23138929

  20. The Effect of Upper Body Mass and Initial Knee Flexion on the Injury Outcome of Post Mortem Human Subject Pedestrian Isolated Legs.

    PubMed

    Petit, Philippe; Trosseille, Xavier; Dufaure, Nicolas; Dubois, Denis; Potier, Pascal; Vallancien, Guy

    2014-11-01

    In the ECE 127 Regulation on pedestrian leg protection, as well as in the Euro NCAP test protocol, a legform impactor hits the vehicle at the speed of 40 kph. In these tests, the knee is fully extended and the leg is not coupled to the upper body. However, the typical configuration of a pedestrian impact differs since the knee is flexed during most of the gait cycle and the hip joint applies an unknown force to the femur. This study aimed at investigating the influence of the inertia of the upper body (modelled using an upper body mass fixed at the proximal end of the femur) and the initial knee flexion angle on the lower limb injury outcome. In total, 18 tests were conducted on 18 legs from 9 Post Mortem Human Subjects (PMHS). The principle of these tests was to impact the leg at 40 kph using a sled equipped with 3 crushing steel tubes, the stiffness of which were representative of the front face of a European sedan (bonnet leading edge, bumper and spoiler). The mass of the equipped sled was 74.5 kg. The test matrix was designed to perform 4 tests in 4 configurations combining two upper body masses (either 0 or 3 kg) and two knee angles (0 or 20 degrees) at 40 kph (11 m/s) plus 2 tests at 9 m/s. Autopsies were performed on the lower limbs and an injury assessment was established. The findings of this study were first that the increase of the upper body mass resulted in more severe injuries, second that an initial flexion of the knee, corresponding to its natural position during the gait cycle, decreased the severity of the injuries, and third that based on the injury outcome, a test conducted with no upper body mass and the knee fully extended was as severe as a test conducted with a 3 kg upper body mass and an initial knee flexion of 20°. PMID:26192955

  1. Peak Torque and Average Power at Flexion/Extension of the Shoulder and Knee when Using a Mouth Guard in Adults with Mild Midline Discrepancy

    PubMed Central

    Lee, Sang-Yeol; Hong, Min-Ho; Choi, Seung-Jun

    2014-01-01

    [Purpose] This study was conducted to investigate the changes in torque and power during flexion and extension of the shoulder and the knee joints caused by midline correction using mouth guards made from different materials in adults with mild midline discrepancy. [Subjects] The subjects of this study were males (n=12) in their 20s who showed a 3–5 mm difference between the midlines of the upper and lower teeth but had normal masticatory function. [Methods] The torque and average power of the lower limb and upper limb were measured during flexion and extension according to various types of mouth guard. [Results] There were significant differences in relative torque and average power between three conditions (no mouth guard, soft-type mouth guard, and hard-type mouth guard) at shoulder flexion and extension. There were no significant differences in relative torque and average power between the three conditions at knee flexion and extension. [Conclusions] These results suggest that use of a mouth guard is a method by which people with a mild midline discrepancy can improve the stability of the entire body. PMID:25140095

  2. The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion

    PubMed Central

    Kerkum, Yvette L.; Buizer, Annemieke I.; van den Noort, Josien C.; Becher, Jules G.; Harlaar, Jaap; Brehm, Merel-Anne

    2015-01-01

    Introduction Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (p<0.05) was used to analyze the effects of different conditions. Compared to shoes-only, all vAFOs improved the knee angle and net moment similarly. Ankle power generation and work were preserved only by the spring-like vAFOs. All vAFOs decreased the net energy cost compared to shoes-only, but no differences were found between vAFOs, showing that the effects of spring-like vAFOs to promote push-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power. Trial

  3. Higher Knee Flexion Moment During the Second Half of the Stance Phase of Gait Is Associated With the Progression of Osteoarthritis of the Patellofemoral Joint on Magnetic Resonance Imaging

    PubMed Central

    Teng, Hsiang-Ling; Macleod, Toran D.; Link, Thomas M.; Majumdar, Sharmila; Souza, Richard B.

    2016-01-01

    STUDY DESIGN Controlled laboratory study, longitudinal design. OBJECTIVE To examine whether baseline knee flexion moment or impulse during walking is associated with the progression of osteoarthritis (OA) with magnetic resonance imaging of the patellofemoral joint (PFJ) at 1 year. BACKGROUND Patellofemoral joint OA is highly prevalent and a major source of pain and dysfunction. The biomechanical factors associated with the progression of PFJ OA remain unclear. METHODS Three-dimensional gait analyses were performed at baseline. Magnetic resonance imaging of the knee (high-resolution, 3-D, fast spin-echo sequence) was used to identify PFJ cartilage and bone marrow edema–like lesions at baseline and a 1-year follow-up. The severity of PFJ OA progression was defined using the modified Whole-Organ Magnetic Resonance Imaging Score when new or increased cartilage or bone marrow edema–like lesions were observed at 1 year. Peak external knee flexion moment and flexion moment impulse during the first and second halves of the stance phase of gait were compared between progressors and nonprogressors, and used to predict progression after adjusting for age, sex, body mass index, and presence of baseline PFJ OA. RESULTS Sixty-one participants with no knee OA or isolated PFJ OA were included. Patellofemoral joint OA progressors (n = 10) demonstrated significantly higher peak knee flexion moment (P = .01) and flexion moment impulse (P = .04) during the second half of stance at baseline compared to nonprogressors. Logistic regression showed that higher peak knee flexion moment during the second half of the stance phase was significantly associated with progression at 1 year (adjusted odds ratio = 3.3, P = .01). CONCLUSION Peak knee flexion moment and flexion moment impulse during the second half of stance are related to the progression of PFJ OA and may need to be considered when treating individuals who are at risk of or who have PFJ OA. PMID:26161626

  4. The Effect of Malrotation of Tibial Component of Total Knee Arthroplasty on Tibial Insert during High Flexion Using a Finite Element Analysis

    PubMed Central

    Todo, Mitsugu

    2014-01-01

    One of the most common errors of total knee arthroplasty procedure is a malrotation of tibial component. The stress on tibial insert is closely related to polyethylene failure. The objective of this study is to analyze the effect of malrotation of tibial component for the stress on tibial insert during high flexion using a finite element analysis. We used Stryker NRG PS for analysis. Three different initial conditions of tibial component including normal, 15° internal malrotation, and 15° external malrotation were analyzed. The tibial insert made from ultra-high-molecular-weight polyethylene was assumed to be elastic-plastic while femoral and tibial metal components were assumed to be rigid. Four nonlinear springs attached to tibial component represented soft tissues around the knee. Vertical load was applied to femoral component which rotated from 0° to 135° while horizontal load along the anterior posterior axis was applied to tibial component during flexion. Maximum equivalent stresses on the surface were analyzed. Internal malrotation caused the highest stress which arose up to 160% of normal position. External malrotation also caused higher stress. Implanting prosthesis in correct position is important for reducing the risk of abnormal wear and failure. PMID:24895658

  5. Computer-assisted surgery patterns of ligamentous deformity of the knee: a clinical and cadaveric study.

    PubMed

    Schwarzkopf, Ran; Hadley, Scott; Abbasi, Mohammed; Meere, Patrick A

    2013-08-01

    Knee malalignment during total knee arthroplasty (TKA) is commonly classified as either varus or valgus on the basis of a standing anteroposterior radiograph. Computer-assisted surgery (CAS) navigation TKA provides precise dynamic evaluation of knee alignment throughout the full range of motion (FROM). The goal of this study was to classify patterns of CAS-generated knee deformity curves that match specific soft tissue contracture combinations. This can then be applied as an algorithm for soft tissue balancing on the basis of the preoperative knee deformity curve. Computer navigation-generated graphs from 65 consecutive TKA procedures performed by a single surgeon were analyzed. A stress-strain curve of the coronal alignment of the knee was recorded throughout FROM before bony resection. All graphs were classified into groups according to their pattern. Cadaveric knee models were then used to test the correlation between isolated and combined ligamentous contractures and identified CAS deformity curves. An analysis of the intraoperative knee alignment graphs revealed four distinct patterns of coronal deformity on the basis of intraoperative data: 13% diagonal, 18.5% C-shaped, 43.5% comma shaped, and 25% S-shaped. Each represents the change in varus and valgus alignment during FROM. All patterns were reproduced with cadaveric knees by recreating specific contracture constellations. A tight posterior capsule gave an S-shaped curve, a tight lateral collateral ligament gave a C-shaped curve, tight medial collateral ligament gave a diagonal curve, and a tight posterior lateral corner gave a comma-shaped curve. Release of the specific contractures resulted in correction of all patterns of deformity as measured by CAS. We propose a new classification system for coronal plane knee deformity throughout FROM. This system intends to match individual and combined soft tissue pathological contractures to specific stress-strain curves obtained through routine knee CAS

  6. Effects of Reduction Osteotomy on Gap Balancing During Total Knee Arthroplasty for Severe Varus Deformity.

    PubMed

    Niki, Yasuo; Harato, Kengo; Nagai, Katsuya; Suda, Yasunori; Nakamura, Masaya; Matsumoto, Morio

    2015-12-01

    This study aimed to assess the effects of down-sizing and lateralizing of the tibial component (reduction osteotomy) on gap balancing in TKA, and the clinical feasibility of an uncemented modular trabecular metal tibial tray in this technique. Reduction osteotomy was performed for 39 knees of 36 patients with knee OA with a mean tibiofemoral angle of 21° varus. In 20 knees, appropriate gap balance was achieved by release of the deep medial collateral ligament alone. Flexion gap imbalance could be reduced by approximately 1.7° and 2.8° for 4-mm osteotomy and 8-mm osteotomy, respectively. Within the first postoperative year, clinically-stable tibial component subsidence was observed in 9 knees, but it was not progressive, and the clinical results were excellent at a mean follow-up of 3.3 years. PMID:26239234

  7. [Total endoprosthesis of knee joint for the severe deformity of the femoral and tibial condyles].

    PubMed

    Ternovoĭ, N K; Zazirnyĭ, I M; Kosiakov, A N; Dubok, V A; Ul'ianich, N V; Kikhniakevich, T G; Evseenko, V G

    2000-06-01

    The method of knee joint endoprosthesis for its pronounced deformity was proposed. As a transplant there was applied the ceramic hydroxiapatite, manufactured according to special technology. The implant was fixed on the transplant adjusted. PMID:11288279

  8. A Novel Medial Soft Tissue Release Method for Varus Deformity during Total Knee Arthroplasty: Femoral Origin Release of the Medial Collateral Ligament

    PubMed Central

    Lee, Seung-Yup; Yang, Jae-Hyuk; Lee, Yong-In

    2016-01-01

    Introduction Numerous methods of medial soft tissue release for severe varus deformity during total knee arthroplasty (TKA) have been reported. These include tibial stripping of the superficial medial collateral ligament (MCL), pie-crusting technique, and medial epicondylar osteotomy. However, there are inherent disadvantages in these techniques. Authors hereby present a novel quantitative method: femoral origin release of the medial collateral ligament (FORM). Surgical Technique For medial tightness remaining even after the release of the deep MCL and semimembranosus, the FORM is initiated with identification of the femoral insertion area of the MCL with the knee in flexion. Starting from the most posterior part of the femoral insertion, one third of the MCL femoral insertion is released from its attachment. If necessary, further sequential medial release is performed. Materials and Methods Seventeen knees that underwent the FORM were evaluated for radiological and clinical outcomes. Results Regardless of the extent of the FORM, no knees showed residual valgus instability at 24 weeks after surgery. Conclusions As the FORM is performed in a stepwise manner, fine adjustment during medial release might be beneficial to prevent inadvertent over-release of the medial structures of the knee. PMID:27274473

  9. Effect of Pedal Deformity on Gait in a Patient With Total Knee Arthroplasty.

    PubMed

    Wynes, Jacob; Lamm, Bradley M; Bhave, Anil; Elmallah, Randa K; Mont, Michael A

    2016-01-01

    The authors present the case of an 81-year-old man who, despite an anatomically aligned total knee arthroplasty, continued to have knee pain. The patient's ipsilateral rigid flatfoot caused by an earlier partial pedal amputation resulted in a valgus moment during gait, thus creating clinical symptoms in the total knee arthroplasty. Because of the deformity and scarring within the flatfoot, this valgus deformity was corrected through a varus distal femoral osteotomy. The result was normalization of the mechanical axis of the lower limb and a pain-free total knee arthroplasty with an excellent clinical outcome. This case shows the importance of comprehensive lower-extremity clinical and radiographic examination as well as gait analysis to understand the biomechanical effect on total knee arthroplasty. Recognition of pedal deformities and lower limb malalignment is paramount for achieving optimal outcomes and long-term success of total knee arthroplasty. The authors show that a rigid or nonflexible pedal deformity can have negative biomechanical effects on total knee arthroplasty. PMID:26709556

  10. 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. PMID:26575489

  11. Mini-midvastus total knee arthroplasty in patients with severe varus deformity.

    PubMed

    Liu, Hao-Chen; Kuo, Feng-Chih; Huang, Chung-Chen; Wang, Jun-Wen

    2015-02-01

    Patients with severe varus deformity of the knee (≥15° varus) usually are not considered good candidates for minimally invasive total knee arthroplasty (TKA). The goal of this study was to retrospectively investigate outcomes in patients with severe varus deformity after minimally invasive TKA. A study group of 52 patients with a tibiofemoral mechanical axis of 195° or greater was compared with a matched control group of 55 patients with a tibiofemoral mechanical axis of less than 195°. Clinical and radiographic evaluations according to the American Knee Society rating system were obtained preoperatively and postoperatively, and postoperative patient satisfaction in the 2 groups was compared. All patients were followed at a mean of 3 years (range, 2-5 years). Preoperatively, clinical knee and function scores and range of motion were inferior in the study group compared with the control group (P<.001). However, at the latest follow-up, both groups of patients were satisfied with the clinical results, and no significant differences were found in the knee and function scores (P>.05). Radiographic evaluation showed no differences in the mechanical axis, femoral component valgus angle, and tibial component valgus angle, and all outliers of the radiographic parameters between the 2 groups postoperatively (P >.05). The study results showed that mini-midvastus TKA did not result in more inaccurate implant positioning in patients with severe varus deformity of the knee. The clinical outcome in the group with severe varus was comparable to that in the group with less severe varus PMID:25665115

  12. Neglected surgically intervened bilateral congenital dislocation of knee in an adolescent

    PubMed Central

    Kumar, Jaswant; Dhammi, Ish Kumar; Jain, Anil K

    2014-01-01

    Neglected bilateral congenital dislocation of knee is unusual. A 12 year old boy presented with inability to walk due to buckling of the knee. The symptoms were present since the child learnt walking. He preferred not to walk. Bilateral supracondylar femoral osteotomy was done at the age of 6 years. Patient had a fixed flexion deformity of both knees, 30° in the right (range of flexion from 30° to 45°) and 45° fixed flexion deformity in left knee respectively (range of flexion from 45° to 65°) when presented to us. The radiological examination revealed bilateral congenital dislocation of knee (CDK). No syndromic association was observed. He was planned for staged treatment. In stage I, the knee joints were distracted by Ilizarov ring fixators and this was followed by open reduction of both the knee joints in stage II. A bilateral supracondylar extension osteotomy was done 18 months after the previous surgery (stage III). The final followup visit at 4 years the patient presented with range of motion 5-100° and 5-80° on the right and left knee respectively with good functional outcome. The case is reported in view of lack of treatment guidelines for long standing neglected CDK in an adolescent child. PMID:24600070

  13. Lateral dislocation of the knee joint after total knee arthroplasty: a case report

    PubMed Central

    Ugutmen, Ender; Ozkan, Korhan; Unay, Koray; Mahirogullari, Mahir; Eceviz, Engin; Taser, Omer

    2008-01-01

    Background Total knee arthroplasty (TKA) is a successful therapy for functional improvement and pain relief in advanced symptomatic degeneration of the knee joint. But it can be associated with many complications, one of which is instability. Case presentation A 70-year-old woman was referred to our hospital because of right knee dislocation after TKA was performed on her right knee due to severe varus deformity and flexion contracture. This instability was caused by persistent MCL tightness and iatrogenic lateral collateral, arcuate ligament, and popliteus tendon injury. The torn lateral collateral ligament and arcuate ligament were sutured with no. 2 non-absorbable (Ethibond) sutures with plication of the posterolateral knee capsule. A deep-dish liner was inserted to optimize soft tissue tension. Conclusion This is a very severe complication, and surgeons must be cautious about ligament balancing and soft tissue resection during TKA for severe varus and valgus deformities. PMID:18687153

  14. Radiologic Outcomes According to Varus Deformity in Minimally Invasive Surgery Total Knee Arthroplasty

    PubMed Central

    Yoo, Ju-Hyung; Han, Chang-Dong; Oh, Hyun-Cheol; Park, Jun-Young; Choi, Seung-Jin

    2016-01-01

    Purpose To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. Materials and Methods The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare the postoperative alignment of the implant: less than 5° varus (Group 1, 351 cases), 5° to less than 10° varus (Group 2, 189 cases), 10° to less than 15° varus (Group 3, 59 cases), and 15° varus or more (Group 4, 28 cases). Results On average, the alignment of the tibial implant was 0.2±1.4°, 0.1±1.3°, 0.1±1.6°, and 0.3±1.7° varus, and the tibiofemoral alignment was 5.2±1.9°, 4.7±1.9°, 4.9±1.9°, and 5.1±2.0° valgus for Groups 1, 2, 3, and 4, respectively, in the preoperative stage, indicating no difference between the groups (p>0.05). With respect to the accuracy of the tibial implant alignment, 98.1%, 97.6%, 87.5%, and 86.7% of Groups 1, 2, 3, and 4, respectively, had 0±3° varus angulation, demonstrating a reduced level of accuracy in Groups 3 and 4 (p<0.0001). There was no difference in terms of tibiofemoral alignment, with 83.9%, 82.9%, 85.4%, and 86.7% of each group, respectively, showing 6±3° valgus angulation (p>0.05). Conclusion Satisfactory component alignment was achieved in minimally invasive surgery in total knee arthroplasty, regardless of the degree of varus deformity. PMID:26632405

  15. Accuracy of implant positioning for minimally invasive total knee arthroplasty in patients with severe varus deformity.

    PubMed

    Niki, Yasuo; Matsumoto, Hideo; Otani, Toshiro; Enomoto, Hiroyuki; Toyama, Yoshiaki; Suda, Yasunori

    2010-04-01

    Minimally invasive surgery (MIS) in total knee arthroplasty (TKA) reportedly yields decreased patient morbidity and a rapid return of function, but how much deformity can be accepted for MIS-TKA remains unclear. This study investigated 238 knees from 218 consecutive patients who underwent MIS-TKA. Patients were divided into groups with tibiofemoral mechanical axis (TFM) 195 degrees or greater and TFM less than 195 degrees, then clinical and radiographic results were compared. Similar improvements in knee score at 3 months postoperatively were obtained in the both groups, whereas radiographic accuracy of the coronal alignment in the TFM >or=195 degrees group was inferior to that in TFM <195 degrees group. Postoperative TFM was significantly worsened in patients with lateral bowing angle of the femoral shaft (LBFS) 4 degrees or greater, and 53% of patients in the TFM >or=195 degrees group displayed LBFS 4 degrees or greater, explaining the inferior radiographic accuracy in this group compared with the TFM <195 degrees group. These results indicate that use of MIS techniques decreases radiographic accuracy, particularly in patients with severe genu varum and increased LBFS. PMID:20347714

  16. Validation of a novel smartphone accelerometer-based knee goniometer.

    PubMed

    Ockendon, Matthew; Gilbert, Robin E

    2012-09-01

    Loss of full knee extension following anterior cruciate ligament surgery has been shown to impair knee function. However, there can be significant difficulties in accurately and reproducibly measuring a fixed flexion of the knee. We studied the interobserver and the intraobserver reliabilities of a novel, smartphone accelerometer-based, knee goniometer and compared it with a long-armed conventional goniometer for the assessment of fixed flexion knee deformity. Five healthy male volunteers (age range 30 to 40 years) were studied. Measurements of knee flexion angle were made with a telescopic-armed goniometer (Lafayette Instrument, Lafayette, IN) and compared with measurements using the smartphone (iPhone 3GS, Apple Inc., Cupertino, CA) knee goniometer using a novel trigonometric technique based on tibial inclination. Bland-Altman analysis of validity and reliability including statistical analysis of correlation by Pearson's method was undertaken. The iPhone goniometer had an interobserver correlation (r) of 0.994 compared with 0.952 for the Lafayette. The intraobserver correlation was r = 0.982 for the iPhone (compared with 0.927). The datasets from the two instruments correlate closely (r = 0.947) are proportional and have mean difference of only -0.4 degrees (SD 3.86 degrees). The Lafayette goniometer had an intraobserver reliability +/- 9.6 degrees. The interobserver reliability was +/- 8.4 degrees. By comparison the iPhone had an interobserver reliability +/- 2.7 degrees and an intraobserver reliability +/- 4.6 degrees. We found the iPhone goniometer to be a reliable tool for the measurement of subtle knee flexion in the clinic setting. PMID:23150162

  17. The pendulum test as a tool to evaluate passive knee stiffness and viscosity of patients with rheumatoid arthritis

    PubMed Central

    Valle, Maria S; Casabona, Antonino; Sgarlata, Rosaria; Garozzo, Rosaria; Vinci, Maria; Cioni, Matteo

    2006-01-01

    Background The pendulum test of Wartenberg is a technique commonly used to measure passive knee motion with the aim to assess spasticity. We used this test to evaluate changes of the knee angular displacement, passive stiffness and viscosity in rheumatoid arthritis patients. Stiffness and viscosity represent passive resistances to joint motion associated with the structural properties of the joint tissue and of the muscular-tendon complex. Stiffness can be considered an intrinsic property of the tissues to resist deformation, while viscosity is related to cohesive forces between adjacent layers of tissues. Both parameters may influence the joint range of motion affecting angular displacement. Methods Nine women with rheumatoid arthritis were compared with a group of healthy women. With the subject half-lying, the relaxed knee was dropped from near-full extension and the characteristics of the ensuring damped unsustained knee oscillation evaluated. The kinematics of leg oscillations was recorded using ultrasonic markers (Zebris CMS HS 10) and the kinetic data were calculated from kinematic and anthropometric measures. Results Knee stiffness significantly increased (p < 0.001) in patients with respect to the control group, while differences in viscosity were not significant. Moreover, the amplitudes of first knee flexion (the maximal flexion excursion after knee release) and first knee extension (the maximal extension excursion after the first knee flexion) were significantly decreased (p < 0.001). A regression analysis showed that disease severity correlated moderately with stiffness (R2 = 0.68) and first flexion (R2 = 0.78). Using a multivariate regression, we found that increasing stiffness was the main factor for the reduction of flexion and extension motions. Conclusion We showed that the Wartenberg test can be considered a practical tool to measure mechanical changes of knee caused by rheumatoid arthritis. This novel application of Wartenberg test could be

  18. Non-invasive quantification of lower limb mechanical alignment in flexion

    PubMed Central

    Deakin, Angela; Fogg, Quentin A.; Picard, Frederic

    2014-01-01

    (coefficient ≤2°) was observed until 40° flexion; however, beyond 50° flexion, the repeatability coefficient was >3°. As was the case with precision, agreement between the invasive and non-invasive systems was satisfactory in extension and worsened with flexion. Mean limits of agreement between the invasive and non-invasive system using fabric strapping to assess MFTA were 3° (range: 2.3–3.8°) with no stress applied and 3.9° (range: 2.8–5.2°) with varus and valgus stress. Using rubber strapping, the corresponding values were 4.4° (range: 2.8–8.5°) with no stress applied, 5.5° (range: 3.3–9.0°) with varus stress, and 5.6° (range: 3.3–11.9°) with valgus stress. Discussion Acceptable precision and accuracy may be possible when measuring knee kinematics in early flexion using a non-invasive system; however, we do not believe passive trackers should be mounted with rubber strapping such as was used in this study. Flexing the knee appears to decrease the precision and accuracy of the system. The functions of this new software using image-free navigation technology have many potential clinical applications, including assessment of bony and soft tissue deformity, pre-operative planning, and post-operative evaluation, as well as in further pure research comparing kinematics of the normal and pathological knee. PMID:24856249

  19. Early range of motion of the scorpio non-restrictive geometry cruciate-retaining total knee system.

    PubMed

    Colwell, Clifford W; Gelber, Jonathan D; Pulido, Pamela A; Casey, Kevin M

    2011-08-01

    Flexion following total knee arthroplasty in the US population generally falls between 100° and 120°. Because of these relatively low flexion arcs, total knee arthroplasty prosthetic designs emerged allowing "high flexion" (≥125°). We hypothesized that a high-flexion implant design, Scorpio Non-Restrictive Geometry cruciate-retaining knee prosthesis, would allow clinical early maximum flexion of at least 125°. A prospective observational cohort study enrolled 87 unselected patients (94 knees) evaluated preoperation and 3 months and 1 year postoperation for clinical flexion, arc of motion, and Knee Society scores. At 1 year, 67% of knees had improved flexion and 23% achieved flexion of at least 125°. Clinically, flexion improved by 6.9° and total arc of motion improved by 10.6° from preoperation to 1-year postoperation. Although this high-flexion design allows increased flexion, many patients fail to achieve flexion of at least 125°. PMID:21036012

  20. The Attenborough total knee replacement.

    PubMed

    Attenborough, C G

    1978-08-01

    The stabilised gliding knee prosthesis is a compromise between hinged joints and condylar prostheses. It is a two-piece implant designed to allow normal gliding movements of flexion and extension and which, stabilised by a connecting rod between the femoral and tibial components, allows a designed laxity of rotation and lateral movements. A modification of the original femoral component is described. Two hundred and forty-five knee replacement operations have been done between January 1973 and September 1977 and the results are reported. The results using this prosthesis are at least equal to those using hinged or condylar prostheses. So far there has been no case of spontaneous loosening of the components and the implant can be used in patients who, because of severe deformities and instability, are unsuitable for condylar prostheses. PMID:681407

  1. A subdivision-based parametric deformable model for surface extraction and statistical shape modeling of the knee cartilages

    NASA Astrophysics Data System (ADS)

    Fripp, Jurgen; Crozier, Stuart; Warfield, Simon K.; Ourselin, Sébastien

    2006-03-01

    Subdivision surfaces and parameterization are desirable for many algorithms that are commonly used in Medical Image Analysis. However, extracting an accurate surface and parameterization can be difficult for many anatomical objects of interest, due to noisy segmentations and the inherent variability of the object. The thin cartilages of the knee are an example of this, especially after damage is incurred from injuries or conditions like osteoarthritis. As a result, the cartilages can have different topologies or exist in multiple pieces. In this paper we present a topology preserving (genus 0) subdivision-based parametric deformable model that is used to extract the surfaces of the patella and tibial cartilages in the knee. These surfaces have minimal thickness in areas without cartilage. The algorithm inherently incorporates several desirable properties, including: shape based interpolation, sub-division remeshing and parameterization. To illustrate the usefulness of this approach, the surfaces and parameterizations of the patella cartilage are used to generate a 3D statistical shape model.

  2. Correction of coronal plane deformities around the knee using a tension band plate in children younger than 10 years

    PubMed Central

    Kulkarni, Ruta M; Ilyas Rushnaiwala, Faizaan M; Kulkarni, GS; Negandhi, Rajiv; Kulkarni, Milind G; Kulkarni, Sunil G

    2015-01-01

    Background: Guided growth through temporary hemiepiphysiodesis has gained acceptance as the preferred primary treatment in treating pediatric lower limb deformities as it is minimally invasive with a lesser morbidity than the traditional osteotomy. The tension band plate is the most recent development in implants used for temporary hemiepiphysiodesis. Our aim was to determine its safety and efficacy in correcting coronal plane deformities around the knee in children younger than 10 years. Materials and Methods: A total of 24 children under the age of 10 were operated for coronal plane deformities around the knee with a single extra periosteal tension band plate and two nonlocking screws. All the children had a pathological deformity for which a detailed preoperative work-up was carried out to ascertain the cause of the deformity and rule out physiological ones. The average age at hemiepiphysiodesis was 5 years 3 months (range: 2 years to 9 years 1 month). Results: The plates were inserted for an average of 15.625 months (range: 7 months to 29 months). All the patients showed improvement in the mechanical axis. Two patients showed partial correction. Two cases of screw loosening were observed. In the genu valgum group, the tibiofemoral angle improved from a preoperative mean of 19.89° valgus (range: 10° valgus to 40° valgus) to 5.72° valgus (range: 2° varus to 10° valgus). In patients with genu varum the tibiofemoral angle improved from a mean of 28.27° varus (range: 13° varus to 41° varus) to 1.59° valgus (range: 0-8° valgus). Conclusion: Temporary hemiepiphysiodesis through the application of the tension band plate is an effective method to correct coronal plane deformities around the knee with minimal complications. Its ease and accuracy of insertion has extended the indication of temporary hemiepiphysiodesis to patients younger than 10 years and across a wide variety of diagnosis including pathological physis, which were traditionally out of the

  3. Importance of the different posterolateral knee static stabilizers: biomechanical study

    PubMed Central

    Lasmar, Rodrigo Campos Pace; Marques de Almeida, Adriano; Serbino, José Wilson; da Mota Albuquerque, Roberto Freire; Hernandez, Arnaldo José

    2010-01-01

    PURPOSE The purpose of this study was to evaluate the relative importance of the different static stabilizers of the posterolateral corner of the knee in cadavers. METHODS Tests were performed with the application of a varus and external rotation force to the knee in extension at 30 and 60 degrees of flexion using 10 cadaver knees. The forces were applied initially to an intact knee and then repeated after a selective sectioning of the ligaments into the following: section of the lateral collateral ligament; section of the lateral collateral ligament and the popliteofibular complex; and section of the lateral collateral ligament, the popliteofibular complex and the posterolateral capsule. The parameters studied were the angular deformity and stiffness when the knees were submitted to a 15 Newton-meter varus torque and a 6 Newton-meter external tibial torque. Statistical analysis was performed using the ANOVA (Analysis of Variance) and Tukey’s tests. RESULTS AND CONCLUSION Our findings showed that the lateral collateral ligament was important in varus stability at 0, 30 and 60 degrees. The popliteofibular complex was the most important structure for external rotation stability at all angles of flexion and was also important for varus stability at 30 and 60 degrees. The posterolateral capsule was important for varus stability at 0 and 30 degrees and for external rotation stability in extension. Level of evidence: Level IV (cadaver study). PMID:20454502

  4. [Scorpio TS prosthesis in severe deformity and revision knee arthroplasty--preliminary report].

    PubMed

    Kowalczewski, Jacek; Marczak, Dariusz; Wielopolski, Aleksander; Milecki, Marcin; Okoń, Tomasz

    2009-01-01

    Authors present early results of Scorpio TS prosthesis in primary and revision total knee arthoplasty due to aseptic and septic loosening. 26 arthroplasties were performed on 25 patients. There were 19 women and 6 men of age from 37 to 80 (average 68.4 years). 11 patients from this group were operated because of septic loosening. The follow up from 2 to 22 months (average 11 months). Early results were access according to Clinical Rating System of The Knee Society: 19 patients had very good and good (73%) including primaries, 1 satisfactory (4%) and 6 poor (23%) results. The satisfactory and poor results were obtained in 7 cases with septic loosening who had had four or more previous operations on the knee. Four of them had instability of prosthesis and we changed it for MRH type. In one case due to reinfection and sepsis amputation above the knee was performed. In another patient tibia fracture below stem and loosening of tibial component occurs after 6 months of revision. ORIF gave fracture union after 8 months and exchange Scorpio TS to MRH was performed. In two cases the wound problems occurred and was solved. There were no reinfection and aseptic loosening in another cases. We didn't notice any thrombosis complications. PMID:20201329

  5. Restoration of Elbow Flexion.

    PubMed

    Loeffler, Bryan J; Lewis, Daniel R

    2016-08-01

    Active elbow flexion is required to position the hand in space, and loss of this function is debilitating. Nerve transfers or nerve grafts to restore elbow flexion may be options when the target muscle is viable, but in delayed reconstruction when the biceps and brachialis are atrophied or damaged, muscle transfer options should be considered. Muscle transfer options are discussed with attention to the advantages and disadvantages of each transfer option. PMID:27387075

  6. Medial over-resection of the tibia in total knee arthroplasty for varus deformity using computer navigation.

    PubMed

    Krackow, Kenneth A; Raju, Sivashanmugam; Puttaswamy, Mohan K

    2015-05-01

    We are reporting a series of 35 cases in which downsizing, lateralizing of the tibial baseplate and resection of the uncovered medial plateau bone releases the medial collateral ligament and tightens the lateral collateral ligament. Result in excellent ligamentous balance and correction to neutral mechanical axis. The mean follow up was 32.8 months (11-95 months) and the average pre-operative varus was 9.47° (3.5-15°) with the average post-operative alignment was 0.65° varus. We obtained a mean correction of 0.45° for every mm (millimeter) of bone resected. We did not have any varus collapse or instability. Medial Over-resection could be employed as a technique in the management of varus OA knee with 2mm of resection giving about 10 correction of deformity. PMID:25575730

  7. Open Knee: Open Source Modeling and Simulation in Knee Biomechanics.

    PubMed

    Erdemir, Ahmet

    2016-02-01

    Virtual representations of the knee joint can provide clinicians, scientists, and engineers the tools to explore mechanical functions of the knee and its tissue structures in health and disease. Modeling and simulation approaches such as finite element analysis also provide the possibility to understand the influence of surgical procedures and implants on joint stresses and tissue deformations. A large number of knee joint models are described in the biomechanics literature. However, freely accessible, customizable, and easy-to-use models are scarce. Availability of such models can accelerate clinical translation of simulations, where labor-intensive reproduction of model development steps can be avoided. Interested parties can immediately utilize readily available models for scientific discovery and clinical care. Motivated by this gap, this study aims to describe an open source and freely available finite element representation of the tibiofemoral joint, namely Open Knee, which includes the detailed anatomical representation of the joint's major tissue structures and their nonlinear mechanical properties and interactions. Three use cases illustrate customization potential of the model, its predictive capacity, and its scientific and clinical utility: prediction of joint movements during passive flexion, examining the role of meniscectomy on contact mechanics and joint movements, and understanding anterior cruciate ligament mechanics. A summary of scientific and clinically directed studies conducted by other investigators are also provided. The utilization of this open source model by groups other than its developers emphasizes the premise of model sharing as an accelerator of simulation-based medicine. Finally, the imminent need to develop next-generation knee models is noted. These are anticipated to incorporate individualized anatomy and tissue properties supported by specimen-specific joint mechanics data for evaluation, all acquired in vitro from varying age

  8. Correction of static axial alignment in children with knee varus or valgus deformities through guided growth: Does it also correct dynamic frontal plane moments during walking?

    PubMed

    Böhm, Harald; Stief, Felix; Sander, Klaus; Hösl, Matthias; Döderlein, Leonhard

    2015-09-01

    Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, p<0.001). Contrary to the correlation of the changes, there was no correlation between static and dynamic measures in both sessions. In consequence two patients that had a natural knee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed. PMID:26159802

  9. A spatial model of the knee for the preoperative planning of knee surgery.

    PubMed

    Olanlokun, K F T; Wills, D P M

    2002-01-01

    A model on the spatial mechanical behaviour of the passive knee is presented. The femoral articular surfaces were represented by generalized, sagittally elliptical, toroidal surfaces. The medial and lateral tibial articular surfaces were represented by a dished spherical surface and the lower hemihyperbolic region of a torus respectively. Anatomical articular cartilage, knee ligaments and the posterior capsule were represented by spring-like deformable elements with non-linear load versus deflection characteristics. All the forces that act on the femur relative to the tibia were represented by three orthogonal forces and three associated moments. Spatial, articulation-dependent femorotibial kinematic constraint equations of the passive knee were formulated in an analytically explicit manner, based on the natural coordinates of the articular surfaces. The constraint equations were solved algebraically in closed form. Equations were derived that describe spatial femoro-tibial motion, ligament length, ligament strain, ligament-based elastic potential energy and the quasi-static equilibrium of the passive knee. Software was written, simulations on the motion characteristics and load versus deflection characteristics of the knee were carried out and graphical results were presented. The simulation of planar flexion/extension was almost spontaneous. The time taken to simulate spatial six-degree-of-freedom femoro-tibial motion was less than 2.5 min. The models were found to be capable of representing real-life passive knees to a high degree of satisfaction. It has been demonstrated that the models can provide knee surgeons with additional information on major aspects of the preoperative planning of knee surgery. The models can be used to enhance the preoperative planning of ligament reconstruction, articular surfaces related surgery, osteotomy and patellar tendon transfer surgery. PMID:11908484

  10. Influence of Hip-Flexion Angle on Hamstrings Isokinetic Activity in Sprinters

    PubMed Central

    Guex, Kenny; Gojanovic, Boris; Millet, Grégoire P.

    2012-01-01

    Context Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting leg's swing phase, when most injuries occur. Objective To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio. Design Descriptive laboratory study. Setting Research laboratory. Patients and Other Participants Ten national-level sprinters (5 men, 5 women; age = 21.2 ± 3.6 years, height = 175 ± 6 cm, mass = 63.8 ± 9.9 kg). Intervention(s) For each hip position (0°, 30°, 60°, and 90° of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45° of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60° per second, (3) 5 maximal eccentric knee flexion-extensions at 60° per second, and (4) 5 maximal eccentric knee flexion-extensions at 150° per second. Main Outcome Measure(s) Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square. Results We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0° of hip flexion than at any other angle (P < .001) and greater at 90° of hip flexion than at 30° and 60° (P < .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P > .05). Conclusions Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at

  11. Anterior cruciate ligament ganglion causing flexion restriction: a case report and review of literature

    PubMed Central

    Koh, Thean Howe Bryan; Lee, Keng Thiam

    2016-01-01

    Ganglion cysts originating from the anterior cruciate ligament (ACL) are uncommon. Often asymptomatic, they infrequently present with non-specific symptoms such as knee pain, stiffness, clicks, locking or restriction of knee extension. However, the patient we report presented with knee flexion restriction. A 37-year-old Chinese gentleman, with no history of knee trauma, presented with left knee pain. Left knee range of motion (ROM) was from 0 to 110 degrees. Magnetic resonance imaging (MRI) scan revealed a 1.5 cm × 3.3 cm × 1.7 cm cyst located in the intercondylar region arising from the ACL and extending predominantly posteriorly. Arthroscopy confirmed an intrasubstance ACL ganglion cyst, which was extending posteriorly. Complete excision of the cyst was performed. At 1-year follow-up, the patient regained knee flexion of 130 degrees. We describe one of the largest ACL ganglion cysts. Such cysts often extend anteriorly and impinge onto the roof of the intercondylar notch during knee extension, thus restricting extension. The restriction in knee motion in our patient was in flexion instead; this was because the cyst took an unusual course of extension predominantly in the posterior direction. Although rare, it must be included as a possible differential diagnosis when patients present with such knee symptoms. PMID:27386493

  12. Patient function after a posterior stabilizing total knee arthroplasty: cam-post engagement and knee kinematics.

    PubMed

    Suggs, Jeremy F; Hanson, George R; Park, Sang Eun; Moynihan, Angela L; Li, Guoan

    2008-03-01

    Even though posterior substituting total knee arthroplasty has been widely used in surgery, how the cam-post mechanism (posterior substituting mechanism) affects knee joint kinematics and function in patients is not known. The objective of the present study was to investigate posterior femoral translation, internal tibial rotation, tibiofemoral contact, and cam-post engagement of total knee arthroplasty patients during in vivo weight-bearing flexion. Twenty-four knees with a PS TKA were investigated while performing a single leg weight-bearing lunge from full extension to maximum flexion as images were recorded using a dual fluoroscopic system. The in vivo knee position at each targeted flexion angle was reproduced using 3D TKA models and the fluoroscopic images. The kinematics of the knee was measured from the series of the total knee arthroplasty models. The cam-post engagement was determined when the surface model of the femoral cam overlapped with that of the tibial post. The mean maximum flexion angle for all the subjects was 112.5 +/- 13.1 degrees . The mean flexion angle where cam-post engagement was observed was 91.1 +/- 10.9 degrees . The femur moved anteriorly from 0 degrees to 30 degrees and posteriorly through the rest of the flexion range. The internal tibial rotation increased approximately 6 degrees from full extension to 90 degrees of flexion and decreased slightly with further flexion. Both the medial and lateral contact point moved posteriorly from 0 degrees to 30 degrees , remained relatively constant from 30 degrees to 90 degrees , and then moved further posterior from 90 degrees to maximum flexion. The in vivo cam-post engagement corresponded to increased posterior translation and reduced internal tibial rotation at high flexion of the posterior substituting total knee arthroplasty. The initial cam-post engagement was also mildly correlated with the maximum flexion angle of the knee (R = 0.51, p = 0.019). A later cam-post engagement might

  13. The influence of joint line position on knee stability after condylar knee arthroplasty.

    PubMed

    Martin, J W; Whiteside, L A

    1990-10-01

    Using a special knee-testing device, ten knees obtained at autopsy were subjected to varus-valgus, anterior-posterior, and flexion-rotation analysis in the intact state and after total knee arthroplasty. The ten knees showed no significant change in stability after knee replacement when the joint line was maintained in its natural position. When the femoral component was repositioned 5 mm proximally and 5 mm anteriorly, a significant increase in laxity occurred during midflexion. When the joint line was shifted 5 mm distal and 5 mm posterior to its anatomic location, significant tightening occurred in midrange of motion. Coupled rotation of the tibia with knee flexion was decreased after surgery in all knees with no specific relationship to joint line position. Coupled rotation with varus-valgus testing, however, remained within the normal range through the first 30 degrees of flexion only when the joint line was restored to its normal anatomic position. Stability in condylar knee arthroplasty is in part dependent on position of the joint line. Surgical techniques that rely on restoring the flexion and extension gap without regard to joint line position may result in alteration of varus-valgus or anterior-posterior displacement in midrange flexion. PMID:2208849

  14. Soft tissue balancing in total knee arthroplasty

    PubMed Central

    MELONI, MARIA CHIARA; HOEDEMAEKER, RUSSALKA W.; VIOLANTE, BRUNO; MAZZOLA, CLAUDIO

    2014-01-01

    A good outcome in total knee arthroplasty depends on many factors: joint alignment, range of motion, patellar tracking and ligament stability. A correct soft tissue balance keeps the joint aligned in flexion and extension, and therefore constitutes the most important factor for durability of the implant. Indeed, incorrect soft tissue balancing is the primary cause of early implant failure necessitating revision surgery. Soft tissue releases, serving to correct imbalances, are performed until the flexion and extension gaps appear symmetrical and balanced. A knee is considered perfectly balanced when the flexion and extension gaps are perfectly rectangular and all the measurements are absolutely equal. PMID:25606540

  15. Knee Brace Would Lock And Unlock Automatically

    NASA Technical Reports Server (NTRS)

    Myers, Neill; Forbes, John; Shadoan, Mike; Baker, Kevin

    1995-01-01

    Proposed knee brace designed to aid rehabilitation of person who suffered some muscle damage in leg. Not limited to locking in straight-leg position and, instead, locks at any bend angle. Does not prevent knee from bearing weight. Instead, knee brace allows knee to bear weight and locks only when foot and lower leg bear weight. Thus, brace prevents flexion that wearer desired to prevent but could not prevent because of weakened muscles. Knee bends freely to exercise knee-related muscles. Knee brace strapped at upper end to leg above knee, and anchored at lower end by stirrup under foot. Joint mechanism (identical mechanisms used in left and right assemblies) allows knee joint to flex freely except when weight applied to heel.

  16. Neuromuscular Activation of the Vastus Intermedius Muscle during Isometric Hip Flexion

    PubMed Central

    Saito, Akira; Akima, Hiroshi

    2015-01-01

    Although activity of the rectus femoris (RF) differs from that of the other synergists in quadriceps femoris muscle group during physical activities in humans, it has been suggested that the activation pattern of the vastus intermedius (VI) is similar to that of the RF. The purpose of present study was to examine activation of the VI during isometric hip flexion. Ten healthy men performed isometric hip flexion contractions at 25%, 50%, 75%, and 100% of maximal voluntary contraction at hip joint angles of 90°, 110° and 130°. Surface electromyography (EMG) was used to record activity of the four quadriceps femoris muscles and EMG signals were root mean square processed and normalized to EMG amplitude during an isometric knee extension with maximal voluntary contraction. The normalized EMG was significantly higher for the VI than for the vastus medialis during hip flexion at 100% of maximal voluntary contraction at hip joint angles of 110° and 130° (P < 0.05). The onset of VI activation was 230–240 ms later than the onset of RF activation during hip flexion at each hip joint angle, which was significantly later than during knee extension at 100% of maximal voluntary contraction (P < 0.05). These results suggest that the VI is activated later than the RF during hip flexion. Activity of the VI during hip flexion might contribute to stabilize the knee joint as an antagonist and might help to smooth knee joint motion, such as in the transition from hip flexion to knee extension during walking, running and pedaling. PMID:26488742

  17. Usefulness of the Korean Knee Score for Evaluation of the Results of Total Knee Arthroplasty

    PubMed Central

    Lee, Jin Kyu; Shim, Ji-Hoon; Chung, Kyu-Sung

    2015-01-01

    Purpose The Korean Knee score (KKS) was designed to reflect the floor-sitting lifestyle that necessitates high knee flexion. The purpose of this study is to assess whether the KKS reflects the floor-sitting lifestyle more accurately than the previously developed Knee Society clinical rating system. In addition, the presence of ceiling effects was compared between the two rating systems. Materials and Methods Eighty-one consecutive patients (120 knees) who were assessed regularly after total knee arthroplasty (TKA) on an outpatient basis between January 2012 and December 2012 were enrolled. All patients were asked to complete a questionnaire to assess the Knee Society Knee score (KSKS), Knee Society Function score (KSFS), and KKS. Results At the final follow-up, the mean KSKS, KSFS, and KKS were 91.2, 86.0, and 70.1, respectively, and the scores were similar between the ≥125° maximum flexion group and <125° maximum flexion group. However, the 'floor life' subdomain score of the KKS was significantly higher in the >125° maximum flexion group (15.13 vs. 11.24, p=0.001). The number of cases with the highest possible score was 24 (20%) for the KSKS and 47 (39%) for the KSFS, whereas none of the cases obtained the highest possible KKS. According to the standard deviation method, more substantial ceiling effects were present in the KSKS (83 cases, 69.1%) and KSFS (67 cases, 55.8%) than in the KKS (23 cases, 19.2%). Conclusions Although, the KKS was effective in reducing the ceiling effect, it demonstrated limited improvement in assessing the ability to perform high knee flexion after TKA. However, the 'floor life' subdomain of KSS appeared to be valid for evaluating high flexion of the knee. PMID:25750889

  18. An improved OpenSim gait model with multiple degrees of freedom knee joint and knee ligaments.

    PubMed

    Xu, Hang; Bloswick, Donald; Merryweather, Andrew

    2015-08-01

    Musculoskeletal models are widely used to investigate joint kinematics and predict muscle force during gait. However, the knee is usually simplified as a one degree of freedom joint and knee ligaments are neglected. The aim of this study was to develop an OpenSim gait model with enhanced knee structures. The knee joint in this study included three rotations and three translations. The three knee rotations and mediolateral translation were independent, with proximodistal and anteroposterior translations occurring as a function of knee flexion/extension. Ten elastic elements described the geometrical and mechanical properties of the anterior and posterior cruciate ligaments (ACL and PCL), and the medial and lateral collateral ligaments (MCL and LCL). The three independent knee rotations were evaluated using OpenSim to observe ligament function. The results showed that the anterior and posterior bundles of ACL and PCL (aACL, pACL and aPCL, pPCL) intersected during knee flexion. The aACL and pACL mainly provided force during knee flexion and adduction, respectively. The aPCL was slack throughout the range of three knee rotations; however, the pPCL was utilised for knee abduction and internal rotation. The LCL was employed for knee adduction and rotation, but was slack beyond 20° of knee flexion. The MCL bundles were mainly used during knee adduction and external rotation. All these results suggest that the functions of knee ligaments in this model approximated the behaviour of the physical knee and the enhanced knee structures can improve the ability to investigate knee joint biomechanics during various gait activities. PMID:24611807

  19. 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

  20. Knee Muscular Control During Jump Landing in Multidirections

    PubMed Central

    Sinsurin, Komsak; Vachalathiti, Roongtiwa; Jalayondeja, Wattana; Limroongreungrat, Weerawat

    2016-01-01

    Background Jump landing is a complex movement in sports. While competing and practicing, athletes frequently perform multi-planar jump landing. Anticipatory muscle activity could influence the amount of knee flexion and prepare the knee for dynamic weight bearing such as landing tasks. Objectives The aim of the present study was to examine knee muscle function and knee flexion excursion as athletes naturally performed multi-direction jump landing. Materials and Methods Eighteen male athletes performed the jump-landing test in four directions: forward (0°), 30° diagonal, 60° diagonal, and lateral (90°). Muscles tested were vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), and biceps femoris (BF). A ViconTM 612 workstation collected the kinematic data. An electromyography was synchronized with the ViconTM Motion system to quantify dynamic muscle function. Repeated measure ANOVA was used to analyze the data. Results Jump-landing direction significantly influenced (P < 0.05) muscle activities of VL, RF, and ST and knee flexion excursion. Jumpers landed with a trend of decreasing knee flexion excursion and ST muscle activity 100 ms before foot contact progressively from forward to lateral directions of jump landing. Conclusions A higher risk of knee injury might occur during lateral jump landing than forward and diagonal directions. Athletes should have more practice in jump landing in lateral direction to avoid injury. Landing technique with high knee flexion in multi-directions should be taught to jumpers for knee injury prevention. PMID:27625758

  1. Influences of trunk flexion on mechanical energy flow in the lower extremities during gait

    PubMed Central

    Takeda, Takuya; Anan, Masaya; Takahashi, Makoto; Ogata, Yuta; Tanimoto, Kenji; Shinkoda, Koichi

    2016-01-01

    [Purpose] The time-series waveforms of mechanical energy generation, absorption, and transfer through the joints indicate how movements are produced and controlled. Previous studies have used these waveforms to evaluate and describe the efficiency of human movements. The purpose of this study was to examine the influence of trunk flexion on mechanical energy flow in the lower extremities during gait. [Subjects and Methods] The subjects were 8 healthy young males (mean age, 21.8 ± 1.3 years, mean height, 170.5 ± 6.8 cm, and mean weight, 60.2 ± 6.8 kg). Subjects walked at a self-selected gait speed under 2 conditions: normal gait (condition N), and gait with trunk flexion formed with a brace to simulate spinal curvature (condition TF). The data collected from initial contact to the mid-stance of gait was analyzed. [Results] There were no significant differences between the 2 conditions in the mechanical energy flow in the knee joint and negative mechanical work in the knee joint. However, the positive mechanical work of the knee joint under condition TF was significantly less than that under condition N. [Conclusion] Trunk flexion led to knee flexion in a standing posture. Thus, a strategy of moving of center of mass upward by knee extension using less mechanical energy was selected during gait in the trunk flexed posture. PMID:27313351

  2. In vivo human knee joint dynamic properties as functions of muscle contraction and joint position.

    PubMed

    Zhang, L Q; Nuber, G; Butler, J; Bowen, M; Rymer, W Z

    1998-01-01

    Information on the dynamic properties (joint stiffness, viscosity and limb inertia) of the human knee joint is scarce in the literature, especially for actively contracting knee musculature. A joint driving device was developed to apply small-amplitude random perturbations to the human knee at several flexion angles with the subject maintaining various levels of muscle contraction. It was found that joint stiffness and viscosity increased with muscle contraction substantially, while limb inertia was constant. Stiffness produced by the quadriceps was highest at 30 degrees flexion and decreased with increasing or decreasing flexion angle, while knee flexors produced highest stiffness at 90 degree flexion. When knee flexion was < 60 degrees, stiffness produced by the quadriceps was higher than that of the hamstrings and gastrocnemius at the same level of background muscle torque, while knee flexor muscles produced higher stiffnesses than the quadriceps at 90 degree flexion. Similar but less obvious trends were observed for joint viscosity. Passive joint stiffness at full knee extension was significantly higher than in more flexed positions. Surprisingly, as the knee joint musculature changed from relaxed to contracting at 50% MVC, system damping ratio remained at about 0.2. This outcome potentially simplifies neuromuscular control of the knee joint. In contrast, the natural undamped frequency increased more than twofold, potentially making the knee joint respond more quickly to the central nervous system commands. The approach described here provides us with a potentially valuable tool to quantify in vivo dynamic properties of normal and pathological human knee joints. PMID:9596540

  3. Open Knee: Open Source Modeling & Simulation to Enable Scientific Discovery and Clinical Care in Knee Biomechanics

    PubMed Central

    Erdemir, Ahmet

    2016-01-01

    Virtual representations of the knee joint can provide clinicians, scientists, and engineers the tools to explore mechanical function of the knee and its tissue structures in health and disease. Modeling and simulation approaches such as finite element analysis also provide the possibility to understand the influence of surgical procedures and implants on joint stresses and tissue deformations. A large number of knee joint models are described in the biomechanics literature. However, freely accessible, customizable, and easy-to-use models are scarce. Availability of such models can accelerate clinical translation of simulations, where labor intensive reproduction of model development steps can be avoided. The interested parties can immediately utilize readily available models for scientific discovery and for clinical care. Motivated by this gap, this study aims to describe an open source and freely available finite element representation of the tibiofemoral joint, namely Open Knee, which includes detailed anatomical representation of the joint's major tissue structures, their nonlinear mechanical properties and interactions. Three use cases illustrate customization potential of the model, its predictive capacity, and its scientific and clinical utility: prediction of joint movements during passive flexion, examining the role of meniscectomy on contact mechanics and joint movements, and understanding anterior cruciate ligament mechanics. A summary of scientific and clinically directed studies conducted by other investigators are also provided. The utilization of this open source model by groups other than its developers emphasizes the premise of model sharing as an accelerator of simulation-based medicine. Finally, the imminent need to develop next generation knee models are noted. These are anticipated to incorporate individualized anatomy and tissue properties supported by specimen-specific joint mechanics data for evaluation, all acquired in vitro from varying age

  4. Collateral soft tissue release in primary total knee replacement

    PubMed Central

    Deep, Kamal

    2014-01-01

    The aim of this study was to assess the rate of collateral soft tissue release required in navigated total knee arthroplasty (TKA) to achieve an intra-operative coronal femoral tibial mechanical axis (FTMA) in extension of 0 ± 2°. The primary outcomes assessed were post-operative coronal plane alignment and rate of collateral soft tissue release. The secondary outcomes were range of motion, function, patient satisfaction, and complication rates at one-year follow-up. This is a prospective study of 224 knees. No exclusions were made on the basis of pathology or severity of deformity. Pre-operative FTMA ranged from 27° valgus to 25° varus (mean: −4.5° SD 7.6). Soft tissue release was carried out in 5 of 224 knees (2.2%). Post-operative weight-bearing radiological FTMA ranged from 7° valgus to 8° varus (mean: −0.4° SD 2.5°). Two hundred and ten knees (96%) were within 0 ± 5° of neutral. At one year, median maximum flexion was 100° (IQR 15°) and extension was 0°; mean post-operative Oxford Knee Score had improved from 42 to 23; and 91% of patients were satisfied or very satisfied, with only 2% being dissatisfied. We have found that in the vast majority of cases, including those with large pre-operative coronal deformity in extension, good outcomes in terms of coronal alignment, range of movement, function and patient satisfaction can be achieved. PMID:24720493

  5. A Preliminary In Vivo Assessment of Anterior Cruciate Ligament–Deficient Knee Kinematics With the KneeM Device

    PubMed Central

    Tardy, Nicolas; Marchand, Philippe; Kouyoumdjian, Pascal; Blin, Dominique; Demattei, Christophe; Asencio, Gérard

    2014-01-01

    Background: Methods of objectively measuring rotational knee laxity are either experimental or difficult to use in daily practice. A new method has been developed to quantitatively assess rotatory laxity using an open MRI system and new tool, the KneeM device. Purpose/Hypothesis: To perform a preliminary evaluation of a novel knee rotation measurement device to assess knee kinematics during flexion in an MRI field, in both anterior cruciate ligament (ACL)–deficient and healthy contralateral knees. The hypothesis was that the KneeM device would allow in vivo reproduction and analysis of knee kinematics during flexion in healthy and ACL-deficient knees. Study Design: Controlled laboratory study. Methods: Ten subjects (7 men and 3 women; mean age ± standard deviation, 32.3 ± 9.4 years) with ACL-deficient knees and contralateral uninjured knees participated in the study. An open MRI was performed with the KneeM device at a mean 4.9 months (range, 3.0-7 months) after ACL injury. The device exerted on the knee an anterior drawer force of 100 N, with an internal rotation of 20°, through the range of flexion (0°, 20°, 40°, and 60°). Both ACL-deficient and healthy contralateral knees were analyzed using the Iwaki method. Results: There was no statistical difference of anterior translation in the medial compartment between intact and ACL-deficient knees at all degrees of flexion. However, significant differences in the anterior translation of the lateral compartment were observed between ACL-deficient and intact contralateral knees at 0° and 20° of flexion (P = .005 and P = .002, respectively). Between 20° and 40°, the lateral plateau of ACL-deficient knees translated 7.7 mm posteriorly, whereas the medial compartment remained stable, reflecting a sudden external rotation of the lateral plateau under the femoral condyle. Conclusion: This preliminary study suggests that measurement of tibiofemoral movements in both compartments during flexion using the Knee

  6. [Indications and Borderline Indications for Medial Mobile Bearing Unicondylar Knee Replacement].

    PubMed

    Walker, T; Streit, M R; Streit, J; Gotterbarm, T; Aldinger, P R

    2015-10-01

    Beside the possibility of bicondylar knee replacement, patients with isolated anteromedial osteoarthritis also have the possibility of unicondylar knee replacement. Therefore some requirements are essential such as functionally intact cruciate and collateral ligaments, intact cartilage in the lateral compartment and an intraoperative flexion of more than 100°. An instability or contracture of the cruciate or collateral ligaments, a varus deformity more than 15°, a flexion deformity of more than 15°, an intraoperative flexion less than 100° as well as failed upper tibial osteotomy are seen as contraindications. In addition, a rheumatoid arthritis and a full thickness cartilage defect in the central part of the lateral compartment are seen as a contraindication because of the risk of a progression of the disease. With respect to these contraindications, excellent functional outcome and survival rates could be demonstrated in the long term. An expansion of these criteria, especially in patients with an insufficiency of the cruciate ligaments or after failed upper tibial osteotomy should only be done in certain cases after careful assessment of the benefits and risks. These patients should be informed about the lack of long-term results and the higher risk of complications. Quite commonly, the criteria of Kozinn and Scott are used for patient selection. These criteria were originally established for fixed-bearing prosthesis and have no relevance on mobile-bearing prosthesis. Criteria such as age, level of activity, weight, chondrocalcinosis and anterior knee pain have no effect on the clinical outcome or the long-term survival of a mobile-bearing prosthesis. PMID:26167771

  7. Posterior cruciate ligament balancing in total knee arthroplasty: a numerical study with a dynamic force controlled knee model

    PubMed Central

    2014-01-01

    Background Adequate soft tissue balancing is a key factor for a successful result after total knee arthroplasty (TKA). Posterior cruciate ligament (PCL) is the primary restraint to posterior translation of the tibia after cruciate retaining TKA and is also responsible for the amount of joint compression. However, it is complex to quantify the amount of ligament release with its effects on load bearing and kinematics in TKA and limited both in vivo and in vitro. The goal of this study was to create a dynamic and deformable finite element model of a full leg and analyze a stepwise release of the PCL regarding knee kinematics, pressure distribution and ligament stresses. Methods A dynamic finite element model was developed in Ansys V14.0 based on boundary conditions of an existing knee rig. A cruciate retraining knee prosthesis was virtually implanted. Ligament and muscle structures were simulated with modified spring elements. Linear elastic materials were defined for femoral component, inlay and patella cartilage. A restart algorithm was developed and implemented into the finite element simulation to hold the ground reaction force constant by adapting quadriceps force. After simulating the unreleased PCL model, two models were developed and calculated with the same boundary conditions with a 50% and 75% release of the PCL stiffness. Results From the beginning of the simulation to approximately 35° of flexion, tibia moves posterior related to the femur and with higher flexion anteriorly. Anterior translation of the tibia ranged from 5.8 mm for unreleased PCL to 3.7 mm for 75% PCL release (4.9 mm 50% release). A decrease of maximum von Mises equivalent stress on the inlay was given with PCL release, especially in higher flexion angles from 11.1 MPa for unreleased PCL to 8.9 MPa for 50% release of the PCL and 7.8 MPa for 75% release. Conclusions Our study showed that dynamic FEM is an effective method for simulation of PCL balancing in knee arthroplasty. A tight

  8. Examination of knee joint moments on the function of knee-ankle-foot orthoses during walking.

    PubMed

    Andrysek, Jan; Klejman, Susan; Kooy, John

    2013-08-01

    The goal of this study was to investigate clinically relevant biomechanical conditions relating to the setup and alignment of knee-ankle-foot orthoses and the influence of these conditions on knee extension moments and orthotic stance control during gait. Knee moments were collected using an instrumented gait laboratory and concurrently a load transducer embedded at the knee-ankle-foot orthosis knee joint of four individuals with poliomyelitis. We found that knee extension moments were not typically produced in late stance-phase of gait. Adding a dorsiflexion stop at the orthotic ankle significantly decreased the knee flexion moments in late stance-phase, while slightly flexing the knee in stance-phase had a variable effect. The findings suggest that where users of orthoses have problems initiating swing-phase flexion with stance control orthoses, an ankle dorsiflexion stop may be used to enhance function. Furthermore, the use of stance control knee joints that lock while under flexion may contribute to more inconsistent unlocking of the stance control orthosis during gait. PMID:23182738

  9. Rotational alignment of the femoral component in total knee arthroplasty

    PubMed Central

    Falvo, Daniele Antonio; Iapicca, Mario Luigi; Gotti, Valerio

    2016-01-01

    We describe here various surgical options to obtain a correct rotational alignment of femoral component in total knee arthroplasty (TKA). The correct rotational alignment is the key point to obtain a rectangular balanced flexion gap as well to have a good patellar tracking. For that reason, rotation alignment largely affects postoperative kinematic results particularly during flexion. PMID:26855940

  10. 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

  11. A dynamic multibody model of the physiological knee to predict internal loads during movement in gravitational field.

    PubMed

    Bersini, Simone; Sansone, Valerio; Frigo, Carlo A

    2016-01-01

    Obtaining tibio-femoral (TF) contact forces, ligament deformations and loads during daily life motor tasks would be useful to better understand the aetiopathogenesis of knee joint diseases or the effects of ligament reconstruction and knee arthroplasty. However, methods to obtain this information are either too simplified or too computationally demanding to be used for clinical application. A multibody dynamic model of the lower limb reproducing knee joint contact surfaces and ligaments was developed on the basis of magnetic resonance imaging. Several clinically relevant conditions were simulated, including resistance to hyperextension, varus-valgus stability, anterior-posterior drawer, loaded squat movement. Quadriceps force, ligament deformations and loads, and TF contact forces were computed. During anterior drawer test the anterior cruciate ligament (ACL) was maximally loaded when the knee was extended (392 N) while the posterior cruciate ligament (PCL) was much more stressed during posterior drawer when the knee was flexed (319 N). The simulated loaded squat revealed that the anterior fibres of ACL become inactive after 60° of flexion in conjunction with PCL anterior bundle activation, while most components of the collateral ligaments exhibit limited length changes. Maximum quadriceps and TF forces achieved 3.2 and 4.2 body weight, respectively. The possibility to easily manage model parameters and the low computational cost of each simulation represent key points of the present project. The obtained results are consistent with in vivo measurements, suggesting that the model can be used to simulate complex and clinically relevant exercises. PMID:26057607

  12. Active knee motion after cruciate ligament rupture. Stereoradiography.

    PubMed

    Kärrholm, J; Selvik, G; Elmqvist, L G; Hansson, L I

    1988-04-01

    In 10 patients with an old injury of the anterior cruciate ligament, the three-dimensional movements of the knee joint were studied when the patients flexed their knees. Tibial motions were recorded using roentgen stereophotogrammetric analysis. Internal rotation and adduction of the tibia were reduced in the injured knees when compared with the intact knees; during flexion of the knee joint, the tibial intercondylar eminence occupied a more lateral and posterior position on the injured side. Our results may indicate that the knee joint is continuously exposed to abnormal stresses when the anterior cruciate ligament is torn. PMID:3364185

  13. A multibody knee model with discrete cartilage prediction of tibio-femoral contact mechanics.

    PubMed

    Guess, Trent M; Liu, Hongzeng; Bhashyam, Sampath; Thiagarajan, Ganesh

    2013-01-01

    Combining musculoskeletal simulations with anatomical joint models capable of predicting cartilage contact mechanics would provide a valuable tool for studying the relationships between muscle force and cartilage loading. As a step towards producing multibody musculoskeletal models that include representation of cartilage tissue mechanics, this research developed a subject-specific multibody knee model that represented the tibia plateau cartilage as discrete rigid bodies that interacted with the femur through deformable contacts. Parameters for the compliant contact law were derived using three methods: (1) simplified Hertzian contact theory, (2) simplified elastic foundation contact theory and (3) parameter optimisation from a finite element (FE) solution. The contact parameters and contact friction were evaluated during a simulated walk in a virtual dynamic knee simulator, and the resulting kinematics were compared with measured in vitro kinematics. The effects on predicted contact pressures and cartilage-bone interface shear forces during the simulated walk were also evaluated. The compliant contact stiffness parameters had a statistically significant effect on predicted contact pressures as well as all tibio-femoral motions except flexion-extension. The contact friction was not statistically significant to contact pressures, but was statistically significant to medial-lateral translation and all rotations except flexion-extension. The magnitude of kinematic differences between model formulations was relatively small, but contact pressure predictions were sensitive to model formulation. The developed multibody knee model was computationally efficient and had a computation time 283 times faster than a FE simulation using the same geometries and boundary conditions. PMID:21970765

  14. Unilateral Congenital Knee and Hip Dislocation with Bilateral Clubfoot - A rare Packaging disorder

    PubMed Central

    Tiwari, Mukesh; Sharma, Nishith

    2013-01-01

    Introduction: Reduced intrauterine space gives rise to ‘packaging disorder’ which may involve joint dislocations or contractures. We present an unique case where mutiple joints were dislocated involving left congenital knee dislocation (CDK), bilateral congenital hip dislocation (CDH) and congenital talipes equino varus (CTEV)deformities. Case Report: A preterm baby boy born to mother with diagnosed oligohydramios presented with left CDK bilateral DDH and CTEV. The knee dislocation was treated first with gradual streaching and weekly above knee cast. At 7th week good flexion was achieved at both knees and abduction splint for DDH (using double diaper) with ponseti cast for CTEV was done. At one year follow up all joints were reduced and maintained well with baby able to stand with support. Conclusion: Packaging disorders may present with multiple dislocations and deformities. Early intervention with serial casting and manipulation minimises disability and prevents ambulatory problems. In our case there was a good response to manipulation and serial casting. This differs from cases with inherent pathology like arthrogryposis where response to treatment is not so good PMID:27298901

  15. A model of human knee ligaments in the sagittal plane. Part 2: Fibre recruitment under load.

    PubMed

    Zavatsky, A B; O'Connor, J J

    1992-01-01

    A mathematical model of the knee ligaments in the sagittal plane is used to study the forces in the cruciate and collateral ligaments produced by anterior/posterior tibial translation. The model is based on ligament fibre functional architecture. Geometric analysis of the deformed configurations of the model ligaments provides the additional compatibility conditions necessary for calculation of the statically indeterminate distributions of strain and stress within the ligaments and the sharing of load between ligaments. The investigation quantifies the process of ligament fibre recruitment, which occurs when fibres made slack by passive flexion/extension of the knee stretch and change their spatial positions in order to resist applied loads. The calculated ligament forces are in reasonable agreement with experimental results reported in the literature. The model explains some subtleties of ligament function not incorporated in models that represent the ligaments by a small number of lines. PMID:1482509

  16. The influence of knee position on ankle dorsiflexion - a biometric study

    PubMed Central

    2014-01-01

    Background Musculus gastrocnemius tightness (MGT) can be diagnosed by comparing ankle dorsiflexion (ADF) with the knee extended and flexed. Although various measurement techniques exist, the degree of knee flexion needed to eliminate the effect of the gastrocnemius on ADF is still unknown. The aim of this study was to identify the minimal degree of knee flexion required to eliminate the restricting effect of the musculus gastrocnemius on ADF. Methods Bilateral ADF of 20 asymptomatic volunteers aged 18-40 years (50% female) was assessed prospectively at six different degrees of knee flexion (0°, 20°, 30°, 45°, 60°, 75°, Lunge). Tests were performed following a standardized protocol, non weightbearing and weightbearing, by two observers. Statistics comprised of descriptive statistics, t-tests, repeated measurement ANOVA and ICC. Results 20 individuals with a mean age of 27 ± 4 years were tested. No significant side to side differences were observed. The average ADF [95% confidence interval] for non weightbearing was 4° [1°-8°] with the knee extended and 20° [16°-24°] for the knee 75° flexed. Mean weightbearing ADF was 25° [22°-28°] for the knee extended and 39° [36°-42°] for the knee 75° flexed. The mean differences between 20° knee flexion and full extension were 15° [12°-18°] non weightbearing and 13° [11°-16°] weightbearing. Significant differences of ADF were only found between full extension and 20° of knee flexion. Further knee flexion did not increase ADF. Conclusion Knee flexion of 20° fully eliminates the ADF restraining effect of the gastrocnemius. This knowledge is essential to design a standardized clinical examination assessing MGT. PMID:25053374

  17. Total Knee Arthroplasty Using a Posterior Cruciate Ligament Sacrificing Medial Pivot Knee: Minimum 5-year Follow-up Results

    PubMed Central

    Youm, Yoon-Seok; Lee, Seon-Ho; Cho, Hye-Yong

    2014-01-01

    Purpose To evaluate minimum 5-year follow-up clinical and radiological results of total knee arthroplasty (TKA) using a posterior cruciate ligament sacrificing (PS), non-substituting Advance Medial Pivot Knee. Materials and Methods One hundred and twenty knees in 80 patients who could be followed up for more than 5 years after TKA using the PS Advance Medial Pivot Knee were evaluated retrospectively. The evaluations included the preoperative and postoperative range of motion (ROM), tibiofemoral angle, Knee Society (KS) knee and function scores, and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score. The Kaplan-Meier method was used for survival analysis. Results The ROM increased from a preoperative mean flexion contracture of 7.6° and further flexion of 115.1° to a postoperative mean flexion contracture of 1.5° and further flexion of 120.5°. The tibiofemoral angle was changed from 4.6° varus preoperatively to 5.8° valgus postoperatively. The KS knee and function scores as well as WOMAC score significantly improved after surgery (p<0.05). Complications developed in 4 cases (3.3%): 2 cases of periprosthetic patellar fracture (1.7%) and 2 cases of aseptic loosening (1.7%). The seven-year survival rate was 98.1% in the Kaplan-Meier survival analysis. Conclusions The minimum 5-year follow-up results of TKA using the PS Medial Pivot Knee were satisfactory. PMID:25229042

  18. Intraarticular osteochondroma of the knee

    PubMed Central

    Morey, Vivek Morey; Jalan, Divesh; Mittal, Ravi; Gamangatti, Shivanand

    2014-01-01

    Osteochondromas are usually extra articular and grow away from the joint towards the diaphysis. Intraarticular osteochondromas are very rare and often misdiagnosed. We report a case of 16-year-old boy who presented with pain and clicking sound in the right knee for last 6 months. On examination, click was felt at the terminal flexion of the knee. The lateral radiograph of the right knee showed a radio opaque shadow at the posterior aspect of the distal end of femur, which was further evaluated with an MRI. Arthroscopy showed a hard lesion arising from the roof of the intercondylar notch of femur. It was excised arthroscopically. Histopathology revealed it to be an osteochondroma. Thus, intraarticular osteochondroma of the knee can be considered as a rare cause of pain in young patients. PMID:24932044

  19. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis

    PubMed Central

    Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

    2015-01-01

    Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0–135° flexion. Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, “rollback” compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. PMID:25591565

  20. Knee pain

    MedlinePlus

    ... the front of your knee around the kneecap Torn ligament. An anterior cruciate ligament (ACL) injury, or ... into your knee, swelling, or an unstable knee. Torn cartilage (a meniscus tear ). Pain felt on the ...

  1. In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee

    PubMed Central

    Chan, Deva D.; Cai, Luyao; Butz, Kent D.; Trippel, Stephen B.; Nauman, Eric A.; Neu, Corey P.

    2016-01-01

    The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment. PMID:26752228

  2. In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee

    NASA Astrophysics Data System (ADS)

    Chan, Deva D.; Cai, Luyao; Butz, Kent D.; Trippel, Stephen B.; Nauman, Eric A.; Neu, Corey P.

    2016-01-01

    The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment.

  3. In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee.

    PubMed

    Chan, Deva D; Cai, Luyao; Butz, Kent D; Trippel, Stephen B; Nauman, Eric A; Neu, Corey P

    2016-01-01

    The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment. PMID:26752228

  4. Total knee arthroplasty using subvastus approach in stiff knee: A retrospective analysis of 110 cases

    PubMed Central

    Shah, Nilen A; Patil, Hitendra Gulabrao; Vaishnav, Vinod O; Savale, Abhijit

    2016-01-01

    Background: Subvastus approach used in total knee arthroplasty (TKA) is known to produce an earlier recovery but is not commonly utilized for TKA when the preoperative range of motion (ROM) of the knee is limited. Subvastus approach is known for its ability to give earlier recovery due to less postoperative pain and early mobilization (due to rapid quadriceps recovery). Subvastus approach is considered as a relative contraindication for TKA in knees with limited ROM due to difficulty in exposure which can increase risk of complications such as patellar tendon avulsion or medial collateral injury. Short stature and obesity are also relative contraindications. Tarabichi successfully used subvastus approach in knees with limited preoperative ROM. However, there are no large series in literature with the experience of the subvatus approach in knees with limited preoperative ROM. We are presenting our experience of the subvastus approach for TKA in knees with limited ROM. Materials and Methods: We conducted retrospective analysis of patients with limited preoperative ROM (flexion ≤90°) of the knee who underwent TKA using subvastus approach and presenting the 2 years results. There were a total 84 patients (110 knees) with mean age 64 (range 49–79 years) years. The mean preoperative flexion was 72° (range 40°–90°) with a total ROM of 64° (range 36°–90°). Results: Postoperatively knee flexion improved by mean 38° (P < 0.05) which was significant as assed by Student's t- test. The mean knee society score improved from 36 (range 20–60) to 80 (range 70–90) postoperatively (P < 0.05). There was one case of partial avulsion of patellar tendon from the tibial tubercle. Conclusions: We concluded that satisfactory results of TKA can be obtained in knees with limited preoperative ROM using subvastus approach maintaining the advantages of early mobilization. PMID:27053806

  5. Reduced Operating Time but Not Blood Loss With Cruciate Retaining Total Knee Arthroplasty

    PubMed Central

    Vermesan, Dinu; Trocan, Ilie; Prejbeanu, Radu; Poenaru, Dan V; Haragus, Horia; Gratian, Damian; Marrelli, Massimo; Inchingolo, Francesco; Caprio, Monica; Cagiano, Raffaele; Tatullo, Marco

    2015-01-01

    Background There is no consensus regarding the use of retaining or replacing cruciate implants for patients with limited deformity who undergo a total knee replacement. Scope of this paper is to evaluate whether a cruciate sparing total knee replacement could have a reduced operating time compared to a posterior stabilized implant. Methods For this purpose, we performed a randomized study on 50 subjects. All procedures were performed by a single surgeon in the same conditions to minimize bias and only knees with a less than 20 varus deviation and/or maximum 15° fixed flexion contracture were included. Results Surgery time was significantly shorter with the cruciate retaining implant (P = 0.0037). The mean duration for the Vanguard implant was 68.9 (14.7) and for the NexGen II Legacy was 80.2 (11.3). A higher range of motion, but no significant Knee Society Scores at 6 months follow-up, was used as controls. Conclusions In conclusion, both implants had the potential to assure great outcomes. However, if a decision has to be made, choosing a cruciate retaining procedure could significantly reduce the surgical time. When performed under tourniquet, this gain does not lead to reduced blood loss. PMID:25584102

  6. Knee Bracing: What Works?

    MedlinePlus

    MENU Return to Web version Knee Bracing: What Works? Knee Bracing: What Works? What are knee braces? Knee braces are supports ... have arthritis in their knees. Do knee braces work? Maybe. Companies that make knee braces claim that ...

  7. Treatment and Rehabilitation of Knee Joints Straight Stiffness After Burns.

    PubMed

    Tang, Jinshu; Xu, Minghuo; Wu, Wenwen; Hu, Yuan; Shi, Xiuxiu; Hou, Shuxun

    2015-12-01

    The knee release surgery and postoperative rehabilitation of patients after burns and knee straight stiffness were investigated. Eleven patients were treated for 16 side burns and knee stiffness who consisted of nine males and two females, aged 19 to 54 years (mean = 33.2). The duration of the patients' knee stiffness ranged from 8 to 26 months, with an average of 12.6 months. Their preoperative flexion ranged from 5° to 50°, with an average of 26.2°. Their preoperative Hospital for Special Surgery (HSS) knee scores ranged from 46 to 72 points, with an average of 55.8 points. All stiff knees were treated with release surgery, along with total release of intra-articular adhesion and excision of vastus intermedius. After the arthrolysis of the stiff knee joint, the tight skin was completely loose in the adhesions. The soft tissue contracture was not grafted, but the shade fascia was freed to increase skin ductility. All knee joints were released to more than 90° of flexion in the operation, and reversed fascia flaps were used to suture the loss of the deep fascia at the position of flexion of 90°. After the operation, the knee joint was fixed in flexion for 72 h while being actively cared for by early rehabilitation. Subsequently, the patient's skin coverage, joint motion, and joint function recovery were observed. Based on the follow-up of the patients for the following 16 to 36 months (mean = 25.7), the knee flexion of the patients ranged from 110° to 135°, with an average of 122.2° and 96° increase (P < 0.01). Furthermore, the patients had better skin ductility to meet the increase in joint flexion. HSS knee function scores at the end of follow-up ranged from 93 to 100 points, with an average of 97.5 points and an increase of 41.7 points (P < 0.01). The joint function improved significantly. The arthrolysis of straight stiff knee joints after burns can ease muscle contracture and free the shade fascia, thus avoiding the need to

  8. Superconducting tape characterization under flexion

    NASA Astrophysics Data System (ADS)

    Álvarez, A.; Suárez, P.; Cáceres, D.; Pérez, B.; Cordero, E.; Castaño, A.

    2002-08-01

    Electrotechnical applications of high temperature superconducting materials are limited by the difficulty of constructing classical windings with ceramic materials. While Bi-2223 tape may be a solution, it cannot be bent to radii less than a certain value since its superconducting capacity disappears. We describe an automated measurement system of the characteristics of this tape under flexion. It consists of a device that coils the tape over cylinders with different radii. At the same time, the parameters of its superconducting behaviour (e.g. resistance) are taken and processed. This system was developed at the “Benito Mahedero Laboratory of Superconducting Electrical Applications” in the University of Extremadura.

  9. Weight-bearing condyle motion of the knee before and after cruciate-retaining TKA: In-vivo surgical transepicondylar axis and geometric center axis analyses.

    PubMed

    Dimitriou, Dimitris; Tsai, Tsung-Yuan; Park, Kwan Kyu; Hosseini, Ali; Kwon, Young-Min; Rubash, Harry E; Li, Guoan

    2016-06-14

    An equal knee joint height during flexion and extension is of critical importance in optimizing soft-tissue balancing following total knee arthroplasty (TKA). However, there is a paucity of data regarding the in-vivo knee joint height behavior. This study evaluated in-vivo heights and anterior-posterior (AP) translations of the medial and lateral femoral condyles before and after a cruciate-retaining (CR)-TKA using two flexion axes: surgical transepicondylar axis (sTEA) and geometric center axis (GCA). Eleven osteoarthritis (OA) knee patients were studied during a weight-bearing single leg lunge, using a validated dual fluoroscopic imaging system (DFIS) based tracking technique. Eight healthy subjects were recruited as controls. The results demonstrated that following TKA, the medial and lateral femoral condyle heights were not equal at mid-flexion (15-45°, medial condyle lower then lateral by 2.4mm at least, p<0.01), although the knees were well-balanced at 0° and 90°. While the femoral condyle heights increased from the pre-operative values (>2mm increase on average, p<0.05), they were similar to the intact knees except that the medial sTEA was lower than the intact medial condyle between 0° and 90°. At deep flexion (>90°), both condyles were significantly higher (>2mm, p<0.01) than the healthy knees. Anterior femoral translation of the TKA knee was more pronounce at mid-flexion, whereas limited posterior translation was found at deep flexion. These data suggest that a well-balanced knee intra-operatively might not necessarily result in mid-flexion and deep flexion balance during functional weight-bearing motion, implying mid-flexion instability and deep flexion tightness of the knee. PMID:27166758

  10. Kinematic analysis of anterior cruciate ligament reconstruction in total knee arthroplasty

    PubMed Central

    Liu, Hua-Wei; Ni, Ming; Zhang, Guo-Qiang; Li, Xiang; Chen, Hui; Zhang, Qiang; Chai, Wei; Zhou, Yong-Gang; Chen, Ji-Ying; Liu, Yu-Liang; Cheng, Cheng-Kung; Wang, Yan

    2016-01-01

    Background: This study aims to retain normal knee kinematics after knee replacement surgeries by reconstructing anterior cruciate ligament during total knee arthroplasty. Method: We use computational simulation tools to establish four dynamic knee models, including normal knee model, posterior cruciate ligament retaining knee model, posterior cruciate ligament substituting knee model, and anterior cruciate ligament reconstructing knee model. Our proposed method utilizes magnetic resonance images to reconstruct solid bones and attachments of ligaments, and assemble femoral and tibial components according representative literatures and operational specifications. Dynamic data of axial tibial rotation and femoral translation from full-extension to 135 were measured for analyzing the motion of knee models. Findings: The computational simulation results show that comparing with the posterior cruciate ligament retained knee model and the posterior cruciate ligament substituted knee model, reconstructing anterior cruciate ligament improves the posterior movement of the lateral condyle, medial condyle and tibial internal rotation through a full range of flexion. The maximum posterior translations of the lateral condyle, medial condyle and tibial internal rotation of the anterior cruciate ligament reconstructed knee are 15.3 mm, 4.6 mm and 20.6 at 135 of flexion. Interpretation: Reconstructing anterior cruciate ligament in total knee arthroplasty has been approved to be an more efficient way of maintaining normal knee kinematics comparing to posterior cruciate ligament retained and posterior cruciate ligament substituted total knee arthroplasty. PMID:27347334

  11. 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. PMID:26802075

  12. Gait Using Pneumatic Brace for End-Stage Knee Osteoarthritis.

    PubMed

    Kapadia, Bhaveen H; Cherian, Jeffrey Jai; Starr, Roland; Chughtai, Morad; Mont, Michael A; Harwin, Steven F; Bhave, Anil

    2016-04-01

    More than 20 million individuals in the United States are affected by knee osteoarthritis (OA), which can lead to altered biomechanics and excessive joint loading. The use of an unloader pneumatic brace with extension assist has been proposed as a nonoperative treatment modality that may improve gait mechanics and correct knee malalignment. We assessed the following parameters in patients who have knee OA treated with and without a brace: (1) changes in temporospatial parameters in gait; (2) knee range of motion, knee extension at heel strike, and foot placement; (3) knee joint moments and impulse; and (4) changes in dynamic stiffness and rate of change of knee flexion during midstance to terminal stance. This 2:1 prospective, randomized, single-blinded trial evaluated 36 patients (24 brace and 12 matching). OA knee patients were randomized to receive either a pneumatic unloader brace or a standard nonoperative treatment regimen as the matching cohort for a 3-month period. They underwent evaluation of gait parameters using a three-dimensional gait analysis system at their initial appointment and at 3 months follow-up. All the testing, pre- and postbracing were performed without wearing the brace to examine for retained effects. Treatment with the brace led to significant improvements versus standard treatment in various gait parameters. Patients in the brace group had improvements in walking speed, knee extension at heel strike, total range of motion, knee joint forces, and rate of knee flexion from midstance to terminal stance when compared with the matching cohort. Knee OA patients who used a pneumatic unloader brace for 3 months for at least 3 hours per day had significant improvements various gait parameters when compared with a standard nonoperative therapy cohort. Braced patients demonstrated gait-modifying affects when not wearing the brace. These results are encouraging and suggest that this device represents a promising treatment modality for knee OA that

  13. WEAK LENSING MASS RECONSTRUCTION: FLEXION VERSUS SHEAR

    SciTech Connect

    Pires, S.

    2010-11-10

    Weak gravitational lensing has proven to be a powerful tool to map directly the distribution of dark matter in the universe. The technique, currently used, relies on the accurate measurement of the gravitational shear that corresponds to the first-order distortion of the background galaxy images. More recently, a new technique has been introduced that relies on the accurate measurement of the gravitational flexion that corresponds to the second-order distortion of the background galaxy images. This technique should probe structures on smaller scales than that of shear analysis. The goal of this paper is to compare the ability of shear and flexion to reconstruct the dark matter distribution by taking into account the dispersion in shear and flexion measurements. Our results show that the flexion is less sensitive than shear for constructing the convergence maps on scales that are physically feasible for mapping, meaning that flexion alone should not be used to do convergence map reconstruction, even on small scales.

  14. Knee Replacement

    MedlinePlus

    ... doctor may recommend it if you have knee pain and medicine and other treatments are not helping you anymore. When you have a total knee replacement, the surgeon removes damaged cartilage and bone ...

  15. Knee Problems

    MedlinePlus

    ... cartilage, a tough, elastic material that helps absorb shock and allows the knee joint to move smoothly. ... The two menisci in each knee act as shock absorbers, cushioning the lower part of the leg ...

  16. Knee Injuries

    MedlinePlus

    ... Sprains A sprain means you've stretched or torn a ligament. Common knee sprains usually involve damage ... A strain means you've partly or completely torn a muscle or tendon. With knee strains, you ...

  17. A Highly Backdrivable, Lightweight Knee Actuator for Investigating Gait in Stroke.

    PubMed

    Sulzer, James S; Roiz, Ronald A; Peshkin, Michael A; Patton, James L

    2009-06-01

    Many of those who survive a stroke develop a gait disability known as stiff-knee gait (SKG). Characterized by reduced knee flexion angle during swing, people with SKG walk with poor energy efficiency and asymmetry due to the compensatory mechanisms required to clear the foot. Previous modeling studies have shown that knee flexion activity directly before the foot leaves the ground, and this should result in improved knee flexion angle during swing. The goal of this research is to physically test this hypothesis using robotic intervention. We developed a device that is capable of assisting knee flexion torque before swing but feels imperceptible (transparent) for the rest of the gait cycle. This device uses sheathed Bowden cable to control the deflection of a compliant torsional spring in a configuration known as a Series Elastic Remote Knee Actuator (SERKA). In this investigation, we describe the design and evaluation of SERKA, which includes a pilot experiment on stroke subjects. SERKA could supply a substantial torque (12 N· m) in less than 20 ms, with a maximum torque of 41 N·m. The device resisted knee flexion imperceptibly when desired, at less than 1 N·m rms torque during normal gait. With the remote location of the actuator, the user experiences a mass of only 1.2 kg on the knee. We found that the device was capable of increasing both peak knee flexion angle and velocity during gait in stroke subjects. Thus, the SERKA is a valid experimental device that selectively alters knee kinetics and kinematics in gait after stroke. PMID:22563305

  18. A Highly Backdrivable, Lightweight Knee Actuator for Investigating Gait in Stroke

    PubMed Central

    Sulzer, James S.; Roiz, Ronald A.; Peshkin, Michael A.; Patton, James L.

    2012-01-01

    Many of those who survive a stroke develop a gait disability known as stiff-knee gait (SKG). Characterized by reduced knee flexion angle during swing, people with SKG walk with poor energy efficiency and asymmetry due to the compensatory mechanisms required to clear the foot. Previous modeling studies have shown that knee flexion activity directly before the foot leaves the ground, and this should result in improved knee flexion angle during swing. The goal of this research is to physically test this hypothesis using robotic intervention. We developed a device that is capable of assisting knee flexion torque before swing but feels imperceptible (transparent) for the rest of the gait cycle. This device uses sheathed Bowden cable to control the deflection of a compliant torsional spring in a configuration known as a Series Elastic Remote Knee Actuator (SERKA). In this investigation, we describe the design and evaluation of SERKA, which includes a pilot experiment on stroke subjects. SERKA could supply a substantial torque (12 N· m) in less than 20 ms, with a maximum torque of 41 N·m. The device resisted knee flexion imperceptibly when desired, at less than 1 N·m rms torque during normal gait. With the remote location of the actuator, the user experiences a mass of only 1.2 kg on the knee. We found that the device was capable of increasing both peak knee flexion angle and velocity during gait in stroke subjects. Thus, the SERKA is a valid experimental device that selectively alters knee kinetics and kinematics in gait after stroke. PMID:22563305

  19. A Study of Knee Joint Kinematics and Mechanics using a Human FE Model.

    PubMed

    Kitagawa, Yuichi; Hasegawa, Junji; Yasuki, Tsuyoshi; Iwamoto, Masami; Miki, Kazuo

    2005-11-01

    Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the knee is flexed, the knee bolster is generally designed with an inclined surface so as not to directly load the projection in frontal crashes. It should be noted, however, that the initial flexion angle of the occupant knee can vary among individuals and the knee flexion angle can change due to the occupant motion. The behavior of the tibial protuberance related to the knee flexion angle has not been described yet. The instantaneous angle of the knee joint at the timing of restraining the knee should be known to manage the geometry and functions of knee restraint devices. The purposes of this study are first to understand the kinematics of the knee joint during flexion, and second to characterize the mechanics of the knee joint under anterior-posterior loading. A finite element model of the knee joint, extracted from the Total Human Model for Safety (THUMS), was used to analyze the mechanism. The model was validated against kinematics and mechanical responses of the human knee joint. By tracking the relative positions and angles between the patella and the tibia in a knee flexing simulation, the magnitude of the tibial anterior protuberance was described as a function of the knee joint angle. The model revealed that the mechanics of the knee joint was characterized as a combination of stiffness of the patella-femur structure and the PCL It was also found that the magnitude of the tibial anterior protuberance determined the amount of initial stretch of the PCL in anterior-posterior loading. Based on the knee joint kinematics and mechanics, an interference boundary was proposed for different knee flexion angles, so

  20. Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study.

    PubMed

    Wentink, E C; Koopman, H F J M; Stramigioli, S; Rietman, J S; Veltink, P H

    2013-06-01

    Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees. PMID:23000012

  1. Image Segmentation and Analysis of Flexion-Extension Radiographs of Cervical Spines

    PubMed Central

    Enikov, Eniko T.

    2014-01-01

    We present a new analysis tool for cervical flexion-extension radiographs based on machine vision and computerized image processing. The method is based on semiautomatic image segmentation leading to detection of common landmarks such as the spinolaminar (SL) line or contour lines of the implanted anterior cervical plates. The technique allows for visualization of the local curvature of these landmarks during flexion-extension experiments. In addition to changes in the curvature of the SL line, it has been found that the cervical plates also deform during flexion-extension examination. While extension radiographs reveal larger curvature changes in the SL line, flexion radiographs on the other hand tend to generate larger curvature changes in the implanted cervical plates. Furthermore, while some lordosis is always present in the cervical plates by design, it actually decreases during extension and increases during flexion. Possible causes of this unexpected finding are also discussed. The described analysis may lead to a more precise interpretation of flexion-extension radiographs, allowing diagnosis of spinal instability and/or pseudoarthrosis in already seemingly fused spines. PMID:27006937

  2. Design characteristics of pediatric prosthetic knees.

    PubMed

    Andrysek, Jan; Naumann, Stephen; Cleghorn, William L

    2004-12-01

    We examined whether pediatric prosthetic single-axis knees can theoretically provide the beneficial functional characteristics of polycentric knees and the design considerations needed to realize this. Five children and their parents provided subjective opinions of the relative importance of functional requirements (FRs) for the knee. FRs related to comfort, fatigue, stability, and falling were found to be of high importance, while sitting appearance and adequate knee flexion were of lower importance. Relationships were drawn between these FRs and deductions were made regarding the importance of associated design parameters. Stance-phase control was rated to be of greatest importance followed by toe clearance. Models were developed for five knees including four- and six-bar knees, corresponding to two commercially available components, and for three configurations of a single-axis knee. Stance-phase control, specifically stability after heel-strike and swing-phase initiation at push-off, and toe clearance were simulated. The results suggest that a single-axis knee design incorporating stance-phase control will mutually satisfy the identified set of highly and moderately important FRs. PMID:15614992

  3. Changes in knee kinematics following total knee arthroplasty.

    PubMed

    Akbari Shandiz, Mohsen; Boulos, Paul; Saevarsson, Stefan Karl; Yoo, Sam; Miller, Stephen; Anglin, Carolyn

    2016-04-01

    Total knee arthroplasty (TKA) changes the knee joint in both intentional and unintentional, known and unknown, ways. Patellofemoral and tibiofemoral kinematics play an important role in postoperative pain, function, satisfaction and revision, yet are largely unknown. Preoperative kinematics, postoperative kinematics or changes in kinematics may help identify causes of poor clinical outcome. Patellofemoral kinematics are challenging to record since the patella is obscured by the metal femoral component in X-ray and moves under the skin. The purpose of this study was to determine the kinematic degrees of freedom having significant changes and to evaluate the variability in individual changes to allow future study of patients with poor clinical outcomes. We prospectively studied the 6 degrees of freedom patellofemoral and tibiofemoral weightbearing kinematics, tibiofemoral contact points and helical axes of rotation of nine subjects before and at least 1 year after total knee arthroplasty using clinically available computed tomography and radiographic imaging systems. Normal kinematics for healthy individuals were identified from the literature. Significant differences existed between pre-TKA and post-TKA kinematics, with the post-TKA kinematics being closer to normal. While on average the pre-total knee arthroplasty knees in this group displayed no pivoting (only translation), individually only five knees displayed this behaviour (of these, two showed lateral pivoting, one showed medial pivoting and one showed central pivoting). There was considerable variability postoperatively as well (five central, two lateral and two medial pivoting). Both preop and postop, flexion behaviour was more hinge-like medially and more rolling laterally. Helical axes were more consistent postop for this group. An inclusive understanding of the pre-TKA and post-TKA kinematics and changes in kinematics due to total knee arthroplasty could improve implant design, patient diagnosis and

  4. Total knee replacement with and without patellar resurfacing: a prospective, randomised trial using the profix total knee system.

    PubMed

    Smith, A J; Wood, D J; Li, M-G

    2008-01-01

    We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006). PMID:18160498

  5. 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 ...

  6. In vivo determination of total knee arthroplasty kinematics

    SciTech Connect

    Komistek, Richard D; Mahfouz, Mohamed R; Bertin, Kim; Rosenberg, Aaron; Kennedy, William

    2008-01-01

    The objective of this study was to determine if consistent posterior femoral rollback of an asymmetrical posterior cruciate retaining (PCR) total knee arthroplasty was mostly influenced by the implant design, surgical technique, or presence of a well-functioning posterior cruciate ligament (PCL). Three-dimensional femorotibial kinematics was determined for 80 subjects implanted by 3 surgeons, and each subject was evaluated under fluoroscopic surveillance during a deep knee bend. All subjects in this present study having an intact PCL had a well-functioning PCR knee and experienced normal kinematic patterns, although less in magnitude than the normal knee. In addition, a surprising finding was that, on average, subjects without a PCL still achieved posterior femoral rollback from full extension to maximum knee flexion. The findings in this study revealed that implant design did contribute to the normal kinematics demonstrated by subjects having this asymmetrical PCR total knee arthroplasty.

  7. 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

  8. The SIGN nail for knee fusion: technique and clinical results

    PubMed Central

    Anderson, Duane Ray; Anderson, Lucas Aaron; Haller, Justin M.; Feyissa, Abebe Chala

    2016-01-01

    Purpose: Evaluate the efficacy of using the SIGN nail for instrumented knee fusion. Methods: Six consecutive patients (seven knees, three males) with an average age of 30.5 years (range, 18–50 years) underwent a knee arthrodesis with SIGN nail (mean follow-up 10.7 months; range, 8–14 months). Diagnoses included tuberculosis (two knees), congenital knee dislocation in two knees (one patient), bacterial septic arthritis (one knee), malunited spontaneous fusion (one knee), and severe gout with 90° flexion contracture (one knee). The nail was inserted through an anteromedial entry point on the femur and full weightbearing was permitted immediately. Results: All knees had clinical and radiographic evidence of fusion at final follow-up and none required further surgery. Four of six patients ambulated without assistive device, and all patients reported improved overall physical function. There were no post-operative complications. Conclusion: The technique described utilizing the SIGN nail is both safe and effective for knee arthrodesis and useful for austere environments with limited fluoroscopy and implant options. PMID:27163095

  9. Total Knee Arthroplasty Designed to Accommodate the Presence or Absence of the Posterior Cruciate Ligament

    PubMed Central

    Harman, Melinda K.; Bonin, Stephanie J.; Leslie, Chris J.; Banks, Scott A.; Hodge, W. Andrew

    2014-01-01

    Evidence for selecting the same total knee arthroplasty prosthesis whether the posterior cruciate ligament (PCL) is retained or resected is rarely documented. This study reports prospective midterm clinical, radiographic, and functional outcomes of a fixed-bearing design implanted using two different surgical techniques. The PCL was completely retained in 116 knees and completely resected in 43 knees. For the entire cohort, clinical knee (96 ± 7) and function (92 ± 13) scores and radiographic outcomes were good to excellent for 84% of patients after 5–10 years in vivo. Range of motion averaged 124° ± 9°, with 126 knees exhibiting ≥120° flexion. Small differences in average knee flexion and function scores were noted, with the PCL-resected group exhibiting an average of 5° more flexion but an average function score that was 7 points lower compared to the PCL-retained group. Fluoroscopic analysis of 33 knees revealed stable tibiofemoral translations. This study demonstrates that a TKA articular design with progressive congruency in the lateral compartment can provide for femoral condyle rollback in maximal flexion activities and achieve good clinical and functional performance in patients with PCL-retained and PCL-resected TKA. This TKA design proved suitable for use with either surgical technique, providing surgeons with the choice of maintaining or sacrificing the PCL. PMID:25374697

  10. Stress fracture of the proximal fibula after total knee arthroplasty.

    PubMed

    Vaish, Abhishek; Vaishya, Raju; Agarwal, Amit Kumar; Vijay, Vipul

    2016-01-01

    We report a rare case of proximal fibular fatigue fracture developing 14 years after total knee arthroplasty in a known case of rheumatoid arthritis. A valgus deformity of the knee can put abnormal stress on the upper fibula leading to its failure. We believe that, as the fibula acts as an important lateral strut, its disruption due to a fracture led to rapid progress of the valgus deformity of the knee in this patient. PMID:27107057

  11. Cartilage loss patterns within femorotibial contact regions during deep knee bend.

    PubMed

    Michael Johnson, J; Mahfouz, Mohamed R

    2016-06-14

    Osteoarthritis (OA) can alter knee kinematics and stresses. The relationship between cartilage loss in OA and kinematics is unclear, with existing work focusing on static wear and morphology. In this work, femorotibial cartilage maps were coupled with kinematics to investigate the relationship between kinematics and cartilage loss, allowing for more precise treatment and intervention. Cartilage thickness maps were created from healthy and OA subgroups (varus, valgus, and neutral) and mapped to a statistical bone atlas. Video fluoroscopy determined contact regions from 0° to 120° flexion. Varus and valgus subgroups displayed different wear patterns across the range of flexion, with varus knees showing more loss in early flexion and valgus in deeper flexion. For the femur, varus knees had more wear in the medial compartment than neutral or valgus and most wear at both 0° and 20° flexion. In the lateral femoral compartment, the valgus subgroup showed significantly more wear from 20° to 60° flexion as compared to other angles, though varus knees displayed highest magnitude of wear. For the tibia, most medial wear occurred at 0-40° flexion and most lateral occurred after 60° flexion. Knowing more about cartilage changes in OA knees provides insight as to expected wear or stresses on implanted components after arthroplasty. Combining cartilage loss patterns with kinematics allows for pre-surgical intervention and treatments tailored to the patient׳s alignment and kinematics. Reported wear patterns may also serve as a gauge for post-operative loading to be considered when placing implant components. PMID:27173594

  12. Accuracy of CT-based patient-specific guides for total knee arthroplasty in patients with post-traumatic osteoarthritis.

    PubMed

    Schotanus, M G M; van Haaren, E H; Hendrickx, R P M; Jansen, E J P; Kort, N P

    2015-12-01

    Published clinical trials who studied the accuracy of patient-specific guides (PSG) for total knee arthroplasty exclude patients with articular deformity of the knee joint. We prospectively analysed a series of 30 patients with post-traumatic osteoarthritis of the knee joint with use of PSG. At 1 year post-operative, the achieved biomechanical (HKA) axis and varus/valgus of the femur and tibia components were measured on anterior-posterior (AP) long-standing weight-bearing radiographs. Flexion/extension of the femoral and AP slope of the tibia component was measured on standard lateral radiographs. Percentages >3° deviation of the pre-operative planned HKA axis and individual implant components were considered as outliers. Approved and used implant size, median blood loss (ml) and operation time (min) were obtained from the operation records. Pre- and 1-year post-operative patient-reported outcome measures (PROMs) were performed. Eighty-three per cent of the patients had a HKA axis restored <3° of the pre-operative planned alignment. Varus/valgus outliers were 0.0 and 6.7 % for the femoral and tibial components, respectively. Percentages of outliers of flexion/extension were 36.7 % for the femoral component and 10.0 % for the AP slope of the tibial component. Median blood loss was 300 ml (50-700), while operation time was 67 min (44-144). In 20 % of all cases, the approved implant size was changed into one size smaller. One-year post-operative PROMs improved significantly. We conclude that the accuracy of CT-based PSG is not impaired in patients with post-traumatic osteoarthritis and this modality can restore biomechanical limb alignment. PMID:26265403

  13. Patient-Specific Computer Model of Dynamic Squatting after Total Knee Arthroplasty

    PubMed Central

    Mizu-uchi, Hideki; Colwell, Clifford W.; Flores-Hernandez, Cesar; Fregly, Benjamin J.; Matsuda, Shuichi; D’Lima, Darryl D.

    2015-01-01

    Knee forces are highly relevant to performance after total knee arthroplasty especially during high flexion activities such as squatting. We constructed subject-specific models of two patients implanted with instrumented knee prosthesis that measured knee forces in vivo. In vivo peak forces ranged from 2.2 to 2.3 times bodyweight but peaked at different flexion angles based on the type of squatting activity. Our model predicted tibiofemoral contact force with reasonable accuracy in both subjects. This model can be a very useful tool to predict the effect of surgical techniques and component alignment on contact forces. In addition, this model could be used for implant design development, to enhance knee function, to predict forces generated during other activities, and for predicting clinical outcomes. PMID:25662671

  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. Contact stresses with an unresurfaced patella in total knee arthroplasty: the effect of femoral component design.

    PubMed

    Matsuda, S; Ishinishi, T; Whiteside, L A

    2000-03-01

    Compressive contact stresses between the patella and the anterior femur were measured with a digital electronic sensor before and after total knee arthroplasty (TKA) in 10 cadaver knee specimens. Contact stresses were measured first in normal knees, then after TKA with the Insall-Burstein Total Condylar, Miller Galante II, Ortholoc II, Porous Coated Anatomic, and Profix knee prostheses implanted without resurfacing the patella. The Insall-Burstein, Miller-Galante II, and Ortholoc II prostheses had significantly higher contact stresses than the normal knee throughout the flexion arc. The Porous Coated Anatomic, which has a smooth patellar groove, maintained contact area as in the normal knee and did not have significantly higher contact stresses at flexion angles <90 degrees. At flexion angles > or =105 degrees, patellofemoral contact occurred in two small areas as the patella encountered the intercondylar notch in all components except the Profix. The Profix maintained full contact and low compressive stresses throughout the full flexion arc because of its posteriorly extended patellar groove. Design features of the patellofemoral portion of TKA components are important factors that affect contact stresses in the patellofemoral joint. These features likely will affect the clinical results of TKA with an unresurfaced patella. PMID:10741365

  16. Runner's Knee

    MedlinePlus

    ... Over the summer he bought a pair of running shoes and took up jogging. He started with ... bending the knee — when walking, kneeling, squatting, or running, for example. Walking or running downhill or even ...

  17. Knee arthroscopy

    MedlinePlus

    ... is cartilage that cushions the space between the bones in the knee. Surgery is done to repair or remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Torn or damaged collateral ligament Swollen (inflamed) or ...

  18. 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 or diseased, you have knee problems. Knee problems can cause pain and difficulty ...

  19. 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

  20. ACL mismatch reconstructions: influence of different tunnel placement strategies in single-bundle ACL reconstructions on the knee kinematics.

    PubMed

    Herbort, Mirco; Lenschow, Simon; Fu, Freddie H; Petersen, Wolf; Zantop, Thore

    2010-11-01

    To evaluate the influence of tibial and femoral tunnel position in ACL reconstruction on knee kinematics, we compared ACL reconstruction with a tibial and femoral tunnel in anteromedial (AM-AM reconstruction) and in posterolateral footprint (PL-PL reconstruction) with a reconstruction technique with tibial posterolateral and femoral anteromedial tunnel placement (PL-AM reconstruction). In 9 fresh-frozen human cadaveric knees, the knee kinematics under simulated Lachman (134 N anterior tibial load) and a simulated pivot shift test (10 N/m valgus and 4 N/m internal tibial torque) were determined at 0°, 30°, 60°, and 90° of flexion. Kinematics were recorded for intact, ACL-deficient, and single-bundle ACL reconstructed knees using three different reconstruction strategies in randomized order: (1) PL-AM, (2) AM-AM and (3) PL-PL reconstructions. Under simulated Lachman test, single-bundle PL-AM reconstruction and PL-PL reconstructions both showed significantly increased anterior tibial translation (ATT) at 60° and 90° when compared to the intact knee. At all flexion angles, AM-AM reconstruction did not show any statistical significant differences in ATT compared to the intact knee. Under simulated pivot shift, PL-AM reconstruction resulted in significantly higher ATT at 0°, 30°, and 60° knee flexion and AM-AM reconstructions showed significantly higher ATT at 30° compared to the intact knee. PL-PL reconstructions did not show any significant differences to the intact knee. AM-AM reconstructions restore the intact knee kinematics more closely when compared to a PL-AM technique resembling a transtibial approach. PL-PL reconstructions showed increased ATT at higher flexion angles, however, secured the rotational stability at all flexion angles. Due to the independent tibial and femoral tunnel location, a medial portal technique may be superior to a transtibial approach. PMID:20461359

  1. Rehabilitation after ACL Injury: A Fluoroscopic Study on the Effects of Type of Exercise on the Knee Sagittal Plane Arthrokinematics

    PubMed Central

    Norouzi, Sadegh; Esfandiarpour, Fateme; Shakourirad, Ali; Salehi, Reza; Akbar, Mohammad; Farahmand, Farzam

    2013-01-01

    A safe rehabilitation exercise for anterior cruciate ligament (ACL) injuries needs to be compatible with the normal knee arthrokinematics to avoid abnormal loading on the joint structures. The objective of this study was to measure the amount of the anterior tibial translation (ATT) of the ACL-deficient knees during selective open and closed kinetic chain exercises. The intact and injured knees of fourteen male subjects with unilateral ACL injury were imaged using uniplanar fluoroscopy, while the subjects performed forward lunge and unloaded/loaded open kinetic knee extension exercises. The ATTs were measured from fluoroscopic images, as the distance between the tibial and femoral reference points, at seven knee flexion angles, from 0° to 90°. No significant differences were found between the ATTs of the ACL-deficient and intact knees at all flexion angles during forward lunge and unloaded open kinetic knee extension (P < 0.05). During loaded open kinetic knee extension, however, the ATTs of the ACL deficient knees were significantly larger than those of the intact knees at 0° (P = 0.002) and 15° (P = 0.012). It was suggested that the forward lunge, as a weight-bearing closed kinetic chain exercise, provides a safer approach for developing muscle strength and functional stability in rehabilitation program of ACL-deficient knees, in comparison with open kinetic knee extension exercise. PMID:24066288

  2. 2003 Hap Paul Award Paper of the International Society for Technology in Arthroplasty. Design and activity dependence of kinematics in fixed and mobile-bearing knee arthroplasties.

    PubMed

    Banks, Scott A; Hodge, W Andrew

    2004-10-01

    Knee arthroplasty implants are designed with features that provide varying articular constraint over the range of flexion such that the pattern of knee motion may also vary. Because the motions of total knee implants have a direct influence on patient function and device longevity, it is important to understand how knee implants based on a variety of design philosophies perform in vivo. Fifty-nine knees in patients with 5 designs of implants were studied with fluoroscopic imaging during gait and stair-climbing activities. Many knees showed significantly different kinematics between the gait and stair activities, as well as differences from knees having other implant designs. The measured motions were consistent with the intrinsic constraint provided by the implant components and the variation in constraint over the flexion range. PMID:15483794

  3. A new method to measure post-traumatic joint contractures in the rabbit knee.

    PubMed

    Hildebrand, Kevin A; Holmberg, Michael; Shrive, Nigel

    2003-12-01

    A new device and method to measure rabbit knee joint angles are described. The method was used to measure rabbit knee joint angles in normal specimens and in knee joints with obvious contractures. The custom-designed and manufactured gripping device has two clamps. The femoral clamp sits on a pinion gear that is driven by a rack attached to a materials testing system. A 100 N load cell in series with the rack gives force feedback. The tibial clamp is attached to a rotatory potentiometer. The system allows the knee joint multiple degrees-of-freedom (DOF). There are two independent DOF (compression-distraction and internal-external rotation) and two coupled motions (medial-lateral translation coupled with varus-valgus rotation; anterior-posterior translation coupled with flexion-extension rotation). Knee joint extension-flexion motion is measured, which is a combination of the materials testing system displacement (converted to degrees of motion) and the potentiometer values (calibrated to degrees). Internal frictional forces were determined to be at maximum 2% of measured loading. Two separate experiments were performed to evaluate rabbit knees. First, normal right and left pairs of knees from four New Zealand White (NZW) rabbits were subjected to cyclic loading. An extension torque of 0.2 Nm was applied to each knee. The average change in knee joint extension from the first to the fifth cycle was 1.9 deg +/- 1.5 deg (mean +/- sd) with a total of 49 tests of these eight knees. The maximum extension of the four left knees (tested 23 times) was 14.6 deg +/- 7.1 deg, and of the four right knees (tested 26 times) was 12.0 deg +/- 10.9 deg. There was no significant difference in the maximum extension between normal left and right knees. In the second experiment, nine skeletally mature NZW rabbits had stable fractures of the femoral condyles of the right knee that were immobilized for five, six or 10 weeks. The left knee served as an unoperated control. Loss of knee joint

  4. Acute effects of anterior thigh foam rolling on hip angle, knee angle, and rectus femoris length in the modified Thomas test.

    PubMed

    Vigotsky, Andrew D; Lehman, Gregory J; Contreras, Bret; Beardsley, Chris; Chung, Bryan; Feser, Erin H

    2015-01-01

    Background. Foam rolling has been shown to acutely increase range of motion (ROM) during knee flexion and hip flexion with the experimenter applying an external force, yet no study to date has measured hip extensibility as a result of foam rolling with controlled knee flexion and hip extension moments. The purpose of this study was to investigate the acute effects of foam rolling on hip extension, knee flexion, and rectus femoris length during the modified Thomas test. Methods. Twenty-three healthy participants (male = 7; female = 16; age = 22 ± 3.3 years; height = 170 ± 9.18 cm; mass = 67.7 ± 14.9 kg) performed two, one-minute bouts of foam rolling applied to the anterior thigh. Hip extension and knee flexion were measured via motion capture before and after the foam rolling intervention, from which rectus femoris length was calculated. Results. Although the increase in hip extension (change = +1.86° (+0.11, +3.61); z(22) = 2.08; p = 0.0372; Pearson's r = 0.43 (0.02, 0.72)) was not due to chance alone, it cannot be said that the observed changes in knee flexion (change = -1.39° (-5.53, +2.75); t(22) = -0.70; p = 0.4933; Cohen's d = - 0.15 (-0.58, 0.29)) or rectus femoris length (change = -0.005 (-0.013, +0.003); t(22) = -1.30; p = 0.2070; Cohen's d = - 0.27 (-0.70, 0.16)) were not due to chance alone. Conclusions. Although a small change in hip extension was observed, no changes in knee flexion or rectus femoris length were observed. From these data, it appears unlikely that foam rolling applied to the anterior thigh will improve passive hip extension and knee flexion ROM, especially if performed in combination with a dynamic stretching protocol. PMID:26421244

  5. Effects of Cervical Flexion on the Flexion-relaxation Ratio during Smartphone Use

    PubMed Central

    Shin, HyeonHui; Kim, KyeongMi

    2014-01-01

    [Purpose] The purpose of this study was to measure the cervical flexion-relaxation ratio (FRR) and intensity of neck pain and identify the differences according to postures adopted while using smartphones. [Subjects] Fifteen healthy adults with no neck pain, spinal trauma, or history cervical surgery participated in this study. [Methods] The activity of the cervical erector spinae muscle was recorded while performing a standardized cervical flexion-extension movement in three phases (flexion, sustained full flexion, extension). And neck pain intensity was recorded using a visual analog scale (VAS) with values between 0 and 10. Postures held while using a smartphone are distinguished between desk postures and lap postures. The FRR was calculated by dividing the maximal muscle activation during the extension phase by average activation during the complete flexion phase. [Results] No significant differences were found in the FRR between desk posture, lap posture, and baseline, though the intensity of the neck pain increased in the lap posture. [Conclusion] The FRR could be a significant criterion of neuromuscular impairment in chronic neck pain or lumbar pain patients, but it is impossible to distinguish neck pain that is caused by performing task for a short time. Prolonged lap posture might cause neck pain, so the use of smartphones for a long time in this posture should be avoided. PMID:25540493

  6. Effects of Cervical Flexion on the Flexion-relaxation Ratio during Smartphone Use.

    PubMed

    Shin, HyeonHui; Kim, KyeongMi

    2014-12-01

    [Purpose] The purpose of this study was to measure the cervical flexion-relaxation ratio (FRR) and intensity of neck pain and identify the differences according to postures adopted while using smartphones. [Subjects] Fifteen healthy adults with no neck pain, spinal trauma, or history cervical surgery participated in this study. [Methods] The activity of the cervical erector spinae muscle was recorded while performing a standardized cervical flexion-extension movement in three phases (flexion, sustained full flexion, extension). And neck pain intensity was recorded using a visual analog scale (VAS) with values between 0 and 10. Postures held while using a smartphone are distinguished between desk postures and lap postures. The FRR was calculated by dividing the maximal muscle activation during the extension phase by average activation during the complete flexion phase. [Results] No significant differences were found in the FRR between desk posture, lap posture, and baseline, though the intensity of the neck pain increased in the lap posture. [Conclusion] The FRR could be a significant criterion of neuromuscular impairment in chronic neck pain or lumbar pain patients, but it is impossible to distinguish neck pain that is caused by performing task for a short time. Prolonged lap posture might cause neck pain, so the use of smartphones for a long time in this posture should be avoided. PMID:25540493

  7. 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

  8. Effect of femoral component design on unresurfaced patellas in knee arthroplasty.

    PubMed

    Whiteside, Leo A; Nakamura, Takashi

    2003-05-01

    Three total knee designs were evaluated to test the hypothesis that femoral component design affects the clinical and mechanical functions of the unresurfaced patella after total knee arthroplasty. Patients with the Ortholoc II, Advantim, and Profix femoral components were followed up for as many as 14 years and revision rate, anterior knee pain, and generalized knee pain were compared. A laboratory protocol was devised to evaluate pressure in the patellofemoral joint of knees from cadavers with a pressure-sensitive transducer using the same three designs at various degrees of knee flexion. Thirty Ortholoc II knee components were followed up for 14 years. Nineteen patients (63%) had severe anterior knee pain and 15 patients (50%) had reoperation to resurface the patella within 2 years. Two hundred one patients (222 knees) with Advantim components were followed up for 10 years and 305 patients (330 knees) with Profix components were followed up for 5 years. No patients with these two knee designs had severe anterior knee pain or reoperation for patellar resurfacing. A significantly higher rate of mild anterior knee pain was seen in the patients with Advantim components than in the patients with Profix components. No apparent relationship was seen between the severity of patellar wear found at the time of surgery and the incidence of anterior knee pain. Patients with rheumatoid arthritis receiving either the Advantim or Profix knee component performed as well as patients with osteoarthritis when the patella was not resurfaced. Pressure was significantly higher in the patellofemoral joints of the laboratory knee specimens with Ortholoc II components than in the specimens with either the Advantim or Profix components. The specimens with Advantim components had significantly higher pressure than did the specimens with normal knees, and the specimens with Profix components differed little from those with normal knees. PMID:12771830

  9. Post-traumatic flexion contractures of the elbow: Operative treatment via the limited lateral approach

    PubMed Central

    Brinsden, Mark D; Carr, Andrew J; Rees, Jonathan L

    2008-01-01

    Varying surgical techniques, patient groups and results have been described regards the surgical treatment of post traumatic flexion contracture of the elbow. We present our experience using the limited lateral approach on patients with carefully defined contracture types. Surgical release of post-traumatic flexion contracture of the elbow was performed in 23 patients via a limited lateral approach. All patients had an established flexion contracture with significant functional deficit. Contracture types were classified as either extrinsic if the contracture was not associated with damage to the joint surface or as intrinsic if it was. Overall, the mean pre-operative deformity was 55 degrees (95%CI 48 – 61) which was corrected at the time of surgery to 17 degrees (95%CI 12 – 22). At short-term follow-up (7.5 months) the mean residual deformity was 25 degrees (95%CI 19 – 30) and at medium-term follow-up (43 months) it was 32 degrees (95%CI 25 – 39). This deformity correction was significant (p < 0.01). One patient suffered a post-operative complication with transient dysaesthesia in the distribution of the ulnar nerve, which had resolved at six weeks. Sixteen patients had an extrinsic contracture and seven an intrinsic. Although all patients were satisfied with the results of their surgery, patients with an extrinsic contracture had significantly (p = 0.02) better results than those with an intrinsic contracture. (28 degrees compared to 48 degrees at medium term follow up). Surgical release of post-traumatic flexion contracture of the elbow via a limited lateral approach is a safe technique, which reliably improves extension especially for extrinsic contractures. In this series all patients with an extrinsic contracture regained a functional range of movement and were satisfied with their surgery. PMID:18783605

  10. A cadaver knee simulator to evaluate the biomechanics of rectus femoris transfer.

    PubMed

    Anderson, Michael C; Brown, Nicholas A T; Bachus, Kent N; Macwilliams, Bruce A

    2009-07-01

    A cadaver knee simulator has been developed to model surgical transfer of the rectus femoris. The simulator allows knee specimens six degrees of freedom and is capable of modeling both the swing and stance phases of human gait. Experiments were conducted using a mechanical hinge analog of the knee to verify that time, flexion angle, and knee extension force measurements recorded when using the simulator were not influenced by its design or operation. A ballistic double pendulum model was used to model the swing phase of gait, and the contributions of hip and ankle torques and hamstrings cocontraction were included when modeling the stance phase of gait. When modeling swing, range of motion and time to peak knee flexion in swing for the hinge knee were similar to those of in vivo test subjects. Measurements of hinge knee extension force when modeling stance under various biomechanical conditions matched those predicted using an analytical model. Future studies using cadaver knee specimens will apply techniques described in this paper to further our understanding of changes in knee biomechanics caused by rectus femoris transfer surgery. PMID:19403312

  11. The effect of mechanical massage on early outcome after total knee arthroplasty: a pilot study

    PubMed Central

    Kim, Sun Mi; Kim, Sang-Rim; Lee, Yong Ki; Kim, Bo Ryun; Han, Eun Young

    2015-01-01

    [Purpose] The aim of this study was to evaluate the efficacy of mechanical massage via Endermologie® after total knee arthroplasty in reducing edema and pain and improving knee range of motion, in the early postoperative period. [Subjects and Methods] Eighteen patients with knee edema following total knee arthroplasty were randomly assigned to the intervention group (n=8) or the control group (n=10). The intervention group received mechanical massage therapy using Endermologie® and the control group received conventional physical therapy for 20 minutes a day, 5 times a week from the seventh day postsurgery. Clinical assessments included active knee flexion and extension range of motion, knee pain using a numeric rating scale, the operated limb circumference, the soft tissue cross-sectional area using ultrasonography, the extracelluar fluid volume, and single frequency bioimpedance analysis at 5 kHz using bioelectrical impedance spectroscopy. [Results] Both groups showed significant reduction in edema and pain, and improvement in active knee flexion at the end of treatment. There were no significant inter-group differences before or after treatment. [Conclusion] Mechanical massage could be an alternative way of managing knee edema after total knee arthroplasty in early postoperative recovery. PMID:26696709

  12. Constant vs variable resistance knee extension training.

    PubMed

    Manning, R J; Graves, J E; Carpenter, D M; Leggett, S H; Pollock, M L

    1990-06-01

    To compare the effect of constant resistance (CR) and variable resistance (VR) training on full range-of-motion (ROM) strength development, 22 men and 27 women (age = 26 +/- 5 yr) were randomly assigned to either a CR training group (N = 17), a VR training group (N = 17), or a control group (N = 15) that did not train. The CR and VR groups trained 2 to 3 d.wk-1 for 10 wk. Subjects completed one set of full ROM (120 to 0 degrees of flexion) bilateral knee extensions with an amount of weight that allowed 8 to 12 repetitions during each training session. For the VR group, resistance was varied with a cam supplied by the manufacturer (Nautilus). For the CR group, the cam was removed and replaced with a round sprocket. Prior to and after training, maximal voluntary isometric torque was measured at 9, 20, 35, 50, 65, 80, 95, and 110 degrees of knee flexion. Analysis of covariance indicated that the VR and CR groups gained strength at all angles (P less than or equal to 0.05) when compared to the control. [table: see text] There was no difference (P greater than 0.05) between the CR and VR groups at any angle, and the magnitude of strength gained was similar (P greater than 0.05) among angles for both groups. These data indicate that both CR and VR knee extension training elicit full ROM strength development. PMID:2381309

  13. Fabella Syndrome as an Uncommon Cause of Posterolateral Knee Pain after Total Knee Arthroplasty: A Case Report and Review of the Literature

    PubMed Central

    Okano, Eriko; Yanai, Takaji; Kohyama, Sho; Kanamori, Akihiro; Yamazaki, Masashi; Tanaka, Toshikazu

    2016-01-01

    The fabella is a sesamoid bone that is located in the lateral head of the gastrocnemius muscle and has been identified on magnetic resonance imaging in 31% of Japanese people. In the present case, a 65-year-old woman experienced posterolateral knee pain, accompanied by a clicking “sound” during active knee flexion, after undergoing total knee arthroplasty for knee osteoarthritis. Eight months of conservative therapy failed to produce an improvement, with progressive osteoarthritic change of the fabella identified on plain radiography. Based on this evidence, a diagnosis of fabella syndrome was made and the patient underwent a fabellectomy. Fabellectomy provided immediate resolution of posterolateral knee pain and the clicking sound with knee flexion, with the patient remaining symptom-free 18 months after fabellectomy and with no limitations in knee function. Fabellectomy eliminated symptoms in all of five case reports that have been previously published and is regarded as an effective first choice for treating fabella syndrome after total knee arthroplasty. PMID:27418991

  14. Muscle activation and knee biomechanics during squatting and lunging after lower extremity fatigue in healthy young women.

    PubMed

    Longpré, Heather S; Acker, Stacey M; Maly, Monica R

    2015-02-01

    Muscle activations and knee joint loads were compared during squatting and lunging before and after lower extremity neuromuscular fatigue. Electromyographic activations of the rectus femoris, vastus lateralis and biceps femoris, and the external knee adduction and flexion moments were collected on 25 healthy women (mean age 23.5 years, BMI of 23.7 kg/m(2)) during squatting and lunging. Participants were fatigued through sets of 50 isotonic knee extensions and flexions, with resistance set at 50% of the peak torque achieved during a maximum voluntary isometric contraction. Fatigue was defined as a decrease in peak isometric knee extension or flexion torque ≥25% from baseline. Co-activation indices were calculated between rectus femoris and biceps femoris; and between vastus lateralis and biceps femoris. Fatigue decreased peak isometric extension and flexion torques (p<0.05), mean vastus lateralis activation during squatting and lunging (p<0.05), and knee adduction and flexion moments during lunging (p<0.05). Quadriceps activations were greater during lunging than squatting (p<0.05). Thus, fatigue altered the recruitment strategy of the quadriceps during squatting and lunging. Lunging challenges quadriceps activation more than squatting in healthy, young women. PMID:25258248

  15. Dynamic knee stability estimated by finite helical axis methods during functional performance approximately twenty years after anterior cruciate ligament injury.

    PubMed

    Grip, Helena; Tengman, Eva; Häger, Charlotte K

    2015-07-16

    Finite helical axis (FHA) measures of the knee joint during weight-bearing tasks may capture dynamic knee stability following Anterior Cruciate Ligament (ACL) injury. The aim was to investigate dynamic knee stability during two-leg squat (TLS) and one-leg side hop (SH) in a long-term follow-up of ACL injury, and to examine correlations with knee laxity (KT-1000), osteoarthritis (OA, Kellgren-Lawrence) and knee function (Lysholm score). Participants were injured 17-28 years ago and then treated with surgery (n=33, ACLR) or physiotherapy only (n=37, ACLPT) and healthy-knee controls (n=33) were tested. Movements were registered with an optical motion capture system. We computed three FHA inclination angles, its' Anterior-Posterior (A-P) position, and an index quantifying directional changes (DI), during stepwise knee flexion intervals of ∼15°. Injured knees were less stable compared to healthy controls' and to contralateral non-injured knees, regardless of treatment: the A-P intersection was more anterior (indicating a more anterior positioning of tibia relative to femur) positively correlating with high laxity/low knee function, and during SH, the FHA was more inclined relative to the flexion-extension axis, possibly due to reduced rotational stability. During the TLS, A-P intersection was more anterior in the non-injured knee than the injured, and DI was higher, probably related to higher load on the non-injured knee. ACLR had less anterior A-P intersection than ACLPT, suggesting that surgery enhanced stability, although rotational stability may remain reduced. More anterior A-P intersection and greater inclination between the FHA and the knee flexion-extension axis best revealed reduced dynamic stability ∼23 years post-injury. PMID:25935685

  16. Quantification of the Effect of Vertical Bone Resection of the Medial Proximal Tibia for Achieving Soft Tissue Balancing in Total Knee Arthroplasty

    PubMed Central

    Lee, Sung Hyun; Kang, Ho Won

    2016-01-01

    Background Degenerative osteoarthritis of the knee usually shows arthritic change in the medial tibiofemoral joint with severe varus deformity. In total knee arthroplasty (TKA), the medial release technique is often used for achieving mediolateral balancing. But, in a more severe varus knee, there are more difficult technical problems. Bony resection of the medial proximal tibia (MPT) as an alternative technique for achieving soft tissue balancing was assessed in terms of its effectiveness and possibility of quantification. Methods TKAs were performed in 78 knees (60 patients) with vertical bone resection of the MPT for soft tissue balancing from September 2011 to March 2013. During operation, the medial and lateral gaps were measured before and after the bony resection technique. First, the correlation between the measured thickness of the resected bone and the change in medial and lateral gaps was analyzed. Second, the possibility of quantification of each parameter was evaluated by linear regression and the coefficient ratio was obtained. Results A significant correlation was identified between alteration in the medial gap change in extension and the measured thickness of the vertically resected MPT (r = 0.695, p = 0.000). In the medial gap change in flexion, there was no statistical significance (r = 0.214, p = 0.059). When the MPT was resected at an average thickness of 8.25 ± 1.92 mm, the medial gap in extension was increased by 2.94 ± 0.87 mm. In simple linear regression, it was predictable that MPT resection at a thickness of 2.80 mm was required to increase the medial gap by 1.00 mm in knee extension. Conclusions The method of bone resection of the MPT can be considered effective with a predictable result for achieving soft tissue balancing in terms of quantification during TKA. PMID:26929799

  17. Functional and radiographic short-term outcome evaluation of the Visionaire system, a patient-matched instrumentation system for total knee arthroplasty.

    PubMed

    Vundelinckx, Bart J; Bruckers, Liesbeth; De Mulder, Kris; De Schepper, Jo; Van Esbroeck, Gert

    2013-06-01

    Patient matched instrumentation is a new operative tool in the field of total knee arthroplasty. Custom made cutting blocks are designed to perform distal femoral and tibial bone cuts according to a pre-operative planning. This study evaluates the Visionaire system of Smith & Nephew. Thirty-one patients, operated with the Visionaire technique, were compared to an equal control group for different clinical and radiographic outcome parameters. Between both groups, no statistical significant difference could be found in post-operative pain, satisfaction, functional outcome, hospital stay, blood loss, radiographic alignment and precision of bone cuts. Only tibial plateau backslope can be created with more precision in the Visionaire group. But there was a statistical significant difference for residual flexion deformity after a mean follow-up time of 200 days. PMID:23535285

  18. Variability of TKR Knee Kinematics and Relationship with Gait Kinetics: Implications for Total Knee Wear

    PubMed Central

    Wimmer, Markus A.

    2015-01-01

    Several factors, including compressive load and knee kinematics, have been shown to influence wear. External knee moments (a surrogate for load) have recently been correlated with the medial and lateral wear scar areas of an unconstrained, PCL retaining knee design. Therefore, the purpose of this study was to determine whether differences in kinetics during level walking are accompanied by specific differences in relative knee kinematics. Thirty TKR patients were gait tested using the point cluster technique to obtain 3D motions of the knee. External knee moments were calculated from ground reaction forces recorded with a multicomponent force plate. The subjects were separated into two distinct anteroposterior (AP) motion categories: a low motion group and a high motion group. Similarly, the low and high motion groups for internal-external (IE) rotation were also identified. For the IE motion, there was no significant difference between the transverse internal rotation moments between the two IE motion groups. However for the AP motion groups, a higher external peak flexion moment was found for the group displaying less AP motion. These observations suggest that subjects with higher joint moments execute smaller ranges of AP motion and thus are likely to incur less wear. PMID:25866770

  19. Biomechanical and clinical evaluation of a newly designed polycentric knee of transfemoral prosthesis.

    PubMed

    Yokogushi, Kazutoshi; Narita, Hiroshi; Uchiyama, Eiichi; Chiba, Susumu; Nosaka, Toshiya; Yamakoshi, Ken-ichi

    2004-09-01

    We have designed a new polycentric knee adopting a hydraulic unit and an intelligent mechanism. The biomechanical parameters of this prototype, such as the stance duration, peak knee flexion angle in stance and swing, peak hip flexion angle, and peak hip extension moments were analyzed at three different cadences (88, 96, 104 steps/min) in three amputees, and then compared to those of polycentric hydraulic knees currently in use. The same parameters were also measured for 10 healthy volunteers and subsequently analyzed. In the prototype, almost all the values of the parameters showed no significant variety in individuals at the different cadences. The situation was the same with the healthy volunteers. However, the values of the parameter for the conventional knee varied significantly with the individual at the different cadences. The prototype may be of practical use, contributing to a stable walk even at different cadences. PMID:15558397

  20. Tibial tubercle osteotomy for exposure of the difficult total knee arthroplasty.

    PubMed

    Whiteside, L A; Ohl, M D

    1990-11-01

    Tibial tubercle osteotomy provides a safe and reliable means of extensile exposure of the knee. A technique was developed using a long osteoperiosteal segment including the tibial tubercle and upper tibial crest leaving lateral muscular attachments intact to this bone fragment. The bone fragment was reattached to its bed with two cobalt-chromium wires passed through the fragment and through the medial tibial cortex. The procedure was used in 71 knees to expose the joint for total knee arthroplasty, and the follow-up period was one to five years. All healed uneventfully, and no significant complications occurred. Mean postoperative flexion was 97 degrees. No extension lag occurred, and mean flexion contracture was 2.5 degrees. Excellent exposure can be achieved by means of a viable bone flap below the knee. Early rehabilitation and weight bearing can be done with low potential for complications. PMID:2225644

  1. [Jumper's knee].

    PubMed

    Hagner, W; Sosnowski, S; Kaziński, W; Frankowski, S

    1993-01-01

    A series of 30 athletes aged about 16 years on an average, exposed to activities putting a strain on the patellar tendon during training has been examined. They were involved in competitive sports for 3 years on an average. In 27 per cent of them jumpers knee symptoms have been found. PMID:7671664

  2. In vivo Kinematics of the Knee after a Posterior Cruciate-Substituting Total Knee Arthroplasty: A Comparison between Caucasian and South Korean Patients

    PubMed Central

    Bae, Ji-Hoon; Hosseini, Ali; Nha, Kyung-Wook; Park, Sang-Eun; Tsai, Tsung Yuan; Kwon, Young-Min

    2016-01-01

    Purpose This study compared in vivo kinematic differences between Caucasian and South Korean patients after a posterior-substituting total knee arthroplasty (PS-TKA). Materials and Methods In vivo motions of 9 Caucasian and 13 South Korean knees with a PS-TKA during weight bearing single leg lunge were determined using a dual fluoroscopic imaging technique. Normalized tibiofemoral condylar motions and articular contact locations were analyzed. Results Femoral condylar motions of the two groups showed a similar trend in anteroposterior translation, but the South Korean patients were more anteriorly positioned than the Caucasian patients at low flexion and maximal flexion angles in both medial and lateral compartments (p<0.05). Mediolateral femoral condyle translations were similar between the two groups. For tibiofemoral articular contact kinematics, the South Korean patients had significantly more anterior contact locations at the medial compartment at low flexion angles, and more lateral contact locations at the lateral compartment at 0° and 90° flexion compared to the Caucasian patients (p<0.05). The South Korean patients had significantly larger distances between the medial and lateral contact locations at 60° and 90° flexion compared to the Caucasian patients (p<0.05). Conclusions The study revealed that while the Caucasian and South Korean knees had similar femoral condylar motions, after PS-TKA the South Korean patients showed different articular contact point kinematics compared to the Caucasian patients. PMID:27274467

  3. Continuous sagittal radiological evaluation of stair-climbing in cruciate-retaining and posterior-stabilized total knee arthroplasties using image-matching techniques.

    PubMed

    Hamai, Satoshi; Okazaki, Ken; Shimoto, Takeshi; Nakahara, Hiroyuki; Higaki, Hidehiko; Iwamoto, Yukihide

    2015-05-01

    In this study, we evaluated the in vivo kinematics of stair-climbing after posterior stabilized (PS) and cruciate retaining (CR) total knee arthroplasty (TKA) using radiographic-based image-matching techniques. Mid-flexion anteroposterior stability was demonstrated in all knees after CR TKA. However, paradoxical femoral translation at low flexion angles was seen in both designs. The post-cam mechanism did not function after PS TKA. Larger posterior tibial slope in PS TKA was linked to forward sliding of the femur at mid-flexion and unintended anterior tibial post impingement at knee extension. CR TKA is more sagittally stable in mid-flexion during stair climbing and attention must be given to minimize posterior tibial slope when using late cam-post engaging PS TKA designs. PMID:25618811

  4. Biomechanical Analysis of Stair Descent in Patients with Knee Osteoarthritis

    PubMed Central

    Igawa, Tatsuya; Katsuhira, Junji

    2014-01-01

    [Purpose] The purposes of this study were to investigate the lower extremity joint kinematics and kinetics of patients with the knee osteoarthritis (knee OA) during stair descent and clarify the biomechanical factors related to their difficulty in stair descent. [Subjects and Methods] Eight healthy elderly persons and four knee OA patients participated in this study. A 3-D motion analysis system and force plates were employed to measure lower extremity joint angles, ranges of motion, joint moments, joint powers, and ratios of contribution for the joint powers while descending stairs. [Results] Knee joint flexion angle, extension moment, and negative power during the early stance phase in the knee OA group were smaller than those in the healthy subjects group. However, no significant changes in these parameters in the ankle joint were observed between the two subject groups. [Conclusion] Knee OA patients could not use the knee joint to absorb impact during the early stance phase of stair descent. Hence, they might compensate for the roles played by the intact knee joint by mainly using ipsilateral ankle kinematics and kinetics. PMID:24926119

  5. Output space tracking control for above-knee prosthesis.

    PubMed

    Popović, D B; Kalanović, V D

    1993-06-01

    The control of a knee joint in an active above-knee prosthesis has been designed using the Lyapunov tracking method. A simulation of locomotion was done to prove that the tracking control in output space is a valuable real time control method for artificial legs. The data used for simulation was collected in able-bodied subjects while they walked on a powered treadmill. Human volunteers were braced with an ankle splint (limiting dorsi- and plantar flexion) and with a knee cage (limiting knee movements to the lateral plane). We studied the achieved tracking of the prescribed knee motion, deviations of the thigh movement from the prescribed trajectory, maximal angular deviations from the desired trajectory and the power consumption as functions of a limited maximal knee torque and a damping constant in the knee actuator. We found that the use of output tracking method is suitable for the design of appropriate hardware of an above-knee prosthesis and for real-time control. PMID:8262536

  6. 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

  7. 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. PMID:26152462

  8. NAVIGATION IN TOTAL KNEE ARTHROPLASTY

    PubMed Central

    da Mota e Albuquerque, Roberto Freire

    2015-01-01

    Navigation was the most significant advance in instrumentation for total knee arthroplasty over the last decade. It provides surgeons with a precision tool for carrying out surgery, with the possibility of intraoperative simulation and objective control over various anatomical and surgical parameters and references. Since the first systems, which were basically used to control the alignment of bone cutting referenced to the mechanical axis of the lower limb, many other surgical steps have been incorporated, such as component rotation, ligament balancing and arranging the symmetry of flexion and extension spaces, among others. Its efficacy as a precision tool with an effective capacity for promoting better alignment of the lower-limb axis has been widely proven in the literature, but the real value of optimized alignment and the impact of navigation on clinical results and the longevity of arthroplasty have yet to be established. PMID:27026979

  9. Injuries to the posterior cruciate ligament of the knee.

    PubMed

    Kannus, P; Bergfeld, J; Järvinen, M; Johnson, R J; Pope, M; Renström, P; Yasuda, K

    1991-08-01

    The posterior cruciate ligament (PCL) is the strongest ligament about the knee and is approximately twice as strong as the anterior cruciate ligament. Its main function is to prevent the posterior dislocation of the tibia in relation to the femur, providing 95% of the strength to resist the tibial posterior displacement. Along with the anterior cruciate ligament (ACL) the PCL controls the passive 'screw home' mechanism of the knee in terminal knee extension. It also provides mechanical support for the collateral ligaments during valgus or varus stress of the knee. PCL ruptures are uncommon apparently due to its strong fibre structure. The most frequent injury mechanism in isolated PCL tears is a direct blow on the anterior tibia with the knee flexed thus driving the tibia posteriorly. Automobile accidents (in which the knee hits the dashboard) and soccer injuries (in which an athlete receives a blow to the anterior surface of the tibia during knee flexion) characteristically produce this type of injury. In other PCL injury mechanisms (hyperextension, hyperflexion or rotational injuries with associated valgum/varum stress), other knee structures are also often damaged. The most characteristic diagnostic finding in a knee with a PCL rupture is the 'posterior sag sign' meaning the apparent disappearance of the tibial tubercle in lateral inspection when the knee is flexed 90 degrees. This is due to gravity-assisted posterior displacement of the tibia in relation to the femur. A positive posterior drawer test performed at 90 degrees of flexion and a knee hyperextension sign are sensitive but nonspecific tests. False negative findings are frequent, especially in acute cases. If necessary, the clinical diagnosis of the PCL tear can be verified by magnetic resonance imaging, examination under anaesthesia, arthroscopy, or a combination of these modalities. If a PCL avulsion fragment has been dislocated, surgical treatment is recommended. In isolated, complete midsubstance

  10. Isokinetic strength training in below-knee amputees.

    PubMed

    Klingenstierna, U; Renström, P; Grimby, G; Morelli, B

    1990-01-01

    Eight below-knee amputees performed isokinetic training of knee extensor- and knee-flexor muscles for a period of 8-12 weeks at angular velocities of 60 degrees/s, 180 degrees/s and 240 degrees/s. Before and after training isokinetic and isometric knee extensor/flexor strength was measured. Muscle biopsies were taken from the vastus lateralis and the cross-sectional area of the thigh muscles was measured with computerized tomography. Peak torque of the amputated leg increased significantly in all knee-extension tests and in knee-flexion at 180 degrees/s, and in the non-amputated leg in extension at 180 degrees/s, 240 degrees/s and for isometric strength at 60 degrees knee angle. Knee-flexion strength increased at 240 degrees/s. The cross-sectional area of the muscle fibers increased in the amputated leg in all patients except one. There was no significant increase in the non-amputated leg which also was trained. The quotient between the cross-sectional areas of type II and type I fibers increased from 1.04 to 1.20 in the amputated leg, demonstrating an increase specially in the type II fibers. There was no difference in the non-amputated leg. The cross-sectional area of the thigh muscles did not show any significant change in either leg. The patients estimated their ability to walk after training to more than double the distance compared to before training. They could also manage better without walking aids. The increase in strength and the synchronous increase in the size of type II (fast twitch) fibers indicate that the training model has activated also these motor units which probably have not been given as much training earlier. PMID:2326608

  11. Cruciate Retaining Versus Cruciate Stabilising Total Knee Arthroplasty – A Prospective Randomised Kinematic Study

    PubMed Central

    Godwin, T L; Bayan, A

    2016-01-01

    Objective: While there is a large body of research in regards to cruciate retaining(CR) and cruciate sacrificing total condylar knee replacement, the literature is spars in regards to highly conforming polyetheylene such as the triatholon cruciate stabilising tibial insert (CS).The aim was to determine whether there is a difference in the range of motion, kinematics as well as the functional outcome for Triathlon CS and CR TKJR. Methods: A single hospital consecutive series of one surgeon between 2011 and 2013 were enrolled. Kinematic data recorded prospectively at the time of surgery utilizing imageless navigation included preoperative and post-replacement extension, gravity flexion, passive flexion and rotation. Intraoperative femoral and tibial cuts and definitive implants were also recorded. Statistically analysis performed to compare CS and CR TKJR range of motion, deformity correction, and rotation pre and post-operatively. Oxford functional scores were obtained at the final follow up. 124 patients were randomised to 71 CS and 53 CR TKJR. The demographics were comparable between the two groups. Results: No significant difference was found between the groups’ preoperative range of motion. The net gain in extension for the CS group was 5.65 degrees (4.14-7.17) and for CR 5.64 degrees (4.24-7.04, p=0.99) with no significant difference shown. Post-operative gravity flexion significantly increased in CS TKJR with 129.01 degrees (127.37130.66) compared with 126.35 degrees (124.39-128.30, p =0.04) for CR. A weak positive correlation was shown between the size of distal femoral cut and post-operative extension for both CS and CR TKJR. A weak positive correlation was also shown for the difference between the intraoperative cuts (tibial and femoral) and the size of the implants used, in relation to post-operative extension. Post-operative oxford scores at average of 3.4 year follow up comparable between groups. Conclusion: The kinematics of CS and CR TKJR are

  12. The Difficult Primary Total Knee Arthroplasty.

    PubMed

    Malkani, Arthur L; Hitt, Kirby D; Badarudeen, Sameer; Lewis, Courtland; Cherian, Jeffrey; Elmallah, Randa; Mont, Michael A

    2016-01-01

    Primary total knee arthroplasty (TKA) for the treatment of knee arthritis has substantially increased over the past decade. Because of its success, the indications for primary TKA have expanded to include younger patients who are more active, elderly patients who have multiple comorbidities, and patients who have more complex issues, such as posttraumatic arthritis and severe deformity. TKA also has been used to salvage failed unicondylar arthroplasty and osteotomies about the knee. Exposure may be challenging and outcomes may not be as successful in patients with soft-tissue contractures, such as a stiff knee, who undergo TKA. Bone graft or augments may be required to correct deformity and attain proper knee alignment in patients who have a substantial varus or valgus deformity. TKA is somewhat challenging in patients who have deformity, bone loss, contracture, or multiple comorbidities, or have had prior surgery; therefore, it is necessary for surgeons to be aware of some general principles that may help minimize complications and improve outcomes. PMID:27049194

  13. Characterising knee motion and laxity in a testing machine for application to total knee evaluation.

    PubMed

    Walker, Peter S; Arno, Sally; Borukhoy, Ilya; Bell, Christopher P

    2015-10-15

    The goal of this study was to determine knee motions in specimens under combined input forces over a full range of flexion, so that the various flexion angles and loading combinations encountered in functional conditions would be contained. The purpose was that the data would act as a benchmark for the evaluation of TKR designs using the same testing methodology. We measured the neutral path of motion and laxity about the neutral path. The femur was flexed in a continuous movement, rather than at discrete flexion angles, using optical tracking. The motion of the femoral circular axis relative to the tibia was determined, as well as the contact patches on the tibial surfaces. The neutral path of motion was independent of compressive load, and consisted of a relatively constant medial contact and steady posterior displacement laterally, in agreement with previous studies. The anterior-posterior laxities of the lateral and medial condyles were similar whether AP forces or torques were applied. The lateral laxity was predominantly anterior with respect to the neutral path, while on the medial side, the laxity was less than lateral and predominantly posterior of the neutral path. Contact on the anterior surface of the medial tibial plateau only occurred in some cases in 5° hyperextension and at 0° flex when an anterior femoral shear or an external femoral torque were applied. The method can be regarded as a development of the ASTM constraint standard, with the addition of the benchmark, for the evaluation of total knee designs. PMID:26315916

  14. Single bundle anterior cruciate reconstruction does not restore normal knee kinematics at six months: an upright MRI study.

    PubMed

    Nicholson, J A; Sutherland, A G; Smith, F W

    2011-10-01

    Abnormal knee kinematics following reconstruction of the anterior cruciate ligament may exist despite an apparent resolution of tibial laxity and functional benefit. We performed upright, weight-bearing MR scans of both knees in the sagittal plane at different angles of flexion to determine the kinematics of the knee following unilateral reconstruction (n = 12). The uninjured knee acted as a control. Scans were performed pre-operatively and at three and six months post-operatively. Anteroposterior tibial laxity was determined using an arthrometer and patient function by validated questionnaires before and after reconstruction. In all the knees with deficient anterior cruciate ligaments, the tibial plateau was displaced anteriorly and internally rotated relative to the femur when compared with the control contralateral knee, particularly in extension and early flexion (mean lateral compartment displacement: extension 7.9 mm (sd 4.8), p = 0.002 and 30° flexion 5.1 mm (sd 3.6), p = 0.004). In all ten patients underwent post-operative scans. Reconstruction reduced the subluxation of the lateral tibial plateau at three months, with resolution of anterior displacement in early flexion, but not in extension (p = 0.015). At six months, the reconstructed knee again showed anterior subluxation in both the lateral (mean: extension 4.2 mm (sd 4.2), p = 0.021 and 30° flexion 3.2 mm (sd 3.3), p = 0.024) and medial compartments (extension, p = 0.049). Our results show that despite improvement in laxity and functional benefit, abnormal knee kinematics remain at six months and actually deteriorate from three to six months following reconstruction of the anterior cruciate ligament. PMID:21969431

  15. Knee joint replacement - series (image)

    MedlinePlus

    ... than 3 blocks because of knee pain Loose knee prosthesis Some knee fractures ... an incision over the affected knee. The patella (knee cap) is moved ... helps the prosthesis to adhere better. The two parts of the ...

  16. 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. PMID:25982776

  17. Software for determining lower extremity muscle-tendon kinematics and moment arm lengths during flexion/extension movements.

    PubMed

    Hawkins, D

    1992-01-01

    A computer program was developed to calculate lower extremity muscle-tendon (MT) kinematics and flexion/extension moment arm (MA) lengths for any subject performing movements constrained to occur in the sagittal plane. The program requires as input subject anthropometric and time series ankle, knee, and hip angle data. Using these data a lower extremity link-segment model is constructed for each time element. Muscle-tendon attachment data and a straight line muscle model are used to calculate MT and flexion/extension moment arm lengths. A finite difference technique is used to determine MT shortening velocity. The utility of this program is demonstrated by calculating MT kinematics and MA lengths for six muscles of a single subject both as a function of joint angles and during gait. PMID:1572164

  18. Knee microfracture surgery

    MedlinePlus

    Cartilage regeneration - knee ... Three types of anesthesia may be used for knee arthroscopy surgery: Medicine to relax you, and shots of painkillers to numb the knee Spinal (regional) anesthesia General anesthesia (you will be ...

  19. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... Saunders; 2015:chap 93. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  20. 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 ...

  1. 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 ...

  2. The effect of knee joint angle on torque control.

    PubMed

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque. PMID:19906637

  3. Kinematic and dynamic analysis of an anatomically based knee joint.

    PubMed

    Lee, Kok-Meng; Guo, Jiajie

    2010-05-01

    This paper presents a knee-joint model to provide a better understanding on the interaction between natural joints and artificial mechanisms for design and control of rehabilitation exoskeletons. The anatomically based knee model relaxes several commonly made assumptions that approximate a human knee as engineering pin-joint in exoskeleton design. Based on published MRI data, we formulate the kinematics of a knee-joint and compare three mathematical approximations; one model bases on two sequential circles rolling a flat plane; and the other two are mathematically differentiable ellipses-based models with and without sliding at the contact. The ellipses-based model taking sliding contact into accounts shows that the rolling-sliding ratio of a knee-joint is not a constant but has an average value consistent with published measurements. This knee-joint kinematics leads to a physically more accurate contact-point trajectory than methods based on multiple circles or lines, and provides a basis to derive a knee-joint kinetic model upon which the effects of a planar exoskeleton mechanism on the internal joint forces and torque during flexion can be numerically investigated. Two different knee-joint kinetic models (pin-joint approximation and anatomically based model) are compared against a condition with no exoskeleton. The leg and exoskeleton form a closed kinematic chain that has a significant effect on the joint forces in the knee. Human knee is more tolerant than pin-joint in negotiating around a singularity but its internal forces increase with the exoskeleton mass-to-length ratio. An oversimplifying pin-joint approximation cannot capture the finite change in the knee forces due to the singularity effect. PMID:20189182

  4. The Effect of ACL Reconstruction on Kinematics of the Knee with Combined ACL Injury and Subtotal Medial Meniscectomy - an in-vitro robotic investigation

    PubMed Central

    Seon, Jong Keun; Gadikota, Hemanth R.; Kozanek, Michal; Oh, Luke S.; Gill, Thomas J.; Li, Guoan

    2009-01-01

    Purpose The aims of this study were to determine: 1) the kinematic effect of subtotal medial meniscectomy on ACL deficient knee and 2) the effect of ACL reconstruction on kinematics of the knee with combined ACL deficiency and subtotal medial meniscectomy under an anterior tibial and a simulated quadriceps loads. Methods Eight human cadaveric knees were sequentially tested using a robotic testing system under 4 conditions: intact, ACL deficiency, ACL deficiency with subtotal medial meniscectomy, and single bundle ACL reconstruction using a bone-patellar tendon-bone graft. Knee kinematics were measured at 0°, 15°, 30°, 60°, and 90° of flex ion under an anterior tibial load of 130 N and a quadriceps muscle load of 400 N. Results Subtotal medial meniscectomy in ACL deficient knee significantly increased anterior and lateral tibial translations under the anterior tibial and quadriceps loads (P < 0.05). These kinematic changes were larger at high flexion (≥ 60°) than at low flexion angles. ACL reconstructio n in knees with ACL deficiency and subtotal medial meniscectomy significantly reduced the increased anterior tibial translation, but could not restore anterior translation to the intact level with differences ranging from 2.6 mm at 0° to 5.5 mm at 30° of flexion. ACL reconstruction did not significantly affect the medial-lateral translation and internal-external tibial rotation in the presence of subtotal meniscectomy. Conclusions Subtotal medial meniscectomy in knees with ACL deficiency altered knee kinematics, especially at high flexion angles. ACL reconstruction significantly reduced the increased tibial translation in knees with combined ACL deficiency and subtotal medial meniscectomy, but could not restore the knee kinematics to the intact knee level. Clinical Relevance This study suggests that meniscus is an important secondary stabilizer against anterior and lateral tibial translations and should be preserved in the setting of ACL reconstruction for

  5. The relationship between leg preference and knee mechanics during sidestepping in collegiate female footballers.

    PubMed

    Brown, Scott R; Wang, Henry; Dickin, D Clark; Weiss, Kaitlyn J

    2014-11-01

    This study examined the relationship between leg preference and knee mechanics in females during sidestepping. Three-dimensional data were recorded on 16 female collegiate footballers during a planned 45° sidestep manoeuvre with their preferred and non-preferred kicking leg. Knee kinematics and kinetics during initial contact, weight acceptance, peak push-off, and final push-off phases of sidestepping were analysed in both legs. The preferred leg showed trivial to small increases (ES = 0.19-0.36) in knee flexion angle at initial contact, weight acceptance, and peak push-off, and small increases (ES = 0.21-0.34) in peak power production and peak knee extension velocity. The non-preferred leg showed a trivial increase (ES = 0.10) in knee abduction angle during weight acceptance; small to moderate increases (ES = 0.22-0.64) in knee internal rotation angle at weight acceptance, peak push-off, and final push-off; a small increase (ES = 0.22) in knee abductor moment; and trivial increases (ES = 0.09-0.14) in peak power absorption and peak knee flexion velocity. The results of this study show that differences do exist between the preferred and non-preferred leg in females. The findings of this study will increase the knowledge base of anterior cruciate ligament injury in females and can aid in the design of more appropriate neuromuscular, plyometric, and strength training protocols for injury prevention. PMID:25204331

  6. Comparison of Upper Cervical Flexion and Cervical Flexion Angle of Computer Workers with Upper Trapezius and Levator Scapular Pain

    PubMed Central

    Yoo, Won-gyu

    2014-01-01

    [Purpose] In this study, we compared upper cervical flexion and cervical flexion angle of computer workers with upper trapezius and levator scapular pain. [Subject] Eight male computer workers with upper trapezius muscle pain and eight others with levator scapular muscle pain participated. [Methods] Each subject was assessed in terms of upper cervical flexion angle and total cervical flexion angles using a cervical range of motion instrument after one hour of computer work. [Results] The upper cervical flexion angle of the group with levator scapular pain was significantly lower than that of the group with upper trapezius pain after computer work. The total cervical flexion angle of the group with upper trapezius pain was significantly lower than that of the group with levator scapular pain after computer work. [Conclusion] For selective and effective intervention for neck pain, therapists should evaluate upper and lower cervical motion individually. PMID:24648646

  7. Wing Flexion and Aerodynamics Performance of Insect Free Flights

    NASA Astrophysics Data System (ADS)

    Dong, Haibo; Liang, Zongxian; Ren, Yan

    2010-11-01

    Wing flexion in flapping flight is a hallmark of insect flight. It is widely thought that wing flexibility and wing deformation would potentially provide new aerodynamic mechanisms of aerodynamic force productions over completely rigid wings. However, there are lack of literatures on studying fluid dynamics of freely flying insects due to the presence of complex shaped moving boundaries in the flow domain. In this work, a computational study of freely flying insects is being conducted. High resolution, high speed videos of freely flying dragonflies and damselflies is obtained and used as a basis for developing high fidelity geometrical models of the dragonfly body and wings. 3D surface reconstruction technologies are used to obtain wing topologies and kinematics. The wing motions are highly complex and a number of different strategies including singular vector decomposition of the wing kinematics are used to examine the various kinematical features and their impact on the wing performance. Simulations are carried out to examine the aerodynamic performance of all four wings and understand the wake structures of such wings.

  8. Construction-conditioned rollback in total knee replacement: fluoroscopic results.

    PubMed

    Wachowski, Martin Michael; Fiedler, Christoph; Walde, Tim Alexander; Balcarek, Peter; Schüttrumpf, Jan Philipp; Frosch, Stephan; Frosch, Karl-Heinz; Fanghänel, Jochen; Gezzi, Riccardo; Kubein-Meesenburg, Dietmar; Nägerl, Hans

    2011-01-01

    Firstly, the way of implementing approximatively the initial rollback of the natural tibiofemoral joint (TFJ) in a total knee replacement (AEQUOS G1 TKR) is discussed. By configuration of the curvatures of the medial and lateral articulating surfaces a cam gear mechanism with positive drive can be installed, which works under force closure of the femoral and tibial surfaces. Briefly the geometric design features in flexion/extension are described and construction-conditioned kinematical and functional properties that arise are discussed. Due to a positive drive of the cam gear under the force closure during the stance phase of gait the articulating surfaces predominantly roll. As a result of rolling, a sliding friction is avoided, thus the resistance to motion is reduced during the stance phase. Secondly, in vivo fluoroscopic measurements of the patella tendon angle during flexion/extension are presented. The patella tendon angle/ knee flexion angle characteristic and the kinematic profile in trend were similar to those observed in the native knee during gait (0°-60°). PMID:22098089

  9. Knee Extensor and Flexor Torque Development with Concentric and Eccentric Isokinetic Training

    ERIC Educational Resources Information Center

    Miller, Larry E.; Pierson, Lee M.; Nickols-Richardson, Sharon M.; Wootten, David F.; Selmon, Serah E.; Ramp, Warren K.; Herbert, William G.

    2006-01-01

    This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training…

  10. Criteria for preserving posterior cruciate ligament depending on intra-operative gap measurement in total knee replacement

    PubMed Central

    Kaneyama, R.; Otsuka, M.; Shiratsuchi, H.; Oinuma, K.; Miura, Y.; Tamaki, T.

    2014-01-01

    Objectives Because posterior cruciate ligament (PCL) resection makes flexion gaps wider in total knee replacement (TKR), preserving or sacrificing a PCL affects the gap equivalence; however, there are no criteria for the PCL resection that consider gap situations of each knee. This study aims to investigate gap characteristics of knees and to consider the criteria for PCL resection. Methods The extension and flexion gaps were measured, first with the PCL preserved and subsequently with the PCL removed (in cases in which posterior substitute components were selected). The PCL preservation or sacrifice was solely determined by the gap measurement results, without considering other functions of the PCL such as ‘roll back.’ Results Wide variations were observed in the extension and flexion gaps. The flexion gaps were significantly larger than the extension gaps. Cases with 18 mm or more flexion gap and with larger flexion than extension gap were implanted with cruciate retaining component. A posterior substitute component was implanted with the other cases. Conclusions In order to make adequate gaps, it is important to decide whether to preserve the PCL based on the intra-operative gap measurements made with the PCL intact. Cite this article: Bone Joint Res 2014;3:95–100. PMID:24719296

  11. Adductor Canal Block for Postoperative Pain Treatment after Revision Knee Arthroplasty: A Blinded, Randomized, Placebo-Controlled Study

    PubMed Central

    Jæger, Pia; Koscielniak-Nielsen, Zbigniew J.; Schrøder, Henrik M.; Mathiesen, Ole; Henningsen, Maria H.; Lund, Jørgen; Jenstrup, Morten T.; Dahl, Jørgen B.

    2014-01-01

    Background Revision knee arthroplasty is assumed to be even more painful than primary knee arthroplasty and predominantly performed in chronic pain patients, which challenges postoperative pain treatment. We hypothesized that the adductor canal block, effective for pain relief after primary total knee arthroplasty, may reduce pain during knee flexion (primary endpoint: at 4 h) compared with placebo after revision total knee arthroplasty. Secondary endpoints were pain at rest, morphine consumption and morphine-related side effects. Methods We included patients scheduled for revision knee arthroplasty in general anesthesia into this blinded, placebo-controlled, randomized trial. Patients were allocated to an adductor canal block via a catheter with either ropivacaine or placebo; bolus of 0.75% ropivacaine/saline, followed by infusion of 0.2% ropivacaine/saline. Clinicaltrials.gov ID: NCT01191593. Results We enrolled 36 patients, of which 30 were analyzed. Mean pain scores during knee flexion at 4 h (primary endpoint) were: 52±22 versus 71±25 mm (mean difference 19, 95% CI: 1 to 37, P = 0.04), ropivacaine and placebo group respectively. When calculated as area under the curve (1–8 h/7 h) pain scores were 55±21 versus 69±21 mm during knee flexion (P = 0.11) and 39±18 versus 45±23 mm at rest (P = 0.43), ropivacaine and placebo group respectively. Groups were similar regarding morphine consumption and morphine-related side effects (P>0.05). Conclusions The only statistically significant difference found between groups was in the primary endpoint: pain during knee flexion at 4 h. However, due to a larger than anticipated dropout rate and heterogeneous study population, the study was underpowered. Trial Registration Clinicaltrials.gov NCT01191593 PMID:25386752

  12. The Effects of a Prophylactic Knee Brace and Two Neoprene Knee Sleeves on the Performance of Healthy Athletes: A Crossover Randomized Controlled Trial

    PubMed Central

    Mortaza, Niyousha; Ebrahimi, Ismail; Jamshidi, Ali Ashraf; Abdollah, Vahid; Kamali, Mohammad; Abas, Wan Abu Bakar Wan; Osman, Noor Azuan Abu

    2012-01-01

    Knee injury is one of the major problems in sports medicine, and the use of prophylactic knee braces is an attempt to reduce the occurrence and/or severity of injuries to the knee joint ligament(s) without inhibiting knee mobility. The aim of the present study was to examine the effect of one recently designed prophylactic knee brace and two neoprene knee sleeves upon performance of healthy athletes. Thirty-one healthy male athletes (age = 21.2±1.5) volunteered as participants to examine the effect of prophylactic knee brace/sleeves on performance using isokinetic and functional tests. All subjects were tested in four conditions in a random order: 1. nonbraced (control) 2. using a neoprene knee sleeve 3. using a knee sleeve with four bilateral metal supports and 4. using a prophylactic knee brace. The study design was a crossover, randomized, controlled trial. Subjects completed single leg vertical jump, cross-over hop, and the isokinetic knee flexion and extension (at 60, 180, 300°/sec). Data were collected from the above tests and analyzed for jump height, cross-over hop distance, peak torque to body weight ratio and average power, respectively. Comparisons of these variables in the four testing conditions revealed no statistically significant difference (p>0.05). The selected prophylactic brace/sleeves did not significantly inhibit athletic performance which might verify that their structure and design have caused no complication in the normal function of the knee joint. Moreover, it could be speculated that, if the brace or the sleeves had any limiting effect, our young healthy athletic subjects were well able to generate a mean peak torque large enough to overcome this possible restriction. Further studies are suggested to investigate the long term effect of these prophylactic knee brace and sleeves as well as their possible effect on the adjacent joints to the knee. PMID:23185549

  13. Motion analysis of knee joint using dynamic volume images

    NASA Astrophysics Data System (ADS)

    Haneishi, Hideaki; Kohno, Takahiro; Suzuki, Masahiko; Moriya, Hideshige; Mori, Sin-ichiro; Endo, Masahiro

    2006-03-01

    Acquisition and analysis of three-dimensional movement of knee joint is desired in orthopedic surgery. We have developed two methods to obtain dynamic volume images of knee joint. One is a 2D/3D registration method combining a bi-plane dynamic X-ray fluoroscopy and a static three-dimensional CT, the other is a method using so-called 4D-CT that uses a cone-beam and a wide 2D detector. In this paper, we present two analyses of knee joint movement obtained by these methods: (1) transition of the nearest points between femur and tibia (2) principal component analysis (PCA) of six parameters representing the three dimensional movement of knee. As a preprocessing for the analysis, at first the femur and tibia regions are extracted from volume data at each time frame and then the registration of the tibia between different frames by an affine transformation consisting of rotation and translation are performed. The same transformation is applied femur as well. Using those image data, the movement of femur relative to tibia can be analyzed. Six movement parameters of femur consisting of three translation parameters and three rotation parameters are obtained from those images. In the analysis (1), axis of each bone is first found and then the flexion angle of the knee joint is calculated. For each flexion angle, the minimum distance between femur and tibia and the location giving the minimum distance are found in both lateral condyle and medial condyle. As a result, it was observed that the movement of lateral condyle is larger than medial condyle. In the analysis (2), it was found that the movement of the knee can be represented by the first three principal components with precision of 99.58% and those three components seem to strongly relate to three major movements of femur in the knee bend known in orthopedic surgery.

  14. Non-invasive, non-radiological quantification of anteroposterior knee joint ligamentous laxity

    PubMed Central

    Russell, D. F.; Deakin, A. H.; Fogg, Q. A.; Picard, F.

    2013-01-01

    Objectives We performed in vitro validation of a non-invasive skin-mounted system that could allow quantification of anteroposterior (AP) laxity in the outpatient setting. Methods A total of 12 cadaveric lower limbs were tested with a commercial image-free navigation system using trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° of knee flexion and 100 N of force was applied perpendicular to the tibia. Acceptable coefficient of repeatability (CR) and limits of agreement (LOA) of 3 mm were set based on diagnostic criteria for anterior cruciate ligament (ACL) insufficiency. Results Reliability and precision within the individual invasive and non-invasive systems was acceptable throughout the range of flexion tested (intra-class correlation coefficient 0.88, CR 1.6 mm). Agreement between the two systems was acceptable measuring AP laxity between full extension and 40° knee flexion (LOA 2.9 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (LOA > 3 mm). Conclusions These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard validated commercial system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative evaluation of ACL pathology. Cite this article: Bone Joint Res 2013;2:233–7. PMID:24184443

  15. Long head of the triceps muscle transfer for active elbow flexion in arthrogryposis.

    PubMed

    Gogola, Gloria R; Ezaki, Marybeth; Oishi, Scott N; Gharbaoui, Idris; Bennett, James B

    2010-06-01

    Arthrogryposis is a condition characterized by symmetric, nonprogressive joint contractures and weak or absent musculature that is present at birth. The amyoplasia form is the most common, and in this group, the elbow is frequently involved, typically in an extension contracture bilaterally. Active elbow flexion is weak or absent, but active extension is spared. This elbow dysfunction poses a significant disability for affected children. Sensation and cognitive development is normal in children with arthrogryposis, and as a group they demonstrate a remarkable degree of adaptability to their deformities. The goal of any treatment is to facilitate the child's functional independence. This article describes the surgical technique of transfer of the long head of the triceps into the proximal ulna to provide active elbow flexion in children with arthrogryposis. The goal of the procedure is to reliably achieve antigravity active flexion while preserving active extension. It has the advantages of technical simplicity and minimal donor site morbidity. By adding this procedure to the existing options for treating this challenging condition, a surgeon is better able to tailor intervention to an individual child's strength and available donor muscles. PMID:20526167

  16. Ligament fibre recruitment at the human ankle joint complex in passive flexion.

    PubMed

    Stagni, Rita; Leardini, Alberto; Ensini, Andrea

    2004-12-01

    Knowledge of ligament fibre recruitment at the human ankle joint complex is a fundamental prerequisite for analysing mobility and stability. Previous experimental and modelling studies have shown that ankle motion must be guided by fibres within the calcaneofibular and tibiocalcaneal ligaments, which remain approximately isometric during passive flexion. The purpose of this study was to identify these fibres. Three below-knee amputated specimens were analysed during passive flexion with combined radiostereometry for bone pose estimation and 3D digitisation for ligament attachment area identification. A procedure based on singular value decomposition enabled matching bone pose with digitised data and therefore reconstructing position in space of ligament attachment areas in each joint position. Eleven ordered fibres, connecting corresponding points on origin and insertion curves, were modelled for each of the following ligaments: posterior talofibular, calcaneofibular, anterior talofibular, posterior tibiotalar, tibiocalcaneal, and anterior tibiotalar. The measured changes in length for the ligament fibres revealed patterns of tightening and slackening. The most anterior fibre of the calcaneofibular and the medio-anterior fibre of the tibiocalcaneal ligament exhibited the most isometric behaviour, as well as the most posterior fibre of the anterior talofibular ligament. Fibres within the calcaneofibular ligament remain parallel in the transverse plane, while those within the tibiocalcaneal ligament become almost parallel in joint neutral position. For both these ligaments, fibres maintain their relative inclination in the sagittal plane throughout the passive flexion range. The observed significant change in both shape and orientation of the ankle ligaments suggest that this knowledge is fundamental for future mechanical analysis of their response to external forces. PMID:15519590

  17. Dynamic and static control of the human knee joint in abduction-adduction.

    PubMed

    Zhang, L Q; Wang, G

    2001-09-01

    It is unclear whether humans can voluntarily control dynamic and static properties in knee abduction-adduction, which may be important in performing functional tasks and preventing injuries, whether the main load is about the abduction axis or not. A joint-driving device was used to perturb the knee in abduction-adduction at full knee extension under both passive (muscle relaxed) and active (muscle contracted in abduction or adduction) conditions. Dynamic control properties in knee abduction-adduction were characterized by joint stiffness, viscosity, and limb inertia, and quasi-static knee torque-angle relationship was characterized by knee abduction-adduction laxity and quasi-static stiffness (at a 20Nm moment). It was found that the subjects were capable of generating net abduction and adduction moment through differential co-contraction of muscles crossing the medial and lateral sides of the knee, which helped to reduce the abduction-adduction joint laxity (p< or =0.01) and increase stiffness (p<0.027) and viscous damping. Knee abduction laxity was significantly lower than adduction laxity (p=0.043) and the quasi-static abduction stiffness was significantly higher than adduction stiffness (p<0.001). The knee joint showed significantly higher stiffness and viscosity in abduction-adduction than their counterparts in knee flexion-extension at comparable levels of joint torque (p<0.05). Similar to dynamic flexion-extension properties, the system damping ratio remained constant over different levels of contraction, indicating simplified control tasks for the central nervous system; while the natural undamped frequency increased considerably with abduction-adduction muscle contraction, presumably making the knee a quicker system during strenuous tasks involving strong muscle contraction. PMID:11506781

  18. Accurate joint space quantification in knee osteoarthritis: a digital x-ray tomosynthesis phantom study

    NASA Astrophysics Data System (ADS)

    Sewell, Tanzania S.; Piacsek, Kelly L.; Heckel, Beth A.; Sabol, John M.

    2011-03-01

    The current imaging standard for diagnosis and monitoring of knee osteoarthritis (OA) is projection radiography. However radiographs may be insensitive to markers of early disease such as osteophytes and joint space narrowing (JSN). Relative to standard radiography, digital X-ray tomosynthesis (DTS) may provide improved visualization of the markers of knee OA without the interference of superimposed anatomy. DTS utilizes a series of low-dose projection images over an arc of +/-20 degrees to reconstruct tomographic images parallel to the detector. We propose that DTS can increase accuracy and precision in JSN quantification. The geometric accuracy of DTS was characterized by quantifying joint space width (JSW) as a function of knee flexion and position using physical and anthropomorphic phantoms. Using a commercially available digital X-ray system, projection and DTS images were acquired for a Lucite rod phantom with known gaps at various source-object-distances, and angles of flexion. Gap width, representative of JSW, was measured using a validated algorithm. Over an object-to-detector-distance range of 5-21cm, a 3.0mm gap width was reproducibly measured in the DTS images, independent of magnification. A simulated 0.50mm (+/-0.13) JSN was quantified accurately (95% CI 0.44-0.56mm) in the DTS images. Angling the rods to represent knee flexion, the minimum gap could be precisely determined from the DTS images and was independent of flexion angle. JSN quantification using DTS was insensitive to distance from patient barrier and flexion angle. Potential exists for the optimization of DTS for accurate radiographic quantification of knee OA independent of patient positioning.

  19. 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

  20. Effect of Prophylactic Knee Bracing on Balance and Joint Position Sense

    PubMed Central

    Kaminski, Thomas W.; Perrin, David H.

    1996-01-01

    Prophylactic knee braces are designed to prevent and reduce the severity of ligamentous injuries to the knee. Conflicting evidence is reported concerning their efficacy. The purpose of this study was to determine the effect of prophylactic knee bracing on the proprioceptive parameters of balance and joint position sense. Active and passive joint position sense were assessed using the Cybex II + Isokinetic Dynamometer (Cybex Division of Lumex, Inc, Ronkonkoma, NY). Sway index and center of balance were assessed using the Chattecx Dynamic Balance System (Chattanooga Group, Hixson, TN). Thirty-six male subjects were measured with and without prophylactic knee braces. Joint position sense was measured in degrees of error from four preselected target angles. Sway index and center of balance measures were recorded in centimeters under the following platform conditions: stable, plantar flexion/dorsiflexion, and inversion/eversion. Separate repeated measures ANOVAs were performed to determine if there were differences between the braced and unbraced conditions for center of balance, sway index, and joint position sense. Center of balance with the platform moving in a dorsi/plantar flexion direction was improved while wearing the knee braces. In addition, differences in both center of balance and sway were recorded across the three platform conditions with and without knee bracing. Bracing did not affect joint position sense. The results of this study suggest that prophylactic knee braces have very little impact on proprioceptive feedback mechanisms. ImagesFig 1.Fig 2.Fig 4. PMID:16558386

  1. Repeatability of gait analysis for measuring knee osteoarthritis pain in patients with severe chronic pain.

    PubMed

    Asay, Jessica L; Boyer, Katherine A; Andriacchi, Thomas P

    2013-07-01

    Gait measures are receiving increased attention in the evaluation of patients with knee osteoarthritis (OA). Yet, there remains a need to assess variability of gait analysis in patients with knee osteoarthritis over time and how pain affects variation in these gait parameters. The purpose of this study was to determine if important gait parameters, such as the knee adduction moment, knee flexion moment, peak vertical ground reaction force, and speed, were repeatable in patients with mild-to-moderate knee OA over a trial period of 12 weeks. Six patients were enrolled in this cross-over study design after meeting strict inclusion criteria. Gait tests were conducted three times at 4 week intervals and once after the placebo arm of a randomized treatment sequence; each gait test followed a 2-week period of receiving a placebo for a pain modifying drug. Repeatability for each gait variable was found using intraclass correlation coefficients (ICC) with a two-way random model. This study found that the knee adduction moment was repeatable throughout the four gait tests. However, normalized peak vertical ground reaction force and knee flexion moment were not as repeatable, varying with pain. This suggests that these gait outcomes could offer a more objective way to measure a patient's level of pain. PMID:23508626

  2. Knee Control and Jump-Landing Technique in Young Basketball and Floorball Players.

    PubMed

    Leppänen, M; Pasanen, K; Kulmala, J-P; Kujala, U M; Krosshaug, T; Kannus, P; Perttunen, J; Vasankari, T; Parkkari, J

    2016-04-01

    Poor knee alignment is associated with increased loading of the joints, ligaments and tendons, and may increase the risk of injury. The study purpose was to compare differences in knee kinematics between basketball and floorball players during a vertical drop jump (VDJ) task. We wanted to investigate whether basketball players, whose sport includes frequent jump-landings, exhibited better knee control compared with floorball players, whose sport involves less jumping. Complete data was obtained from 173 basketball and 141 floorball players. Peak knee valgus and flexion angles during the VDJ were analyzed by 3D motion analysis.Larger knee valgus angles were observed among basketball players (- 3.2°, 95%CI -4.5 to - 2.0) compared with floorball players (- 0.9°, 95%CI -2.3 to 0.6) (P=0.022). Basketball players landed with a decreased peak knee flexion angle (83.1°, 95%CI 81.4 to 84.8) compared with floorball players (86.5°, 95%CI 84.6 to 88.4) (P=0.016). There were no significant differences in height, weight or BMI between basketball and floorball players. Female athletes exhibited significantly greater valgus angles than males. This study revealed that proper knee control during jump-landing does not seem to develop in young athletes simply by playing the sport, despite the fact that jump-landings occur frequently in practice and games. PMID:26701826

  3. An in vivo biomechanical analysis of the soft-tissue envelope of osteoarthritic knees.

    PubMed

    Zalzal, Paul; Papini, Marcello; Petruccelli, Danielle; de Beer, Justin; Winemaker, Mitchell J

    2004-02-01

    Soft-tissue balancing and the amount of tension applied to the ligaments in a well-functioning total knee arthroplasty (TKA) has, thus far, not been accurately quantified. A ligament-tensioning device was used to measure displacement between the tibia and femur versus load during 86 consecutive TKAs. Measurements were made in flexion and extension following bone cuts and final soft-tissue balancing to calculate mean effective stiffness (MES) of the soft-tissue envelope and mean resting force on the implanted polyethylene component. MES was not affected by age or gender and did not differ in flexion versus extension. MES was significantly higher in posterior cruciate-retaining knees compared with posterior cruciate-sacrificing knees. There was no statistical difference between mean resting force on the polyethylene in flexion versus extension, or in posterior cruciate-retaining versus -sacrificing knees. These biomechanical data will serve as a good starting point for which to compare the expected stiffness of the ligaments and resting load on the polyethylene in well-balanced knees. PMID:14973866

  4. Comparison of the angles and corresponding moments in the knee and hip during restricted and unrestricted squats.

    PubMed

    Lorenzetti, Silvio; Gülay, Turgut; Stoop, Mirjam; List, Renate; Gerber, Hans; Schellenberg, Florian; Stüssi, Edgar

    2012-10-01

    The aim of this study was to compare the angles and corresponding moments in the knee and hip during squats. Twenty subjects performed restricted and unrestricted squats with barbell loads that were 0, ¼, and ½ their body weight. The experimental setup consisted of a motion capture system and 2 force plates. The moments were calculated using inverse dynamics. During the unrestricted squats, the maximum moments in the knee were significantly higher, and those in the hip were significantly lower than during restricted squats. At the lowest position, the maximum knee flexion angles were approximately 86° for the restricted and approximately 106° for the unrestricted techniques, whereas the maximum hip flexion angle was between 95° and 100°. The higher moments in the hip during restricted squats suggest a higher load of the lower back. Athletes who aim to strengthen their quadriceps should consider unrestricted squats because of the larger knee load and smaller back load. PMID:22801421

  5. 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. PMID:26134453

  6. The preferential contraction ratios of transversus abdominis on the variations of knee angles during abdominal drawing-in maneuver in wall support standing

    PubMed Central

    Hwang, Young-In; Kim, Jwa-Jun; Park, Du-Jin

    2014-01-01

    The objective of this study was to determine appropriate knee angles for the abdominal drawing-in maneuver (ADIM) through evaluation of changes in contraction ratios of the abdominal muscles and activity of quadriceps muscle in relation to changes in knee angles occurring while the ADIM is performed in the wall support standing (WSS). 20 subjects performed the ADIM at different knee angles (0°, 20°, 40°, 60°) in random order, standing at a point 6 inches away from the wall with the spine maintained in the neutral position. The WSS with knee flexion at 20° showed significantly higher preferential contraction ratio (PCR) of transversus abdominis (TrA) compared to other positions (0°, 40°, 60°). Therefore, performing the ADIM in the WSS with knee flexion at 20° appears to be the most appropriate position for TrA PCR. PMID:24877045

  7. In vivo imaging of superficial femoral artery (SFA) stents for deformation analysis

    NASA Astrophysics Data System (ADS)

    Ganguly, A.; Schneider, A.; Keck, B.; Bennett, N. R.; Fahrig, R.

    2008-03-01

    A high-resolution (198 μm) C-arm CT imaging system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) was optimized for imaging superficial femoral artery (SFA) stents in humans. The SFA is susceptible to the development of atherosclerotic lesions. These are typically treated with angioplasty and stent deployment. However, these stents can have a fracture rate as high as 35%. Fracture is usually accompanied by restenosis and reocclusion. The exact cause of breakage is unknown and is hypothesized to result from deforming forces due to hip and knee flexion. Imaging was performed with the leg placed in both straight and bent positions. Projection images obtained during 20 s scans with ~200° of rotation of the C-arm were back-projected to obtain 3D volumes. Using a semi-automatic software algorithm developed in-house, the stent centerlines were found and ellipses were fitted to the slice normals. Image quality was adequate for calculations in 11/13 subjects. Bending the leg was found to shorten the stents in 10/11 cases with the maximum change being 9% (12 mm in a 133 mm stent), and extend the stent in one case by 1.6%. The maximum eccentricity change was 36% with a bend angle of 72° in a case where the stent extended behind the knee.

  8. Effect of kinesio taping on the isokinetic muscle function in football athletes with a knee injury

    PubMed Central

    Hong, SoonKwon; Shim, JeMyung; Kim, SungJoong; Namkoong, Seung; Roh, HyoLyun

    2016-01-01

    [Purpose] The purpose of this study was to determine the difference in isokinetic muscle function in football athletes with a knee injury with and without kinesio taping. [Subjects] The subjects for this study were 10 football athletes (males) with a knee injury. [Methods] Measurements were performed by using Cybex dynamometer under uniform motion before and after the application of kinesio tape to the quadriceps and hamstring muscle. Maximal concentric knee extension and flexion at three angular velocities (60°/s, 120°/s, and 180°/s) were measured. [Results] A significant difference was found in peak torque and total work of the flexion at 120°/s and 180°/s, as well as in the average power of extension at 180°/s. [Conclusion] Though it is not the main therapy for muscle function in football athletes with injury, kinesio taping was an effective adjunct therapy. PMID:26957761

  9. Effect of kinesio taping on the isokinetic muscle function in football athletes with a knee injury.

    PubMed

    Hong, SoonKwon; Shim, JeMyung; Kim, SungJoong; Namkoong, Seung; Roh, HyoLyun

    2016-01-01

    [Purpose] The purpose of this study was to determine the difference in isokinetic muscle function in football athletes with a knee injury with and without kinesio taping. [Subjects] The subjects for this study were 10 football athletes (males) with a knee injury. [Methods] Measurements were performed by using Cybex dynamometer under uniform motion before and after the application of kinesio tape to the quadriceps and hamstring muscle. Maximal concentric knee extension and flexion at three angular velocities (60°/s, 120°/s, and 180°/s) were measured. [Results] A significant difference was found in peak torque and total work of the flexion at 120°/s and 180°/s, as well as in the average power of extension at 180°/s. [Conclusion] Though it is not the main therapy for muscle function in football athletes with injury, kinesio taping was an effective adjunct therapy. PMID:26957761

  10. Clinical Outcomes in Men and Women following Total Knee Arthroplasty with a High-Flex Knee: No Clinical Effect of Gender

    PubMed Central

    Nassif, Jeffrey M.; Pietrzak, William S.

    2015-01-01

    While it is generally recognized that anatomical differences exist between the male and female knee, the literature generally refutes the clinical need for gender-specific total knee prostheses. It has been found that standard, unisex knees perform as well, or better, in women than men. Recently, high-flex knees have become available that mechanically accommodate increased flexion yet no studies have directly compared the outcomes of these devices in men and women to see if gender-based differences exist. We retrospectively compared the performance of the high-flex Vanguard knee (Biomet, Warsaw, IN) in 716 male and 1,069 female knees. Kaplan-Meier survivorship was 98.5% at 5.6–5.7 years for both genders. After 2 years, mean improvements in Knee Society Knee and Function scores for men and women (50.9 versus 46.3; 26.5 versus 23.1) and corresponding SF-12 Mental and Physical scores (0.2 versus 2.2; 13.7 versus 12.2) were similar with differences not clinically relevant. Postoperative motion gains as a function of preoperative motion level were virtually identical in men and women. This further confirms the suitability of unisex total knee prostheses for both men and women. PMID:26451389

  11. Growth changes in internal and craniofacial flexion measurements.

    PubMed

    May, R; Sheffer, D B

    1999-09-01

    Growth changes in both internal and craniofacial flexion angles are presented for Pan troglodytes, Gorilla gorilla, and modern humans. The internal flexion angle (IFA) was measured from lateral radiographs, and the craniofacial flexion angle (CFA) was calculated from coordinate data. Stage of dental development is used as a baseline for examination of growth changes and nonparametric correlations between flexion angles and dental development stage are tested for significance. In Gorilla, the IFA increases during growth. The IFA is relatively stable in Pan and modern humans. Pan and Gorilla display an increase in the CFA. However, this angle decreases during growth in modern humans. Flexion angles were derived from coordinate data collected for several early hominid crania. Measurements for two robust australopithecine crania indicate strong internal flexion. It has been suggested that cerebellar expansion in this group may relate to derived features of the posterior cranial base. In general, australopithecine crania exhibit craniofacial flexion intermediate between great apes and modern humans. The "archaic" Homo sapiens specimen from Kabwe is most similar to modern humans. PMID:10490467

  12. Achieving ligament stability and correct rotational alignment of the femur in knee arthroplasty: a study using the Medial Pivot knee.

    PubMed

    Shakespeare, David; Kinzel, Vera; Ledger, Michael

    2005-12-01

    In a series of 90 Medial Pivot arthroplasties rotational alignment of the femur was achieved by provisionally reconstructing the lateral side of the joint and tensioning the medial side with feeler gauges. Axial CT scans were employed to measure the rotational alignment relative to surgical epicondylar axis. In valgus knees the cutting block was externally rotated to adjust for posterolateral bone loss. The mean rotational alignment of the femur was 0.6 degrees of external rotation (S.D. 1.3, range 3 degrees of ER to 4 degrees of IR). The mean laxity of the medial ligament was 1 mm in flexion (SD 1, range 0-5 mm) and 0.5 mm in flexion (S.D. 0.5, range 0-2 mm) In those knees in which the medial ligament had been released the CT alignment was perfect, but when internally rotated against the hip 3-4 mm of gapping was noted. In valgus knees the mean rotation of the femoral component was 0.8 degrees of internal rotation (S.D. 1.5, range 1 degrees of IR to 4 degrees of ER). In spite of externally rotating the cutting block there was still a tendency to internally rotate the femur in some knees. This simple technique achieves the two goals of ligament stability and correct rotational alignment in a high proportion of cases. It may be applicable to any instrument system which employs posterior referencing. PMID:15967668

  13. Acute patellar dislocation with multiple ligament injuries after knee dislocation and single session reconstruction.

    PubMed

    Gormeli, Gokay; Gormeli, Cemile Ayse; Karakaplan, Mustafa; Gurbuz, Sukru; Ozdemir, Zeynep; Ozer, Mustafa

    2016-06-01

    Knee dislocation is a relatively rare condition of all orthopaedic injuries. Accompanying multiple ligament injuries are common after knee dislocations. A 41-year-old male presented to the emergency department suffering from right knee dislocation in June 2013. The patient had anterior cruciate ligament, medial collateral ligament (MCL), medial patellofemoral ligament (MPFL) rupture, and lateral meniscal tear. A single-bundle anatomic reconstruction, medial collateral ligament reconstruction, medial patellofemoral ligament reconstruction and meniscus repair were performed in single session. At twelve months follow-up; there was 160º flexion and 10° extension knee range of motion. Lysholm knee score was 90. Extensive forces can cause both MCL and MPFL injury due to overload and the anatomical relationship between these two structures. Therefore, patients with valgus instability should be evaluated for both MPFL and MCL tears to facilitate successful treatment. PMID:27339584

  14. The effect of sagittal laxity on function after posterior cruciate-retaining total knee replacement.

    PubMed

    Jones, David P Gwynne; Locke, Conlin; Pennington, Jonathon; Theis, Jean-Claude

    2006-08-01

    We studied sagittal laxity using the KT1000 arthrometer in 97 total knee arthroplasties (TKAs) in 83 patients using the porous-coated anatomic knee or Duracon TKA (Howmedica, Rutherford, NJ) with 5.4- to 9.9-year follow-up. Two differing tibial inserts were used: flat (group 1) and anteroposterior (AP) lipped (group 2). Greater posterior and total laxity at 75 degrees was seen in group 2 despite the AP-lipped insert. No differences were seen in functional outcome scores between groups. No significant relationship was seen between laxity and functional outcome. Knees with more than 10 mm of AP laxity at 75 degrees had significantly less flexion and lower Knee Society Scores than knees with 5 to 10 mm of AP laxity. We conclude that the optimal sagittal laxity in this cruciate-retaining TKA is between 5 and 10 mm, although this may not hold for posterior-stabilized designs. PMID:16877159

  15. Preoperative Predictors of Pain Following Total Knee Arthroplasty

    PubMed Central

    Noiseux, Nicolas O.; Callaghan, John J.; Clark, Charles R.; Zimmerman, M. Bridget; Sluka, Kathleen A.; Rakel, Barbara A.

    2014-01-01

    Total knee arthroplasty has provided dramatic improvements in function and pain for the majority of patients with knee arthritis, yet a significant proportion of patients remain dissatisfied with their results. We performed a prospective analysis of 215 patients undergoing TKA who underwent a comprehensive array of evaluations to discover whether any preoperative assessment could predict high pain scores and functional limitations postoperatively. Patients with severe pain with a simple knee range-of-motion test prior to TKA had a 10x higher likelihood of moderate to severe pain at 6 months. A simple test of pain intensity with active flexion and extension preoperatively was a significant predictor of postoperative pain at 6 months after surgery. Strategies to address this particular patient group may improve satisfaction rates of TKA. PMID:24630598

  16. Comparison of kinematic analysis by mapping tibiofemoral contact with movement of the femoral condylar centres in healthy and anterior cruciate ligament injured knees.

    PubMed

    Scarvell, Jennifer M; Smith, Paul N; Refshauge, Kathryn M; Galloway, Howard R; Woods, Kevin R

    2004-09-01

    Two methods of analysis of knee kinematics from magnetic resonance images (MRI) in vivo have been developed independently: mapping the tibiofemoral contact, and tracking the femoral condylar centre. These two methods are compared for the assessment of kinematics in the healthy and the anterior cruciate ligament injured knee. Sagittal images of both knees of 20 subjects with unilateral anterior cruciate ligament injury were analysed. The subjects had performed a supine leg press against a 150 N load. Images were generated at 15 degrees intervals from 0 degrees to 90 degrees knee flexion. The tibiofemoral contact, and the centre of the femoral condyle (defined by the flexion facet centre (FFC)), were measured from the posterior tibial cortex. The pattern of contact in the healthy knee showed the femoral roll back from 0 degrees to 30 degrees, then from 30 degrees to 90 degrees the medial condyle rolled back little, while the lateral condyle continued to roll back on the tibial plateau. The contact pattern was more posterior in the injured knee (p=0.012), particularly in the lateral compartment. The medial FFC moved back very little during knee flexion, while the lateral FFC moved back throughout the flexion arc. The FFC was not significantly different in the injured knee (p=0.17). The contact and movement of the FFC both demonstrated kinematic events at the knee, such as longitudinal rotation. Both methods are relevant to design of total knee arthroplasty: movement of the FFC for consideration of axis alignment, and contact pattern for issues of interface wear and arthritic change in ligament injury. PMID:15304265

  17. Arthroscopic capsular release of flexion contractures (arthrofibrosis) of the elbow.

    PubMed

    Jones, G S; Savoie, F H

    1993-01-01

    Twelve patients with flexion contractures of the elbow were managed by arthroscopic release of the proximal capsule and debridement of the olecranon fossa. Postoperatively the mean flexion contracture improved from 38 to 3 degrees with supination improving from 45 to 84 degrees and pronation improving from 80 to 88 degrees. All patients reported a decrease in pain level as well as improvement in motion. There was one severe complication in this series, in which a patient sustained a permanent posterior interosseous nerve palsy. Arthroscopic limited capsular release appears to be satisfactory management modality for flexion contracture of the elbow. PMID:8323612

  18. 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

  19. Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury

    PubMed Central

    Grindem, Hege; Eitzen, Ingrid; Engebretsen, Lars; Snyder-Mackler, Lynn; Risberg, May Arna

    2014-01-01

    Background: While there are many opinions about the expected knee function, sports participation, and risk of knee reinjury following nonsurgical treatment of injuries of the anterior cruciate ligament (ACL), there is a lack of knowledge about the clinical course following nonsurgical treatment compared with that after surgical treatment. Methods: This prospective cohort study included 143 patients with an ACL injury. Isokinetic knee extension and flexion strength and patient-reported knee function as recorded on the International Knee Documentation Committee (IKDC) 2000 form were collected at baseline, six weeks, and two years. Sports participation was reported monthly for two years with use of an online activity survey. Knee reinjuries were reported at the follow-up evaluations and in a monthly online survey. Repeated analysis of variance (ANOVA), generalized estimating equation (GEE) models, and Cox regression analysis were used to analyze group differences in functional outcomes, sports participation, and knee reinjuries, respectively. Results: The surgically treated patients (n = 100) were significantly younger, more likely to participate in level-I sports, and less likely to participate in level-II sports prior to injury than the nonsurgically treated patients (n = 43). There were no significant group-by-time effects on functional outcome. The crude analysis showed that surgically treated patients were more likely to sustain a knee reinjury and to participate in level-I sports in the second year of the follow-up period. After propensity score adjustment, these differences were nonsignificant; however, the nonsurgically treated patients were significantly more likely to participate in level-II sports during the first year of the follow-up period and in level-III sports over the two years. After two years, 30% of all patients had an extensor strength deficit, 31% had a flexor strength deficit, 20% had patient-reported knee function below the normal range, and

  20. Clinical and Biomechanical Evaluations of Staged Bilateral Total Knee Arthroplasty Patients with Two Different Implant Designs

    PubMed Central

    Renaud, Alexandre; Fuentes, Alexandre; Hagemeister, Nicola; Lavigne, Martin; Vendittoli, Pascal-André

    2016-01-01

    Background: Various implants of total knee arthroplasty (TKA) are used in clinical practice and each presents specific design characteristics. No implant managed this day to reproduce perfectly the biomechanics of the natural knee during gait. Objectives: We therefore asked whether (1) differences in tridimensional (3D) kinematic data during gait could be observed in two different designs of TKA on the same patients, (2) if those gait kinematic data are comparable with those of asymptomatic knees and (3) if difference in clinical subjective scores can be observed between the two TKA designs on the same patient. Methods: We performed knee kinematic analysis on 15 patients (30 TKAs) with two different TKA implant designs (Nexgen, Zimmer and Triathlon, Stryker) on each knee and on 25 asymptomatic subjects (35 knees). Clinical evaluation included range of motion, weight bearing radiographs, questionnaire of joint perception, KOOS, WOMAC and SF-12. Results: Comparison between TKAs and asymptomatic knees revealed that asymptomatic knees had significantly less knee flexion at initial contact (p < 0.04) and more flexion for most of the swing phase (p between 0.004 and 0.04). Asymptomatic knees also had less varus at loading response, during stance phase and during most of the swing phase (p between 0.001 - 0.05). Transverse plane analysis showed a tendency for asymptomatic knees to be more in internal rotation during stance phase (p 0.02 - 0.04). Comparing both TKA designs, NexgenTM implant had significantly more flexion at the end of swing phase (p = 0.04) compared to knees with the TriathlonTM implant. In frontal plane, from initial contact to maximum mid stance angle and between the mean mid stance angle and initial contact NexgenTM TKA had significantly more adduction (varus, p =0.02 – 0.03). Clinical scores of both TKAs did not have significant difference. Conclusions: TKA with the tested implants did not reproduce natural knee kinematics during gait. In our cohort

  1. Study of Wearable Knee Assistive Instruments for Walk Rehabilitation

    NASA Astrophysics Data System (ADS)

    Zhu, Yong; Nakamura, Masahiro; Ito, Noritaka; Fujimoto, Hiroshi; Horikuchi, Kenichi; Wakabayashi, Shojiro; Takahashi, Rei; Terada, Hidetsugu; Haro, Hirotaka

    A wearable Knee Assistive Instrument for the walk rehabilitation was newly developed. Especially, this system aimed at supporting the rehabilitation for the post-TKA (Total Knee Arthroplasty) which is a popular surgery for aging people. This system consisted of an assisting mechanism for the knee joint, a hip joint support system and a foot pressure sensor system. The driving system of this robot consisted of a CPU board which generated the walking pattern, a Li-ion battery, DC motors with motor drivers, contact sensors to detect the state of foot and potentiometers to detect the hip joint angle. The control method was proposed to reproduce complex motion of knee joint as much as possible, and to increase hip or knee flexion angle. Especially, this method used the timing that heel left from the floor. This method included that the lower limb was raised to prevent a subject's fall. Also, the prototype of knee assisting system was tested. It was confirmed that the assisting system is useful.

  2. Unique Anatomic Feature of the Posterior Cruciate Ligament in Knees Associated With Osteochondritis Dissecans

    PubMed Central

    Ishikawa, Masakazu; Adachi, Nobuo; Yoshikawa, Masahiro; Nakamae, Atsuo; Nakasa, Tomoyuki; Ikuta, Yasunari; Hayashi, Seiju; Deie, Masataka; Ochi, Mitsuo

    2016-01-01

    Background: Osteochondritis dissecans (OCD) of the knee is a disorder in juveniles and young adults; however, its etiology still remains unclear. For OCD at the medial femoral condyle (MFC), it is sometimes observed that the lesion has a connection with fibers of the posterior cruciate ligament (PCL). Although this could be important information related to the etiology of MFC OCD, there is no report examining an association between the MFC OCD and the PCL anatomy. Purpose: To investigate the anatomic features of knees associated with MFC OCD, focusing especially on the femoral attachment of the PCL, and to compare them with knees associated with lateral femoral condyle (LFC) OCD and non-OCD lesions. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively reviewed 39 patients (46 knees) with OCD lesions who had undergone surgical treatment. Using magnetic resonance imaging (MRI) scans, the PCL attachment at the lateral wall of the MFC was measured on the coronal sections, and the knee flexion angle was also measured on the sagittal sections. As with non-OCD knees, we reviewed and analyzed 25 knees with anterior cruciate ligament (ACL) injuries and 16 knees with meniscal injuries. Results: MRIs revealed that the femoral PCL footprint was located in a significantly more distal position in the patients with MFC OCD compared with patients with LFC OCD and ACL and meniscal injuries. There was no significant difference in knee flexion angle among the 4 groups. Conclusion: The PCL in patients with MFC OCD attached more distally at the lateral aspect of the MFC compared with knees with LFC OCD and ACL and meniscal injuries. PMID:27294170

  3. Gait kinematics and passive knee joint range of motion in children with hypermobility syndrome.

    PubMed

    Fatoye, Francis A; Palmer, Shea; van der Linden, Marietta L; Rowe, Philip J; Macmillan, Fiona

    2011-03-01

    Hypermobility syndrome (HMS) is characterised by generalised joint laxity and musculoskeletal complaints. Gait abnormalities have been reported in children with HMS but have not been empirically investigated. The extent of passive knee joint range of motion (ROM) has also not been well reported in children with HMS. This study evaluated gait kinematics and passive knee joint ROM in children diagnosed with HMS and healthy controls. Thirty-seven healthy children (mean age±SD=11.5±2.6 years) and 29 children with HMS (mean age±SD=11.9±1.8 years) participated. Sagittal knee motion and gait speed were evaluated using a VICON 3D motion analysis system. Passive knee ROM was measured with a manual goniometer. Independent t-tests compared the values of sagittal knee motion and gait speed between the two groups. Mann-Whitney U tests compared passive knee ROM between groups. Passive ROM (extension and flexion) was significantly higher (both p<0.001) in children with HMS than the healthy controls. Peak knee flexion (during loading response and swing phase) during walking was significantly lower (both p<0.001) in children with HMS. Knee extension in mid stance during walking was significantly increased (p<0.001) in children with HMS. However, gait speed was not statistically (p=0.496) different between the two groups. Children with HMS had higher passive knee ROM than healthy children and also demonstrated abnormal knee motion during gait. Gait re-education and joint stability exercise programmes may be of value to children with HMS. PMID:21300548

  4. Shape, shear and flexion - II. Quantifying the flexion formalism for extended sources with the ray-bundle method

    NASA Astrophysics Data System (ADS)

    Fluke, C. J.; Lasky, P. D.

    2011-09-01

    Flexion-based weak gravitational lensing analysis is proving to be a useful adjunct to traditional shear-based techniques. As flexion arises from gradients across an image, analytic and numerical techniques are required to investigate flexion predictions for extended image/source pairs. Using the Schwarzschild lens model, we demonstrate that the ray-bundle method for gravitational lensing can be used to accurately recover second flexion, and is consistent with recovery of zero first flexion. Using lens plane to source plane bundle propagation, we find that second flexion can be recovered with an error no worse than 1 per cent for bundle radii smaller than Δθ= 0.01θE and lens plane impact pararameters greater than θE+Δθ, where θE is the angular Einstein radius. Using source plane to lens plane bundle propagation, we demonstrate the existence of a preferred flexion zone. For images at radii closer to the lens than the inner boundary of this zone, indicative of the true strong lensing regime, the flexion formalism should be used with caution (errors greater than 5 per cent for extended image/source pairs). We also define a shear-zone boundary, beyond which image shapes are essentially indistinguishable from ellipses (1 per cent error in ellipticity). While suggestive that a traditional weak lensing analysis is satisfactory beyond this boundary, a potentially detectable non-zero flexion signal remains. Research undertaken as part of the Commonwealth Cosmology Initiative (CCI, ), an international collaboration supported by the Australian Research Council.

  5. Influence of increasing construct constraint in the presence of posterolateral deficiency at knee replacement: A biomechanical study.

    PubMed

    Ghosh, Kanishka M; Manning, William A; Blain, Alasdair P; Rushton, Steve P; Longstaff, Lee M; Amis, Andrew A; Deehan, David J

    2016-03-01

    When faced with posterolateral corner (PLC) deficiency, surgeons must choose a total knee replacement (TKR) construct that provides the appropriate level of constraint. This should match the internal constraint of the device to the soft tissue host laxity pattern. Little guidance is available peroperatively, with factors influencing final component choice remaining ill defined. This study aimed to quantify the effect of PLC insufficiency on the "envelope of laxity" (EoL) after TKR and the effect of increasingly component constraint upon knee behavior through a functional arc of flexion. Using computer navigation, mixed effect modeling and loaded cadaveric legs--laxity was quantified under separate states: the native knee, after implantation of a posterior stabilized (PS)-TKR, after sectioning the lateral (fibular) collateral ligament and popliteus tendon (PS-TKR-PLC), and after re-implantation with a semi-constrained "total stabilized" knee replacement (TS-TKR). Laxity was quantified from 0 to 110° of flexion for anterior draw, varus-valgus, and internal-external rotation. Implantation of the PS-TKR was consistently associated with increased constraint when compared to the native knee. PLC sectioning led to significantly increased laxity during varus stress from mid to deep flexion. Revision to a TS-TKR construct restored constraint mimicking that of the primary state but only for the arc of motion 0-90°. In a posterolateral deficient state, a fixed bearing semi-constrained TS-TKR restored the knee to near normal kinematics but this was only achieved from an arc of motion 0-90° of flexion. At higher flexion angles, there remained an unfavorable laxity pattern with varus stress opening. PMID:26267425

  6. Does dragonfly's abdomen flexion help with fast turning maneuvers?

    NASA Astrophysics Data System (ADS)

    Liu, Geng; Li, Chengyu; Dong, Haibo; Flow Simulation Research Group Team

    2013-11-01

    Dragonflies are able to achieve fast turning maneuvers during take-off flights. Both asymmetric wing flapping and abdomen flexion have been observed during the fast turning. It's widely thought that the asymmetric wing beats are responsible of producing the aerodynamic moment needed for the body rotation. However, the dynamic effect of the abdomen flexion is not clear yet. In this study, an integrated experimental and computational approach is used to study the underlying dynamic effect of dragonfly abdomen flexion. It's found that dragonfly abdomen tended to bend towards the same side as the body reorienting to. Quantitative analysis have shown that during take-off turning maneuver the abdomen flexion can modulate the arm of force by changing the position of the center of mass relative to the thorax. As a result, roll and yaw moments produced by the wing flapping can be enhanced. This work is supported by NSF CBET-1313217. This work is supported by NSF CBET-1313217.

  7. Anatomic Versus Mechanically Aligned Total Knee Arthroplasty for Unicompartmental Knee Arthroplasty Revision

    PubMed Central

    Toliopoulos, Panagiota; LeBlanc, Marc-Andre; Hutt, Jonathan; Lavigne, Martin; Desmeules, Francois; Vendittoli, Pascal-Andre

    2016-01-01

    Objectives: The purpose of this study was to compare the intra-operative benefits and the clinical outcomes from kinematic or mechanical alignment for total knee arthroplasty (TKA) in patients undergoing revision of failed unicompartmental kneel arthroplasty (UKA) to TKA. Methods: Ten revisions were performed with a kinematic alignment technique and 11 with a mechanical alignment. Measurements of the hip-knee-ankle angle (HKA), the lateral distal femoral angle (LDFA), and the medial proximal tibial angle (MPTA) were performed using long-leg radiographs. The need for augments, stems, and constrained inserts was compared between groups. Clinical outcomes were compared using the WOMAC score along with maximum distance walked as well as knee range of motion obtained prior to discharge. All data was obtained by a retrospective review of patient files. Results: The kinematic group required less augments, stems, and constrained inserts than the mechanical group and thinner polyethylene bearings. There were significant differences in the lateral distal femoral angle (LDFA) and the medial proximal tibial angle (MPTA) between the two groups (p<0.05). The mean WOMAC score obtained at discharge was better in the kinematic group as was mean knee flexion. At last follow up of 34 months for the kinematic group and 58 months for the mechanical group, no orthopedic complications or reoperations were recorded. Conclusion: Although this study has a small patient cohort, our results suggest that kinematic alignment for TKA after UKA revision is an attractive method. Further studies are warranted. PMID:27563365

  8. Anatomic Anterolateral Ligament Reconstruction of the Knee Leads to Overconstraint at any Fixation Angle

    PubMed Central

    Schon, Jason; Brady, Alex; Moatshe, Gilbert; Cruz, Raphael; Chahla, Jorge; Dornan, Grant; Turnbull, Travis L.; Engebretsen, Lars

    2016-01-01

    Objectives: Anterior cruciate ligament (ACL) tears are one of the most common injuries among athletes. However, the ability to fully restore rotational stability with ACL reconstruction (ACLR) remains a challenge because up to 25% of patients may present with a residual pivot shift following surgery. Advocacy for reconstruction of the anterolateral ligament (ALL) is rapidly increasing because biomechanical studies have reported that the ALL is a significant contributor to internal rotational stability of the knee. Although several graft fixation angles for the anatomic ALL reconstruction (ALLR) have been reported in literature, none have been biomechanically validated. Therefore, the purpose of this study was to assess the effect of ALLR graft fixation angle on knee joint kinematics in the clinically relevant setting of a concomitant ACLR. The goal was to find the optimal knee flexion angle for fixation of the ALLR graft that would most accurately restore native knee kinematics without introducing overconstraint to the knee. It was hypothesized that all fixation angles would significantly reduce rotational laxity compared to the sectioned ALL state and that fixation at 30° would best reproduce native joint kinematics. Methods: Eight non-paired fresh-frozen human cadaveric knees with no prior injury, surgical history, or gross anatomic abnormality were evaluated with a 6 degree-of-freedom robotic system. Each specimen underwent a full kinematic assessment in each of the following states: 1) intact, 2) anatomic single-bundle (SB) ACLR with intact ALL, 3) anatomic SB ACLR with sectioned ALL, 4) 7 anatomic SB ACLR and ALLR states utilizing ALL graft fixation knee flexion angles of 0°, 15°, 30°, 45°, 60°, 75° and 90°, and 5) sectioned ACL and ALL. Internal rotation during a 5 N-m internal rotation torque and anterior displacement during an 88 N anterior load were recorded at 15° intervals between 0° and 120° of knee flexion. Axial plane displacement and

  9. Which total knee replacement implant should I pick? Correcting the pathology: the role of knee bearing designs.

    PubMed

    Berend, K R; Lombardi, A V; Adams, J B

    2013-11-01

    Debate has raged over whether a cruciate retaining (CR) or a posterior stabilised (PS) total knee replacement (TKR) provides a better range of movement (ROM) for patients. Various sub-sets of CR design are frequently lumped together when comparing outcomes. Additionally, multiple factors have been proven to influence the rate of manipulation under anaesthetic (MUA) following TKR. The purpose of this study was to determine whether different CR bearing insert designs provide better ROM or different MUA rates. All primary TKRs performed by two surgeons between March 2006 and March 2009 were reviewed and 2449 CR-TKRs were identified. The same CR femoral component, instrumentation, and tibial base plate were consistently used. In 1334 TKRs a CR tibial insert with 3° posterior slope and no posterior lip was used (CR-S). In 803 there was an insert with no slope and a small posterior lip (CR-L) and in 312 knees the posterior cruciate ligament (PCL) was either resected or lax and a deep-dish, anterior stabilised insert was used (CR-AS). More CR-AS inserts were used in patients with less pre-operative ROM and greater pre-operative tibiofemoral deformity and flexion contracture (p < 0.05). The mean improvement in ROM was highest for the CR-AS inserts (5.9° (-40° to 55°) vs CR-S 3.1° (-45° to 70°) vs CR-L 3.0° (-45° to 65°); p = 0.004). There was a significantly higher MUA rate with the CR-S and CR-L inserts than CR-AS (Pearson rank 6.51; p = 0.04). Despite sacrificing or not substituting for the PCL, ROM improvement was highest, and the MUA rate was lowest in TKRs with a deep-dish, anterior-stabilised insert. Substitution for the posterior cruciate ligament (PCL) in the form of a PS design may not be necessary even when the PCL is deficient. PMID:24187370

  10. Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk.

    PubMed

    Mornieux, Guillaume; Gehring, Dominic; Fürst, Patrick; Gollhofer, Albert

    2014-01-01

    Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement. Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact. With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009). Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs. PMID:24742137

  11. Serial elongation-derotation-flexion casting for children with early-onset scoliosis

    PubMed Central

    Canavese, Federico; Samba, Antoine; Dimeglio, Alain; Mansour, Mounira; Rousset, Marie

    2015-01-01

    Various early-onset spinal deformities, particularly infantile and juvenile scoliosis (JS), still pose challenges to pediatric orthopedic surgeons. The ideal treatment of these deformities has yet to emerge, as both clinicians and surgeons still face multiple challenges including preservation of thoracic motion, spine and cage, and protection of cardiac and lung growth and function. Elongation-derotation-flexion (EDF) casting is a technique that uses a custom-made thoracolumbar cast based on a three-dimensional correction concept. EDF can control progression of the deformity and - in some cases-coax the initially-curved spine to grow straighter by acting simultaneously in the frontal, sagittal and coronal planes. Here we provide a comprehensive review of how infantile and JS can affect normal spine and thorax and how serial EDF casting can be used to manage these spinal deformities. A fresh review of the literature helps fully understand the principles of the serial EDF casting technique and the effectiveness of conservative treatment in patients with early-onset spinal deformities, particularly infantile and juvenile scolisois. PMID:26716089

  12. High resolution weak lensing mass mapping combining shear and flexion

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Starck, J.-L.; Leonard, A.; Pires, S.

    2016-06-01

    Aims: We propose a new mass mapping algorithm, specifically designed to recover small-scale information from a combination of gravitational shear and flexion. Including flexion allows us to supplement the shear on small scales in order to increase the sensitivity to substructures and the overall resolution of the convergence map without relying on strong lensing constraints. Methods: To preserve all available small scale information, we avoid any binning of the irregularly sampled input shear and flexion fields and treat the mass mapping problem as a general ill-posed inverse problem, which is regularised using a robust multi-scale wavelet sparsity prior. The resulting algorithm incorporates redshift, reduced shear, and reduced flexion measurements for individual galaxies and is made highly efficient by the use of fast Fourier estimators. Results: We tested our reconstruction method on a set of realistic weak lensing simulations corresponding to typical HST/ACS cluster observations and demonstrate our ability to recover substructures with the inclusion of flexion, which are otherwise lost if only shear information is used. In particular, we can detect substructures on the 15'' scale well outside of the critical region of the clusters. In addition, flexion also helps to constrain the shape of the central regions of the main dark matter halos. Our mass mapping software, called Glimpse2D, is made freely available at http://www.cosmostat.org/software/glimpse

  13. Combined magnetic resonance and diffusion tensor imaging analyses provide a powerful tool for in vivo assessment of deformation along human muscle fibers.

    PubMed

    Pamuk, Uluç; Karakuzu, Agah; Ozturk, Cengizhan; Acar, Burak; Yucesoy, Can A

    2016-10-01

    Muscle fiber direction strain provides invaluable information for characterizing muscle function. However, methods to study this for human muscles in vivo are lacking. Using magnetic resonance (MR) imaging based deformation analyses and diffusion tensor (DT) imaging based tractography combined, we aimed to assess muscle fiber direction local tissue deformations within the human medial gastrocnemius (GM) muscle. Healthy female subjects (n=5, age=27±1 years) were positioned prone within the MR scanner in a relaxed state with the ankle angle fixed at 90°. The knee was brought to flexion (140.8±3.0°) (undeformed state). Sets of 3D high resolution MR, and DT images were acquired. This protocol was repeated at extended knee joint position (177.0±1.0°) (deformed state). Tractography and Demons nonrigid registration algorithm was utilized to calculate local deformations along muscle fascicles. Undeformed state images were also transformed by a synthetic rigid body motion to calculate strain errors. Mean strain errors were significantly smaller then mean fiber direction strains (lengthening: 0.2±0.1% vs. 8.7±8.5%; shortening: 3.3±0.9% vs. 7.5±4.6%). Shortening and lengthening (up to 23.3% and 116.7%, respectively) occurs simultaneously along individual fascicles despite imposed GM lengthening. Along-fiber shear strains confirm the presence of much shearing between fascicles. Mean fiber direction strains of different tracts also show non-uniform distribution. Inhomogeneity of fiber strain indicates epimuscular myofascial force transmission. We conclude that MR and DT imaging analyses combined provide a powerful tool for quantifying deformation along human muscle fibers in vivo. This can help substantially achieving a better understanding of normal and pathological muscle function and mechanisms of treatment techniques. PMID:27429070

  14. Press-fit condylar total knee arthroplasty. 5- to 9-year follow-up evaluation.

    PubMed

    Martin, S D; McManus, J L; Scott, R D; Thornhill, T S

    1997-09-01

    Between November 1984 and December 1987, 378 consecutive Press-Fit Condylar (PFC, Johnson & Johnson Professional, Raynham, MA) total knee arthroplasties were performed in 290 patients. The average age at surgery was 67 years (range, 22-91 years). The average follow-up period was 6.5 years (range, 5-9 years). Scoring was carried out according to the Knee Society scoring system. The average preoperative knee score was 28, and the average postoperative knee score was 88. The average preoperative functional knee score was 49, and the average postoperative functional knee score was 72. Ninety-five percent of the patients had no pain on level walking and were satisfied with their functional result. The average postoperative knee flexion was 110 degrees. No implant showed any evidence of radiographic loosening. There were 17 complications, all requiring reoperation. Complications included excessive wear of a metal-backed patella in 8 knees. If complications resulting from the earlier use of a metal-backed patella are eliminated, the overall complication rate is 2.9%, which is comparable to or lower than the rates for other total knee systems with similar follow-up periods. PMID:9306210

  15. 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

  16. Knee arthroscopy - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100117.htm Knee arthroscopy - series To use the sharing features on ... 5 out of 5 Normal anatomy Overview The knee is a complex joint made up of the ...

  17. Knee braces - unloading

    MedlinePlus

    ... most people talk about the arthritis in their knees, they are referring to a type of arthritis ... is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions ...

  18. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series To use the sharing features on ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  19. Osteotomy of the knee

    MedlinePlus

    ... is not affected unless you have had a knee injury in the past. Osteotomy surgery works by shifting ... M. Editorial team. Related MedlinePlus Health Topics Arthritis Knee Injuries and Disorders Browse the Encyclopedia A.D.A. ...

  20. Knee joint replacement

    MedlinePlus

    The results of a total knee replacement are often excellent. The operation relieves pain for most people. Most people do not need help walking after they fully recover. Most artificial knee joints last 10 ...

  1. Partial knee replacement

    MedlinePlus

    Most people recover quickly and have much less pain than they did before surgery. People who have a partial knee replacement recover faster than those who have a total knee replacement. Many people are able to walk ...

  2. Knee joint replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100088.htm Knee joint replacement - series—Normal anatomy To use the sharing ... of 4 Overview The knee is a complex joint. It contains the distal end of the femur ( ...

  3. Ambulatory measurement of knee motion and physical activity: preliminary evaluation of a smart activity monitor

    PubMed Central

    Huddleston, James; Alaiti, Amer; Goldvasser, Dov; Scarborough, Donna; Freiberg, Andrew; Rubash, Harry; Malchau, Henrik; Harris, William; Krebs, David

    2006-01-01

    Background There is currently a paucity of devices available for continuous, long-term monitoring of human joint motion. Non-invasive, inexpensive devices capable of recording human activity and joint motion have many applications for medical research. Such a device could be used to quantify range of motion outside the gait laboratory. The purpose of this study was to test the accuracy of the modified Intelligent Device for Energy Expenditure and Activity (IDEEA) in measuring knee flexion angles, to detect different physical activities, and to quantify how often healthy subjects use deep knee flexion in the ambulatory setting. Methods We compared Biomotion Laboratory (BML) "gold standard" data to simultaneous IDEEA measures of knee motion and gait, step up/down, and stair descent in 5 healthy subjects. In addition, we used a series of choreographed physical activities outside the BML to confirm the IDEEA's ability to accurately measure 7 commonly-performed physical activities. Subjects then continued data collection during ordinary activities outside the gait laboratory. Results Pooled correlations between the BML and IDEEA knee flexion angles were .97 +/- .03 for step up/down, .98 +/- .02 for stair descent, and .98 +/- .01 for gait. In the BML protocol, the IDEEA accurately identified gait, but was less accurate in identifying step up/down and stair descent. During sampling outside the BML, the IDEEA accurately detected walking, running, stair ascent, stair descent, standing, lying, and sitting. On average, subjects flexed their knees >120° for 0.17% of their data collection periods outside the BML. Conclusion The modified IDEEA system is a useful clinical tool for evaluating knee motion and multiple physical activities in the ambulatory setting. These five healthy subjects rarely flexed their knees >120°. PMID:16970818

  4. [Is knee osteotomy still indicated in knee osteoarthritis?].

    PubMed

    Antonescu, D N

    2000-12-01

    This study was undertaken to investigate whether high tibial osteotomy (HTO) still had a role in the treatment of osteoarthritis of the knee joint. The author has performed photoelasticity studies which confirmed abnormal stress distribution over the joint, as soon as its mechanical axis was deviated and the joint line had an obliquity over 10 degrees. High tibial osteotomy to correct varus or valgus deformity restores a symmetrical stress distribution and represents the only etiological treatment of secondary osteoarthritis of the knee. Two hundred and fifty HTO's were performed between 1971 and 1985 for osteoarthritis of the knee. The short-term result was good or very good in 75%, fair in 20% and poor in 5%. Fair and poor results were related to insufficient correction, to infection or mostly to incorrect indications. In 152 cases with a good or very good short term result, a further evaluation was made between 8 years and 15 years after operation. It was noted that osteoarthritis had been arrested in 105 cases (69%) whereas it had deteriorated in 47 cases. The main factors associated with further deterioration were insufficient correction and persistence of joint line obliquity. Provided on optimal correction is achieved (3 degrees to 6 degrees hypercorrection in valgus osteotomy, 0 degree in varus osteotomy) and provided a horizontal joint line is restored, HTO performed in good indications (Ahlback grade I or II) may provide good results for at least 10 to 15 years. PMID:11196365

  5. Knee braces - unloading

    MedlinePlus

    ... is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions all of your bones and joints, lets the bones glide over one another. If ... the knee become weaker. Over time, your whole knee becomes ...

  6. 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

  7. An acoustic startle alters knee joint stiffness and neuromuscular control.

    PubMed

    DeAngelis, A I; Needle, A R; Kaminski, T W; Royer, T R; Knight, C A; Swanik, C B

    2015-08-01

    Growing evidence suggests that the nervous system contributes to non-contact knee ligament injury, but limited evidence has measured the effect of extrinsic events on joint stability. Following unanticipated events, the startle reflex leads to universal stiffening of the limbs, but no studies have investigated how an acoustic startle influences knee stiffness and muscle activation during a dynamic knee perturbation. Thirty-six individuals were tested for knee stiffness and muscle activation of the quadriceps and hamstrings. Subjects were seated and instructed to resist a 40-degree knee flexion perturbation from a relaxed state. During some trials, an acoustic startle (50 ms, 1000 Hz, 100 dB) was applied 100 ms prior to the perturbation. Knee stiffness, muscle amplitude, and timing were quantified across time, muscle, and startle conditions. The acoustic startle increased short-range (no startle: 0.044 ± 0.011 N·m/deg/kg; average startle: 0.047 ± 0.01 N·m/deg/kg) and total knee stiffness (no startle: 0.036 ± 0.01 N·m/deg/kg; first startle 0.027 ± 0.02 N·m/deg/kg). Additionally, the startle contributed to decreased [vastus medialis (VM): 13.76 ± 33.6%; vastus lateralis (VL): 6.72 ± 37.4%] but earlier (VM: 0.133 ± 0.17 s; VL: 0.124 ± 0.17 s) activation of the quadriceps muscles. The results of this study indicate that the startle response can significantly disrupt knee stiffness regulation required to maintain joint stability. Further studies should explore the role of unanticipated events on unintentional injury. PMID:25212407

  8. Development and validation of a weight-bearing finite element model for total knee replacement.

    PubMed

    Woiczinski, M; Steinbrück, A; Weber, P; Müller, P E; Jansson, V; Schröder, Ch

    2016-08-01

    Total knee arthroplasty (TKA) is a successful procedure for osteoarthritis. However, some patients (19%) do have pain after surgery. A finite element model was developed based on boundary conditions of a knee rig. A 3D-model of an anatomical full leg was generated from magnetic resonance image data and a total knee prosthesis was implanted without patella resurfacing. In the finite element model, a restarting procedure was programmed in order to hold the ground reaction force constant with an adapted quadriceps muscle force during a squat from 20° to 105° of flexion. Knee rig experimental data were used to validate the numerical model in the patellofemoral and femorotibial joint. Furthermore, sensitivity analyses of Young's modulus of the patella cartilage, posterior cruciate ligament (PCL) stiffness, and patella tendon origin were performed. Pearson's correlations for retropatellar contact area, pressure, patella flexion, and femorotibial ap-movement were near to 1. Lowest root mean square error for retropatellar pressure, patella flexion, and femorotibial ap-movement were found for the baseline model setup with Young's modulus of 5 MPa for patella cartilage, a downscaled PCL stiffness of 25% compared to the literature given value and an anatomical origin of the patella tendon. The results of the conducted finite element model are comparable with the experimental results. Therefore, the finite element model developed in this study can be used for further clinical investigations and will help to better understand the clinical aspects after TKA with an unresurfaced patella. PMID:26618541

  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. PMID:22687046

  10. The effects of a valgus collapse knee position on in vivo ACL elongation.

    PubMed

    Utturkar, G M; Irribarra, L A; Taylor, K A; Spritzer, C E; Taylor, D C; Garrett, W E; Defrate, Louis E

    2013-01-01

    There are conflicting data regarding what motions increase ACL injury risk. More specifically, the mechanical role of valgus collapse positions during ACL injury remains controversial. Our objective was to evaluate ACL elongation in a model that mimics knee movements thought to occur during ACL injury. Eight healthy male subjects were imaged using MR and biplanar fluoroscopy to measure the in vivo elongation of the ACL and its functional bundles during three static knee positions: full extension, 30° of flexion, and a position intended to mimic a valgus collapse position described in the literature. For this study, the valgus collapse position consisted of 30° of knee flexion, internal rotation of the hip, and 10° of external tibial rotation. ACL length decreased significantly from full extension (30.2 ± 2.6 mm) to 30° of flexion (27.1 ± 2.2 mm). ACL length further decreased in the valgus collapse position (25.6 ± 2.4 mm). Both functional bundles of the ACL followed similar trends with regards to decreases in length in each of the three positions. Since strain would follow patterns of ACL length, landing on an extended knee may be a more relevant risk factor for ACL injuries than the valgus collapse position in males. Future studies should evaluate the effects of dynamic motion patterns on in vivo ACL strains. PMID:22855117

  11. Prosthesis alignment affects axial rotation motion after total knee replacement: a prospective in vivo study combining computed tomography and fluoroscopic evaluations

    PubMed Central

    2012-01-01

    Background Clinical consequences of alignment errors in total knee replacement (TKR) have led to the rigorous evaluation of surgical alignment techniques. Rotational alignment in the transverse plane has proven particularly problematic, with errors due to component malalignment relative to bone anatomic landmarks and an overall mismatch between the femoral and tibial components’ relative positions. Ranges of nominal rotational alignment are not well defined, especially for the tibial component and for relative rotational mismatch, and some studies advocate the use of mobile-bearing TKR to accommodate the resulting small rotation errors. However, the relationships between prosthesis rotational alignment and mobile-bearing polyethylene insert motion are poorly understood. This prospective, in vivo study evaluates whether component malalignment and mismatch affect axial rotation motions during passive knee flexion after TKR. Methods Eighty patients were implanted with mobile-bearing TKR. Rotational alignment of the femoral and tibial components was measured from postoperative CT scans. All TKR were categorized into nominal or outlier groups based on defined norms for surgical rotational alignment relative to bone anatomic landmarks and relative rotational mismatch between the femoral and tibial components. Axial rotation motion of the femoral, tibial and polyethylene bearing components was measured from fluoroscopic images acquired during passive knee flexion. Results Axial rotation motion was generally accomplished in two phases, dominated by polyethylene bearing rotation on the tibial component in early to mid-flexion and then femoral component rotation on the polyethylene articular surface in later flexion. Opposite rotations of the femur-bearing and bearing-baseplate articulations were evident at flexion greater than 80°. Knees with outlier alignment had lower magnitudes of axial rotation and distinct transitions from external to internal rotation during mid-flexion

  12. Knee range of motion in isolated femoral lengthening.

    PubMed

    Herzenberg, J E; Scheufele, L L; Paley, D; Bechtel, R; Tepper, S

    1994-04-01

    Twenty-five patients underwent isolated Ilizarov femoral lengthenings (mean lengthening, 6 cm). A retrospective review of the charts showed the specific changes in knee range of motion (ROM) during lengthening, after removal of the frame, and at the final follow-up examination. A decrease in ROM was seen during lengthening to an average minimum of 37 degrees +/- 15 degrees. Toward the end of the consolidation phase, improvement to 69 degrees +/- 28 degrees was noted. A progressive increase in ROM was seen after frame removal. Mean preoperative flexion was 127 degrees +/- 16 degrees, and at follow-up flexion was 122 degrees +/- 23 degrees (p = 0.191). Of the five patients who did not achieve 120 degrees flexion at the final follow-up examination, three had a diminished ROM (average, 107 degrees) at the outset. Two patients lost more than 15% of their preoperative flexion. There was no correlation noted between worst ROM (during lengthening) and final ROM at the last follow-up examination. PMID:8156696

  13. Comparisons of knee and ankle joint angles and ground reaction force according to functional differences during single-leg drop landing

    PubMed Central

    Kim, Kewwan; Jeon, Kyoungkyu

    2016-01-01

    [Purpose] The purpose of this study was to determine potential predictors of functional instability of the knee and ankle joints during single-leg drop landing based on the prior history of injury. [Subjects and Methods] The subjects were 24 collegiate soccer players without pain or dysfunction. To compare the differences between the stable and unstable sides during single-leg drop landing, 8 motion analysis cameras and a force plate were used. The Cortex 4 software was used for a biomechanical analysis of 3 events. An independent t-test was used for statistical comparison between both sides; p<0.05 indicated significance. [Results] The knee joint movements showed gradual flexion in the sagittal plane. The unstable-side ankle joint showed plantar flexion of approximately 2° relative to the stable side. In the coronal plane, the unstable-side knee joint differed from the stable side in its tendency for valgus movement. The unstable-side ankle joint showed contrasting movement compared with the stable side, and the difference was significant. Regarding the vertical ground reaction force, the stable side showed maximum knee flexion that was approximately 0.1 BW lower than that of the unstable side. [Conclusion] Increasing the flexion angle of the knee joint can help prevent injury during landing. PMID:27190444

  14. Position-Specific Hip and Knee Kinematics in NCAA Football Athletes

    PubMed Central

    Deneweth, Jessica M.; Pomeroy, Shannon M.; Russell, Jason R.; McLean, Scott G.; Zernicke, Ronald F.; Bedi, Asheesh; Goulet, Grant C.

    2014-01-01

    Background: Femoroacetabular impingement is a debilitating hip condition commonly affecting athletes playing American football. The condition is associated with reduced hip range of motion; however, little is known about the range-of-motion demands of football athletes. This knowledge is critical to effective management of this condition. Purpose: To (1) develop a normative database of game-like hip and knee kinematics used by football athletes and (2) analyze kinematic data by playing position. The hypothesis was that kinematics would be similar between running backs and defensive backs and between wide receivers and quarterbacks, and that linemen would perform the activities with the most erect lower limb posture. Study Design: Descriptive laboratory study. Methods: Forty National Collegiate Athletic Association (NCAA) football athletes, representing 5 playing positions (quarterback, defensive back, running back, wide receiver, offensive lineman), executed game-like maneuvers while lower body kinematics were recorded via optical motion capture. Passive hip range of motion at 90° of hip flexion was assessed using a goniometer. Passive range of motion, athlete physical dimensions, hip function, and hip and knee rotations were submitted to 1-way analysis of variance to test for differences between playing positions. Correlations between maximal hip and knee kinematics and maximal hip kinematics and passive range of motion were also computed. Results: Hip and knee kinematics were similar across positions. Significant differences arose with linemen, who used lower maximal knee flexion (mean ± SD, 45.04° ± 7.27°) compared with running backs (61.20° ± 6.07°; P < .001) and wide receivers (54.67° ± 6.97°; P = .048) during the cut. No significant differences were found among positions for hip passive range of motion (overall means: 102° ± 15° [flexion]; 25° ± 9° [internal rotation]; 25° ± 8° [external rotation]). Several maximal hip measures were found

  15. Extrinsic versus intrinsic hand muscle dominance in finger flexion.

    PubMed

    Al-Sukaini, A; Singh, H P; Dias, J J

    2016-05-01

    This study aims to identify the patterns of dominance of extrinsic or intrinsic muscles in finger flexion during initiation of finger curl and mid-finger flexion. We recorded 82 hands of healthy individuals (18-74 years) while flexing their fingers and tracked the finger joint angles of the little finger using video motion tracking. A total of 57 hands (69.5%) were classified as extrinsic dominant, where the finger flexion was initiated and maintained at proximal interphalangeal and distal interphalangeal joints. A total of 25 (30.5%) were classified as intrinsic dominant, where the finger flexion was initiated and maintained at the metacarpophalangeal joint. The distribution of age, sex, dominance, handedness and body mass index was similar in the two groups. This knowledge may allow clinicians to develop more efficient rehabilitation regimes, since intrinsic dominant individuals would not initiate extrinsic muscle contraction till later in finger flexion, and might therefore be allowed limited early active motion. For extrinsic dominant individuals, by contrast, initial contraction of extrinsic muscles would place increased stress on the tendon repair site if early motion were permitted. PMID:26744509

  16. Results of Revision Surgery and Causes of Unstable Total Knee Arthroplasty

    PubMed Central

    Sun, Doo-Hoon; Chon, Jae-Gyun; Jang, Sung-Won; Sun, Dong-Hyuk

    2014-01-01

    Background The aim of this study was to evaluate causes of unstable total knee arthroplasty and results of revision surgery. Methods We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment results according to its cause. Stress radiographs, postoperative component position, and joint level were measured. Clinical outcomes were assessed using the Hospital for Special Surgery (HSS) score and range of motion. Results Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees, coronal instability with posteromedial polyethylene wear in 6 knees and coronal and sagittal instability in 3 knees including post breakage in 1 knee, global instability in 1 knee and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8°/3.2° (p = 0.713) and 22.5°/5.6° (p = 0.032). Mean postoperative α, β, γ, δ angle were 5.34°, 89.65°, 2.74°, 6.77°. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123° to 122° (p = 0.82). Conclusions Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to cause is very important and seems to be helpful to avoid unnecessary over-constrained implant selection in revision surgery for total knee instability. PMID:24900897

  17. A biomechanical evaluation of hinged total knee replacement prostheses.

    PubMed

    Long, Robin; Gheduzzi, Sabina; Bucher, Thomas A; Toms, Andrew D; Miles, Anthony W

    2013-08-01

    The number of total knee replacements being performed worldwide is undergoing an unprecedented increase. Hinged total knee replacements, used in complex salvage and revision procedures, currently account for a small but growing proportion of prostheses implanted. Modern hinged prostheses share the same basic configuration, allowing flexion-extension and tibial rotation. One aspect on which designs differ is the anteroposterior location of the hinge. A more posterior hinge is designed to increase the patellar tendon moment arm, reducing the quadriceps force required for a given activity and benefiting the patient. Five commonly used total knee replacements were evaluated in terms of quadriceps force and patellar tendon moment arm using a laboratory-based rig. Significant differences were identified between the five prostheses in quadriceps force and patellar tendon moment arm. Analysis of the correlation between these two parameters indicates that while patellar tendon moment arm influences quadriceps force, it is not the only factor. Also important is the lever function of the patella, and it is suggested here that the non-physiological nature of the prosthetic patellofemoral geometry may result in unnatural joint function. Thus, a thorough understanding of the resulting kinematic function of hinged total knee replacements is becoming increasingly important in complex revision total knee replacement to meet rising patient expectations and functional demands. PMID:23722496

  18. Patellofemoral Crepitus after Total Knee Arthroplasty: Etiology and Preventive Measures

    PubMed Central

    Conrad, David N.

    2014-01-01

    Patellofemoral crepitus and clunk syndrome are infrequent, yet troublesome complications of total knee arthroplasty with a reported incidence of 0%-18%. They are primarily associated with implantation of posterior cruciate substituting designs. These entities are the result of peripatellar fibrosynovial hyperplasia at the junction of the superior pole of the patella and the distal quadriceps tendon which becomes entrapped within the superior aspect of the intercondylar box of the femoral component during knee flexion. When the knee extends, a crepitant sensation occurs as the fibrosynovial tissue exits the intercondylar box. Numerous etiologies have been proposed such as femoral component designs with a high intercondylar box ratio, previous knee surgery, reduced patellar tendon length, thinner patellar components, reduced patella-patellar component composite thickness, and smaller femoral components. Preventative measures include choice of femoral components with a reduced intercondylar box ratio, use of thicker patellar components, avoidance of over-resection of the patella, and debridement of the fibrosynovial tissue at the time of knee arthroplasty. Most patients with crepitus are unaware of the problem or have minimal symptoms so that no treatment is required. If significant disability is incurred, symptoms can be eliminated in a high percentage of patients with arthroscopic debridement of the fibrosynovial hyperplasia. PMID:24605184

  19. Evolution of trochlear compartment geometry in total knee arthroplasty

    PubMed Central

    Demey, Guillaume; Nover, Luca; Dejour, David

    2016-01-01

    Background The study aimed to compare trochlear profiles in recent total knee arthroplasty (TKA) models and to determine whether they feature improvements compared to their predecessors. The hypothesis was that recent TKA models have more anatomic trochlear compartments and would display no signs of trochlear dysplasia. Methods The authors analyzed the geometry of the 6 following TKA models using engineering software: PFC and Attune (DePuy), NexGen and Persona (Zimmer), Noetos and KneeTec (Tornier). The mediolateral trochlear profiles were plotted at various flexion angles (0°, 15°, 30° and 45°) to deduce the sulcus angle. Results Analysis of sulcus angles reveals general convergence of recent designs towards anatomic values. At 0° of flexion, sulcus angles of recent implant models were between 156.0–157.4°, while those of previous generation models between 154.5–165.5°. At 30° of flexion, sulcus angles of recent models also lie within 145.7–148.6°, but those of previous models are between 149.5–152.0°. All three manufacturers deepened their trochlear profile at 30° of flexion in recent models compared to earlier designs. Sulcus angles converge towards anatomic values but still exceed radiologic signs of dysplasia by 2–5°. Conclusions Recent TKA designs have more anatomic trochlear geometries than earlier TKA models by the same manufacturers, but trochlear compartments still exceed radiologic signs of trochlear dysplasia by 2° to 5°. The hypothesis that recent TKA models display no signs of trochlear dysplasia is therefore refuted. Surgeons should be aware of design limitations to optimize choice of implant and extensor mechanisms alignment. Level of evidence: IV geometric implant analysis. PMID:26855943

  20. Definition and evaluation of testing scenarios for knee wear simulation under conditions of highly demanding daily activities.

    PubMed

    Schwiesau, Jens; Schilling, Carolin; Kaddick, Christian; Utzschneider, Sandra; Jansson, Volkmar; Fritz, Bernhard; Blömer, Wilhelm; Grupp, Thomas M

    2013-05-01

    The objective of our study was the definition of testing scenarios for knee wear simulation under various highly demanding daily activities of patients after total knee arthroplasty. This was mainly based on a review of published data on knee kinematics and kinetics followed by the evaluation of the accuracy and precision of a new experimental setup. We combined tibio-femoral load and kinematic data reported in the literature to develop deep squatting loading profiles for simulator input. A servo-hydraulic knee wear simulator was customised with a capability of a maximum flexion of 120°, a tibio-femoral load of 5000N, an anterior-posterior (AP) shear force of ±1000N and an internal-external (IE) rotational torque of ±50Nm to simulate highly demanding patient activities. During the evaluation of the newly configurated simulator the ability of the test machine to apply the required load and torque profiles and the flexion kinematics in a precise manner was examined by nominal-actual profile comparisons monitored periodically during subsequent knee wear simulation. For the flexion kinematics under displacement control a delayed actuator response of approximately 0.05s was inevitable due to the inertia of masses in movement of the coupled knee wear stations 1-3 during all applied activities. The axial load and IE torque is applied in an effective manner without substantial deviations between nominal and actual load and torque profiles. During the first third of the motion cycle a marked deviation between nominal and actual AP shear load profiles has to be noticed but without any expected measurable effect on the latter wear simulation due to the fact that the load values are well within the peak magnitude of the nominal load amplitude. In conclusion the described testing method will be an important tool to have more realistic knee wear simulations based on load conditions of the knee joint during activities of daily living. PMID:22922096

  1. Imaging knee position using MRI, RSA/CT and 3D digitisation.

    PubMed

    McPherson, A; Kärrholm, J; Pinskerova, V; Sosna, A; Martelli, S

    2005-02-01

    The purpose of this study was to compare 3 methods of imaging knee position. Three fresh cadaver knees were imaged at 6 flexion angles between 0 degrees and 120 degrees by MRI, a combination of RSA and CT and 3D digitisation (in two knees). Virtual models of all 42 positions were created using suitable computer software. Each virtual model was aligned to a newly defined anatomically based Cartesian coordinate system. The angular rotations around the 3 coordinate system axes were calculated directly from the aligned virtual models using rigid body kinematics and found to be equally accurate for the 3 methods. The 3 rotations in each knee could be depicted using anatomy-based diagrams for all 3 methods. We conclude that the 3 methods of data acquisition are equally and adequately accurate in vitro. MRI may be the most useful in vivo. PMID:15598452

  2. Evidence based factors influencing outcome of arthroscopy in osteoarthritis of the knee.

    PubMed

    Dearing, Jonathan; Nutton, Richard W

    2008-06-01

    Arthroscopy continues to be widely used in the management of knee osteoarthritis despite concerns regarding its effectiveness. The Scottish Arthroplasty Project has demonstrated a three-fold variation in rates of arthroscopy for osteoarthritis of the knee across different regions of Scotland. This has clear ramifications for the utilisation of finite health care resources. In light of such variations in national clinical practice this review identifies the evidence based factors which permit identification of patients who will obtain sustained benefit from arthroscopic treatment of knee osteoarthritis. Such a patient should have symptoms of short duration affecting the medial compartment of the knee, have localised tenderness at the medial joint line, mechanical symptoms and positive findings on meniscal stress testing. There should be neither significant mechanical malalignment nor flexion contracture, there should be preservation of the joint space on radiographs and the patient should not be obese. If these criteria are fulfilled the likelihood for long lasting reduction in symptoms is increased. PMID:18378147

  3. Does joint line elevation after revision knee arthroplasty affect tibio-femoral kinematics, contact pressure or collateral ligament lengths? An in vitro analysis

    PubMed Central

    Kowalczewski, Jacek B.; Chevalier, Yan; Okon, Tomasz; Innocenti, Bernardo; Bellemans, Johan

    2015-01-01

    Introduction Correct restoration of the joint line is generally considered as crucial when performing total knee arthroplasty (TKA). During revision knee arthroplasty however, elevation of the joint line occurs frequently. The general belief is that this negatively affects the clinical outcome, but the reasons are still not well understood. Material and methods In this cadaveric in vitro study the biomechanical consequences of joint line elevation were investigated using a previously validated cadaver model simulating active deep knee squats and passive flexion-extension cycles. Knee specimens were sequentially tested after total knee arthroplasty with joint line restoration and after 4 mm joint line elevation. Results The tibia rotated internally with increasing knee flexion during both passive and squatting motion (range: 17° and 7° respectively). Joint line elevation of 4 mm did not make a statistically significant difference. During passive motion, the tibia tended to become slightly more adducted with increasing knee flexion (range: 2°), while it went into slighlty less adduction during squatting (range: –2°). Neither of both trends was influenced by joint line elevation. Also anteroposterior translation of the femoral condyle centres was not affected by joint line elevation, although there was a tendency for a small posterior shift (of about 3 mm) during squatting after joint line elevation. In terms of kinetics, ligaments lengths and length changes, tibiofemoral contact pressures and quadriceps forces all showed the same patterns before and joint line elevation. No statistically significant changes could be detected. Conclusions Our study suggests that joint line elevation by 4 mm in revision total knee arthroplasty does not cause significant kinematic and kinetic differences during passive flexion/extension movement and squatting in the tibio-femoral joint, nor does it affect the elongation patterns of collateral ligaments. Therefore, clinical

  4. Proximity of arteries to the anterior ulna with changing flexion.

    PubMed

    Enad, Jerome G; Douglas, Thomas J; Ruland, Robert T

    2015-04-01

    During surgery for elbow fracture, wires and screws crossing the elbow from posterior to anterior place the brachial and ulnar arteries at risk for inadvertent penetration. The authors' goal was to define the sagittal proximity of the brachial and ulnar arteries to the proximal ulna throughout an arc of elbow motion using dynamic fluoroscopy. The brachial artery was injected with barium in 10 fresh-frozen cadaveric elbows. Sagittal fluoroscopic images were obtained at elbow flexion angles of 0°, 30°, 60°, 90°, and 120°. Two measurements were obtained at each flexion angle: (1) the distance between the coronoid tip and the brachial artery and (2) the distance between the coronoid base and the ulnar artery. One-way analysis of variance was used to compare mean distances for each flexion angle within each measurement group. A coronal image identified the mediolateral course of the brachial artery. The distance from the coronoid tip to the brachial artery significantly increased with increasing flexion from 0° to 60° (P<.001). The distance from the ulnar artery to the coronoid base significantly increased with increasing flexion from 0° to 120° (P<.002). The brachial artery traversed lateral to the coronoid in 9 of 10 specimens. The brachial and ulnar arteries are located further from the coronoid with increasing elbow flexion to at least 60°, and the brachial artery is typically located lateral to the coronoid in the coronal plane. These measurements can be used as surgical guides to reduce the risk of arterial injury during olecranon fracture surgery. PMID:25901616

  5. Acute effects of anterior thigh foam rolling on hip angle, knee angle, and rectus femoris length in the modified Thomas test

    PubMed Central

    Lehman, Gregory J.; Contreras, Bret; Beardsley, Chris; Chung, Bryan; Feser, Erin H.

    2015-01-01

    Background. Foam rolling has been shown to acutely increase range of motion (ROM) during knee flexion and hip flexion with the experimenter applying an external force, yet no study to date has measured hip extensibility as a result of foam rolling with controlled knee flexion and hip extension moments. The purpose of this study was to investigate the acute effects of foam rolling on hip extension, knee flexion, and rectus femoris length during the modified Thomas test. Methods. Twenty-three healthy participants (male = 7; female = 16; age = 22 ± 3.3 years; height = 170 ± 9.18 cm; mass = 67.7 ± 14.9 kg) performed two, one-minute bouts of foam rolling applied to the anterior thigh. Hip extension and knee flexion were measured via motion capture before and after the foam rolling intervention, from which rectus femoris length was calculated. Results. Although the increase in hip extension (change = +1.86° (+0.11, +3.61); z(22) = 2.08; p = 0.0372; Pearson’s r = 0.43 (0.02, 0.72)) was not due to chance alone, it cannot be said that the observed changes in knee flexion (change = −1.39° (−5.53, +2.75); t(22) = −0.70; p = 0.4933; Cohen’s d = − 0.15 (−0.58, 0.29)) or rectus femoris length (change = −0.005 (−0.013, +0.003); t(22) = −1.30; p = 0.2070; Cohen’s d = − 0.27 (−0.70, 0.16)) were not due to chance alone. Conclusions. Although a small change in hip extension was observed, no changes in knee flexion or rectus femoris length were observed. From these data, it appears unlikely that foam rolling applied to the anterior thigh will improve passive hip extension and knee flexion ROM, especially if performed in combination with a dynamic stretching protocol. PMID:26421244

  6. Spine lateral flexion strength development differences between exercises with pelvic stabilization and without pelvic stabilization

    NASA Astrophysics Data System (ADS)

    Straton, Alexandru; Gidu, Diana Victoria; Micu, Alexandru

    2015-02-01

    Poor lateral flexor muscle strength can be an important source of lumbar/thoracic back pain in women. The purpose of this study was to evaluate pelvic stabilization (PS) and no pelvic stabilization (NoPS) lateral flexion strength exercise training on the development of isolated right and left lateral flexion strength. Isometric torque of the isolated right and left lateral flexion muscles was measured at two positions (0° and 30° opposed angle range of motion) on 42 healthy women before and after 8 weeks of PS and NoPS lateral flexion strength exercise training. Subjects were assigned in three groups, the first (n=14) trained 3 times/week with PS lateral flexion strength exercise, the second (n=14) trained 3 times/week with NoPS lateral flexion strength exercise and the third (control, n=14) did not train. Post training isometric strength values describing PS and NoPS lateral flexion strength improved in greater extent for the PS lateral flexion strength exercise group and in lesser extent for the NoPS lateral flexion strength exercise group, in both angles (p<0.05) relative to controls. These data indicate that the most effective way of training the spine lateral flexion muscles is PS lateral flexion strength exercises; NoPS lateral flexion strength exercises can be an effective way of training for the spine lateral flexion muscles, if there is no access to PS lateral flexion strength training machines.

  7. The influence of component alignment on patellar kinematics in total knee arthroplasty

    PubMed Central

    Keshmiri, Armin; Maderbacher, Günther; Baier, Clemens; Sendtner, Ernst; Schaumburger, Jens; Zeman, Florian; Grifka, Joachim; Springorum, Hans R

    2015-01-01

    Background and purpose Postoperative anterior knee pain is one of the most frequent complications after total knee arthroplasty (TKA). Changes in patellar kinematics after TKA relative to the preoperative arthritic knee are not well understood. We compared the patellar kinematics preoperatively with the kinematics after ligament-balanced navigated TKA. Patients and methods We measured patellar tracking before and after ligament-balanced TKA in 40 consecutive patients using computer navigation. Furthermore, the influences of different femoral and tibial component alignment on patellar kinematics were analyzed using generalized linear models. Results After TKA, the patellae shifted statistically significantly more laterally between 30° and 60°. The lateral tilt increased at 90° of flexion whereas the epicondylar distance decreased between 45° and 75° of flexion. Sagittal component alignment, but not rotational component alignment, had a significant influence on patellar kinematics. Interpretation There are major differences in patellar kinematics between the preoperative arthritic knee and the knee after TKA. Combined sagittal component alignment in particular appears to have a major effect on patellar kinematics. Surgeons should be especially aware of altering preoperative sagittal alignment until the possible clinical relevance has been investigated. PMID:25582349

  8. Knee Kinematics is Altered Post-Fatigue While Performing a Crossover Task

    PubMed Central

    Cortes, Nelson; Greska, Eric; Ambegaonkar, Jatin P.; Kollock, Roger O.; Caswell, Shane V.; Onate, James A.

    2013-01-01

    Purpose To examine the effect of a sequential fatigue protocol on lower extremity biomechanics during a crossover cutting task in female soccer players. Methods Eighteen female collegiate soccer players alternated between a fatigue protocol and two consecutive unanticipated crossover trials until fatigue was reached. Lower extremity biomechanics were evaluated during the crossover using a 3D motion capture system and two force plates. Repeated measures ANOVAs analyzed differences between three sequential stages of fatigue (pre, 50%, 100%) for each dependent variable (α=0.05). Results Knee flexion angles at initial contact (IC) for pre- (−32±9°) and 50% (−29±11°) were significantly higher than at 100% fatigue (−22±9°) (p<0.001 and p=0.015, respectively). Knee adduction angles at IC for pre- (9±5°) and 50% (8±4°) were significantly higher (p=0.006 and p=0.049, respectively) than at 100% fatigue (6±4°). Conclusions Fatigue altered sagittal and frontal knee kinematics after 50% fatigue whereupon participants had diminished knee control at initial contact. Interventions should attempt to reduce the negative effects of fatigue on lower extremity biomechanics by promotion appropriate frontal plane alignment, and increased knee flexion during fatigue status. PMID:24045915

  9. Valgus knee stress in lumbosacral myelomeningocele: a gait-analysis evaluation.

    PubMed

    Lim, R; Dias, L; Vankoski, S; Moore, C; Marinello, M; Sarwark, J

    1998-01-01

    Twenty-five independent community-ambulating patients with lumbosacral-level myelomeningocele (N = 50 limbs) underwent gait analysis. The limbs of these patients were divided into two groups based on thigh-foot angle (TFA): Group I (n = 20) had marked external tibial torsion, TFA > or = 20 degrees, and group II had TFA between 10 and 20 degrees. Ten limbs were excluded because of neutral or internal alignment. Twenty normal limbs with TFA = 10 degrees served as controls. An abnormal internal varus knee stress during stance was identified in all group I limbs and 12 (70%) of 20 limbs group II limbs compared with controls, which demonstrated an internal valgus stress. This internal varus moment was greater in group I limbs than in the abnormal limbs in group II (p < 0.05). Knee flexion was the only other parameter found to correlate with this stress and only in group I limbs. We conclude that (a) in this patient group, increased external tibial torsion is likely to result in an abnormal internal varus knee stress; (b) TFA > 20 degrees appears significantly to increase this stress; and (c) knee flexion is an important related parameter, but only in limbs with TFA between 10 and 20 degrees. We believe that this abnormal stress may predispose the knee to late arthrosis and that derotational osteotomies to normalize the TFA may prove to have a favorable long-term effect. PMID:9661845

  10. 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. PMID:16311188

  11. Role of pelvic translation and lower-extremity compensation to maintain gravity line position in spinal deformity.

    PubMed

    Ferrero, Emmanuelle; Liabaud, Barthelemy; Challier, Vincent; Lafage, Renaud; Diebo, Bassel G; Vira, Shaleen; Liu, Shian; Vital, Jean Marc; Ilharreborde, Brice; Protopsaltis, Themistocles S; Errico, Thomas J; Schwab, Frank J; Lafage, Virginie

    2016-03-01

    OBJECT Previous forceplate studies analyzing the impact of sagittal-plane spinal deformity on pelvic parameters have demonstrated the compensatory mechanisms of pelvis translation in addition to rotation. However, the mechanisms recruited for this pelvic rotation were not assessed. This study aims to analyze the relationship between spinopelvic and lower-extremity parameters and clarify the role of pelvic translation. METHODS This is a retrospective study of patients with spinal deformity and full-body EOS images. Patients with only stenosis or low-back pain were excluded. Patients were grouped according to T-1 spinopelvic inclination (T1SPi): sagittal forward (forward, > 0.5°), neutral (-6.3° to 0.5°), or backward (< -6.3°). Pelvic translation was quantified by pelvic shift (sagittal offset between the posterosuperior corner of the sacrum and anterior cortex of the distal tibia), hip extension was measured using the sacrofemoral angle (SFA; the angle formed by the middle of the sacral endplate and the bicoxofemoral axis and the line between the bicoxofemoral axis and the femoral axis), and chin-brow vertical angle (CBVA). Univariate and multivariate analyses were used to compare the parameters and correlation with the Oswestry Disability Index (ODI). RESULTS In total, 336 patients (71% female; mean age 57 years; mean body mass index 27 kg/m(2)) had mean T1SPi values of -8.8°, -3.5°, and 5.9° in the backward, neutral, and forward groups, respectively. There were significant differences in the lower-extremity and spinopelvic parameters between T1SPi groups. The backward group had a normal lumbar lordosis (LL), negative SVA and pelvic shift, and the largest hip extension. Forward patients had a small LL and an increased SVA, with a large pelvic shift creating compensatory knee flexion. Significant correlations existed between lower-limb parameter and pelvic shift, pelvic tilt, T-1 pelvic angle, T1SPi, and sagittal vertical axis (0.3 < r < 0.8; p < 0.001). ODI

  12. Analysis of Early Postoperative Pain in the First and Second Knee in Staged Bilateral Total Knee Arthroplasty: A Retrospective Controlled Study

    PubMed Central

    Sun, Jiuyi; Li, Lintao; Yuan, Shuai; Zhou, Yiqin

    2015-01-01

    Objective A retrospective analysis of early postoperative pain in the first and second knee in staged bilateral total knee arthroplasty (TKA) to provide a clinical evidence for the change of analgesic strategy. Methods From January 2009 to January 2013, 87 cases which meet the inclusion criterion were retrospectively reviewed. In stage TKA, the postoperative pain in the first and second knee at 24h, 48h, 72h after operation were compared using the visual analogue scale (VAS) score in the rest and maximum knee flexion position. The difference in pain scores (ΔVAS) was also compared between the second and first knee at different time intervals (less than 6 months, 6-12 months, more than 12 months). Results The VAS scores in the second knee were significantly higher than those in the first knee at 24h, 48h after surgery, but with no difference at 72h. The ΔVAS in the group of less than 6 months was significantly higher than of those more than 6 months, and there was no difference in ΔVAS between group of 6-12 months and group of more than 12 months. Conclusions Patient receiving staged bilateral TKA experiences greater postoperative pain within 48h after operation in the second knee than in the first knee, which can provide a clinical evidence to enhance the analgesic strategy in the second operation of the staged bilateral TKA. And for the management of postoperative pain in staged bilateral TKA, it’s better to recommend that the interval between two operations should be more than 6 months, which may reduce the postoperative pain in the second knee, improve patient satisfaction, and speed up patient‘s rehabilitation process. PMID:26068371

  13. Soft tissue artifact evaluation of the cervical spine in motion patterns of flexion and lateral bending: a preliminary study.

    PubMed

    Wang, Jiajia; Lui, Zhongwen; Qian, Zhihui; Ren, Luquan

    2016-01-01

    Background. Soft tissue artifact (STA) is increasingly becoming a focus of research as the skin marker method is widely employed in motion capture technique. At present, medical imaging methods provide reliable ways to investigate the cervical STA. Among these approaches, magnetic resonance imaging (MRI) is a highly preferred tool because of its low radiation. Methods. In the study, the 3D spatial location of vertebral landmarks and corresponding skin markers of the spinous processes of the second (C2), fifth (C5), and sixth (C6) cervical levels during flexion and lateral bending were investigated. A series of static postures were scanned using MRI. Skin deformation was obtained by the Mimics software. Results. Results shows that during flexion, the maximum skin deformation occurs at C6, in the superior-inferior (Z) direction. Upon lateral bending, the maximum skin displacement occurs at C2 level, in the left-right (Y) direction. The result presents variability of soft tissue in the terms of direction and magnitude, which is consistent with the prevailing opinion. Discussion. The results testified variability of cervical STA. Future studies involving large ranges of subject classification, such as age, sex, height, gravity, and etc. should be performed to completely verify the existing hypothesis on human cervical skin deformation. PMID:27069821

  14. Soft tissue artifact evaluation of the cervical spine in motion patterns of flexion and lateral bending: a preliminary study

    PubMed Central

    Wang, Jiajia; Lui, Zhongwen; Ren, Luquan

    2016-01-01

    Background. Soft tissue artifact (STA) is increasingly becoming a focus of research as the skin marker method is widely employed in motion capture technique. At present, medical imaging methods provide reliable ways to investigate the cervical STA. Among these approaches, magnetic resonance imaging (MRI) is a highly preferred tool because of its low radiation. Methods. In the study, the 3D spatial location of vertebral landmarks and corresponding skin markers of the spinous processes of the second (C2), fifth (C5), and sixth (C6) cervical levels during flexion and lateral bending were investigated. A series of static postures were scanned using MRI. Skin deformation was obtained by the Mimics software. Results. Results shows that during flexion, the maximum skin deformation occurs at C6, in the superior–inferior (Z) direction. Upon lateral bending, the maximum skin displacement occurs at C2 level, in the left–right (Y) direction. The result presents variability of soft tissue in the terms of direction and magnitude, which is consistent with the prevailing opinion. Discussion. The results testified variability of cervical STA. Future studies involving large ranges of subject classification, such as age, sex, height, gravity, and etc. should be performed to completely verify the existing hypothesis on human cervical skin deformation. PMID:27069821

  15. Viscoelastic Response of the Human Lower Back to Passive Flexion: The Effects of Age.

    PubMed

    Shojaei, Iman; Allen-Bryant, Kacy; Bazrgari, Babak

    2016-09-01

    Low back pain is a leading cause of disability in the elderly. The potential role of spinal instability in increasing risk of low back pain with aging was indirectly investigated via assessment of age-related differences in viscoelastic response of lower back to passive deformation. The passive deformation tests were conducted in upright standing posture to account for the effects of gravity load and corresponding internal tissues responses on the lower back viscoelastic response. Average bending stiffness, viscoelastic relaxation, and dissipated energy were quantified to characterize viscoelastic response of the lower back. Larger average bending stiffness, viscoelastic relaxation and dissipated energy were observed among older vs. younger participants. Furthermore, average bending stiffness of the lower back was found to be the highest around the neutral standing posture and to decrease with increasing the lower back flexion angle. Larger bending stiffness of the lower back at flexion angles where passive contribution of lower back tissues to its bending stiffness was minimal (i.e., around neutral standing posture) highlighted the important role of active vs. passive contribution of tissues to lower back bending stiffness and spinal stability. As a whole our results suggested that a diminishing contribution of passive and volitional active subsystems to spinal stability may not be a reason for higher severity of low back pain in older population. The role of other contributing elements to spinal stability (e.g., active reflexive) as well as equilibrium-based parameters (e.g., compression and shear forces under various activities) in increasing severity of low back pain with aging should be investigated in future. PMID:26883956

  16. Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic Signals

    PubMed Central

    Wang, Z.; Ji, Q.; Miller, K. J.; Schalk, Gerwin

    2011-01-01

    Brain–computer interfaces (BCIs) use brain signals to convey a user’s intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG) recordings from the surface of the brain in humans can give information about kinematic parameters (e.g., hand velocity or finger flexion). The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS). Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation. PMID:22144944

  17. lower limbs kinematic assessment of the effect of a gym and hydrotherapy rehabilitation protocol after knee megaprosthesis: a case report.

    PubMed

    Lovecchio, Nicola; Sciumè, Luciana; Zago, Matteo; Panella, Lorenzo; Lopresti, Maurizio; Sforza, Chiarella

    2016-03-01

    [Purpose] To quantitatively assess the effect of a personalized rehabilitation protocol after knee megaprosthesis. [Subject and Methods] The gait patterns of a 33-year-old male patient with knee synovial sarcoma were assessed by a computerized analysis before and after 40 rehabilitation sessions. [Results] The rehabilitation protocol improved the gait pattern. After rehabilitation, hip flexion was nearly symmetric, with normalized affected limb hip flexion, and improved ankle flexion. Ankle in/eversion was asymmetric and did not improve after physiotherapy. Before physiotherapy, the hip flexion on the affected side anticipated the movement but nearly normalized in the follow-up assessment. Hip abduction range of motion increased, with wider movements and good balance. Knee range of motion nearly symmetrized, but maintained an anticipated behavior, without shock absorption at heel-strike. [Conclusion] Instrumental gait analysis allowed us to gain evidence about the training and how to expand rehabilitative interventions to improve efficacy. In particular, we recommend quadriceps and gastrocnemius eccentric contraction training (to improve the shock absorption phase, preventing early failures of the prosthesis); one-leg standing performance (to improve the support phase of the affected limb); adductor strength training (to aid in hip control during the swing phase); and peroneus strength training (to increase ankle joint stabilization). PMID:27134413

  18. lower limbs kinematic assessment of the effect of a gym and hydrotherapy rehabilitation protocol after knee megaprosthesis: a case report

    PubMed Central

    Lovecchio, Nicola; Sciumè, Luciana; Zago, Matteo; Panella, Lorenzo; Lopresti, Maurizio; Sforza, Chiarella

    2016-01-01

    [Purpose] To quantitatively assess the effect of a personalized rehabilitation protocol after knee megaprosthesis. [Subject and Methods] The gait patterns of a 33-year-old male patient with knee synovial sarcoma were assessed by a computerized analysis before and after 40 rehabilitation sessions. [Results] The rehabilitation protocol improved the gait pattern. After rehabilitation, hip flexion was nearly symmetric, with normalized affected limb hip flexion, and improved ankle flexion. Ankle in/eversion was asymmetric and did not improve after physiotherapy. Before physiotherapy, the hip flexion on the affected side anticipated the movement but nearly normalized in the follow-up assessment. Hip abduction range of motion increased, with wider movements and good balance. Knee range of motion nearly symmetrized, but maintained an anticipated behavior, without shock absorption at heel-strike. [Conclusion] Instrumental gait analysis allowed us to gain evidence about the training and how to expand rehabilitative interventions to improve efficacy. In particular, we recommend quadriceps and gastrocnemius eccentric contraction training (to improve the shock absorption phase, preventing early failures of the prosthesis); one-leg standing performance (to improve the support phase of the affected limb); adductor strength training (to aid in hip control during the swing phase); and peroneus strength training (to increase ankle joint stabilization). PMID:27134413

  19. Age-Related Changes in Strength, Joint Laxity, and Walking Patterns: Are They Related to Knee Osteoarthritis?

    PubMed Central

    Rudolph, Katherine S; Schmitt, Laura C; Lewek, Michael D

    2008-01-01

    Background and Purpose Aging is associated with musculoskeletal changes and altered walking patterns. These changes are common in people with knee osteoarthritis (OA) and may precipitate the development of OA. We examined age-related changes in musculoskeletal structures and walking patterns to better understand the relationship between aging and knee OA. Methods Forty-four individuals without OA (15 younger, 15 middle-aged, 14 older adults) and 15 individuals with medial knee OA participated. Knee laxity, quadriceps femoris muscle strength (force-generating capacity), and gait were assessed. Results Medial laxity was greater in the OA group, but there were no differences between the middle-aged and older control groups. Quadriceps femoris strength was less in the older control group and in the OA group. During the stance phase of walking, the OA group demonstrated less knee flexion and greater knee adduction, but there were no differences in knee motion among the control groups. During walking, the older control group exhibited greater quadriceps femoris muscle activity and the OA group used greater muscle co-contraction. Discussion and Conclusion Although weaker, the older control group did not use truncated motion or higher co-contraction. The maintenance of movement patterns that were similar to the subjects in the young control group may have helped to prevent development of knee OA. Further investigation is warranted regarding age-related musculoskeletal changes and their influence on the development of knee OA. PMID:17785376

  20. Changes in Fatigue, Multiplanar Knee Laxity, and Landing Biomechanics During Intermittent Exercise

    PubMed Central

    Shultz, Sandra J.; Schmitz, Randy J.; Cone, John R.; Henson, Robert A.; Montgomery, Melissa M.; Pye, Michele L.; Tritsch, Amanda J.

    2015-01-01

    Context: Knee laxity increases during exercise. However, no one, to our knowledge, has examined whether these increases contribute to higher-risk landing biomechanics during prolonged, fatiguing exercise. Objectives: To examine associations between changes in fatigue (measured as sprint time [SPTIME]), multiplanar knee laxity (anterior-posterior [APLAX], varus-valgus [VVLAX] knee laxity, and internal-external rotation [IERLAX]) knee laxity and landing biomechanics during prolonged, intermittent exercise. Design: Descriptive laboratory study. Setting: Laboratory and gymnasium. Patients or Other Participants: A total of 30 male (age = 20.3 ± 2.0 years, height = 1.79 ± 0.05 m, mass = 75.2 ± 7.2 kg) and 29 female (age = 20.5 ± 2.3 years, height = 1.67 ± 0.08 m, mass = 61.8 ± 9.0 kg) competitive athletes. Intervention(s): A 90-minute intermittent exercise protocol (IEP) designed to simulate the physiologic and biomechanical demands of a soccer match. Main Outcome Measure(s): We measured SPTIME, APLAX, and landing biomechanics before and after warm-up, every 15 minutes during the IEP, and every 15 minutes for 1 hour after the IEP. We measured VVLAX and IERLAX before and after the warm-up, at 45 and 90 minutes during the IEP, and at 30 minutes after the IEP. We used hierarchical linear modeling to examine associations between exercise-related changes in SPTIME and knee laxity with exercise-related changes in landing biomechanics while controlling for initial (before warm-up) knee laxity. Results: We found that SPTIME had a more global effect on landing biomechanics in women than in men, resulting in a more upright landing and a reduction in landing forces and out-of-plane motions about the knee. As APLAX increased with exercise, women increased their knee internal-rotation motion (P = .02), and men increased their hip-flexion motion and energy-absorption (P = .006) and knee-extensor loads (P = .04). As VVLAX and IERLAX increased, women went through greater knee

  1. Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load.

    PubMed

    Hartmann, Hagen; Wirth, Klaus; Klusemann, Markus

    2013-10-01

    It has been suggested that deep squats could cause an increased injury risk of the lumbar spine and the knee joints. Avoiding deep flexion has been recommended to minimize the magnitude of knee-joint forces. Unfortunately this suggestion has not taken the influence of the wrapping effect, functional adaptations and soft tissue contact between the back of thigh and calf into account. The aim of this literature review is to assess whether squats with less knee flexion (half/quarter squats) are safer on the musculoskeletal system than deep squats. A search of relevant scientific publications was conducted between March 2011 and January 2013 using PubMed. Over 164 articles were included in the review. There are no realistic estimations of knee-joint forces for knee-flexion angles beyond 50° in the deep squat. Based on biomechanical calculations and measurements of cadaver knee joints, the highest retropatellar compressive forces and stresses can be seen at 90°. With increasing flexion, the wrapping effect contributes to an enhanced load distribution and enhanced force transfer with lower retropatellar compressive forces. Additionally, with further flexion of the knee joint a cranial displacement of facet contact areas with continuous enlargement of the retropatellar articulating surface occurs. Both lead to lower retropatellar compressive stresses. Menisci and cartilage, ligaments and bones are susceptible to anabolic metabolic processes and functional structural adaptations in response to increased activity and mechanical influences. Concerns about degenerative changes of the tendofemoral complex and the apparent higher risk for chondromalacia, osteoarthritis, and osteochondritis in deep squats are unfounded. With the same load configuration as in the deep squat, half and quarter squat training with comparatively supra-maximal loads will favour degenerative changes in the knee joints and spinal joints in the long term. Provided that technique is learned accurately

  2. Effects of lumbar stabilization exercises on the flexion-relaxation phenomenon of the erector spinae.

    PubMed

    Park, San-Seong; Choi, Bo-Ram

    2016-06-01

    [Purpose] This study evaluated the differences in the flexion-relaxation phenomenon (FRP) of the right and left erector spinae muscles in asymptomatic subjects and the effect of lumbar stabilization exercises on these differences. [Subjects and Methods] Twenty-six participants (12 in the exercise group and 14 in the control group) with a difference in the FRP in the right and left erector spinae muscles were recruited from among healthy students attending Silla University. The exercise group performed two lumbar stabilization exercises (back bridge exercise and hand-knee exercise) for 4 weeks. The control group did not exercise. [Results] No significant group-by-exercise interaction was found. The right and left erector spinae muscles did show a difference in FRP between the control and exercise groups (119.2 ± 69.2 and 131.1 ± 85.2 ms, respectively). In addition, the exercise group showed a significant decrease in post-exercise (50.0 ± 27.0 ms) compared to pre-exercise (112.3 ± 41.5 ms) differences in the right and left FRP. [Conclusion] These results suggest that lumbar stabilization exercises may counter asymmetry of the FRP in the erector spinae muscles, possibly preventing low back pain in the general population. PMID:27390399

  3. Effects of lumbar stabilization exercises on the flexion-relaxation phenomenon of the erector spinae

    PubMed Central

    Park, San-seong; Choi, Bo-ram

    2016-01-01

    [Purpose] This study evaluated the differences in the flexion-relaxation phenomenon (FRP) of the right and left erector spinae muscles in asymptomatic subjects and the effect of lumbar stabilization exercises on these differences. [Subjects and Methods] Twenty-six participants (12 in the exercise group and 14 in the control group) with a difference in the FRP in the right and left erector spinae muscles were recruited from among healthy students attending Silla University. The exercise group performed two lumbar stabilization exercises (back bridge exercise and hand-knee exercise) for 4 weeks. The control group did not exercise. [Results] No significant group-by-exercise interaction was found. The right and left erector spinae muscles did show a difference in FRP between the control and exercise groups (119.2 ± 69.2 and 131.1 ± 85.2 ms, respectively). In addition, the exercise group showed a significant decrease in post-exercise (50.0 ± 27.0 ms) compared to pre-exercise (112.3 ± 41.5 ms) differences in the right and left FRP. [Conclusion] These results suggest that lumbar stabilization exercises may counter asymmetry of the FRP in the erector spinae muscles, possibly preventing low back pain in the general population. PMID:27390399

  4. Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome.

    PubMed

    Casabona, Antonino; Valle, Maria Stella; Pisasale, Mariangela; Pantò, Maria Rosita; Cioni, Matteo

    2012-12-01

    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

  5. 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

  6. 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. PMID:24941915

  7. Preventing Knee Injuries

    MedlinePlus

    ... to tearing. Growth Plate Injuries, Fractures, and Dislocations Knee fractures rarely occur in childhood sports, but with any ... is the bump on the front of the knee where the patellar tendon attaches. Fractures to the growth plate in this area often ...

  8. Outcomes of Varus Valgus Constrained Versus Rotating-Hinge Implants in Total Knee Arthroplasty.

    PubMed

    Malcolm, Tennison L; Bederman, S Samuel; Schwarzkopf, Ran

    2016-01-01

    The stability of a total knee arthroplasty is determined by the ability of the prosthesis components in concert with supportive bone and soft tissue structures to sufficiently resist deforming forces transmitted across the knee joint. Constrained prostheses are used in unstable knees due to their ability to resist varus and valgus transformative forces across the knee. Constraint requires inherent rigidity, which can facilitate early implant failure. The purpose of this study was to describe the comparative indications for surgery and postoperative outcomes of varus valgus constrained knee (VVK) and rotating-hinge knee (RHK) total knee arthroplasty prostheses. Seven retrospective observational studies describing 544 VVK and 254 RHK patients with an average follow-up of 66 months (range, 7-197 months) were evaluated. Patients in both groups experienced similar failure rates (P=.74), ranges of motion (P=.81), and Knee Society function scores (P=.29). Average Knee Society knee scores were 4.2 points higher in VVK patients compared with RHK patients, indicating minimal mid-term clinical differences may exist (P<.0001). Absent collateral ligament support is an almost universal indication for RHK implantation vs VVK. Constrained device implantation is routinely guided by inherent stability of the knee, and, when performed, similar postoperative outcomes can be achieved with VVK and RHK prostheses. PMID:26730689

  9. Sex Differences in Proximal Control of the Knee Joint

    PubMed Central

    Mendiguchia, Jurdan; Ford, Kevin R.; Quatman, Carmen E.; Alentorn-Geli, Eduard; Hewett, Timothy E.

    2014-01-01

    Following the onset of maturation, female athletes have a significantly higher risk for anterior cruciate ligament (ACL) injury compared with male athletes. While multiple sex differences in lower-extremity neuromuscular control and biomechanics have been identified as potential risk factors for ACL injury in females, the majority of these studies have focused specifically on the knee joint. However, increasing evidence in the literature indicates that lumbopelvic (core) control may have a large effect on knee-joint control and injury risk. This review examines the published evidence on the contributions of the trunk and hip to knee-joint control. Specifically, the sex differences in potential proximal controllers of the knee as risk factors for ACL injury are identified and discussed. Sex differences in trunk and hip biomechanics have been identified in all planes of motion (sagittal, coronal and transverse). Essentially, female athletes show greater lateral trunk displacement, altered trunk and hip flexion angles, greater ranges of trunk motion, and increased hip adduction and internal rotation during sport manoeuvres, compared with their male counterparts. These differences may increase the risk of ACL injury among female athletes. Prevention programmes targeted towards trunk and hip neuromuscular control may decrease the risk for ACL injuries. PMID:21688868

  10. [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. PMID:26486536

  11. Bicompartmental knee arthroplasty

    PubMed Central

    Giachino, Matteo; Risitano, Salvatore; Atzori, Francesco

    2016-01-01

    Total knee arthroplasty (TKA) is the most worldwide practiced surgery for knee osteoarthritis and its efficacy is mightily described by literature. Concerns about the invasiveness of TKA let the introduction of segmental resurfacing of the joint for younger patients with localized osteoarthritis. Bone stock sparing and ligaments preservation are the essence of both unicompartmental knee arthroplasty (UKA) and bicompartmental knee arthroplasty (BKA). Advantages related to BKA are the respect of knee biomechanics, lower complications rates, shorter hospital stay, faster rehabilitation. Moreover, in case of failure of the first implant the conversion to TKA is undemanding and can be compared to a standard prosthesis. Our experience suggest that BKA is a reliable technique in selected cases and especially younger people with higher functional requests can favourably profit from it. Although those results are encouraging, we still need further prospective, randomized, long-term studies to finally assess BKA indications and outcomes. PMID:26855941

  12. Bicompartmental knee arthroplasty.

    PubMed

    Sabatini, Luigi; Giachino, Matteo; Risitano, Salvatore; Atzori, Francesco

    2016-01-01

    Total knee arthroplasty (TKA) is the most worldwide practiced surgery for knee osteoarthritis and its efficacy is mightily described by literature. Concerns about the invasiveness of TKA let the introduction of segmental resurfacing of the joint for younger patients with localized osteoarthritis. Bone stock sparing and ligaments preservation are the essence of both unicompartmental knee arthroplasty (UKA) and bicompartmental knee arthroplasty (BKA). Advantages related to BKA are the respect of knee biomechanics, lower complications rates, shorter hospital stay, faster rehabilitation. Moreover, in case of failure of the first implant the conversion to TKA is undemanding and can be compared to a standard prosthesis. Our experience suggest that BKA is a reliable technique in selected cases and especially younger people with higher functional requests can favourably profit from it. Although those results are encouraging, we still need further prospective, randomized, long-term studies to finally assess BKA indications and outcomes. PMID:26855941

  13. Antiinflammatory effect of peripheral nerve blocks after knee surgery: clinical and biologic evaluation

    PubMed Central

    Martin, Frédéric; Martinez, Valéria; Mazoit, Jean Xavier; Bouhassira, Didier; Cherif, Kamel; Gentili, Marc Edouard; Piriou, Philippe; Chauvin, Marcel; Fletcher, Dominique

    2008-01-01

    Background Nerve blocks provide analgesia after surgery. We tested whether they have anti-inflammatory effects. Methods Patient had combined sciatic (single shot) and continuous femoral block (48 hours) (block group) or morphine patient-controlled analgesia (PCA group) after total knee arthroplasty. Pain at rest and upon movement was monitored at one (D1), four (D4) and seven days (D7) and one (M1) and three months (M3) after surgery. Knee inflammation was evaluated (skin temperature, knee circumference) before surgery and at D1, D4, D7, M1 and M3. Plasma cytokine concentrations (IL6, IL1β, TNF, IL10, sTNF-R1) were measured before surgery, then at four hours, D1, D4 and D7 after surgery. Capsule and synovial membrane cytokines were measured (IL6, TNF, IL1, IL10). Knee flexion was evaluated before surgery and at D1, D4, D7, M1 and M3. We monitored morphine use and recovery time to autonomy. Results Pain at rest and upon movement was lower in the block group than in PCA patients between D1 and D7 (Anova; P<0.005). Knee flexion was improved in the block group for D1 to M1 (Anova; p<0.0001). Block group patients recovered non-assisted mobilization (t test; p=0.04) and toilet use (t test; p=0.03) more rapidly. Knee circumference and skin temperature were lower in the block group between D1 and D7 (Anova; p<0.05). Synovial membrane IL1 (p<0.05) and IL10 (p<0.01) increased and plasma IL6 and sTNF-R1 peaked at 24 hours, with no difference between groups. Conclusion Nerve blocks inhibited clinical inflammation after total knee arthroplasty with no change in tissue and plasma cytokine concentrations. PMID:18719447

  14. Surgical Anatomy of the Knee A Review of Common Open Approaches.

    PubMed

    Manning, Blaine T; Frank, Rachel M; Wetters, Nathan G; Bach, Bernard R; Rosenberg, Aaron G; Levine, Brett R

    2016-09-01

    Knee-related complaints are among the most commonly encountered conditions by orthopaedic surgeons. Knee pathology varies widely and includes arthritis, deformities, fractures, infections, neuromuscular disorders, oncologic diseases, and soft-tissue injury. While nonoperative treatment modalities (activity modification, medications, injections, and physical therapy) are typically used as primary interventions, surgical treatment may ultimately become necessary. The purpose of this review is to discuss the most common open approaches to the knee, with an emphasis on surgically relevant anatomy for each approach. Understanding of the anatomy of the knee joint and associated neurovascular structures is necessary in order to avoid intraoperative complications and optimize postoperative recovery. PMID:27620546

  15. Medical restraints to anterior-posterior motion of the knee.

    PubMed

    Sullivan, D; Levy, I M; Sheskier, S; Torzilli, P A; Warren, R F

    1984-07-01

    We investigated the motion of cadaver knees before and after section of the medial structures and anterior cruciate ligament. The knees were tested using a 5-degrees-of-freedom in vitro knee-testing apparatus that measured anterior-posterior, medial-lateral, and axial displacement as well as internal-external and valgus-varus rotation. The flexion angle could be varied but was fixed for each individual test. A 125-newton anterior-posterior force was applied perpendicular to the tibial shaft and the resulting motion of the knee was measured. In five knees the anterior cruciate ligament was cut first, followed by progressive cuts of the structures on the medial side (superficial medial collateral ligament, deep medial ligament, oblique fibers of the superficial medial ligament, and the posteromedial part of the capsule). Conversely, in five knees the medial structures were progressively cut first, followed by section of the anterior cruciate ligament. Tests were performed after each cut. With an intact anterior cruciate ligament, progressive cutting of the medial side had no effect on anterior and posterior displacements. When section of the medial structures followed cutting of the anterior cruciate ligament, anterior displacement exceeded that seen after isolated section of the anterior cruciate ligament. The anterior and posterior load-tests were repeated with the tibia fixed in 5 degrees of internal and 5 degrees of external rotation. Fixed external rotation had no effect on anterior and posterior displacements. Fixed internal rotation significantly decreased anterior displacement only when both the anterior cruciate ligament and the medial structures were cut.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6736094

  16. Midterm survivorship and clinical outcome of INDUS knee prosthesis: 5 year followup study

    PubMed Central

    Sancheti, Kantilal H; Sancheti, Parag K; Joshi, Rajeev S; Patil, Kailash R; Shyam, Ashok K; Bhaskar, Raja R

    2016-01-01

    Background: INDUS knee implant has been designed as per the anatomical morphology of the Indian population and has shown good clinical outcome in short term studies. The purpose of the present study was to report the midterm survivorship and clinical outcome of this implant. Materials and Methods: Two hundred and twenty three primary total knee arthroplasties in 209 consecutive patients using the INDUS knee prosthesis were prospectively enrolled. There were 145 females (155 knees) and 64 males (68 knees) with a mean age of 69.95 years (range 42–86 years). Annual followup with clinical and radiological examination was conducted, and a survivorship analysis was done using the Kaplan–Meier analysis. Results: Mean followup was 5.8 years (range 5–6.5 years). Eleven patients died while eight were lost to followup and a total of 204 knees were available for followup. The mean knee flexion improved from preoperative 110.4° ± 11.24° (range 60°–130°) to 128.17° ± 8.32° (range 100°–140°) at the final followup. The mean knee score improved from 40.1 ± 10.7 to 90.3 ± 5.34 while the function score improved from 44.35 ± 12.9 to 89.58 ± 7.43. Two patient developed infection and required revision. The Kaplan–Meier analysis reported a survivorship of 98.6% (confidence interval 95.7–99.6%) at the end for 5 years for INDUS knee prosthesis. Conclusion: INDUS knee prosthesis has excellent survivorship with a good clinical outcome and low failure rate. PMID:27053801

  17. Treating Osteoarthritis of the Knee

    MedlinePlus

    ... osteotomy may need knee replacement surgery in the future. Arthroplasty is also called joint or knee replacement therapy. A surgeon removes the part of the knee damaged by osteoarthritis and replaces it with an artificial joint made from metals and plastic. All or part of the knee joint may ...

  18. Current surgical strategies for total arthroplasty in valgus knee

    PubMed Central

    Nikolopoulos, Dimitrios; Michos, Ioannis; Safos, George; Safos, Petros

    2015-01-01

    The majority of orthopaedic surgeons even currently agree that primary total arthroplasty in valgus knees with a deformity of more than ten degrees may prove challenging. The unique sets of bone and soft tissue abnormalities that must be addressed at the time of the operation make accurate axis restoration, component orientation and joint stability attainment a difficult task. Understanding the specific pathologic anatomic changes associated with the valgus knee is a prerequisite so as to select the proper surgical method, to optimize component position and restore soft-tissue balance. The purpose of this article is to review the valgus knee anatomical variations, to assess the best pre-operative planning and to evaluate how to choose the grade of constraint of the implant. It will also be underlying the up-to-date main approaches and surgical techniques be proposed in the English literature both for bone cuts and soft tissue management of valgus knees. PMID:26191494

  19. Knee osteoarthritis image registration: data from the Osteoarthritis Initiative

    NASA Astrophysics Data System (ADS)

    Galván-Tejada, Jorge I.; Celaya-Padilla, José M.; Treviño, Victor; Tamez-Peña, José G.

    2015-03-01

    Knee osteoarthritis is a very common disease, in early stages, changes in joint structures are shown, some of the most common symptoms are; formation of osteophytes, cartilage degradation and joint space reduction, among others. Based on a joint space reduction measurement, Kellgren-Lawrence grading scale, is a very extensive used tool to asses radiological OA knee x-ray images, based on information obtained from these assessments, the objective of this work is to correlate the Kellgren-Lawrence score to the bilateral asymmetry between knees. Using public data from the Osteoarthritis initiative (OAI), a set of images with different Kellgren-Lawrencescores were used to determine a relationship of Kellgren-Lawrence score and the bilateral asymmetry, in order to measure the asymmetry between the knees, the right knee was registered to match the left knee, then a series of similarity metrics, mutual information, correlation, and mean squared error where computed to correlate the deformation (mismatch) of the knees to the Kellgren-Lawrence score. Radiological information was evaluated and scored by OAI radiologist groups. The results of the study suggest an association between Radiological Kellgren-Lawrence score and image registration metrics, mutual information and correlation is higher in the early stages, and mean squared error is higher in advanced stages. This association can be helpful to develop a computer aided grading tool.

  20. Impact response and biomechanical analysis of the knee-thigh-hip complex in frontal impacts with a full human body finite element model.

    PubMed

    Ruan, Jesse S; El-Jawahri, Raed; Barbat, Saeed; Rouhana, Stephen W; Prasad, Priya

    2008-11-01

    Changes in vehicle safety design technology and the increasing use of seat-belts and airbag restraint systems have gradually changed the relative proportion of lower extremity injuries. These changes in real world injuries have renewed interest and the need of further investigation into occupant injury mechanisms and biomechanical impact responses of the knee-thigh-hip complex during frontal impacts. This study uses a detailed finite element model of the human body to simulate occupant knee impacts experienced in frontal crashes. The human body model includes detailed anatomical features of the head, neck, shoulder, chest, thoracic and lumbar spine, abdomen, pelvis, and lower and upper extremities. The material properties used in the model for each anatomic part of the human body were obtained from test data reported in the literature. The human body model used in the current study has been previously validated in frontal and side impacts. It was further validated with cadaver knee-thigh-hip impact tests in the current study. The effects of impactor configuration and flexion angle of the knee on biomechanical impact responses of the knee-thigh-hip complex were studied using the validated human body finite element model. This study showed that the knee flexion angle and the impact direction and shape of the impactors affected the injury outcomes of the knee-thigh-hip complex significantly. The 60 degrees flexed knee impact showed the least impact force, knee pressure, femoral von Mises stress, and pelvic von Mises stress but largest relative displacements of the Posterior Cruciate Ligament (PCL) and Anterior Cruciate Ligament (ACL). The 90 degrees flexed knee impact resulted in a higher impact force, knee pressure, femoral von Mises stress, and pelvic von Mises stress; but smaller PCL and ACL displacements. Stress distributions of the patella, femur, and pelvis were also given for all the simulated conditions. PMID:19085174

  1. Management of flexion distraction injuries to the thoracolumbar spine.

    PubMed

    Lopez, Alejandro J; Scheer, Justin K; Smith, Zachary A; Dahdaleh, Nader S

    2015-12-01

    We present an updated overview of the literature regarding the management of flexion distraction injuries (FDI). FDI are unstable fractures of the thoracolumbar spine, which require surgical management by long segment open fusion or minimally invasive posterior fixation with pedicle screws. While associated with concomitant intra-abdominal injuries that may delay operative stabilization, FDI frequently involve reversible spinal cord injuries and rapid correction is indicated. Modern biomechanical studies have identified valuable prognostic indicators that may be elucidated from determining the mechanism of injury, including the degree of flexion and presence of compression at the time of injury. An improved understanding of FDI will contribute to more appropriate diagnoses and treatment of these fractures. PMID:26209922

  2. Comparative Effects of Periarticular Multimodal Drug Injection and Single-Shot Femoral Nerve Block on Pain Following Total Knee Arthroplasty and Factors Influencing Their Effectiveness

    PubMed Central

    Nakagawa, Shuji; Inoue, Hiroaki; Kan, Hiroyuki; Hino, Manabu; Ichimaru, Shohei; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Amaya, Fumimasa; Sawa, Teiji; Kubo, Toshikazu

    2016-01-01

    Purpose This study compared the analgesic effects of local infiltration analgesia (LIA) and femoral nerve block (FNB) after total knee arthroplasty (TKA) and assessed factors associated with analgesia obtained by these two methods. Materials and Methods Study subjects included 66 patients (72 knees) who underwent TKA for osteoarthritis of the knee. Pain visual analogue scale (VAS), the amount of analgesics used, number of days to achieve 90° of flexion of the knee joint, date of initiating parallel-bar walking, range of motion of the knee joint at discharge, and adverse events were investigated. Results The VAS scores did not differ significantly between two groups, whereas the amount of analgesics used was significantly lower in the LIA group. Preoperative flexion contracture was significantly more severe in the LIA group with high VAS compared with low VAS. No serious adverse event occurred in the LIA or FNB group. Conclusions The lower analgesic usage in the LIA group than the FNB group indicates that the analgesic effect of LIA was greater than that of singleshot FNB after TKA. There were no serious complications in either group. The postoperative analgesic effect of LIA was smaller in patients with severe than less severe preoperative flexion contracture. PMID:27595078

  3. Differences in Anatomy and Kinematics in Asian and Caucasian TKA Patients: Influence on Implant Positioning and Subsequent Loading Conditions in Mobile Bearing Knees

    PubMed Central

    Kim, Tae Kyun; Miehlke, Rolf K.; Grupp, Thomas M.

    2014-01-01

    The objective of our study was to determine the mechanical stress conditions under tibiofemoral loading with an overlay of knee kinematics in deep flexion on two different mobile bearing designs in comparison to in vivo failure modes. This study investigates the seldom but severe complication of fatigue failure of polyethylene components at mobile bearing total knee arthroplasty designs. Assuming a combination of a floor-based lifestyle and tibial malrotation as a possible reason for a higher failure rate in Asian countries we developed a simplified finite element model considering a tibiofemoral roll-back angle of 22° and the range of rotational motion of a clinically established floating platform design (e.motion FP) at a knee flexion angle of 120° in order to compare our results to failure modes found in retrieved implants. Compared to the failure mode observed in the clinical retrievals the locations of the occurring stress maxima as well as the tensile stress distribution show analogies. From our observations, we conclude that the newly introduced finite element model with an overlay of deep knee flexion (lateral roll-back) and considerable internally rotated tibia implant positioning is an appropriate analysis for knee design optimizations and a suitable method to predict clinical failure modes. PMID:25538943

  4. Differences in anatomy and kinematics in Asian and Caucasian TKA patients: influence on implant positioning and subsequent loading conditions in mobile bearing knees.

    PubMed

    Maas, Allan; Kim, Tae Kyun; Miehlke, Rolf K; Hagen, Thomas; Grupp, Thomas M

    2014-01-01

    The objective of our study was to determine the mechanical stress conditions under tibiofemoral loading with an overlay of knee kinematics in deep flexion on two different mobile bearing designs in comparison to in vivo failure modes. This study investigates the seldom but severe complication of fatigue failure of polyethylene components at mobile bearing total knee arthroplasty designs. Assuming a combination of a floor-based lifestyle and tibial malrotation as a possible reason for a higher failure rate in Asian countries we developed a simplified finite element model considering a tibiofemoral roll-back angle of 22° and the range of rotational motion of a clinically established floating platform design (e.motion FP) at a knee flexion angle of 120° in order to compare our results to failure modes found in retrieved implants. Compared to the failure mode observed in the clinical retrievals the locations of the occurring stress maxima as well as the tensile stress distribution show analogies. From our observations, we conclude that the newly introduced finite element model with an overlay of deep knee flexion (lateral roll-back) and considerable internally rotated tibia implant positioning is an appropriate analysis for knee design optimizations and a suitable method to predict clinical failure modes. PMID:25538943

  5. Lumbopelvic flexibility modulates neuromuscular responses during trunk flexion-extension.

    PubMed

    Sánchez-Zuriaga, Daniel; Artacho-Pérez, Carla; Biviá-Roig, Gemma

    2016-06-01

    Various stimuli such as the flexibility of lumbopelvic structures influence the neuromuscular responses of the trunk musculature, leading to different load sharing strategies and reflex muscle responses from the afferents of lumbopelvic mechanoreceptors. This link between flexibility and neuromuscular response has been poorly studied. The aim of this study was to investigate the relationship between lumbopelvic flexibility and neuromuscular responses of the erector spinae, hamstring and abdominal muscles during trunk flexion-extension. Lumbopelvic movement patterns were measured in 29 healthy women, who were separated into two groups according to their flexibility during trunk flexion-extension. The electromyographic responses of erector spinae, rectus abdominis and biceps femoris were also recorded. Subjects with greater lumbar flexibility had significantly less pelvic flexibility and vice versa. Subjects with greater pelvic flexibility had a higher rate of relaxation and lower levels of hamstring activation during maximal trunk flexion. The neuromuscular response patterns of the hamstrings seem partially modulated by pelvic flexibility. Not so with the lumbar erector spinae and lumbar flexibility, despite the assertions of some previous studies. The results of this study improve our knowledge of the relationships between trunk joint flexibility and neuromuscular responses, a relationship which may play a role in low back pain. PMID:27155332

  6. Differential impact of visual feedback on plantar- and dorsi-flexion maximal torque output.

    PubMed

    Toumi, Anis; Jakobi, Jennifer M; Simoneau-Buessinger, Emilie

    2016-05-01

    The effect of visual feedback on enhancing isometric maximal voluntary contractions (MVC) was evaluated. Twelve adults performed plantar-flexion and dorsi-flexion MVCs in 3 conditions (no visual feedback, visual feedback, and visual feedback with target). There was no significant effect of visual conditions on dorsi-flexion MVC but there was an effect on plantar-flexion. Irrespective of whether a target was evident, visual feedback increased plantar-flexion MVC by ∼15%. This study highlights the importance of optimal feedback to enhance MVC. PMID:27031663

  7. Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Czaplicki, Adam; Jarocka, Marta; Walawski, Jacek

    2015-01-01

    The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age. PMID:26646385

  8. Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction.

    PubMed

    Czaplicki, Adam; Jarocka, Marta; Walawski, Jacek

    2015-01-01

    The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age. PMID:26646385

  9. Advanced concepts in knee arthrodesis

    PubMed Central

    Wood, Jennifer H; Conway, Janet D

    2015-01-01

    The aim is to describe advanced strategies that can be used to diagnose and treat complications after knee arthrodesis and to describe temporary knee arthrodesis to treat infected knee arthroplasty. Potential difficult complications include nonunited knee arthrodesis, limb length discrepancy after knee arthrodesis, and united but infected knee arthrodesis. If a nonunited knee arthrodesis shows evidence of implant loosening or failure, then bone grafting the nonunion site as well as exchange intramedullary nailing and/or supplemental plate fixation are recommended. If symptomatic limb length discrepancy cannot be satisfactorily treated with a shoe lift, then the patient should undergo tibial lengthening over nail with a monolateral fixator or exchange nailing with a femoral internal lengthening device. If a united knee arthrodesis is infected, the nail must be removed. Then the surgeon has the option of replacing it with a long, antibiotic cement-coated nail. The authors also describe temporary knee arthrodesis for infected knee arthroplasty in patients who have the potential to undergo insertion of a new implant. The procedure has two goals: eradication of infection and stabilization of the knee. A temporary knee fusion can be accomplished by inserting both an antibiotic cement-coated knee fusion nail and a static antibiotic cement-coated spacer. These advanced techniques can be helpful when treating difficult complications after knee arthrodesis and treating cases of infected knee arthroplasty. PMID:25793160

  10. A Chick Embryo in-Vitro Model of Knee Morphogenesis

    PubMed Central

    Rodriguez, Edward K.; Munasinghe, Jeeva

    2016-01-01

    Background: In this feasibility study, a mechanically loaded in-vitro tissue culture model of joint morphogenesis using the isolated lower extremity of the 8 day old chick embryo was developed to assess the effects of mechanical loading on joint morphogenesis. Methods: The developed in-vitro system allows controlled flexion and extension of the chick embryonic knee with a range of motion of 20 degrees from a resting position of 90-100 degrees of flexion. Joint morphogenesis at 2, 3, 4 and 7 days of culture was assessed by histology and micro MRI in 4 specimen types: undisturbed in-ovo control embryos, in-ovo paralyzed embryos, in-vitro unloaded limb cultures, and in-vitro loaded limb cultures. Relative glycosaminoglycan (GAG) concentration across the joint was assessed with an MRI technique referred to as dGEMRIC (delayed gadolinium enhanced MRI of cartilage) where T1 is proportional to glycosaminoglycan concentration. Results: Average T1 over the entire tissue image for the normal control (IC) knee was 480 msec; for the 4 day loaded specimen average T1 was 354 msec; and for the 7 day loaded specimens T1 was 393 msec. The 4 day unloaded specimen had an average T1 of 279 msec while the 7 day unloaded specimen had an average T1 of 224 msec. The higher T1 values in loaded than unloaded specimens suggest that more glycosaminoglycan is produced in the loaded culture than in the unloaded preparation. Conclusion: Isolated limb tissue cultures under flexion-extension load can be viable and exhibit more progression of joint differentiation and glycosaminoglycan production than similarly cultured but unloaded specimens. However, when compared with controls consisting of intact undisturbed embryos in-ovo, the isolated loaded limbs in culture do not demonstrate equivalent amounts of absolute growth or joint differentiation. PMID:27200386

  11. Multi-Axis Prosthetic Knee Resembles Alpine Skiing Movements of an Intact Leg

    PubMed Central

    Demšar, Ivan; Duhovnik, Jože; Lešnik, Blaž; Supej, Matej

    2015-01-01

    The purpose of the study was to analyse the flexion angles of the ski boot, ankle and knee joints of an above-knee prosthesis and to compare them with an intact leg and a control group of skiers. One subject with an above-knee amputation of the right leg and eight healthy subjects simulated the movement of a skiing turn by performing two-leg squats in laboratory conditions. By adding additional loads in proportion to body weight (BW; +1/3 BW, +2/3 BW, +3/3 BW), various skiing regimes were simulated. Change of Flexion Angle (CoFA) and Range of Motion (RoM) in the ski boot, ankle and knee joints were calculated and compared. An average RoM in the skiing boot on the side of prosthesis (4.4 ± 1.1°) was significantly lower compared to an intact leg (5.9 ± 1.8°) and the control group (6.5 ± 2.3°). In the ankle joint, the average RoM was determined to be 13.2±2.9° in the prosthesis, 12.7 ± 2.8° in an intact leg and 14.8±3.6 in the control group. However, the RoM of the knee joint in the prosthesis (42.2 ± 4.2°) was significantly larger than that of the intact leg (34.7 ± 4.4°). The average RoM of the knee joint in the control group was 47.8 ± 5.4°. The influences of additional loads on the kinematics of the lower extremities were different on the side of the prosthesis and on the intact leg. In contrast, additional loads did not produce any significant differences in the control group. Although different CoFAs in the ski boot, ankle and knee joints were used, an above-knee prosthesis with a built-in multi-axis prosthetic knee enables comparable leg kinematics in simulated alpine skiing. Key points The RoM in the ski boot on the side of the prosthetic leg was smaller than the RoM of the intact leg and the control group of healthy subjects. The RoM in the ankle joint of prosthetic leg was comparable to that of the intact leg and the control group of healthy subjects. The RoM in the prosthetic knee joint was greater than the RoM in the knee joint of the

  12. Factors to consider in identifying critical points in lumbar spine flexion relaxation.

    PubMed

    Zwambag, Derek P; Brown, Stephen H M

    2015-12-01

    Flexion relaxation (FR), a myoelectric silence of extensor muscles near end range of lumbar flexion, is commonly reported as the lumbar flexion angle at the instant the extensor muscles become silent. However, lumbar flexion angle alone is insufficient to characterize mechanisms that modulate FR. As FR requires the moment generated by passive lumbar extensor tissues to equilibrate the moment due to gravity, the inter-relationships between lumbar moment, flexion angle, and myoelectrical silence will provide added information in the understanding of FR. The purpose of this study was to examine the relationship between lumbar moment and flexion angle throughout various flexion manoeuvres. It was hypothesized that lumbar moment and flexion angle would not be linearly related and would be affected by lower limb position, range of motion, and the addition of mass to the torso. Eleven participants performed four different lumbar flexion trials. Results showed that lumbar flexion was correlated with the lumbar moment (r = 0.92); however an analysis of residuals found that these measures were not linearly related. The moment was, however, correlated (r = 0.99) and linearly related to the sine of trunk inclination (T12 rigid body with respect to global horizontal). Future studies of FR could use trunk inclination as a simple kinematic measure to predict relative changes in lumbar moment with flexion. PMID:26559463

  13. The in vivo assessment of tibial motion in the transverse plane in anterior cruciate ligament-reconstructed knees.

    PubMed

    Nordt, W E; Lotfi, P; Plotkin, E; Williamson, B

    1999-01-01

    Twenty-one knees with acutely injured anterior cruciate ligaments were reconstructed with patellar tendon autografts. Eight of the knees had concomitant medial ligament injuries that were not addressed surgically. Follow-up evaluation (average, 25 months) included computed tomography measurements to analyze transverse-plane laxity in both translation and rotation. These measurements were performed with the patient's leg in a load cell device that stabilizes the distal femur and applies known anterior translational force to the proximal tibia at approximately 20 degrees of flexion. A torque apparatus was used to apply internal and external rotational torque to the leg. Images of the tibial plateau in neutral, internal, and external rotation were performed, with and without an anterior translational force. Both knees of each patient were tested and categorized as group I (anterior cruciate ligament-reconstructed) or group II (uninjured). Translation as measured by computed tomography averaged 1 mm side-to-side difference. Internal rotation averaged 8.7 degrees in group I knees and 10.8 degrees in group II knees. External rotation averaged 9.1 degrees in group I knees and 7.4 degrees in group II knees. The eight knees with concomitant medial ligament injuries were analyzed separately; external rotation without anterior load in group I was 9.5 degrees, compared with 5 degrees in group II. This difference was significant (P < 0.01). PMID:10496578

  14. LATERAL PAIN IN AN ATHLETE'S KNEE: A RARE CASE OF DISLOCATION OF THE FEMORAL BICEPS TENDON

    PubMed Central

    Duarte, Aires; Severino, Nilson; da Silva, Ana Paula Simões; de Lima, Marcos Vaz; Resende, Vanessa Ribeiro; Kertzman, Paulo F.

    2015-01-01

    Dislocation of the femoral biceps tendon is rare and is described clinically in the literature as a lateral pain in the knee. It was initially reported as an anomalous insertion of the long head of the femoral biceps. Subsequently, it was found to be caused by abnormal mobility of the tendon over the prominence of the fibular head at certain angles of knee flexion. The objective of the present report was to describe and discuss a condition of lateral knee pain in a swimmer who started to present subluxation of the femoral biceps during sports practice, which incapacitated him from taking part in trials and competitions. The case is discussed in the light of the literature surveyed; the likelihood that the etiology for the trauma leading to this condition was repetition; and the surgical treatment instituted, which led to excellent results and the patient's return to his habitual sports practice. PMID:27047902

  15. Knee MRI scan

    MedlinePlus

    ... magnetic resonance imaging) scan uses energy from strong magnets to create pictures of the knee joint and ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  16. Anterior knee pain

    MedlinePlus

    ... places extra stress on the kneecap (such as running, jumping or twisting, skiing, or playing soccer). You ... noticeable with: Deep knee bends Going down stairs Running downhill Standing up after sitting for awhile

  17. Total Knee Replacement

    MedlinePlus

    ... as anti- inflammatory medications, cortisone injections, lubricating injections, physical therapy, or other surgeries A knee that has become ... your function. Other treatment options — including medications, injections, physical therapy, or other types of surgery — will also be ...

  18. Tourniquetless Total Knee Arthroplasty

    MedlinePlus Videos and Cool Tools

    Tourniquetless Total Knee Arthroplasty You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and Legal Notice © 2010 OR- ...

  19. Knee arthroscopy - discharge

    MedlinePlus

    ... is cartilage that cushions the space between the bones in the knee. Surgery is done to repair or remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Inflamed or damaged lining of the joint. This ...

  20. Knee arthroscopy - discharge

    MedlinePlus

    ... knee arthroscopy). You may have been checked for: Torn meniscus. Meniscus is cartilage that cushions the space ... Surgery is done to repair or remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior ...

  1. Taking care of your new knee joint

    MedlinePlus

    Knee arthroplasty - precautions; Knee replacement - precautions ... After you have knee replacement surgery , you will need to be careful about how you move your knee, especially for the first few months after ...

  2. Baseline ambulatory knee kinematics are associated with changes in cartilage thickness in osteoarthritic patients over 5 years.

    PubMed

    Favre, Julien; Erhart-Hledik, Jennifer C; Chehab, Eric F; Andriacchi, Thomas P

    2016-06-14

    Although kinematic alterations during walking have been reported with knee osteoarthritis (OA), there is a paucity of longitudinal data, therefore limiting our understanding of the role of kinematics in OA development. This study tested the hypothesis that less knee extension angle and less posterior displacement of the femur relative to the tibia during the heel-strike portion of the gait cycle are associated with greater loss of medial cartilage thickness during a follow-up period of five years. This study also tested for associations between flexion-extension angle and anterior-posterior displacement during other periods of the gait cycle and 5-year cartilage thinning. 16 subjects with moderate medial knee OA were tested with gait analysis and MRI at baseline and had a follow-up MRI after 5 years. Linear regressions were used to assess the relationship between changes in cartilage thickness and baseline kinematics using Pearson correlation coefficients. Multivariate regressions were also performed to adjust for gender, baseline age, BMI, walking speed, Kellgren/Lawrence grade, and baseline knee pain score. As hypothesized, baseline knee flexion angle and femoral displacement during heel-strike and other gait cycle periods were significantly associated with medial femoral and tibial cartilage thinning at the 5 year follow-up; these associations were strengthened after adjustment for covariates. This study provided new insight into the pathogenesis of knee OA where baseline knee kinematics were associated with longitudinal disease progression. These results could serve as a basis for developing newer gait modification interventions to reduce the risk for developing knee OA. PMID:27178021

  3. Reading Knee-Deep

    ERIC Educational Resources Information Center

    Jewett, Pamela

    2007-01-01

    Freire told his audience at a seminar at the University of Massachusetts, "You need to read knee-deep in texts, for deeper than surface meanings, and you need to know the words to be able to do it" (quoted in Cleary, 2003). In a children's literature class, fifteen teachers and I traveled along a path that moved us toward reading knee-deep as we…

  4. Dashboard (in the) knee.

    PubMed

    Patel, M S; Qureshi, A A; Green, T P

    2015-03-01

    We present the case of a 19-year-old individual presenting to an orthopaedic outpatient clinic several months following a dashboard knee injury during a road traffic accident with intermittent mechanical symptoms. Despite unremarkable examination findings and normal magnetic resonance imaging, the patient was identified subsequently as having an intra-articular plastic foreign body consistent with a piece of dashboard on arthroscopic knee assessment, the retrieval of which resulted in a complete resolution of symptoms. PMID:25723676

  5. Effects of two different knee tape procedures on lower-limb kinematics and kinetics in recreational runners.

    PubMed

    Howe, A; Campbell, A; Ng, L; Hall, T; Hopper, D

    2015-08-01

    The purpose of this study was to compare the effects of Mulligan's tape (MT) and kinesio tape (KT) with no tape (NT) on hip and knee kinematics and kinetics during running. Twenty-nine female recreational runners performed a series of 'run-throughs' along a 10-m runway under the three taping conditions. Two force plates and a 14-camera Vicon motion analysis system (Oxford Metrics, Inc., Oxford, UK) captured kinematic and kinetic data for each dependent variable from ground contact to toe off. Comparisons of each dependent variable under three taping conditions were assessed through Statistical Package for the Social Sciences (SPSS; SPSS, Inc., Chicago, Illinois, USA; P-value < 0.01) using repeated measure analyses of variance. For each dependent variable with a P-value < 0.01, repeated measures with pairwise comparisons and Bonferroni adjustment were conducted to compare the three taping conditions. MT induced a significant reduction in anterior and posterior hip forces, knee flexion angular velocity, knee extensor moments, and hip flexion and extension moments compared with NT and KT (P = 0.001). There was no difference in hip or knee, kinematics or kinetics, between KT and NT (P = 1.000). MT appears to influence hip and knee biomechanics during running in an asymptomatic sample, whereas KT appeared to be biomechanically not different from NT. PMID:24989992

  6. The effect of co-stabilizer muscle activation on knee joint position sense: a single group pre-post test

    PubMed Central

    Nam, Yeongyo; Lee, Ho Jun; Choi, Myongryol; Chung, Sangmi; Park, Junhyung; Yu, Jaeho

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effect of co-stabilizer muscle activation on knee joint position sense. [Subjects and Methods] This study was a pre-post, single-blinded randomly controlled trial (angle sequence randomly selected) design. Seven healthy adults with no orthopaedic or neurological problems participated in this study. Knee joint position sense was measured by a target matching test at target angles of 30°, 45° and 80° of knee flexion a using digital inclinometer under two conditions: erect sitting, which is known to highly activate co-stabilizer muscle and slump sitting, which is known to little activate the co-stabilizer muscle. [Results] A significant difference in joint position matching error at the knee flexion angle of 45° was founded between two conditions erect sitting: (3.83 ± 1.47) and slump sitting: (1.00 ± 0.63). There were no significant differences in joint position matching error at the other target angles. [Conclusion] Knee joint position sense at 45° is likely to be affected by activation of co-stabilizer muscle, and this value is suitable for facilitation of joint position sense with skilled movement. PMID:27512279

  7. Torque variations during repeated passive isokinetic movements of the knee in subjects with Parkinson's disease and healthy control subjects.

    PubMed

    Nuyens; De Weerdt W; Dom; Nieuwboer; Spaepen

    2000-04-01

    The purpose of this study was to quantify response variations during isokinetic passive movements of the knee in subjects with Parkinson's disease. Parkinsonian patients demonstrated a greater decrease of resistive torque compared to healthy control subjects, particularly in tests at higher velocities and during knee flexion movements. Responses were influenced by electromyographic activity in stretched and shortened muscle groups and also by mechanical factors. The results indicate that repetition of movements needs to be taken into account when measuring hypertonia in parkinsonian subjects. PMID:10699389

  8. 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

  9. Kinematics of the human knee using an open chain cadaver model.

    PubMed

    Blaha, J David; Mancinelli, Corrie A; Simons, William H; Kish, Vincent L; Thyagarajan, Ganesh

    2003-05-01

    There continues to be controversy about the kinematics of the human knee. This study used seven knees from cadavers moved by pulling on the quadriceps tendon in an open chain fashion using video motion analysis to determine the instantaneous helical axis of movement. Computed tomography scans of the specimens allowed the axes to be related to condyles. The parameter beta was defined by the relationship of the helical axis to the center of the condyle (pure spinning motion) and the contact point of the condyle on the tibia (pure rolling motion). Axes above the center of the condyle represent countertranslation, those between the center and the contact point combined spinning and rolling, and those below represent concordant translation. If the motion of the knee is guided by the crossed four-bar link then this model, that allows the knee to 'seek its own path' throughout the range of motion, should show the rollback that commonly is thought to be an important feature of knee motion. The results of this study show that the medial side of the knee stays stable in spinning kinematics whereas the lateral side has a rolling motion in full flexion progressing to a spinning motion in midflexion and counter-translation near full extension. The kinematics that would be expected from rollback were not observed. PMID:12771814

  10. 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. PMID:26644651

  11. Persons with reconstructed ACL exhibit altered knee mechanics during high-speed maneuvers.

    PubMed

    Lee, S-P; Chow, J W; Tillman, M D

    2014-06-01

    Anterior cruciate ligament (ACL) injury is a sports trauma that causes long-term disability. The function of the knee during dynamic activities can be severely limited even after successful surgical reconstruction. This study examined the effects of approach velocity during side-step cutting on knee joint mechanics in persons with reconstructed ACL (ACLR). 22 participants (11 with unilateral ACLR, 11 matched-controls) participated. Knee joint mechanics were tested in 3 approach conditions: counter-movement, one-step, and running. Dependent variables, including peak knee flexion, extension, valgus, varus, internal rotation, external rotation angles and corresponding peak joint moments, were assessed during the stance phase of cutting. Two 2×3 ("group" by "approach condition") mixed MANOVA tests were used to examine the effects of ACLR and approach velocity on knee mechanics. ACLR participants exhibited higher knee internal rotator moment (0.22 vs. 0.13 Nm/kg, p=0.003). Inter-group comparisons revealed that the ACLR participants exhibited significantly higher abductor and internal rotator moments only in the running condition (1.86 vs. 1.16 Nm/kg, p=0.018; 0.28 vs. 0.17 Nm/kg, p=0.010, respectively). Our findings suggested that patients with ACLR may be at increased risk of re-injury when participating in high-demand physical activities. Task demand should be considered when prescribing progressive therapeutic interventions to ACLR patients. PMID:24408765

  12. Ambulatory estimation of knee-joint kinematics in anatomical coordinate system using accelerometers and magnetometers.

    PubMed

    Kun, Liu; Inoue, Yoshio; Shibata, Kyoko; Enguo, Cao

    2011-02-01

    Knee-joint kinematics analysis using an optimal sensor set and a reliable algorithm would be useful in the gait analysis. An original approach for ambulatory estimation of knee-joint angles in anatomical coordinate system is presented, which is composed of a physical-sensor-difference-based algorithm and virtual-sensor-difference-based algorithm. To test the approach, a wearable monitoring system composed of accelerometers and magnetometers was developed and evaluated on lower limb. The flexion/extension (f/e), abduction/adduction (a/a), and inversion/extension (i/e) rotation angles of the knee joint in the anatomical joint coordinate system were estimated. In this method, since there is no integration of angular acceleration or angular velocity, the result is not distorted by offset and drift. The three knee-joint angles within the anatomical coordinate system are independent of the orders, which must be considered when Euler angles are used. Besides, since there are no physical sensors implanted in the knee joint based on the virtual-sensor-difference-based algorithm, it is feasible to analyze knee-joint kinematics with less numbers and types of sensors than those mentioned in some others methods. Compared with results from the reference system, the developed wearable sensor system is available to do gait analysis with fewer sensors and high degree of accuracy. PMID:21257363

  13. 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

  14. Physical deformity as sequela of chronic catatonia and response to electroconvulsive therapy: a case report.

    PubMed

    Devi, Sugnyani; Behere, Rishikesh V; Varambally, Shivarama; Rao, Naren P; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

    2011-09-01

    Chronic catatonia with posturing can cause joint contractures leading to greater morbidity associated with the physical deformity. We report a case of a young man with chronic catatonic schizophrenia with posturing of bilateral upper limbs in flexion leading to fixed flexion contracture of left metacarpophalangeal joints. Initiation of electroconvulsive therapy along with physical rehabilitation measures helped him regain full range of motion in the right upper limb. The fixed flexion contracture, however, remained resistant to intensive treatment efforts. Early interventions in the form of electroconvulsive therapy and physical rehabilitation can be useful in reversing such potentially disabling complications. PMID:21865951

  15. Right-Left Differences in Knee Extension Stiffness for the Normal Rat Knee: In Vitro Measurements Using a New Testing Apparatus.

    PubMed

    Markolf, Keith L; Evseenko, Denis; Petrigliano, Frank

    2016-04-01

    Knee stiffness following joint injury or immobilization is a common clinical problem, and the rat has been used as a model for studies related to joint stiffness and limitation of motion. Knee stiffness measurements have been reported for the anesthetized rat, but it is difficult to separate the contributions of muscular and ligamentous restraints to the recorded values. in vitro testing of isolated rat knees devoid of musculature allows measurement of joint structural properties alone. In order to measure the effects of therapeutic or surgical interventions designed to alter joint stiffness, the opposite extremity is often used as a control. However, right-left stiffness differences for the normal rat knee have not been reported in the literature. If stiffness changes observed for a treatment group are within the normal right-left variation, validity of the results could be questioned. The objectives of this study were to utilize a new testing apparatus to measure right-left stiffness differences during knee extension in a population of normal rat knees and to document repeatability of the stiffness measurements on successive testing days. Moment versus rotation curves were recorded for 15 right-left pairs of normal rat knees on three consecutive days, with overnight specimen storage in a refrigerator. Each knee was subjected to ten loading-unloading cycles, with the last loading curve used for analysis. Angular rotation (AR), defined here as the change in flexion-extension angle from a specified applied joint moment, is commonly used as a measure of overall joint stiffness. For these tests, ARs were measured from the recorded test curves with a maximum applied extension moment of 100 g cm. Mean rotations for testing days 2 and 3 were 0.81-1.25 deg lower (p < 0.001) than for day 1, but were not significantly different from each other. For each testing day, mean rotations for right knees were 1.12-1.30 deg greater (p < 0.001) than left knees. These right

  16. Prolonged Epidural Infusion Improves Functional Outcomes Following Knee Arthroscopy in Patients with Arthrofibrosis after Total Knee Arthroplasty: A Retrospective Evaluation.

    PubMed

    Saltzman, Bryan M; Dave, Ankur; Young, Adam; Ahuja, Mukesh; Amin, Sandeep D; Bush-Joseph, Charles A

    2016-01-01

    A total of 20 consecutive patients with knee stiffness post total knee arthroplasty (TKA) underwent arthroscopic lysis of adhesions and manipulation plus indwelling epidural were evaluated retrospectively. Epidural catheters were placed preoperatively for an intended 6 weeks of postoperative analgesia to facilitate intensive physical therapy. The mean loss of knee extension immediately before incision was 13.5 ± 9.1 degrees (range, 0-35 degrees) and flexion was 77.65 ± 19.2 degrees (range, 45-125 degrees). At the 6-week and final (mean, 0.47 years) follow-up, the loss of extension was 1.5 ± 5.1 degrees (range, -10 to +7 degrees) and 5.4 ± 4.7 degrees (range, 0-15 degrees), respectively, and flexion was 99.7 ± 12.3 degrees (range, 75-120 degrees) and 98.5 ± 16.1 degrees (range, 75-130 degrees), respectively. Of the 20 patients, 2 missed their 6-week clinic visit. Improvements in motion immediately preoperative to 6-week and final follow-up were each significant (p < 0.01). At examination 6 weeks postoperatively, 94.4% of patients met the definition for clinical motion success and 70% maintained success at final follow-up. Visual analog scale improved significantly from 5.4 to 2.0 (p < 0.01) at 6 weeks postoperative in the 12 patients with this data recorded. On the basis of this data, use of tunneled epidurals with arthroscopic lysis of adhesions for arthrofibrosis after TKA is correlated with a high likelihood of functional success postoperatively as measured by range of motion improvement. PMID:25300008

  17. Modern perceptions and expectations regarding total knee arthroplasty.

    PubMed

    Meneghini, Robert Michael; Russo, Glenn S; Lieberman, Jay R

    2014-04-01

    It is established that patients and surgeons share different perceptions regarding total knee replacement (TKA). This study's objective was to determine patient perceptions regarding TKA as well as the influence of the various information sources in shaping these perceptions. All patients presenting with knee pain for evaluation of TKA were offered a questionnaire. Multivariate statistical analysis correlated response and demographic variables. Approximately 81% of patients felt the main reason for TKA was to alleviate pain, whereas only 19% felt return to sports-related activities was the main reason. Approximately 37% of patients felt TKAs should last for 20 years or more, which was strongly correlated with TV, newspaper, or Internet exposure (p ≤ 0.01). Approximately 38% of respondents had heard of partial knee replacement, whereas relatively few had received information regarding patient-specific, gender-specific, mobile-bearing, or high-flexion TKA designs. Men were likelier than women to get their information from friends, family, or another patient (p = 0.04). Although most respondents perceived pain relief as the primary goal, patients getting information from the media are likelier to expect TKA to last longer than 20 years. This suggests direct-to-patient marketing with such claims as 30-year durability may influence patient perceptions regarding TKA. PMID:23775544

  18. Midflexion instability in primary total knee replacement: a review

    PubMed Central

    Ramappa, Manjunath

    2015-01-01

    Introduction: Midflexion instability in primary total knee replacement (TKR) is an evolving concept. Successful treatment of instability requires an understanding of the different types of instability. Methods: A literature review was performed to identify information pertinent to midflexion instability in primary total knee replacement, utilising PRISMA guidelines. Databases searched included Embase, Medline, All of the Cochrane Library, PubMed and cross references. Results: Three factors, i.e., elevated joint line, multiradii femoral component and medial collateral ligament (MCL) laxity, were identified to influence midflexion instability. Literature suggested mediolateral instability at 30–60° of flexion as diagnostic of midflexion instability. Literature search also revealed paucity in clinical studies analysing midflexion instability. Most of the evidence was obtained from cadaveric studies for elevated joint line and MCL laxity. Clinical studies on multiradii femoral component were limited by their small study size and early followup period. Conclusion: Elevated joint line, multiradii femoral component and MCL laxity have been suggested to cause midflexion laxity in primary TKR. Due to limitations in available evidence, this review was unable to raise the strength of overall evidence. Future well-designed clinical studies are essential to make definitive conclusions. This review serves as a baseline for future researchers and creates awareness for routine assessment of midflexion instability in primary total knee replacement. PMID:27163080

  19. Differentiating between types and levels of isokinetic knee musculature efforts.

    PubMed

    Almosnino, Sivan; Stevenson, Joan M; Day, Andrew G; Bardana, Davide D; Diaconescu, Elena D; Dvir, Zeevi

    2011-12-01

    This investigation assessed whether a measure of moment curve shape similarity, and a measure quantifying curve magnitude differences, enables differentiation between types (sincere vs. feigned) and levels (maximal vs. submaximal) of effort exerted during isokinetic testing of the knee. Healthy participants (n=37) performed four sets of six concentric knee extension-flexion repetitions on two occasions. The sets consisted of: (1) maximal effort; (2) self-perceived 75% of maximal effort; (3) self-perceived 50% of maximal effort; and (4) a set attempting to feign injury. Average cross-correlation and percent root mean square difference values were computed between moment curves in each direction. Logistic regression was used to derive decision rules for differentiating between maximal and submaximal effort levels; and between sincere and feigned effort types. Using a cutoff criteria corresponding to 100% specificity, maximal effort production could be ascertained with 96% sensitivity within the sample. Feigned efforts, however, could be ascertained with only 31% sensitivity due to overlap with sincere submaximal effort. Using the proposed models, clinicians may be able to ascertain whether maximal efforts were produced during isokinetic knee musculature testing. Additionally, evidence regarding participant's intentions with regard to influencing test results may be gauged, although to a lesser extent. PMID:21925901

  20. Comparison of strain-gage and fiber-optic goniometry for measuring knee kinematics during activities of daily living and exercise.

    PubMed

    Mohamed, Abeer A; Baba, Jennifer; Beyea, James; Landry, John; Sexton, Andrew; McGibbon, Chris A

    2012-08-01

    There is increasing interest in wearable sensor technology as a tool for rehabilitation applications in community or home environments. Recent studies have focused on evaluating inertial based sensing (accelerometers, gyroscopes, etc.) that provide only indirect measures of joint motion. Measurement of joint kinematics using flexible goniometry is more direct, and still popular in laboratory environments, but has received little attention as a potential tool for wearable systems. The aim of this study was to compare two goniometric devices: a traditional strain-gauge flexible goniometer, and a fiberoptic flexible goniometer, for measuring dynamic knee flexion/extension angles during activity of daily living: chair rise, and gait; and exercise: deep knee bends, against joint angles computed from a "gold standard" Vicon motion tracking system. Six young adults were recruited to perform the above activities in the lab while wearing a goniometer on each knee, and reflective markers for motion tracking. Kinematic data were collected simultaneously from the goniometers (one on each leg) and the motion tracking system (both legs). The results indicate that both goniometers were within 2-5 degrees of the Vicon angles for gait and chair rise. For some deep knee bend trials, disagreement with Vicon angles exceeded ten degrees for both devices. We conclude that both goniometers can record ADL knee movement faithfully and accurately, but should be carefully considered when high (>120 deg) knee flexion angles are required. PMID:22938362

  1. Proprioception in the ACL-ruptured knee: the contribution of the medial collateral ligament and patellar ligament. An in vivo experimental study in the cat.

    PubMed

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

    2007-01-01

    In the absence of anterior cruciate ligament (ACL), secondary restraints such as menisci, ligaments, and tendons restrict anterior knee laxity. Strain detection at these sites could define the contribution of this alternative signalling system to knee proprioception after ACL injury. The hypothesis in this study questions if measurements of anterior tibial translation (ATT) from surface strain gauges on the insertions of the medial collateral ligament (MCL) and the patellar tendon (PT) are sufficiently sensitive and specific to differentiate normal, stable knees from acutely unstable knees due to ACL section. Twelve cats received miniaturized strain gauges on the surface of MCL and PT distal insertions. A purpose-made receiver transformed into measurements any voltage variation obtained during passive knee flexion-extension and anterior tibial translation manoeuvres. Variables under evaluation included first peak latency, normalized amplitude, and slope of voltage along time. Femorotibial displacements were video recorded, digitized, and used as the ATT reference. The proposed system detected significant changes in the slope of the voltage/time signal, with higher specificity and sensitivity during ATT after experimental ACL section. Changes were not significant during flexion or extension. It was found that a pattern of earlier and more intense strain in MCL and PT distal insertions was found during ATT in the ACL deficient knee. Enhanced pattern recognition learning from these structures could be a future target for proprioceptive training after ACL injury. PMID:17070686

  2. Women with knee osteoarthritis have more pain and poorer function than men, but similar physical activity prior to total knee replacement

    PubMed Central

    2011-01-01

    Background Osteoarthritis of the knee is a major clinical problem affecting a greater proportion of women than men. Women generally report higher pain intensity at rest and greater perceived functional deficits than men. Women also perform worse than men on function measures such as the 6-minute walk and timed up and go tests. Differences in pain sensitivity, pain during function, psychosocial variables, and physical activity levels are unclear. Further the ability of various biopsychosocial variables to explain physical activity, function and pain is unknown. Methods This study examined differences in pain, pain sensitivity, function, psychosocial variables, and physical activity between women and men with knee osteoarthritis (N = 208) immediately prior to total knee arthroplasty. We assessed: (1) pain using self-report measures and a numerical rating scale at rest and during functional tasks, (2) pain sensitivity using quantitative sensory measures, (3) function with self-report measures and specific function tasks (timed walk, maximal active flexion and extension), (4) psychosocial measures (depression, anxiety, catastrophizing, and social support), and (5) physical activity using accelerometry. The ability of these mixed variables to explain physical activity, function and pain was assessed using regression analysis. Results Our findings showed significant differences on pain intensity, pain sensitivity, and function tasks, but not on psychosocial measures or physical activity. Women had significantly worse pain and more impaired function than men. Their levels of depression, anxiety, pain catastrophizing, social support, and physical activity, however, did not differ significantly. Factors explaining differences in (1) pain during movement (during gait speed test) were pain at rest, knee extension, state anxiety, and pressure pain threshold; (2) function (gait speed test) were sex, age, knee extension, knee flexion opioid medications, pain duration, pain

  3. The behavior of reinforced concrete knee joints under earthquake loads

    NASA Astrophysics Data System (ADS)

    Angelakos, Bill

    The poor performance of knee joint connections during recent earthquakes motivated a number of experimental investigations of knee joint behavior under reversed cyclic loading. In this work the knee joint design problem is studied through a collective evaluation of the available experimental results and analytical modeling. The objective is to identify the critical response variables controlling the mechanics of knee joints under earthquake loads and to quantify the influence they have on the strength and deformation capacity of the joint. A knee joint model is derived from simple mechanical constructs of equilibrium and compatibility. The parametric dependence of knee joint behavior is investigated for critical design parameters such as concrete strength, amounts and yield strengths of horizontal and vertical transverse reinforcement, and bond demand. Three different limiting equations are developed from the model limiting the joint shear resistance according with the three alternative modes of joint shear failure. These are: (i) yielding of horizontal and vertical transverse reinforcement, (ii) and (iii) yielding in either of the two principal reinforcing directions accompanied by crushing of the concrete in compression (here the softening influence of orthogonal tensile deformations is considered). For those test specimens from the experimental database that experienced a joint shear failure, the simple knee joint model predicts their joint shear capacity well. Consistent with observations from interior connections it is shown that anchorage of the main reinforcement in the knee joint region prevails as the determining factor of the response of the joint panel. In addition, the same basic physical model that describes the source of resistance in interior connections also applies to knee joints; truss action, and diagonal strut action. By favorably anchoring the beam and column bars it is possible to develop the joint shear strength which is associated with one

  4. Facilitating Cervical Flexion Using a Feldenkrais Method: Awareness through Movement.

    PubMed

    Ruth, S; Kegerreis, S

    1992-01-01

    Feldenkrais methods appear to be gaining popularity and utilization by physical therapists. The need for scientific justification of their usage is indicated. The purpose of this study was to quantify the results of a Feldenkrais method-Awareness Through Movement-involving a neck flexion task. The study examined 30 normal subjects to determine if a Feldenkrais Awareness Through Movement sequence would result in an increase in neck flexion range of motion and if the subjects would indicate a significantly lower level of perceived effort posttest. Measurements of range of motion were taken using a gravity-based cervical range of motion goniometer. The subjects recorded their perceived efforts on a visual analogue scale. The range of motion data were analyzed using a one-way ANOVA. The visual analogue scale data were analyzed with a Mann-Whitney U test. The data supported both hypotheses. Based on these findings, further investigation of Feldenkrais methods in the treatment of patients appears warranted. J Orthop Sports Phys Ther 1992;16(1):25-29. PMID:18796776

  5. Muscle recruitment variations during wrist flexion exercise: MR evaluation

    NASA Technical Reports Server (NTRS)

    Fleckenstein, J. L.; Watumull, D.; Bertocci, L. A.; Nurenberg, P.; Peshock, R. M.; Payne, J. A.; Haller, R. G.; Blomqvist, C. G. (Principal Investigator)

    1994-01-01

    OBJECTIVE: Many exercise protocols used in physiological studies assume homogeneous and diffuse muscle recruitment. To test this assumption during a "standard" wrist flexion protocol, variations in muscle recruitment were assessed using MRI in eight healthy subjects. MATERIALS AND METHODS: Variations were assessed by comparing the right to the left forearms and the effect of slight (15 degrees) pronation or supination at the wrist. RESULTS: Postexercise imaging showed focal regions of increased signal intensity (SI), indicating relatively strong recruitment, most often in entire muscles, although occasionally only in subvolumes of muscles. In 15 of 26 studies, flexor carpi radialis (FCR) showed more SI than flexor carpi ulnaris, while in 11 studies SI in these muscles increased equivalently. Relatively greater FCR recruitment was seen during pronation and/or use of the nondominant side. Palmaris longus, a wrist flexor, did not appear recruited in 4 of 11 forearms in which it was present. A portion of the superficial finger flexor became hyperintense in 89% of studies, while recruitment of the deep finger flexor was seen only in 43%. CONCLUSION: Inter- and intraindividual variations in forearm muscle recruitment should be anticipated in physiological studies of standard wrist flexion exercise protocols.

  6. Kinematic and Electromyographic Analysis of Elbow Flexion During Inertial Exercise

    PubMed Central

    Tracy, James E.; Obuchi, Shuchi; Johnson, Ben

    1995-01-01

    Inertial exercise protocols are currently used clinically to improve and restore normal muscle function even though research to substantiate their effectiveness cannot be cited in the literature. The purpose of this study was to compare simultaneous kinematic and electromyographic (EMG) data obtained from 12 subjects during elbow flexion on the Impulse Inertial Exercise System. Testing sessions consisted of inertial exercise performed using phasic and tonic techniques with loads of: a) 0 kg, b) 2.27 kg, c) 4.54 kg, d) 6.80 kg, e) 9.07 kg. Greater peak angular velocities, peak platform accelerations (change in velocity of platform during elbow flexion), mean and peak triceps brachii muscle EMG activity, and less range of motion were observed during phasic exercise. There was also a general trend for peak angular velocities and peak platform acceleration to increase as the load decreased. No significant difference in mean or peak EMG activity of the biceps brachii muscle was seen between techniques. Clinicians and athletic trainers using inertial exercise should consider both the exercise technique and load characteristics when designing protocols to meet the specific needs of patients. Imagesp255-a PMID:16558345

  7. Decoding flexion of individual fingers using electrocorticographic signals in humans

    NASA Astrophysics Data System (ADS)

    Kubánek, J.; Miller, K. J.; Ojemann, J. G.; Wolpaw, J. R.; Schalk, G.

    2009-12-01

    Brain signals can provide the basis for a non-muscular communication and control system, a brain-computer interface (BCI), for people with motor disabilities. A common approach to creating BCI devices is to decode kinematic parameters of movements using signals recorded by intracortical microelectrodes. Recent studies have shown that kinematic parameters of hand movements can also be accurately decoded from signals recorded by electrodes placed on the surface of the brain (electrocorticography (ECoG)). In the present study, we extend these results by demonstrating that it is also possible to decode the time course of the flexion of individual fingers using ECoG signals in humans, and by showing that these flexion time courses are highly specific to the moving finger. These results provide additional support for the hypothesis that ECoG could be the basis for powerful clinically practical BCI systems, and also indicate that ECoG is useful for studying cortical dynamics related to motor function.

  8. Principal component modeling of isokinetic moment curves for discriminating between the injured and healthy knees of unilateral ACL deficient patients.

    PubMed

    Almosnino, Sivan; Brandon, Scott C E; Day, Andrew G; Stevenson, Joan M; Dvir, Zeevi; Bardana, Davide D

    2014-02-01

    Bilateral knee strength evaluations of unilateral anterior cruciate ligament (ACL) deficient patients using isokinetic dynamometry are commonly performed in rehabilitation settings. The most frequently-used outcome measure is the peak moment value attained by the knee extensor and flexor muscle groups. However, other strength curve features may also be of clinical interest and utility. The purpose of this investigation was to identify, using Principal Component Analysis (PCA), strength curve features that explain the majority of variation between the injured and uninjured knee, and to assess the capabilities of these features to detect the presence of injury. A mixed gender cohort of 43 unilateral ACL deficient patients performed 6 continuous concentric knee extension and flexion repetitions bilaterally at 60°s(-1) and 180°s(-1) within a 90° range of motion. Moment waveforms were analyzed using PCA, and binary logistic regression was used to develop a discriminatory decision rule. For all directions and speeds, a statistically significant overall reduction in strength was noted for the involved knee in comparison to the uninvolved knee. The discriminatory decision rule yielded a specificity and sensitivity of 60.5% and 60.5%, respectively, corresponding to an accuracy of ∼62%. As such, the curve features extracted using PCA enabled only limited clinical usefulness in discerning between the ACL deficient and contra lateral, healthy knee. Improvement in discrimination capabilities may perhaps be achieved by consideration of different testing speeds and contraction modes, as well as utilization of other data analysis techniques. PMID:24280243

  9. Combined magnetic resonance imaging approach for the assessment of in vivo knee joint kinematics under full weight-bearing conditions.

    PubMed

    Al Hares, Ghaith; Eschweiler, Jörg; Radermacher, Klaus

    2015-06-01

    The development of detailed and specific knowledge on the biomechanical behavior of loaded knee structures has received increased attention in recent years. Stress magnetic resonance imaging techniques have been introduced in previous work to study knee kinematics under load conditions. Previous studies captured the knee movement either in atypical loading supine positions, or in upright positions with help of inclined supporting backrests being insufficient for movement capture under full-body weight-bearing conditions. In this work, we used a combined magnetic resonance imaging approach for measurement and assessment in knee kinematics under full-body weight-bearing in single legged stance. The proposed method is based on registration of high-resolution static magnetic resonance imaging data acquired in supine position with low-resolution data, quasi-static upright-magnetic resonance imaging data acquired in loaded positions for different degrees of knee flexion. The proposed method was applied for the measurement of tibiofemoral kinematics in 10 healthy volunteers. The combined magnetic resonance imaging approach allows the non-invasive measurement of knee kinematics in single legged stance and under physiological loading conditions. We believe that this method can provide enhanced understanding of the loaded knee kinematics. PMID:25979443

  10. Patellofemoral contact patterns before and after total knee arthroplasty: an in vitro measurement

    PubMed Central

    2013-01-01

    Background Patellofemoral complications are one of the main problems after Total Knee Arthroplasty (TKA). Retropatellar pressure distribution after TKA can contribute to these symptoms. Therefore we evaluated retropatellar pressure distribution subdivided on the ridge, medial and lateral surface on non-resurfaced patella before and after TKA. Additionally, we analyzed axial femorotibial rotation and quadriceps load before and after TKA. Methods Seven fresh frozen cadaver knees were tested in a force controlled knee rig before and after TKA (Aesculap, Tuttlingen, Germany, Columbus CR) while isokinetic flexing the knee from 20° to 120° under weight bearing. Ridge, medial and lateral retropatellar surface were defined and pressure distribution was dynamically measured while quadriceps muscles and hamstring forces were applied. Aside axial femorotibial rotation and quadriceps load was recorded. Results There was a significant change of patella pressure distribution before and after TKA (p = 0.004). In physiological knees pressure distribution on medial and lateral retropatellar surface was similar. After TKA the ridge of the patella was especially in higher flexion grades strongly loaded (6.09 +/−1.31 MPa) compared to the natural knee (2.92 +/−1.15 MPa, p < 0.0001). Axial femorotibial rotation showed typical internal rotation with increasing flexion both before and after TKA, but postoperatively it was significantly lower. The average amount of axial rotation was 3.5° before and after TKA 1.3° (p = 0.001). Mean quadriceps loading after implantation of knee prosthesis did not change significantly (575 N ±60 N in natural knee and after TKA 607 N ±96 N; p = 0.28). Conclusions The increased retropatellar pressure especially on the ridge may be one important reason for anterior knee pain after TKA. The trochlea of the femoral component might highly influence the pressure distribution of the non-resurfaced retropatellar surface. Additionally

  11. Total knee arthroplasty in valgus knees using minimally invasive medial-subvastus approach

    PubMed Central

    Shah, Nilen Amulak; Jain, Nimesh Prakash

    2016-01-01

    Background: An ideal approach for valgus knees must provide adequate exposure with minimal complications due to approach per se. Median parapatellar approach is most commonly used approach in TKA including valgus knees. A medial subvastus approach is seldom used for valgus knees and has definite advantages of maintaining extensor mechanism integrity and minimal effect on patellar tracking. The present study was conducted to evaluate outcomes of total knee arthroplasty (TKA) and efficacy of subvastus approach in valgus knees in terms of early functional recovery, limb alignment and complications. Materials and Methods: We retrospectively reviewed 112 knees with valgus deformity between January 2006 and December 2011. All patients were assessed postoperatively for pain using Visual Analog Scale (VAS) and quadriceps recovery in form of time to active straight leg raising (SLR) and staircase competency and clinical outcomes using American Knee Society (AKS) score and radiographic evaluation with average followup of 40 months (range 24–84 months). Results: The mean VAS on postoperative day (POD) 1 and POD2 at rest was 2.73 and 2.39, respectively and after mobilization was 3.28 and 3.08, respectively (P < 0.001). The quadriceps recovery was very early and 92 (86.7%) patients were able to do active SLR by POD1 with mean time of 21.98 h while reciprocal gait and staircase competency was possible at 43.05 h. The AKS and function score showed significant improvement from preoperative mean score of 39 and 36 to 91 and 79 (P < 0.001), respectively, and the mean range of motion increased from 102° preoperatively to 119° at recent followup (P < 0.001). The mean tibiofemoral valgus was corrected from preoperative 16° (range 10°–35°) to 5° (range 3°–9°) valgus (P < 0.001). Conclusions: Mini-subvastus quadriceps approach provides adequate exposure and excellent early recovery for TKA in valgus knees, without increase in incidence of complications. PMID:26955174

  12. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces.

    PubMed

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F; Fregly, Benjamin J; Delp, Scott L; Banks, Scott A; Pandy, Marcus G; D'Lima, Darryl D; Lloyd, David G

    2013-11-15

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

  13. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces

    PubMed Central

    Gerus, Pauline; Sartori, Massimo; Besier, Thor F.; Fregly, Benjamin J.; Delp, Scott L.; Banks, Scott A.; Pandy, Marcus G.; D’Lima, Darryl D.; Lloyd, David G.

    2013-01-01

    Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

  14. Intra-articular hyaluronic acid and corticosteroids in the treatment of knee osteoarthritis: A meta-analysis

    PubMed Central

    WANG, FANG; HE, XIJING

    2015-01-01

    The aim of the present study was to evaluate the therapeutic effect of intra-articular hyaluronic acid (HA) in comparison to corticosteroids (CS) for knee osteoarthritis (OA). The data sources included PubMed, EMBASE, The Cochrane Central Register of Controlled Trials and hand searched reviews. Randomized controlled trials that reported the effects of intra-articular HA and CS in the treatment of knee OA were selected based on specific inclusion criteria. A meta-analysis was performed for the visual analog scale (VAS), Lequesne index, Knee Society Clinical Rating System (KSS), maximum flexion and adverse events of knee OA. Sensitivity analysis was also conducted to avoid bias. The seven eligible trials included 583 participants and the majority of the trials were of high quality. After one month, the mean difference in the VAS was 1.66 [95% confidence interval (CI); −0.90, 4.23), indicating equal efficacy for HA and CS. However, after three months, the mean difference was −12.58 (95% CI; −17.76, −7.40), while after six months, the difference was −9.01 (95% CI; −12.62, −5.40), favoring HA. For the additional indicators, including the Lequesne index, the KSS, maximum flexion and adverse events, no statistically significant differences were observed between the two treatment approaches for knee OA. Therefore, the results of the meta-analysis highlight a therapeutic trajectory for intra-articular HA in knee OA pain, as compared with CS, over six months post-intervention. After one month, the two approaches exhibited equal efficacy; however, in the long term, HA was found to have an enhanced effect. No statistically significant difference was observed in the adverse events caused by the two interventions. Further investigation and understanding into the trend observed in the present study may aid clinicians in the treatment of knee OA. PMID:25574222

  15. Effects of Lumbosacral Manipulation on Isokinetic Strength of the Knee Extensors and Flexors in Healthy Subjects: A Randomized, Controlled, Single-Blind Crossover Trial

    PubMed Central

    Sanders, Grant D.; Nitz, Arthur J.; Abel, Mark G.; Symons, T. Brock; Shapiro, Robert; Black, W. Scott; Yates, James W.

    2015-01-01

    Objective The purpose of this study was to investigate the effect of manual manipulations targeting the lumbar spine and/or sacroiliac joint on concentric knee extension and flexion forces. Torque production was measured during isometric and isokinetic contractions. Methods This was a randomized, controlled, single-blind crossover design with 21 asymptomatic, college-aged subjects who had never received spinal manipulation. During 2 separate sessions, subjects’ peak torques were recorded while performing maximal voluntary contractions on an isokinetic dynamometer. Isometric knee extension and flexion were recorded at 60° of knee flexion, in addition to isokinetic measurements obtained at 60°/s and 180°/s. Baseline measurements were acquired before either treatment form of lumbosacral manipulation or sham manipulation, followed by identical peak torque measurements within 5 and 20 minutes posttreatment. Data were analyzed with a repeated measures analysis of variance. Results A statistically significant difference did not occur between the effects of lumbosacral manipulation or the sham manipulation in the percentage changes of knee extension and flexion peak torques at 5 and 20 minutes posttreatment. Similar, nonsignificant results were observed in the overall percentage changes of isometric contractions (spinal manipulation 4.0 ± 9.5 vs sham 1.2 ± 6.3, P = .067), isokinetic contractions at 60°/s (spinal manipulation − 4.0 ± 14.2 vs sham − 0.3 ± 8.2, P = .34), and isokinetic contractions at 180°/s (spinal manipulation − 1.4 ± 13.9 vs sham − 5.5 ± 20.0, P = .18). Conclusion The results of the current study suggest that spinal manipulation does not yield an immediate strength-enhancing effect about the knee in healthy, college-aged subjects when measured with isokinetic dynamometry. PMID:26793035

  16. 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. PMID:21474701

  17. Comparison of Two-dimensional Measurement Techniques for Predicting Knee Angle and Moment during a Drop Vertical Jump

    PubMed Central

    Mizner, Ryan L.; Chmielewski, Terese L.; Toepke, John J.; Tofte, Kari B.

    2011-01-01

    Objective To determine the association of two dimensional (2D) video-based techniques and three-dimensional (3D) motion analysis to assess potential knee injury risk factors during jump landing. Design Observational study Setting Research Laboratory Participants Thirty-six female athletes in cutting and pivoting sports. Assessment Athletes performed a drop vertical jump during which movement was recorded with a motion analysis system and a digital video camera positioned in the frontal plane. Main Outcome Measures The 2D variables were the frontal plane projection angle (FPPA), the angle formed between thigh and leg, and the knee:ankle separation ratio, the distance between knee joints divided by the distance between ankles. The 3D variables were knee abduction angle and external abduction moment. All variables were assessed at peak knee flexion. Linear regression assessed the relationship between the 2D and 3D variables. In addition, intraclass correlation coefficients determined rater reliability for the 2D variables and compared the 2D measurements made from digital video to the same measurements from the motion analysis. Results The knee:ankle separation ratio accounted for a higher variance of 3D knee abduction angle (r2 =0.350) and knee abduction moment (r2=0.394) when compared to the FPPA (r2=0.145, 0.254). The digital video measures had favorable rater reliability (ICC:0.89–0.94) and were comparable to the motion analysis system (ICC≥0.92). Conclusion When compared to the FPPA, the knee:ankle separation ratio had better association with previously cited knee injury risk factors in female athletes. The 2D measures have adequate consistency and validity to merit further clinical consideration in jump landing assessments. PMID:22544058

  18. [Biomechanics of the knee joint].

    PubMed

    Witzel, U

    1993-01-01

    The capsular and ligamentous structures as control system of a healthy knee-joint supported by the muscular system are responsible for the rolling and gliding motion of the femoral condyles on the tibial plateau. Both the condyles and the tibial plateau have individually developed but to each other adjusted shapes and fine structures thereby. These structures consist of hyaline cartilage at their three-dimensional surfaces and of closely packed fibrils (lamina splendens) as the final gliding zone for tensile load. The orientation of the collagenous fibres can be made visible by split lines. The chondral surfaces are indirectly in contact to each other and orthogonally stressed at the particular point of contact. The indirect contact of the cartilaginous surfaces happens under interposition of the menisci. The meniscus serves to reduce and equalize the surface pressure by its own projected surface on the one hand and by maintaining of a hydraulic pressure of the synovial fluid on the other hand. Deviations of the condylar position as a result on ligamentous instabilities or ruptures with a following occurring loss of congruence, meniscal lesions or traumatic ruptures lead to a rapid discharge of the synovial fluid under load. The result is a hydraulic head loss with direct contact of the chondral surfaces under stress leading to arthrotic deformations. Severe arthrotic deformations or very much every meniscectomy produce intraarticular lumped loads resulting in a hyper-physiologic chondral pressure and malnutrition thereby. Further on there develop subchondral stress concentrations (caused by the lumped loads) leading to osseous damages, too. MR-pictures can make visible these damages. Chondromalacia, fissure or even chondrolysis are arthroscopically detectable sometimes. As after-effects of deficient knee ligaments occur pathological deviations of the femoral condyles and resulting destructions of the articular surfaces under stress enormously intensified by

  19. Three-dimensional analysis of alignment error in using femoral intramedullary guides in unicompartmental knee arthroplasty.

    PubMed

    Ma, Burton; Long, William; Rudan, John F; Ellis, Randy E

    2006-02-01

    We used computerized simulations with 3-dimensional models of 20 cadaver femora, calculated from computed tomographic scans, and a model of a rod measuring 200 x 5 mm to study femoral alignment accuracy for unicompartmental knee arthroplasty via minimally invasive reconstruction. The anatomical axis and insertion site were identified on each femur. A simulation of all feasible flexion-extension and varus-valgus orientations was performed. The average rod orientation was 3.2 degrees flexion and 2.5 degrees valgus. The range of orientation was 3.2 degrees extension to 9.7 degrees flexion and 4.5 degrees varus to 8.9 degrees valgus. The study suggests that a short narrow intramedullary rod inserted according to the manufacturer's specifications does not accurately find the anatomical axis and may lead to poor alignment of the femoral prosthesis. Given our finding of consistent bias toward excessive flexion and valgus alignment, we recommend that the operating surgeon carefully plan the insertion point of the intramedullary rod during surgery to compensate for this bias. PMID:16520218

  20. Cementless total knee arthroplasty

    PubMed Central

    Risitano, Salvatore; Sabatini, Luigi; Giachino, Matteo; Agati, Gabriele; Massè, Alessandro

    2016-01-01

    Interest for uncemented total knee arthroplasty (TKA) has greatly increased in recent years. This technique, less used than cemented knee replacement in the last decades, sees a revival thanks an advance in prosthetic design, instrumentation and operative technique. The related literature in some cases shows conflicting data on survival and on the revision’s rate, but in most cases a success rate comparable to cemented TKA is reported. The optimal fixation in TKA is a subject of debate with the majority of surgeons favouring cemented fixation. PMID:27162779

  1. Comparison of wear behaviors for an artificial cervical disc under flexion/extension and axial rotation motions.

    PubMed

    Wang, Song; Song, Jian; Liao, Zhenhua; Feng, Pingfa; Liu, Weiqiang

    2016-06-01

    The wear behaviors of a ball-on-socket (UHMWPE-on-Ti6Al4V) artificial cervical disc were studied with 1.5MC (million cycles) wear simulation under single flexion/extension and axial rotation motion and their composite motion. The wear rates, wear traces, and contact stress were analyzed and contrasted based on mass loss, optical microscopy and SEM as well as 3D profilometer, and ANSYS software, respectively. A much higher wear rate and more severe wear scars appeared under multi-directional motion. Flexion/extension motion of 7.5° lead to more severe wear than that under axial rotation motion of 4°. The above results were closely related to the contact compression stress and shear stress. The wear surface in FE motion showed typical linear wear scratches while revealing obvious arc-shaped wear tracks in AR motion. However, the central zone of both ball and socket components revealed more severe wear tracks than that in the edge zone under these two different motions. The dominant wear mechanism was plowing/scratching and abrasive wear as well as a little oxidation wear for the titanium socket while it was scratching damage with adhesive wear and fatigue wear due to plastic deformation under cyclic load and motion profiles for the UHMWPE ball. PMID:27040218

  2. Movement Analysis of Flexion and Extension of Honeybee Abdomen Based on an Adaptive Segmented Structure

    PubMed Central

    Zhao, Jieliang; Wu, Jianing; Yan, Shaoze

    2015-01-01

    Honeybees (Apis mellifera) curl their abdomens for daily rhythmic activities. Prior to determining this fact, people have concluded that honeybees could curl their abdomen casually. However, an intriguing but less studied feature is the possible unidirectional abdominal deformation in free-flying honeybees. A high-speed video camera was used to capture the curling and to analyze the changes in the arc length of the honeybee abdomen not only in free-flying mode but also in the fixed sample. Frozen sections and environment scanning electron microscope were used to investigate the microstructure and motion principle of honeybee abdomen and to explore the physical structure restricting its curling. An adaptive segmented structure, especially the folded intersegmental membrane (FIM), plays a dominant role in the flexion and extension of the abdomen. The structural features of FIM were utilized to mimic and exhibit movement restriction on honeybee abdomen. Combining experimental analysis and theoretical demonstration, a unidirectional bending mechanism of honeybee abdomen was revealed. Through this finding, a new perspective for aerospace vehicle design can be imitated. PMID:26223946

  3. Haglund's Deformity

    MedlinePlus

    ... Is Haglund’s Deformity? Haglund’s deformity is a bony enlargement on the back of the heel. The soft ... the Achilles tendon becomes irritated when the bony enlargement rubs against shoes. This often leads to painful ...

  4. Development of a six station knee wear simulator and preliminary wear results.

    PubMed

    Burgess, I C; Kolar, M; Cunningham, J L; Unsworth, A

    1997-01-01

    In order to assess the wear performance of different designs of total knee replacements (TKR), a six station multi-axis knee simulator has been designed, built and commissioned. The most important features of a knee simulator are representative angles of flexion-extension synchronized with a dynamically applied load, and a combination of rolling and sliding motion. The simulator typically applies flexion-extension of 0-65, anterior-posterior translation of up to 15 mm, a dynamic load of up to 5.0 kN, and operates at 1.0 Hz. The loads and motions are applied using computer controlled servohydraulic actuators and hence their profiles are easily modified. A preliminary wear test has been conducted using a Kinemax (Howmedica, United Kingdom) TKR. The test was conducted in 30 per cent bovine serum which was changed every 150,000 cycles, at which time the bearing surfaces were examined and the UHMWPE tibial component was weighed. Over eight million cycles, a tibial wear rate of 2.62 mg/10(6) cycles was measured. The mild wear observed was characterized by burnishing and slight scratching in the anterior posterior direction. These observations are broadly in line with both in vitro and ex vivo studies reported in the literature for this type of prosthesis. Delamination wear sometimes observed in vivo was not seen. PMID:9141889

  5. Descriptive analysis of kinematics and kinetics of catchers throwing to second base from their knees.

    PubMed

    Plummer, Hillary A; Oliver, Gretchen D

    2016-08-01

    In order to decrease the amount of time that it takes the catcher to throw the ball, a catcher may chose to throw from the knees. Upper extremity kinematics may play a significant role in the kinetics about the elbow observed in catchers throwing from the knees. If relationships between kinematics and kinetics exist then the development of training and coaching instruction may help in reduced upper extremity injury risk. Twenty-two baseball and softball catchers (14.36±3.86years; 165.11±17.54cm; 65.67±20.60kg) volunteered. The catchers exhibited a less trunk rotation (5.6±16.2°), greater elbow flexion (87.9±21.4°) and decreased humeral elevation (71.1±12.3°) at the event of maximum shoulder external rotation as compared to what has previously reported in catchers. These variables are important, as they have previously been established as potential injury risk factors in pitchers, however it is not yet clear the role these variables play in catchers' risk of injury. A positive relationship between elbow varus torque during the deceleration phase and elbow flexion at MIR was observed (r=0.609; p=0.003). Throwing from the knees reduces a catcher's ability to utilize the proximal kinetic chain and this may help to explain why their kinematics and kinetics differ from what has previously been presented in the literature. PMID:26360828

  6. Primary rotating-hinge total knee arthroplasty: good outcomes at mid-term follow-up.

    PubMed

    Kowalczewski, Jacek; Marczak, Dariusz; Synder, Marek; Sibiński, Marcin

    2014-06-01

    We evaluated the clinical and radiologic outcomes of primary knee replacements using a rotating-hinge knee prosthesis in 12 knees with a minimum follow-up of 10 years. Indications for the operation included gross joint destruction, significant axial deformities and contracture with a dysfunctional medial collateral ligament in all cases. The patients' WOMAC and Knee Society scores improved, and the use of mobility aids decreased. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around three tibial components. Three patients required marginal wound excision with resuturing and thereafter healed uneventfully. With significant improvement in function, pain and range of motion, the rotating-hinge knee prosthesis can be used as a salvage device in patients with medial collateral ligament deficiency, contracture, and gross joint destruction. PMID:24418767

  7. Madelung Deformity.

    PubMed

    Kozin, Scott H; Zlotolow, Dan A

    2015-10-01

    Madelung deformity of the wrist is more common in females and is often associated with Leri Weill dyschondrosteosis, a mesomelic form of dwarfism. Patients with Madelung deformity often report wrist deformity resulting from the prominence of the relatively long ulna. The typical Madelung deformity is associated with a Vickers ligament that creates a tether across the volar-ulnar radial physis that restricts growth across this segment. The distal radius deforms in the coronal (increasing radial inclination) and the sagittal (increasing volar tilt) planes. There is lunate subsidence and the proximal carpal row adapts to the deformity by forming an upside-down pyramid shape or triangle. Treatment depends on the age at presentation, degree of deformity, and magnitude of symptoms. Mild asymptomatic deformity warrants a period of nonsurgical management with serial x-ray examinations because the natural history is unpredictable. Many patients never require surgical intervention. Progressive deformity in the young child with considerable growth potential remaining requires release of Vickers ligament and radial physiolysis to prevent ongoing deterioration Concomitant ulnar epiphysiodesis may be necessary. Advanced asymptomatic deformity in older children with an unacceptable-appearing wrist or symptomatic deformity are indications for surgery. A dome osteotomy of the radius allows 3-dimensional correction of the deformity. Positive radiographic and clinical results after dome osteotomy have been reported. PMID:26341718

  8. Effects of changing speed on knee and ankle joint load during walking and running.

    PubMed

    de David, Ana Cristina; Carpes, Felipe Pivetta; Stefanyshyn, Darren

    2015-01-01

    Joint moments can be used as an indicator of joint loading and have potential application for sports performance and injury prevention. The effects of changing walking and running speeds on joint moments for the different planes of motion still are debatable. Here, we compared knee and ankle moments during walking and running at different speeds. Data were collected from 11 recreational male runners to determine knee and ankle joint moments during different conditions. Conditions include walking at a comfortable speed (self-selected pacing), fast walking (fastest speed possible), slow running (speed corresponding to 30% slower than running) and running (at 4 m · s(-1) ± 10%). A different joint moment pattern was observed between walking and running. We observed a general increase in joint load for sagittal and frontal planes as speed increased, while the effects of speed were not clear in the transverse plane moments. Although differences tend to be more pronounced when gait changed from walking to running, the peak moments, in general, increased when speed increased from comfortable walking to fast walking and from slow running to running mainly in the sagittal and frontal planes. Knee flexion moment was higher in walking than in running due to larger knee extension. Results suggest caution when recommending walking over running in an attempt to reduce knee joint loading. The different effects of speed increments during walking and running should be considered with regard to the prevention of injuries and for rehabilitation purposes. PMID:25105739

  9. Isolated hamstrings fatigue alters hip and knee joint coordination during a cutting maneuver.

    PubMed

    Samaan, Michael A; Hoch, Matthew C; Ringleb, Stacie I; Bawab, Sebastian; Weinhandl, Joshua T

    2015-04-01

    The aim of this study was to determine the effects of hamstrings fatigue on lower extremity joint coordination variability during a sidestep cutting maneuver. Twenty female recreational athletes performed five successful trials of a sidestep cutting task pre- and postfatigue. Each participant completed an isolated hamstrings fatigue protocol consisting of isokinetic maximum effort knee flexion and passive extension contractions. Vector coding was used to examine hip and knee joint couplings (consisting of various planar motions) during the impact and weight acceptance phases of the sidestep cut stance phase. Paired t tests were used to analyze differences of each phase as an effect of fatigue, where alpha was set a priori at .05. The hip rotation/knee rotation coupling exhibited a significant decrease in coordination variability as a function of fatigue in both the impact (P = .015) and weight acceptance phases (P = .043). Similarly, the hip adduction-abduction/knee rotation coupling exhibited a significant decrease in coordination variability in the weight acceptance phase (P = .038). Hamstrings fatigue significantly decreased coordination variability within specific lower extremity joint couplings that included knee rotation. Future studies should be conducted to determine if this decrease in coordination variability is related to lower extremity injury mechanisms. PMID:25411821

  10. Effects of high heel wear and increased weight on the knee during walking.

    PubMed

    Titchenal, Matthew R; Asay, Jessica L; Favre, Julien; Andriacchi, Thomas P; Chu, Constance R

    2015-03-01

    Knee osteoarthritis (OA), a leading cause of disability, is more prevalent in women than men. Wearing high heeled shoes has been implicated as a potential contributing factor for the higher lifetime risk of osteoarthritis in women. This study tests the hypotheses that changes to knee kinematics and kinetics observed during high heeled walking increase in magnitude with increasing heel height and are accentuated by a 20% increase in weight. Fourteen healthy females were tested using marker-based gait analysis in combinations of footwear (flat athletic shoe, 3.8 cm and 8.3 cm heeled shoes) and weight (with and without 20% bodyweight vest). At preferred walking speed, knee flexion angle at heel-strike and midstance increased with increasing heel height and weight. Maximum knee extension moment during loading response decreased with added weight; maximum knee extension moment during terminal stance decreased with heel height; maximum adduction moments increased with heel height. Many of the changes observed with increasing heel height and weight were similar to those seen with aging and OA progression. This suggests that high heel use, especially in combination with additional weight, may contribute to increased OA risk in women. PMID:25532875

  11. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device

    PubMed Central

    Zavieh,, Minoo Khalkhali; Amirshakeri,, Bahram; Rezasoltani,, Asghar; Talebi,, Ghadam Ali; Kalantari,, Khosro Khademi; Nedaey,, Vahab; Baghban,, Alireza Akbarzadeh

    2016-01-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint.

  12. Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps.

    PubMed

    Gheller, Rodrigo G; Dal Pupo, Juliano; Ache-Dias, Jonathan; Detanico, Daniele; Padulo, Johnny; dos Santos, Saray G

    2015-08-01

    This study aimed to analyze the effect of different knee starting angles on jump performance, kinetic parameters, and intersegmental coupling coordination during a squat jump (SJ) and a countermovement jump (CMJ). Twenty male volleyball and basketball players volunteered to participate in this study. The CMJ was performed with knee flexion at the end of the countermovement phase smaller than 90° (CMJ(<90)), greater than 90° (CMJ(>90)), and in a preferred position (CMJ(PREF)), while the SJ was performed from a knee angle of 70° (SJ(70)), 90° (SJ(90)), 110° (SJ(110)), and in a preferred position (SJ(PREF)). The best jump performance was observed in jumps that started from a higher squat depth (CMJ(<90)-SJ(70)) and in the preferred positions (CMJ and SJ), while peak power was observed in the SJ(110) and CMJ(>90). Analysis of continuous relative phase showed that thigh-trunk coupling was more in-phase in the jumps (CMJ and SJ) performed with a higher squat depth, while the leg-thigh coupling was more in-phase in the CMJ(>90) and SJ(PREF). Jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance. Intersegmental coordination and jump performance (CMJ and SJ) were affected by different knee starting angles. PMID:25965000

  13. The Arterial Folding Point During Flexion of the Hip Joint

    SciTech Connect

    Park, Sung Il; Won, Je Hwan Kim, Byung Moon; Kim, Jae Keun; Lee, Do Yun

    2005-04-15

    Purpose: Endovascular stents placed in periarticular vessels may be at a greater risk of neointimal hyperplasia and eventual occlusion than those placed in non-periarticular vessels. The purpose of this study was to investigate the location of maximal conformational change along the iliac and femoral artery, the folding point, during flexion of the hip joint and its location relative to the hip joint and the inguinal ligament. Methods: Seventy patients undergoing femoral artery catheterization were evaluated. The patients were 47 men and 23 women and ranged in age from 26 to 75 years (mean 54 years). The arteries (right:left = 34:36) were measured using a marked catheter for sizing vessels. Fluoroscopic images were obtained in anteroposterior and lateral projections in neutral position, and in the lateral projection in flexed position of the hip joint. The folding point was determined by comparing the lateral projection images in the neutral and flexed positions. The distance from the acetabular roof to the folding point and the distance from the inguinal ligament to the folding point was evaluated. Results: : The folding point was located 42.8 {+-} 28.6 mm cranial to the acetabular roof and 35.1 {+-} 30.1 mm cranial to the inguinal ligament. As the patient's age increased, the folding point was located more cranially (p < 0.001). Conclusions: The folding point during flexion of the hip joint was located 42.8 {+-} 28.6 mm cranial to the acetabular roof and 35.1 {+-} 30.1 mm cranial to the inguinal ligament. As the patient's age increased, the folding point was located more cranially. When a stent is inserted over this region, more attention may be needed during follow-up to monitor possible occlusion and stent failure.

  14. Hypermobility and Knee Injuries.

    ERIC Educational Resources Information Center

    Steiner, Mark E.

    1987-01-01

    A review of research on the effect of hypermobility on knee injury indicates that greater than normal joint flexibility may be necessary for some athletic endeavors and that it may be possible to change one's underlying flexibility through training. However, for most athletes, inherited flexibility probably plays only a small role, if any, in…

  15. In vivo kinematics of knee prostheses patients during level walking compared with the ISO force-controlled simulator standard

    PubMed Central

    Ngai, Valentina; Schwenke, Thorsten; Wimmer, Markus A.

    2013-01-01

    Background Differences between wear-scar features of simulator-tested and retrieved tibial total knee replacement (TKR) liners have been reported. This disagreement may result from differences between in vivo kinematic profiles and those defined by the standard. Purpose To determine the knee kinematics of a TKR subject group during level walking and compare them with the motion profiles produced by a wear test conducted according to the force-controlled knee wear testing ISO 14243-1 (ISO-1)standard. Methods Ten patients with a posterior cruciate ligament-retaining TKR design were gait tested using the point cluster technique (PCT) to obtain flexion-extension (FE) rotation, anterior-posterior (AP) translation and internal-external (IE) rotation motions during a complete cycle of level walking. Motion data were directly compared against the output kinematics from the wear test. Results The subjects exhibited a FE rotation pattern similar to the output from ISO-1; however had higher midstance knee flexion angles. For both AP translation and IE rotation, the standard profiles had significantly smaller total ranges of motion than seen in vivo, with noticeably different patterns of motions. Conclusions For this particular implant design, significant differences were found in both the pattern and magnitudes of in vivo motion during level walking compared with the ISO-1 standard. PMID:19908427

  16. Compartment syndrome after total knee arthroplasty: regarding a clinical case☆

    PubMed Central

    Pinheiro, Ana Alexandra da Costa; Marques, Pedro Miguel Dantas Costa; Sá, Pedro Miguel Gomes; Oliveira, Carolina Fernandes; da Silva, Bruno Pombo Ferreira; de Sousa, Cristina Maria Varino

    2015-01-01

    Although compartment syndrome is a rare complication of total knee arthroplasty, it is one of the most devastating complications. It is defined as a situation of increased pressure within a closed osteofascial space that impairs the circulation and the functioning of the tissues inside this space, thereby leading to ischemia and tissue dysfunction. Here, a clinical case of a patient who was followed up in orthopedic outpatient consultations due to right gonarthrosis is presented. The patient had a history of arthroscopic meniscectomy and presented knee flexion of 10° before the operation, which consisted of total arthroplasty of the right knee. The operation seemed to be free from intercurrences, but the patient evolved with compartment syndrome of the ipsilateral leg after the operation. Since compartment syndrome is a true surgical emergency, early recognition and treatment of this condition through fasciotomy is crucial in order to avoid amputation, limb dysfunction, kidney failure and death. However, it may be difficult to make the diagnosis and cases may not be recognized if the cause of compartment syndrome is unusual or if the patient is under epidural analgesia and/or peripheral nerve block, which thus camouflages the main warning sign, i.e. disproportional pain. In addition, edema of the limb that underwent the intervention is common after total knee arthroplasty operations. This study presents a review of the literature and signals that the possible rarity of cases is probably due to failure to recognize this condition in a timely manner and to placing these patients in other diagnostic groups that are less likely, such as neuropraxia caused by using a tourniquet or peripheral nerve injury. PMID:26401507

  17. The Effects of Psoas Major and Lumbar Lordosis on Hip Flexion and Sprint Performance

    ERIC Educational Resources Information Center

    Copaver, Karine; Hertogh, Claude; Hue, Olivier

    2012-01-01

    In this study, we analyzed the correlations between hip flexion power, sprint performance, lumbar lordosis (LL) and the cross-sectional area (CSA) of the psoas muscle (PM). Ten young adults performed two sprint tests and isokinetic tests to determine hip flexion power. Magnetic resonance imaging was used to determine LL and PM CSA. There were…

  18. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  19. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.136... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer to §§ 572.130(a)(1)(v) and (vi)) for the purpose of...

  20. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  1. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.126...-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg assembly (drawing 127-4000-1 and -2). (b) When the...

  2. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  3. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.136... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer to §§ 572.130(a)(1)(v) and (vi)) for the purpose of...

  4. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  5. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.126...-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg assembly (drawing 127-4000-1 and -2). (b) When the...

  6. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  7. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.126...-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg assembly (drawing 127-4000-1 and -2). (b) When the...

  8. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.136... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer to §§ 572.130(a)(1)(v) and (vi)) for the purpose of...

  9. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.126...-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg assembly (drawing 127-4000-1 and -2). (b) When the...

  10. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.126...-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg assembly (drawing 127-4000-1 and -2). (b) When the...

  11. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  12. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.136... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer to §§ 572.130(a)(1)(v) and (vi)) for the purpose of...

  13. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  14. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  15. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.136... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer to §§ 572.130(a)(1)(v) and (vi)) for the purpose of...

  16. Strain measurement at the knee ligament insertion sites.

    PubMed

    Hinterwimmer, S; Baumgart, R; Plitz, W

    2003-01-01

    We describe the modification of an existing method of ligament strain measurement at the knee joint in detail. At ten fresh joint specimens we used that technique where strain gauges are attached to the ligamentous insertions and origins. We both improved the preparation of the attachment site and the application of the strain gauges. In a special apparatus the specimens were moved from 0 degree extension to 100 degrees flexion while simulating muscle strength and axial force. Testing was performed at the posterior cruciate ligament with both intact and transsected anterior cruciate ligament. In contrast to other existing techniques it does not affect the motion of the joint or the integrity and the function of the ligaments. Unlike the original description of that method we could register a loading behaviour of the posterior cruciate ligament that is similar to those reported in the literature. PMID:12655843

  17. The relationship between the flexion synergy and stretch reflexes in individuals with chronic hemiparetic stroke.

    PubMed

    McPherson, Jacob G; Stienen, Arno H A; Drogos, Justin M; Dewald, Julius P A

    2011-01-01

    This study utilized a novel robotic device, the ACT-4D, to investigate the relationship between the flexion synergy and stretch reflexes in individuals with chronic hemiparetic stroke. Because the flexion synergy influences the amount of elbow flexor muscle activation present in the paretic limb during tasks requiring shoulder abduction loading, it was hypothesized that stretch reflexes may be modulated by expression of this abnormal muscle coactivation pattern. To test this hypothesis, the ACT-4D was used to enable 10 individuals with chronic hemiparetic stroke to generate varying amounts of shoulder abduction torque while concurrently receiving elbow extension position perturbations. It was found that increased expression of the flexion synergy led to greater reflex amplitudes as well as lower reflex velocity thresholds. The physiological basis of the flexion synergy is briefly discussed, as are the implications of the flexion synergy and stretch reflexes for purposeful movement. PMID:22275712

  18. A new protocol from real joint motion data for wear simulation in total knee arthroplasty: stair climbing.

    PubMed

    Battaglia, Santina; Belvedere, Claudio; Jaber, Sami Abdel; Affatato, Saverio; D'Angeli, Valentina; Leardini, Alberto

    2014-12-01

    In its normal lifespan, a knee prosthesis must bear highly demanding loading conditions, going beyond the sole activity of level walking required by ISO standard 14243. We have developed a protocol for in vitro wear simulation of stair climbing on a displacement controlled knee simulator. The flexion/extension angle, intra/extra rotation angle, and antero/posterior translation were obtained in patients by three-dimensional video-fluoroscopy. Axial load data were collected by gait analysis. Kinematics and load data revealed a good consistence across patients, in spite of the different prosthesis size. The protocol was then implemented and tested on a displacement controlled knee wear simulator, showing an accurate reproduction of stair climbing waveforms with a relative error lower than 5%. PMID:25242732

  19. Can a total knee arthroplasty be both rotationally unconstrained and anteroposteriorly stabilised?

    PubMed Central

    Imam, M. A.; Eifert, A.; Freeman, M. A. R.; Pinskerova, V.; Field, R. E.; Skinner, J.; Banks, S. A.

    2016-01-01

    Objectives Throughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back – a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements in situ/in vivo. Methods The pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m2 (20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities. Results During maximally flexed kneeling and lunging activities, the mean tibial internal rotation was 8° (standard deviation (sd) 6). At a mean 112° flexion (sd 16) during lunging, the medial and lateral condyles were a mean of 2 mm (sd 3) and 8 mm (sd 4) posterior to a transverse line passing through the centre of the medial tibial concavity. With a mean flexion of 117° (sd 14) during kneeling, the medial and lateral condyles were a mean of 1 mm (sd 4) anterior and 6 mm (sd 4) posterior to the same line. During dynamic stair and pivoting activities, there was a mean anteroposterior translation of 0 mm to 2 mm of the medial femoral condyle. Backward lateral condylar translation occurred and was linearly related to tibial rotation. Conclusion The GMK Sphere TKA in our study group shows movements similar in

  20. Spontaneous Knee Ankylosis through Heterotopic Ossification after Total Knee Arthroplasty

    PubMed Central

    Boulezaz, Samuel; Gibon, Emmanuel; Loriaut, Philippe; Casabianca, Laurent; Rousseau, Romain; Dallaudiere, Benjamin; Pascal-Moussellard, Hugues

    2016-01-01

    This paper reports on a case of total ankylosis of the knee after a cruciate-sacrificing cemented total knee arthroplasty (TKA). An 82-year-old female patient previously underwent primary TKA for osteoarthritis twenty years ago in our institution. She had recovered uneventfully and returned to her regular activities. There was no history of postsurgical trauma; however, she progressively lost knee range of motion. Radiographs revealed severe bridging heterotopic ossification. PMID:27119034

  1. Medium-term results of a mobile bearing total knee replacement.

    PubMed

    Kaper, B P; Smith, P N; Bourne, R B; Rorabeck, C H; Robertson, D

    1999-10-01

    Mobile bearing total knee arthroplasty kinematically allows the advantages of large and congruent surface contact and low contact pressures, while preserving flexion, extension, and rotation in knee motion. In allowing for these degrees of freedom, the interface between bone and component also is protected from high stress. The Self Aligning I total knee arthroplasty initially was implanted in patients after its development at the authors' institution in 1990. Between 1990 and 1994, 141 patients with osteoarthritis of the knee underwent 172 total knee replacements using this system. At average followup of 5.6 years (range, 5-8 years), clinical results using this system showed a 94% satisfaction rate (good or very good). Two revision surgeries have been performed for polyethylene wear, with none of the remaining knees showing evidence of discernible wear. Complications included four cases of deep infection, four cases where a press fit femoral component failed (nonporous coated) and the patients required revision surgery, four traumatic fractures (three patellar and one supracondylar), one popliteal artery occlusion, and one revision for stiffness. Three patients required manipulation under anesthesia for arthrofibrosis. Kaplan-Meier survival curves show the probability of survival to be 91.7%, with revision surgery for any reason as an end point, and 98.8% for revision surgery because of polyethylene wear as an end point. Following the initial learning curve with this prosthesis, the medium term results using this system show maintenance of clinical success. No progressive evidence of polyethylene wear with time has been found, supporting the concept of mobile bearing arthroplasty in extending the service life of total knee arthroplasty. PMID:10546616

  2. Load Sharing Among Collateral Ligaments, Articular Surfaces, and the Tibial Post in Constrained Condylar Knee Arthroplasty.

    PubMed

    Wang, Xiaonan; Malik, Aamer; Bartel, Donald L; Wright, Timothy M; Padgett, Douglas E

    2016-08-01

    The normal knee joint maintains stable motion during activities of daily living. After total knee arthroplasty (TKA), stability is achieved by the conformity of the bearing surfaces of the implant components, ligaments, and constraint structures incorporated in the implant design. The large, rectangular tibial post in constrained condylar knee (CCK) arthroplasty, often used in revision surgery, provides added stability, but increases susceptibility to polyethylene wear as it contacts the intercondylar box on the femoral component. We examined coronal plane stability to understand the relative contributions of the mechanisms that act to stabilize the CCK knee under varus-valgus loading, namely, load distribution between the medial and lateral condyles, contact of the tibial post with the femoral intercondylar box, and elongation of the collateral ligaments. A robot testing system was used to determine the joint stability in human cadaveric knees as described by the moment versus angular rotation behavior under varus-valgus moments at 0 deg, 30 deg, and 90 deg of flexion. The angular rotation of the CCK knee in response to the physiological moments was limited to ≤1.5 deg. The primary stabilizing mechanism was the redistribution of the contact force on the bearing surfaces. Contact between the tibial post and the femoral box provided a secondary stabilizing mechanism after lift-off of a condyle had occurred. Collateral ligaments provide limited stability because little ligament elongation occurred under such small angular rotations. Compressive loads applied across the knee joint, such as would occur with the application of muscle forces, enhanced the ability of the bearing surfaces to provide resisting internal varus-valgus moment and, thus, reduced the exposure of the tibial post to the external varus-valgus loads. Our results suggest that the CCK stability can be refined by considering both the geometry of the bearing surfaces and the contacting geometry

  3. 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

  4. The Combination of the Tunnel View and Weight-Bearing Anteroposterior Radiographs Improves the Detection of Knee Arthritis

    PubMed Central

    Babatunde, Oladapo M.; Danoff, Jonathan R.; Patrick, David A.; Lee, Jonathan H.; Kazam, Jonathan K.; Macaulay, William

    2016-01-01

    Imaging used for the evaluation of knee pain has historically included weight-bearing anteroposterior (AP), lateral, and sunrise radiographs. We wished to evaluate the utility of adding the weight-bearing (WB) posteroanterior (PA) view of the knee in flexion. We hypothesize that (1) the WB tunnel view can detect radiographic osteoarthritis (OA) not visualized on the WB AP, (2) the combination of the AP and tunnel view increases the radiographic detection of OA, and (3) this may provide additional information to the clinician evaluating knee pain. We retrospectively reviewed the WB AP and tunnel view radiographs of 100 knees (74 patients) presenting with knee pain and analyzed for evidence of arthritis. The combination of the WB tunnel view and WB AP significantly increased the detection of joint space narrowing in the lateral (p < 0.001) and medial (p = 0.006) compartments over the AP view alone. The combined views significantly improved the identification of medial subchondral cysts (p = 0.022), sclerosis of the lateral tibial plateau (p = 0.041), and moderate-to-large osteophytes in the medial compartment (p = 0.012), intercondylar notch (p < 0.001), and tibial spine (p < 0.001). The WB tunnel view is an effective tool to provide additional information on affected compartments in the painful knee, not provided by the AP image alone. PMID:26925264

  5. Clinical Evaluation of a Mobile Sensor-Based Gait Analysis Method for Outcome Measurement after Knee Arthroplasty

    PubMed Central

    Calliess, Tilman; Bocklage, Raphael; Karkosch, Roman; Marschollek, Michael; Windhagen, Henning; Schulze, Mareike

    2014-01-01

    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. PMID:25171119

  6. Does the rectus femoris nerve block improve knee recurvatum in adult stroke patients? A kinematic and electromyographic study.

    PubMed

    Gross, R; Delporte, L; Arsenault, L; Revol, P; Lefevre, M; Clevenot, D; Boisson, D; Mertens, P; Rossetti, Y; Luauté, J

    2014-02-01

    Knee recurvatum (KR) during gait is common in hemiplegic patients. Quadriceps spasticity has been postulated as a cause of KR in this population. The aim of this study was to assess the role of rectus femoris spasticity in KR by using selective motor nerve blocks of the rectus femoris nerve in hemiparetic stroke patients. The data from six adult, post-stroke hemiplegic patients who underwent a rectus femoris nerve block for a stiff-knee gait were retrospectively analyzed. An extensive clinical and functional evaluation was performed and gait was assessed by motion analysis (kinematic, kinetic and electromyographic parameters) before and during the block realized using 2% lidocaine injected under a neurostimulation and ultrasonographic targeting procedure. The main outcome measures were the peak knee extension in stance and peak knee extensor moment obtained during gait analysis. No serious adverse effect of the nerve block was observed. The block allowed a reduction of rectus femoris overactivity in all patients. Peak knee extension and extensor moment in stance did not improve in any patient, but peak knee flexion during the swing phase was significantly higher after block (mean: 31.2° post, 26.4 pre, p < 0.05). Our results provide arguments against the hypothesis that the spasticity of the rectus femoris contributes to KR. PMID:24286615

  7. The Combination of the Tunnel View and Weight-Bearing Anteroposterior Radiographs Improves the Detection of Knee Arthritis.

    PubMed

    Babatunde, Oladapo M; Danoff, Jonathan R; Patrick, David A; Lee, Jonathan H; Kazam, Jonathan K; Macaulay, William

    2016-01-01

    Imaging used for the evaluation of knee pain has historically included weight-bearing anteroposterior (AP), lateral, and sunrise radiographs. We wished to evaluate the utility of adding the weight-bearing (WB) posteroanterior (PA) view of the knee in flexion. We hypothesize that (1) the WB tunnel view can detect radiographic osteoarthritis (OA) not visualized on the WB AP, (2) the combination of the AP and tunnel view increases the radiographic detection of OA, and (3) this may provide additional information to the clinician evaluating knee pain. We retrospectively reviewed the WB AP and tunnel view radiographs of 100 knees (74 patients) presenting with knee pain and analyzed for evidence of arthritis. The combination of the WB tunnel view and WB AP significantly increased the detection of joint space narrowing in the lateral (p < 0.001) and medial (p = 0.006) compartments over the AP view alone. The combined views significantly improved the identification of medial subchondral cysts (p = 0.022), sclerosis of the lateral tibial plateau (p = 0.041), and moderate-to-large osteophytes in the medial compartment (p = 0.012), intercondylar notch (p < 0.001), and tibial spine (p < 0.001). The WB tunnel view is an effective tool to provide additional information on affected compartments in the painful knee, not provided by the AP image alone. PMID:26925264

  8. Reconstruction of knee joint soft tissue and patellar tendon defects using a composite anterolateral thigh flap with vascularized fascia lata.

    PubMed

    Kuo, Yur-Ren; An, Po-Chung; Kuo, Mei-Hui; Kueh, Nai-Siong; Yao, Sheng-Fa; Jeng, Seng-Feng

    2008-01-01

    Reconstruction of a complex knee trauma with knee joint exposure and composite soft tissue and patellar tendon deficiency remains a challenging task. Multiple-stage reconstruction is time-consuming and produces considerable suffering for patients. Early mobilization following knee reconstruction has achieved good outcomes. Herein, we reported one-stage reconstruction with an ALT myocutaneous flap with vascularized fascia lata was utilized for one patient with a large complex knee joint soft tissue defect, and segmental deficiency of the patellar tendon. The fascia lata sheet was rolled to mimic a patellar tendon. The exposed knee joint was obturated by the vastus lateralis muscle of the ALT myocutaneous flap. The skin and soft tissue defect was reconstructed using the skin paddle of the ALT flap. The patient's postoperative course was uneventful. An MRI examination demonstrated good continuity of the reconstructed patellar tendon. The active ROM of the injured knee reached 100 degrees (extension deficiency 20 degrees and flexion 120 degrees ) at 5 years. Objective functional assessment of the patella-femoral joint utilized a kinetic communicator machine (Kin-Com 500H, Chattecx, Chattanooga, TN, USA) revealed still mild extension insufficiency. However, the patient reported that he was able to perform normal daily activities without difficulty at 5-year follow-up. PMID:18215803

  9. Relationship Between Functional Knee Joint Position Sense and Functional Performance Scores Following Anterior Cruciate Ligament Reconstruction (Pilot Study)

    PubMed Central

    Kafa, Nihan; Ataoglu, Muhammed Baybars; Hazar, Zeynep; Citaker, Seyit; Ozer, Mustafa

    2014-01-01

    Objectives: The aim of this study was to assess the relationship between functional knee joint position sense (JPS) and functional performance following ACL reconstruction Methods: Seven male patients (mean age=32,66 ±6,47) who had undergone ACL reconstruction and 10 male healthy control subjects participated in the study. Knee joint position sense was evaluated by reproduction of 20° knee flexion angle in weight-bearing position with single and bilateral limb movement into flexion and extension. The deviations in the angle were recorded and compared to both noninjured side and healthy controls’. Functional performance was evaluated with Single Leg Hop Test in both injured and non-injured sides. The scores were also compared with healthy controls and non-injured sides. Relationship between measured values was tested with Spearman Correlation Analysis. Results: There was no significant difference in knee joint position sense in functional position between the operated and uninjured knees of patients or between patients and healthy controls (p>0,05). However, there is significant difference in Single Leg Hop test scores between operated and non-operated or between patients and healthy controls (p=0,037; p<0,05). There was no significant correlation between Single Leg Hop test scores and knee joint position sense (p>0,05). Conclusion: There was no evidence of impaired joint position sense in weight-bearing positions in subjects with ACL reconstruction but there was a decrease in functional performance. This decrease in functional performance may depend on the other parameters except proprioceptive deficits.

  10. Asymmetric varus and valgus stability of the anatomic cadaver knee and the load sharing between collateral ligaments and bearing surfaces.

    PubMed

    Wang, Xiaonan; Malik, Aamer; Bartel, Donald L; Wickiewicz, Thomas L; Wright, Timothy

    2014-08-01

    Knee joint stability is important in maintaining normal joint motion during activities of daily living. Joint instability not only disrupts normal motion but also plays a crucial role in the initiation and progression of osteoarthritis. Our goal was to examine knee joint coronal plane stability under varus or valgus loading and to understand the relative contributions of the mechanisms that act to stabilize the knee in response to varus-valgus moments, namely, load distribution between the medial and lateral condyles and the ligaments. A robot testing system was used to determine joint stability in human cadaveric knees as described by the moment versus angular rotation behavior under varus and valgus loads at extension and at 30 deg and 90 deg of flexion. The anatomic knee joint was more stable in response to valgus than varus moments, and stability decreased with flexion angle. The primary mechanism for providing varus-valgus stability was the redistribution of the contact force on the articular surfaces from both condyles to a single condyle. Stretching of the collateral ligaments provided a secondary stabilizing mechanism after the lift-off of a condyle occurred. Compressive loads applied across the knee joint, such as would occur with the application of muscle forces, enhanced the ability of the articular surface to provide varus-valgus moment, and thus, helped stabilize the joint in the coronal plane. Coupled internal/external rotations and anteroposterior and medial-lateral translations were variable and in the case of the rotations were often as large as the varus-valgus rotations created by the applied moment. PMID:24828416

  11. Reliability and concurrent validity of knee angle measurement: smart phone app versus universal goniometer used by experienced and novice clinicians.

    PubMed

    Milanese, Steven; Gordon, Susan; Buettner, Petra; Flavell, Carol; Ruston, Sally; Coe, Damien; O'Sullivan, William; McCormack, Steven

    2014-12-01

    The use of goniometers to measure joint angles is a key part of musculoskeletal practice. Recently smartphone goniometry applications have become available to clinicians. This study examined the intra- and inter-measurer reliability of novice and experienced clinicians and the concurrent validity of assessing knee range of motion using a smartphone application (the Knee Goniometer App (Ockendon(©))) (KGA) and a standard universal goniometer (UG). Three clinicians, each with over seven years' experience as musculoskeletal physiotherapists and three final year physiotherapy students, measured 18 different knee joint angles three times, using both the universal goniometer and the smartphone goniometric application. The universal goniometer and the smartphone goniometric application were reliable in repeated measures of knee flexion angles (average Concordance Correlation Coefficient (CCC) > 0.98) with both experienced clinicians and final year physiotherapy students (average CCCs > 0.96). There were no significant differences in reliability between the experienced and the novice practitioners for either device. Agreement between the universal goniometer and smartphone goniometric application measurements was also high for all examiners with average CCCs all above 0.96. The Standard Error of Measurement ranged between 1.56° (0.52-2.66) for the UG and 0.62° (0.29-1.27) for the KGA. The universal goniometer and the smartphone goniometric application were reliable in repeated measures of knee flexion angles. Smaller error of measurement values for the smartphone goniometric application might indicate superiority for assessment where clinical situations demand greater precision of knee range of motion. PMID:24942491

  12. Synovial plicae of the knee

    SciTech Connect

    Apple, J.S.; Martinez, S.; Daffner, R.H.; Gehweiler, J.A.; Hardaker, W.T.

    1982-01-01

    This report describes the anatomy, patho-physiology, clinical, and radiographic findings, and treatment of the synovial plicae of the knee joint. The suprapatellar plica is a synovial fold present in the suprapatellar pouch of the knee joint in approximately 20% of the population. This fold may become symptomatic after injury and cause symptoms similar to other common internal derangements of the knee. Double contrast arthrography of the knee can be used to identify the presence of plicae. Although arthrography can identify the presence of a plica, its clinical significance requires close correlation with symptoms and an accurate clinical examination.

  13. Multiligamentous injuries and knee dislocations.

    PubMed

    Gimber, Lana H; Scalcione, Luke R; Rowan, Andrew; Hardy, Jolene C; Melville, David M; Taljanovic, Mihra S

    2015-11-01

    Complex capsular ligamentous structures contribute to stability of the knee joint. Simultaneous injury of two or more knee ligaments, aside from concurrent tears involving the anterior cruciate and medial collateral ligaments, is considered to be associated with femorotibial knee dislocations. Proximal tibiofibular joint dislocations are not always easily recognized and may be overlooked or missed. Patellofemoral dislocations can be transient with MR imaging sometimes required to reach the diagnosis. In this article, the authors describe the mechanism of injury, ligamentous disruptions, imaging, and treatment options of various types of knee dislocations including injuries of the femorotibial, proximal tibiofibular, and patellofemoral joints. PMID:26002747

  14. 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

  15. Radiographic comparison of mobile-bearing partial knee single-peg versus twin-peg design.

    PubMed

    Hurst, Jason M; Berend, Keith R; Adams, Joanne B; Lombardi, Adolph V

    2015-03-01

    The femoral component and proprietary instrumentation of a mobile-bearing unicompartmental knee arthroplasty (UKA) was redesigned with an additional peg for enhanced fixation, 15° of extra femoral surface for contact in deep flexion, more rounded profile, better fit into the milled surface, and redesigned intramedullary based instrumentation. To assess the benefit of these changes, we compared postoperative radiographs of 219 single-peg and 186 twin-peg UKAs done in 2008-2011. All surviving knees demonstrated satisfactory position and alignment with no radiolucencies observed. Radiographic analysis showed improved and consistent component positioning with the twin-peg design implanted with updated instrumentation compared with the single-peg. The radiographic benefits of improved implant positioning using the twin-peg component and updated instrumentation are clear and carry tremendous potential. More robust follow-up is imperative. PMID:25453627

  16. Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: a meta-analysis.

    PubMed

    Bercik, Michael J; Joshi, Ashish; Parvizi, Javad

    2013-03-01

    The objective of this meta-analysis was to compare outcomes of posterior cruciate-retaining and posterior stabilized prostheses. A computerized literature search was conducted to identify randomized controlled trials comparing the clinical outcomes of cruciate-retaining and posterior-stabilized designs. The table of contents of four major Orthopaedic journals and the references section of two arthroplasty text books were reviewed to identify other relevant studies. Ultimately, 1114 patients (1265 knees) were compared. Statistical analysis revealed a significant difference in flexion and range of motion in favor of posterior-stabilized knees, but no difference in complication rates. The clinical importance of this remains unknown. The decision to use one design versus the other should rest with the surgeon's preference and comfort with a particular design. PMID:23433255

  17. Outcomes of a Newer-Generation Cementless Total Knee Arthroplasty Design.

    PubMed

    Harwin, Steven F; Elmallah, Randa K; Jauregui, Julio J; Cherian, Jeffrey J; Mont, Michael A

    2015-10-01

    Newer-generation cementless total knee arthroplasties (TKAs) aim to improve durability, function, and longevity. In a large series of cementless TKAs at a mean 4-year follow-up, the authors evaluated (1) survivorship, (2) range of motion, (3) patient-reported outcomes, and (4) complications. Mean age was 66 years (range, 34-88 years) and mean body mass index was 32.5 kg/m(2) (range, 20-54 kg/m(2)). Aseptic and septic implant survivorships were 99.6% and 99.5%, respectively. Mean extension, flexion, and Knee Society scores improved significantly. There were 3 septic failures. Aseptic failures included 3 aseptic loosenings, 1 polyethylene revision, and 1 revision to a cemented patella. This study showed excellent clinical and patient-reported outcomes of cementless TKA. PMID:26488775

  18. Rotational knee strain resulting in patellar dislocation. An experimental study in rabbits.

    PubMed

    Finsterbush, A

    1982-09-01

    The right lower extremities of 64 young rabbits were immobilized by a plaster spica. The animals developed a gait pattern, which included internal tibial rotation and adduction of the left (unimmobilized) tibia. Twenty-one of the animals developed medial patellar dislocation in the unimmobilized lower extremity. The mechanism of the patellar dislocation in this experimental model was possibly overstretching of the lateral colateral ligament and the lateral side of the joint capsule, associated with medial rotation of the tibia and the tibial tubercle. The direction of patellar pull when gliding inferiorly during knee flexion was shifted medially, resulting in patellar dislocation and secondarily, in formation of an exostosis under the displaced patella. Hip arthrodesis in humans, as a course of rotational instability of the contralateral knee, resembles some aspects of this experimental condition. PMID:7105585

  19. The relative cost of bent-hip bent-knee walking is reduced in water.

    PubMed

    Kuliukas, Algis V; Milne, Nick; Fournier, Paul

    2009-01-01

    The debate about how early hominids walked may be characterised as two competing hypotheses: They moved with a fully upright (FU) gait, like modern humans, or with a bent-hip, bent-knee (BK) gait, like apes. Both have assumed that this bipedalism was almost exclusively on land, in trees or a combination of the two. Recent findings favoured the FU hypothesis by showing that the BK gait is 50-60% more energetically costly than a FU human gait on land. We confirm these findings but show that in water this cost differential is markedly reduced, especially in deeper water, at slower speeds and with greater knee flexion. These data suggest that the controversy about australopithecine locomotion may be eased if it is assumed that wading was a component of their locomotor repertoire and supports the idea that shallow water might have been an environment favourable to the evolution of early forms of "non-optimal" hominid bipedalism. PMID:19853850

  20. Selectively Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    Myers, W. Neill (Inventor); Shadoan, Michael D. (Inventor); Forbes, John C. (Inventor); Baker, Kevin J. (Inventor); Rice, Darron C. (Inventor)

    1996-01-01

    A knee brace for aiding in rehabilitation of damaged leg muscles includes upper and lower housings normally pivotable one relative to the other about the knee joint axis of a patient. The upper housing is attachable to the thigh of the patient above the knee joint while the lower housing is secured to a stirrup which extends downwardly along the patient's leg and is attached to the patient's shoe. An actuation rod is carried within the lower housing and is coupled to a cable. The upper and lower housings carry cooperative clutch/brake elements which normally are disengaged to permit relative movement between the upper and lower housings. When the cable is extended the clutch/brake elements engage and lock the housings together. A heel strike mechanism fastened to the stirrup and the heel of the shoe is connected to the cable to selectively extend the cable and lock the brace in substantially any position when the patient places weight on the heel.

  1. Selectively lockable knee brace

    NASA Technical Reports Server (NTRS)

    Myers, Neill (Inventor); Shadoan, Mike (Inventor); Forbes, John (Inventor); Baker, Kevin (Inventor)

    1994-01-01

    A knee brace for aiding in rehabilitation of damaged leg muscles includes upper and lower housings, normally pivotable, one relative to the other about the knee joint axis of a patient. The upper housing is attachable to the thigh of the patient above the knee joint, while the lower housing is secured to a stirrup which extends downwardly along the patient's leg and is attached to the patient's shoe. An actuation rod is carried within the lower housing and is coupled to a cable. The upper and lower housings carry cooperative clutch/brake elements which normally are disengaged to permit relative movement between the upper and lower housings. When the cable is extended, the clutch/brake elements engage and lock the housings together. A heel strike mechanism fastened to the stirrup and the heel of the shoe is connected to the cable to selectively extend the cable and lock the brace in substantially any position when the patient places weight on the heel.

  2. Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke

    PubMed Central

    Drogos, Justin; Carmona, Carolina; Keller, Thierry; Dewald, Julius P. A.

    2012-01-01

    The effect of reticular formation excitability on maximum voluntary torque (MVT) generation and associated muscle activation at the shoulder and elbow was investigated through natural elicitation (active head rotation) of the asymmetric tonic neck reflex (ATNR) in 26 individuals with stroke and 9 age-range-matched controls. Isometric MVT generation at the shoulder and elbow was quantified with the head rotated (face pointing) contralateral and ipsilateral to the paretic (stroke) and dominant (control) arm. Given the dominance of abnormal torque coupling of elbow flexion with shoulder abduction (flexion synergy) in stroke and well-developed animal models demonstrating a linkage between reticular formation and ipsilateral elbow flexors and shoulder abductors, we hypothesized that constituent torques of flexion synergy, specifically elbow flexion and shoulder abduction, would increase with contralateral head rotation. The findings of this investigation support this hypothesis. Increases in MVT for three of four flexion synergy constituents (elbow flexion, shoulder abduction, and shoulder external rotation) were observed during contralateral head rotation only in individuals with stroke. Electromyographic data of the associated muscle coactivations were nonsignificant but are presented for consideration in light of a likely underpowered statistical design for this specific variable. This study not only provides evidence for the reemergence of ATNR following stroke but also indicates a common neuroanatomical link, namely, an increased reliance on ipsilateral reticulospinal pathways, as the likely mechanism underlying the expression of both ATNR and flexion synergy that results in the loss of independent joint control. PMID:22956793

  3. Flexion strength of the toes in the normal foot. An evaluation using magnetic resonance imaging.

    PubMed

    Green, S M; Briggs, P J

    2013-12-01

    Flexion of the toes may be active from muscle contraction or passive from the reversed windlass function of the plantar aponeurosis. The aim of this study was to estimate the flexion moments the muscles of the foot and long digital flexors may be capable of generating and compare these calculations with published data. Magnetic resonance images were used to measure the maximal cross-sectional area of the foot muscles and long digital flexors, along with the radius of curvature of the metatarsal heads. Using known physiological data the maximal flexion moments the muscles may be able to generate at the metatarsophalangeal (MTP) joints were calculated. The methodology overestimates muscle strength and flexion moments at the metatarsophalangeal joints. The calculated maximal flexion moment at the 1st MTP joint is 4.27-6.84 Nm, for the 2nd, 3rd and 4th MTP joints 3.06-4.91 Nm, and the 5th MTP joint 0.47-0.75 Nm. The flexion moments the muscles may generate at the MTP joints do not account for the flexion forces seen in normal walking. Given that maximal strength is not used in normal walking, we conclude that the reversed windlass mechanism of the plantar aponeurosis must be important in normal function of the toes. PMID:23954110

  4. In vivo flexion/extension of the normal cervical spine.

    PubMed

    Dvorak, J; Panjabi, M M; Novotny, J E; Antinnes, J A

    1991-11-01

    Twenty-two women (age range 25-49 years, average 30.9 years) and twenty-two men (age range 23-42 years, average 31.6 years), all healthy and asymptomatic, underwent passive flexion/extension examinations of the cervical spine. Functional x-rays were taken and analyzed using a computer-assisted method that quantified intervertebral rotations, translations, and locations of the centers of rotation for each level C1-C2-C6-C7. The aim of the study was to establish values for these parameters for a normal population as related to age and gender. In the process, a statistically significant difference was found in the average value of rotation between male and female groups at the C5-C6 level. A new parameter, the ratio between translation and rotation, was also established and may prove useful for clinical diagnoses. This parameter has a smaller error associated with it than do pure translations and may aid the clinician by helping to account for the large variation in rotatory ranges of motion within the population. This translation/rotation ratio indicated highly significant differences in the lower segments of the cervical spine between gender groups. PMID:1919845

  5. Subjective Visual Vertical in PD Patients with Lateral Trunk Flexion

    PubMed Central

    Gandor, F.; Basta, D.; Gruber, D.; Poewe, W.; Ebersbach, G.

    2016-01-01

    Lateral trunk flexion (LTF) is a common phenomenon in patients with Parkinson's disease (PD) and has recently been associated with peripheral vestibular dysfunction. Since deviation of the subjective visual vertical (SVV) is a well-recognized feature of disorders involving vestibular processing, we analyzed SVV angles in 30 PD patients with and without LTF to assess the possible role of vestibular dysfunction in the pathogenesis of LTF in PD. Quantification of SVV was obtained using a simple bedside test. PD patients with LTF had significantly greater SVV angles as compared to PD patients without LTF (median: 4.3° [range: 0.1–17.7], n = 21, versus 0.8° [0.1–1.9], n = 9; p < 0.001). 14 of 21 patients with LTF showed pathological SVV, while all 9 patients without LTF had normal SVV. Abnormal SVV was more frequent when LTF was reversible in the supine position compared to fixed LTF. In a subgroup of PD patients with LTF, pathological SVV suggests vestibular dysbalance, which might be involved in the pathophysiological mechanisms underlying LTF. PMID:27073710

  6. Attempted rapid elbow flexion movements in patients with athetosis.

    PubMed Central

    Hallett, M; Alvarez, N

    1983-01-01

    Voluntary rapid elbow flexion movements were studied in 14 patients with athetosis on the basis of cerebral palsy. When the movement was attempted with one arm, other muscles inappropriate for the task, such as muscles in the opposite limb, were also activated. EMG activity of the biceps and triceps was analysed in detail, and the patterns seen in the different patients were divided into six groups: (1) The normal "ballistic" triphasic pattern, with bursts of normal duration, alternating in biceps and triceps, but the triceps might be activated first, causing the limb to extend rather than flex, (2) The triphasic pattern, with bursts of long duration, (3) Repetitive cycles of the triphasic pattern with particularly long antagonist bursts, apparently limiting the movement in each cycle, (4) Long bursts synchronous in agonist and antagonist muscles, (5) Continuous activity of the agonist, with reduction in activity of the antagonist, (6) Failure to be able to do the task. The pathophysiology of athetosis is that voluntary movement is characterised by excessive muscular activity, most prominently in inappropriate muscles, both extraneous to the task and directly antagonistic. PMID:6886719

  7. Wrist flexion as an adjunct to the diagnosis of carpal tunnel syndrome.

    PubMed

    Dunnan, J B; Waylonis, G W

    1991-03-01

    The effects of five minutes of wrist flexion on median motor and sensory evoked potential latencies in 87 individuals were studied. Nineteen subjects had carpal tunnel syndrome (CTS) as diagnosed by increased median nerve latencies across the wrist, and 68 had values in the normal range and were assigned to the control group. A slight prolongation of up to 0.5m sec of evoked potential latencies was observed in both groups after flexion, but the differences between the two groups were not significant to establish the value of adding wrist flexion to conventional screening methods. PMID:1998456

  8. Patient specific guides for total knee arthroplasty are ready for primetime

    PubMed Central

    Schotanus, Martijn GM; Boonen, Bert; Kort, Nanne P

    2016-01-01

    AIM: To present the radiological results of total knee arthroplasty (TKA) with use of patient specific matched guides (PSG) from different manufacturer in patients suffering from severe osteoarthritis of the knee joint. METHODS: This study describes the results of 57 knees operated with 4 different PSG systems and a group operated with conventional instrumentation (n = 60) by a single surgeon. The PSG systems were compared with each other and subdivided into cut- and pin PSG. The biomechanical axis [hip-knee-ankle angle (HKA)], varus/valgus of the femur [frontal femoral component (FFC)] and tibia (frontal tibial component) component, flexion/extension of the femur [flexion/extension of the femur component (LFC)] and posterior slope of the tibia [lateral tibial component (LTC)] component were evaluated on long-leg standing and lateral X-rays. A percentage of > 3° deviation was seen as an outlier. RESULTS: The inter class correlation coefficient (ICC) revealed that radiographic measurements between both assessors were reliable (ICC > 0.8). Fisher exact test was used to test differences of proportions. The percentage of outliers of the HKA-axis was comparable between both the PSG and conventional groups (12.28% vs 18.33%, P < 0.424) and the cut- and pin PSG groups (14.3% vs 10.3%, P < 1.00). The percentage of outliers of the FFC (0% vs 18.33%, P < 0.000), LFC (15.78% vs 58.33%, P < 0.000) and LTC (15.78% vs 41.67%, P < 0.033) were significant different in favour of the PSG group. There were no significant differences regarding the outliers between the individual PSG systems and the PSG group subdivided into cut- and pin PSG. CONCLUSION: PSG for TKA show significant less outliers compared to the conventional technique. These single surgeon results suggest that PSG are ready for primetime. PMID:26807358

  9. Imaging of traumatic injury and impingement of anterior knee fat.

    PubMed

    Lapègue, F; Sans, N; Brun, C; Bakouche, S; Brucher, N; Cambon, Z; Chiavassa, H; Larbi, A; Faruch, M

    2016-01-01

    Fat is not just used by the body as bulk tissue. In addition to its role in storing energy and regulating hormone action, fat is used in some parts of the body for its mechanical properties. The anatomy of anterior knee fat is more complex than it appears at first sight and is capable of withstanding considerable compressive and shear stress. Specific lesions occur when such mechanical stress exceeds the physiological limits and are yet little known. Superficial fat can be the site of either acute injury by closed degloving called the Morel-Lavallée lesion or chronic injury, when subject to repeat excessive shear forces, due to more complex and less well-defined disruptions that result in pseudo-bursitis. There are three main anterior, intracapsular and extrasynovial fat pads in the knee joint, which are the infrapatellar fat pad (IFP) or Hoffa's fat pad, the quadriceps fat pad and the prefemoral fat pad. The IFP plays an important role as a mechanical shock absorber and guides the patella tendon and even the patella itself during flexion-extension movements. In response to repeated excessive stress, an inflammatory reaction and swelling of the IFP is first observed, followed by a fibrotic reaction with metaplastic transformation into fibrous, cartilaginous or bone tissue. More rarely, the two other deep fat pads (quadriceps and prefemoral) can, if subject to repeated stress, undergo similar restructuring inflammatory reactions with metaplasia resulting in tissue hardening, anterior pain and partial loss of function. PMID:27118690

  10. Knee joint immobilization decreases aggrecan gene expression in the meniscus.

    PubMed

    Djurasovic, M; Aldridge, J W; Grumbles, R; Rosenwasser, M P; Howell, D; Ratcliffe, A

    1998-01-01

    Aggrecan is the major proteoglycan of the meniscus, and its primary function is to give the meniscus its viscoelastic compressive properties. The objective of this study was to determine the effect of joint immobilization on aggrecan gene expression in the meniscus. The right hindlimbs of six mature beagles were knee cast-immobilized in 90 degrees of flexion and supported by a sling to prevent weightbearing, while the contralateral limb was left free to bear weight. The animals were sacrificed at 4 weeks, and the anterior and posterior halves of the medial and lateral menisci were analyzed separately. Analysis of aggrecan gene expression by quantitative polymerase chain reaction showed decreased aggrecan gene expression in menisci from immobilized knees (P < 0.01, two-way analysis of variance). Aggrecan gene expression decreased by a factor of 2 to 5.5 in the different regions examined. Analysis of the composition of the meniscus also showed decreased proteoglycan content and increased water content with immobilization (P < 0.05, two-way analysis of variance). These results show that joint immobilization can significantly affect meniscal cellular activity and composition and can therefore potentially affect meniscal function. PMID:9617414

  11. Plantar-flexion of the ankle joint complex in terminal stance is initiated by subtalar plantar-flexion: A bi-planar fluoroscopy study.

    PubMed

    Koo, Seungbum; Lee, Kyoung Min; Cha, Young Joo

    2015-10-01

    Gross motion of the ankle joint complex (AJC) is a summation of the ankle and subtalar joints. Although AJC kinematics have been widely used to evaluate the function of the AJC, the coordinated movements of the ankle and subtalar joints are not well understood. The purpose of this study was to accurately quantify the individual kinematics of the ankle and subtalar joints in the intact foot during ground walking by using a bi-planar fluoroscopic system. Bi-planar fluoroscopic images of the foot and ankle during walking and standing were acquired from 10 healthy subjects. The three-dimensional movements of the tibia, talus, and calcaneus were calculated with a three-dimensional/two-dimensional registration method. The skeletal kinematics were quantified from 9% to 86% of the full stance phase because of the limited camera speed of the X-ray system. At the beginning of terminal stance, plantar-flexion of the AJC was initiated in the subtalar joint on average at 75% ranging from 62% to 76% of the stance phase, and plantar-flexion of the ankle joint did not start until 86% of the stance phase. The earlier change to plantar-flexion in the AJC than the ankle joint due to the early plantar-flexion in the subtalar joint was observed in 8 of the 10 subjects. This phenomenon could be explained by the absence of direct muscle insertion on the talus. Preceding subtalar plantar-flexion could contribute to efficient and stable ankle plantar-flexion by locking the midtarsal joint, but this explanation needs further investigation. PMID:26238571

  12. Bilateral Volleyball-Related Deformity of the Little Fingers: Mallet Finger and Clinodactyly Mimic

    PubMed Central

    Uslu, Mustafa; Solak, Kazim; Ozsahin, Mustafa; Uzun, Hakan

    2011-01-01

    A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP) joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis. Key points As a result of repeated micro traumas to the physial region, flexion and valgus deformities of the distal interphalangeal (DIP) joints should be occurred. Sports injuries to the hand often require treatment in orthopedic departments to avoid permanent deformities. Short- or long-term functional results can be gained by simple splinting procedures and abstention from play. PMID:24149318

  13. Automatic locking orthotic knee device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1993-01-01

    An articulated tang in clevis joint for incorporation in newly manufactured conventional strap-on orthotic knee devices or for replacing such joints in conventional strap-on orthotic knee devices is discussed. The instant tang in clevis joint allows the user the freedom to extend and bend the knee normally when no load (weight) is applied to the knee and to automatically lock the knee when the user transfers weight to the knee, thus preventing a damaged knee from bending uncontrollably when weight is applied to the knee. The tang in clevis joint of the present invention includes first and second clevis plates, a tang assembly and a spacer plate secured between the clevis plates. Each clevis plate includes a bevelled serrated upper section. A bevelled shoe is secured to the tank in close proximity to the bevelled serrated upper section of the clevis plates. A coiled spring mounted within an oblong bore of the tang normally urges the shoes secured to the tang out of engagement with the serrated upper section of each clevic plate to allow rotation of the tang relative to the clevis plate. When weight is applied to the joint, the load compresses the coiled spring, the serrations on each clevis plate dig into the bevelled shoes secured to the tang to prevent relative movement between the tang and clevis plates. A shoulder is provided on the tang and the spacer plate to prevent overextension of the joint.

  14. Exercise and the Knee Joint.

    ERIC Educational Resources Information Center

    Clarke, H. Harrison, Ed.

    1976-01-01

    This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

  15. 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.

  16. Minimally Invasive Total Knee Arthroplasty: A Comparative Study to the Standard Approach

    PubMed Central

    Dabboussi, Naji; Sakr, Mazen; Girard, Julien; Fakih, Riad

    2012-01-01

    Background: Minimally invasive surgery has gained popularity over the past several years. Early results have shown better functional outcome with early recovery and rapid rehabilitation. Aim: Evaluation of the short-term clinical and functional outcome of minimally invasive surgery total knee arthroplasty (MIS-TKA) compared with the traditional total knee arthroplasty (TKA). Materials and Methods: During 2009, all cases scheduled for primary TKA through the modified mini-mid-vastus approach (MIS group) were studied. This group included 40 knees and was compared to a cohort control group of similar number of patients (40 knees) that underwent the procedure through the standard conventional technique (standard group). Results: Patients in the MIS group showed significant decrease in postoperative pain, blood loss in first 24 hours, and in hospital stay. Furthermore, they achieved motion considerably faster than the standard group with earlier return of quadriceps function and greater early flexion. Conclusion: This study proved that MIS-TPA has the ability to couple the benefits of less invasive surgical approach. PMID:22408753

  17. Comparison of wear in a total knee replacement under different kinematic conditions.

    PubMed

    Barnett, P I; Fisher, J; Auger, D D; Stone, M H; Ingham, E

    2001-01-01

    A six station ProSim (Manchester, UK) knee simulator was used to assess the wear of six PFC (DePuy) fixed bearing total knee replacements under two different kinematic conditions defined as low and high kinematic inputs. The high kinematics displacement and rotation inputs were based on the kinematics of the natural knee with ISO standards used for the axial load and flexion. Low kinematics were defined as approximately half the magnitude. The six specimens were run for three million cycles under low kinematics and three million cycles under high kinematics. The mean wear rate found during the low kinematics phase was 7.7 +/- 2 mm3 per million cycles. This then increased significantly to an average wear rate of 41 +/- 14 mm3 during the high kinematics input phase. The wear areas were characterized by a predominant damage mode of burnishing with some abrasive wear occurring during the high kinematics phase. This study supports the findings that introduction of cross-shearing of the polyethylene by introducing both rotational and anterior/posterior displacement increases the wear rate. This has implications for younger patients with higher levels of activity that need knee replacements. PMID:15348361

  18. Hamstrings and iliotibial band forces affect knee kinematics and contact pattern.

    PubMed

    Kwak, S D; Ahmad, C S; Gardner, T R; Grelsamer, R P; Henry, J H; Blankevoort, L; Ateshian, G A; Mow, V C

    2000-01-01

    Many clinical studies have emphasized the role of the hamstrings and the iliotibial band on knee mechanics, although few biomechanical studies have investigated it. This study therefore examined two hypotheses: (a) with loading of the hamstrings, the tibia translates posteriorly and rotates externally and the tibial contact pattern shifts anteriorly; furthermore, the changes in tibial kinematics alter patellar kinematics and contact; and (b) loading the iliotibial band alters the kinematics and contact pattern of the tibiofemoral joint similarly to loading the hamstrings, and loading the iliotibial band laterally translates the patella and its contact location. Five cadaveric knee specimens were tested with a specially designed knee-joint testing machine in an open-chain configuration. At various flexion angles, the knees were tested always with a quadriceps force but with and without a hamstrings force and with and without an iliotibial band force. The results support the first hypothesis. Hence, the hamstrings may be important anterior and rotational stabilizers of the tibia, a role similar to that of the anterior cruciate ligament. The results also support the second hypothesis, although the iliotibial band force had a smaller effect on the tibia than did the hamstrings force. Both forces also changed patellar kinematics and contact, demonstrating that these structures should also be considered during the clinical management of patellar disorders. PMID:10716285

  19. Baseline Articular Contact Stress Levels Predict Incident Symptomatic Knee Osteoarthritis Development in the MOST Cohort

    PubMed Central

    Segal, Neil A.; Anderson, Donald D.; Iyer, Krishna S.; Baker, Jennifer; Torner, James C.; Lynch, John A.; Felson, David T.; Lewis, Cora E.; Brown, Thomas D.

    2010-01-01

    We studied whether contact stress estimates from knee magnetic resonance images (MRI) predict the development of incident symptomatic tibiofemoral osteoarthritis (OA) 15 months later in an at-risk cohort. This nested case-control study was conducted within a cohort of 3026 adults, age 50 to 79 years. Thirty cases with incident symptomatic tibiofemoral OA by their 15-month follow-up visit were randomly selected and matched with 30 control subjects. Symptomatic tibiofemoral OA was defined as daily knee pain/stiffness and Kellgren-Lawrence Grade ≥2 on weight bearing, fixed-flexion radiographs. Tibiofemoral geometry was segmented on baseline knee MRI, and contact stresses were estimated using discrete element analysis. Linear mixed models for repeated measures were used to examine the association between articular contact stress and case/control status. No significant inter-group differences were found for age, sex, BMI, weight, height, or limb alignment. However, the maximum articular contact stress was 0.54 ± 0.77 MPa (mean ± SD) higher in incident OA cases compared to that in control knees (p=0.0007). The interaction between case-control status and contact stress was significant above 3.2 MPa (p<0.0001). The presence of differences in estimated contact stress 15 months prior to incidence suggests a biomechanical mechanism for symptomatic tibiofemoral OA and supports the ability to identify risk by subject-specific biomechanical modeling. PMID:19533741

  20. A model of flexion-extension movement in hip joint using polynomial interpolation

    NASA Astrophysics Data System (ADS)

    Toth-Taşcǎu, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    The study proposes a mathematical model of flexion-extension movement in hip joint based on Lagrange polynomial interpolation. In order to develop and validate the proposed model the angle of flexion-extension (F-E) in hip joint was analyzed. The two main reasons of this option rely on the importance of the hip joint in human locomotion and the fact that flexion-extension movement is developed in most of the human joints. The mathematical model of joint movement allows developing a more detailed kinematic analysis of the joint movements. The raw data representing the variation of the flexion-extension angle in hip joint was achieved by experimental kinematic analysis of a lot of ten young healthy subjects.

  1. 49 CFR 572.145 - Upper and lower torso assemblies and torso flexion test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... lumbar spine and abdomen of a fully assembled dummy (drawing 210-0000) to flexion articulation between... in paragraph (c) of this section, the lumbar spine-abdomen assembly shall flex by an amount...

  2. 49 CFR 572.145 - Upper and lower torso assemblies and torso flexion test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... lumbar spine and abdomen of a fully assembled dummy (drawing 210-0000) to flexion articulation between... in paragraph (c) of this section, the lumbar spine-abdomen assembly shall flex by an amount...

  3. Investigating the effects of movement speed on the lumbopelvic coordination during trunk flexion.

    PubMed

    Zhou, Jie; Ning, Xiaopeng; Fathallah, Fadi

    2016-08-01

    Movement speed during trunk flexion has long been reported to affect task performance and biomechanical responses. The current study investigated how movement speed changed lumbopelvic coordination, especially lumbopelvic continuous relative phase and phase variability during trunk flexion. Eighteen subjects executed a paced trunk flexion routine over time periods of 3, 7, 11 and 15seconds. The results demonstrated that compared with the 3-s condition, lumbopelvic continuous relative phase was 98.8% greater in the 15-s condition, indicating a more anti-phase coordination pattern. This pattern is suggested to mitigate the increased spinal loading associated with the longer duration of muscle exertion. Additionally, phase variability was 18.8% greater in the 15-s trials than the 3-s trials, such an unstable coordination pattern is likely caused by the more active neuromuscular control. Findings of this study provide important information about the effects of movement speed on lumbopelvic coordination during trunk flexion. PMID:27209236

  4. A sloped seat wedge can change the kinematics of the lumbar spine of seated workers with limited hip flexion.

    PubMed

    Kim, Ji-Won; Kang, Min-Hyeok; Noh, Kyung-Hee; Kim, Jun-Seok; Oh, Jae-Seop

    2014-08-01

    [Purpose] The purpose of this study was to determine whether a wedge type seat decreases the lumbar flexion angle of seated workers with limited hip flexion. [Subjects] Twelve sedentary workers with limited hip flexion were recruited. [Methods] Three seat surfaces were used: a level surface, a forward-inclining wedge, and a backward-reclining wedge. The angles of lumbar flexion and pelvic tilt were measured using a three-dimensional motion analysis system. Differences in kinematic data of the subjects seated on the three seat surfaces were analyzed using repeated one-way analysis of variance. [Results] The degree of lumbar flexion decreased significantly when using the forward-inclining wedge compared with the level surface and backward-reclining wedge. [Conclusion] These findings suggest that sitting on a forward-inclining wedge may be useful for minimizing the compensatory lumbar flexion of individuals with limited hip flexion who work in a seated position. PMID:25202175

  5. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.176... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.176 Knees and knee impact test procedure. (a) The knee assembly for the purpose of this test is the part of the leg assembly shown in drawing...

  6. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N). ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure....

  7. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N). ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure....

  8. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.176... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.176 Knees and knee impact test procedure. (a) The knee assembly for the purpose of this test is the part of the leg assembly shown in drawing...

  9. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  10. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N). ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure....

  11. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.176... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.176 Knees and knee impact test procedure. (a) The knee assembly for the purpose of this test is the part of the leg assembly shown in drawing...

  12. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  13. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N). ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure....

  14. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  15. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N). ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure....

  16. Cementless porous-coated total knee arthroplasty: 10-year results in a consecutive series.

    PubMed

    Schrøder, H M; Berthelsen, A; Hassani, G; Hansen, E B; Solgaard, S

    2001-08-01

    We report the results of 114 AGC 2000 porous-coated, cementless total knee arthroplasties (TKA) performed consecutively in 102 patients during the period 1984-1986. After 10 years, 58 TKAs in 52 patients were evaluated with patient assessment, Hospital for Special Surgery knee score, weight-bearing radiographs done under fluoroscopic control, and survivorship analysis. All dropouts within the first 9 years were patients dying with a functioning TKA except 1 revision secondary to a supracondylar fracture after 8.5 years. Of the patients, 53 (92%) were satisfied or very satisfied with their TKA, and 55 (95%) of the knees were rated good or excellent. There was no pain in 53 knees, and the median knee flexion was 110 degrees. Six radiolucencies >1 mm were found beneath parts of the tibial component, and 5 radiolucencies were seen beneath the femoral component. None had progressed compared with the 5-year follow-up, and in all cases trabeculae could be seen reaching the prosthetic component. No migrations had occurred since the 5-year follow-up. No obvious joint space reduction was seen. Osteolysis presenting as an isolated cyst was found in 1 knee in the lateral tibial condyle and was not progressive. Two tibial components had been revised because of aseptic loosening and 1 because of septic loosening, all within the first 3 years. No femoral or patellar components were revised. The cumulative prosthesis survival rate after 10 to 11 years was 97%. When pain and radiographic loosening also were considered, the success rate was 87%. Cementless insertion of a nonmodular, porous-coated TKA resulted in a long-term durable bone-prosthesis interface. The flat-on-flat articulation did not result in catastrophic polyethylene wear or osteolysis within the first 10 years. PMID:11503114

  17. Dislocation following total knee arthroplasty: A report of six cases

    PubMed Central

    Villanueva, Manuel; Ríos-Luna, Antonio; Pereiro, Javier; Fahandez-Saddi, Homid; Pérez-Caballer, Antonio

    2010-01-01

    Background: Dislocation following total knee arthroplasty (TKA) is the worst form of instability. The incidence is from 0.15 to 0.5%. We report six cases of TKA dislocation and analyze the patterns of dislocation and the factors related to each of them. Materials and Methods: Six patients with dislocation of knee following TKA are reported. The causes for the dislocations were an imbalance of the flexion gap (n=4), an inadequate selection of implants (n=1), malrotation of components (n=1) leading to incompetence of the extensor mechanism, or rupture of the medial collateral ligament (MCC). The patients presented complained of pain, giving way episodes, joint effusion and difficulty in climbing stairs. Five patients suffered posterior dislocation while one anterior dislocation. An urgent closed reduction of dislocation was performed under general anaesthesia in all patients. All patients were operated for residual instability by revision arthroplasty after a period of conservative treatment. Results: One patient had deep infection and knee was arthrodesed. Two patients have a minimal residual lag for active extension, including a patient with a previous patellectomy. Result was considered excellent or good in four cases and fair in one, without residual instability. Five out of six patients in our series had a cruciate retaining (CR) TKA designs: four were revised to a posterior stabilized (PS) TKA and one to a rotating hinge design because of the presence of a ruptured MCL. Conclusion: Further episodes of dislocation or instability will be prevented by identifying and treating major causes of instability. The increase in the level of constraint and correction of previous technical mistakes is mandatory. PMID:20924487

  18. Constrained Implants in Total Knee Replacement.

    PubMed

    Touzopoulos, Panagiotis; Drosos, Georgios I; Ververidis, Athanasios; Kazakos, Konstantinos

    2015-05-01

    Total knee replacement (TKR) is a successful procedure for pain relief and functional restoration in patients with advanced osteoarthritis. The number of TKRs is increasing, and this has led to an increase in revision surgeries. The key to long-term success in both primary and revision TKR is stability, as well as adequate and stable fixation between components and underlying bone. In the vast majority of primary TKRs and in some revision cases, a posterior cruciate retaining or a posterior cruciate substituting device can be used. In some primary cases with severe deformity or ligamentous instability and in most of the revision cases, a more constrained implant is required. The purpose of this paper is to review the literature concerning the use of condylar constrained knee (CCK) and rotating hinge (RH) implants in primary and revision cases focusing on the indications and results. According to this review, although excellent and very good results have been reported, there are limitations of the existing literature concerning the indications for the use of constrained implants, the absence of long-term results, and the limited comparative studies. PMID:26055025

  19. Queen Alexandra's Knee.

    PubMed

    Pinals, Robert S

    2016-06-01

    In 1867, Alexandra, the 22-year-old Princess of Wales, late in her third pregnancy, had sudden onset of a febrile illness. There was a brief period of migratory arthritis, followed by persistent, severe inflammation in 1 knee. A diagnosis of rheumatic fever was made by her physicians, but the course of her illness differed greatly from the expected one. In this report reviewing her disorder, the suggestion is made that she more likely had gonococcal arthritis and that the infection was transmitted to her by her husband, the future King Edward VII, then known as "The Playboy Prince." PMID:27219308

  20. Conversion of lateral unicompartmental arthroplasty to anterior cruciate retaining tricompartmental knee arthroplasty.

    PubMed

    Rolston, Lindsey; Moore, Christopher

    2010-06-01

    This case report presents the conversion of a lateral unicompartmental arthroplasty (UKA) to an anterior cruciate retaining tricompartmental knee arthroplasty. The patient presented with disease progression to the medial and patellofemoral compartments of the knee, in addition to significant varus deformity. During revision surgery, the previously implanted UKA device was found to be well fixed and in good condition. The conventional treatment option would be conversion to total knee arthroplasty (TKA). However, in this case conversion to a tricompartmental, ligament sparing arthroplasty via implantation of a bicompartmental knee arthroplasty (BKA) device was found to be feasible. In UKA revision cases where the device is functional, the current surgical approach may be an appropriate alternative to conventional TKA. PMID:19875295

  1. Median nerve deformation and displacement in the carpal tunnel during index finger and thumb motion.

    PubMed

    van Doesburg, Margriet H M; Yoshii, Yuichi; Villarraga, Hector R; Henderson, Jacqueline; Cha, Stephen S; An, Kai-Nan; Amadio, Peter C

    2010-10-01

    The purpose of this study was to investigate the deformation and displacement of the normal median nerve in the carpal tunnel during index finger and thumb motion, using ultrasound. Thirty wrists from 15 asymptomatic volunteers were evaluated. Cross-sectional images during motion from full extension to flexion of the index finger and thumb were recorded. On the initial and final frames, the median nerve, flexor pollicis longus (FPL), and index finger flexor digitorum superficialis (FDS) tendons were outlined. Coordinate data were recorded and median nerve cross-sectional area, perimeter, aspect ratio of the minimal-enclosing rectangle, and circularity in extension and flexion positions were calculated. During index finger flexion, the tendon moves volarly while the nerve moves radially. With thumb flexion, the tendon moves volarly, but the median nerve moves toward the ulnar side. In both motions, the area and perimeter of the median nerve in flexion were smaller than in extension. Thus, during index finger or thumb flexion, the median nerve in a healthy human subject shifts away from the index finger FDS and FPL tendons while being compressed between the tendons and the flexor retinaculum in the carpal tunnel. We are planning to compare these data with measurements in patients with carpal tunnel syndrome (CTS) and believe that these parameters may be useful tools for the assessment of CTS and carpal tunnel mechanics with ultrasound in the future. PMID:20225286

  2. Spinal deformity.

    PubMed

    Bunnell, W P

    1986-12-01

    Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis. PMID:3786010

  3. Anatomical versus Non-Anatomical Single Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Comparison of Knee Stability

    PubMed Central

    Lim, Hong-Chul; Yoon, Yong-Cheol; Wang, Joon-Ho

    2012-01-01

    Background The purpose of this study was to compare the initial stability of anatomical and non-anatomical single bundle anterior cruciate ligament (ACL) reconstruction and to determine which would better restore intact knee kinematics. Our hypothesis was that the initial stability of anatomical single bundle ACL reconstruction would be superior to that of non-anatomical single bundle ACL reconstruction. Methods Anterior tibial translation (ATT) and internal rotation of the tibia were measured with a computer navigation system in seven pairs of fresh-frozen cadaveric knees under two testing conditions (manual maximum anterior force, and a manual maximum anterior force combined with an internal rotational force). Tests were performed at 0, 30, 60, and 90 degrees of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either anatomical or non-anatomical single bundle ACL reconstruction. Results Under manual maximal anterior force, both reconstruction techniques showed no significant difference of ATT when compared to ACL intact knee state at 30° of knee flexion (p > 0.05). Under the combined anterior and internal rotatory force, non-anatomical single-bundle ACL reconstruction showed significant difference of ATT compared to those in ACL intact group (p < 0.05). In contrast, central anatomical single bundle ACL reconstruction showed no significant difference of ATT compared to those in ACL intact group (p > 0.05). Internal rotation of the tibia showed no significant difference in the ACL intact, the ACL transected, non-anatomical reconstructed and anatomical reconstructed knees. Conclusions Anatomical single bundle ACL reconstruction restored the initial stability closer to the native ACL under combined anterior and internal rotational forces when compared to non-anatomical ACL single bundle reconstruction. PMID:23205233

  4. [Intraoperative Evaluation of Total Knee Arthroplasty: Anatomic and Kinematic Assessment with Trial Components].

    PubMed

    von Roth, P; Pfitzner, T; Fuchs, M; Perka, C

    2015-06-01

    The intraoperative use of trial components in total knee arthroplasty (TKA) is of paramount importance to prevent inadequate ligament balance and to achieve optimal position of the definitive components. This review demonstrates an 8-step algorithm to assess the anatomy of the femoral, tibial and patellar component as well as the kinematics of the tibiofemoral and patellofemoral joints. Trial components allow an easy assessment of the anatomic fit of the final implants. Upon the trials insertion, bone coverage and the component overhang should be evaluated. The femoral rotation should be assessed using the transepicondylar axis and for the tibial component rotation assessment, the tibial tuberosity would be the most reliable bony landmark. Addressing the patella, sizing and bone coverage should be thoroughly evaluated. In order to restore physiological kinematics the remnants of the meniscus rim can be used to determine the correct reconstruction of the joint line. A tight extension gap results in limited extension, whereas a tight or unbalanced flexion gap leads to "booking" or "spin-out" of the inlay. The POLO test (pull-out, lift- off) allows an easy assessment of the posterior cruciate ligament tension and the size of the flexion gap as well. To prevent postoperative dislocation and overstuffing, specific tests for correct patellar positioning and tracking support should be performed. The anatomy and kinematics of total knee arthroplasty have to be evaluated by trial components on a routine basis before inserting the final implants in order to identify implant positioning errors and inadequate ligament balance. PMID:26114563