Ankle Loading Research Articles

Concomitant osteochondral lesion of the talus affects in vivo ankle kinetics in patients with chronic ankle instability.

This cross-sectional study aimed to investigate the in vivo ankle kinetic alterations in patients with concomitant chronic ankle instability (CAI) and osteochondral lesion of the talus (OLT), which may offer opportunities for clinician intervention in treatment and rehabilitation. A total of 16 subjects with CAI (eight without OLT and eight with OLT) and eight healthy subjects underwent gait analysis in a stair descent setting. Inverse dynamic analysis was applied to ground reaction forces and marker trajectories using the AnyBody Modeling System. One-dimensional statistical parametric mapping was performed to compare ankle joint reaction force and joint moment curve among groups. The patients with OLT showed significantly increased dorsiflexion moment in the ankle joint compared with healthy subjects during 38.2% to 40.9% of the gait cycle, and increased eversion moment in the ankle joint compared with patients without OLT during 25.5% to 27.6% of the gait cycle. Compared with healthy subjects, the patients with OLT showed increased anterior force during 42% to 43% of the gait cycle, and maximal medial force (p = 0.005, ηp2 = 0.399). The patients with concomitant CAI and OLT exhibit increased dorsiflexion and eversion moment, as well as increased anterior and medial ankle joint reaction force during stair descent, compared with patients with CAI but without OLT and healthy subjects, respectively. Thus, a rehabilitative regimen targeting excessive ankle dorsiflexion and eversion moment may help to reduce ankle joint loading.

DOES A NOVEL INTRAOPERATIVE NAVIGATION PLATFORM ALLOW TO RETAIN NATIVE KNEE FUNCTION FOLLOWING TOTAL KNEE ARTHROPLASTY?

IntroductionThis study aimed to evaluate the effectiveness of a novel intraoperative navigation platform for total knee arthroplasty (TKA) in restoring native knee joint kinematics and strains in the medial collateral ligament (MCL) and lateral collateral ligament (LCL) during squatting motions.MethodSix cadaver lower limbs underwent computed tomography scans to design patient-specific guides. Using these scans, bony landmarks and virtual single-line collateral ligaments were identified to provide intraoperative real-time feedback, aided in bone resection, implant alignment, tibiofemoral kinematics, and collateral ligament elongations, using the navigation platform. The specimens were subjected to squatting (35°-100°) motions on a physiological ex vivo knee simulator, maintaining a constant 110N vertical ankle load regulated by active quadriceps and bilateral hamstring actuators. Subsequently, each knee underwent a medially-stabilized TKA using the mechanical alignment technique, followed by a retest under the same conditions used preoperatively. Using a dedicated wand, MCL and LCL insertions—anterior, middle, and posterior bundles—were identified in relation to bone-pin markers. The knee kinematics and collateral ligament strains were analyzed from 3D marker trajectories captured by a six-camera optical system.ResultBoth native and TKA conditions demonstrated similar patterns in tibial valgus orientation (Root Mean Square Error (RMSE=1.7°), patellar flexion (RMSE=1.2°), abduction (RMSE=0.5°), and rotation (RMSE=0.4°) during squatting (p>0.13). However, a significant difference was found in tibial internal rotation between 35° and 61° (p<0.045, RMSE=3.3°). MCL strains in anterior (RMSE=1.5%), middle (RMSE=0.8%), and posterior (RMSE=0.8%) bundles closely matched in both conditions, showing no statistical differences (p>0.05). Conversely, LCL strain across all bundles (RMSE<4.6%) exhibited significant differences from mid to deep flexion (p<0.048).ConclusionThe novel intraoperative navigation platform not only aims to achieve planned knee alignment but also assists in restoring native knee kinematics and collateral ligament behavior through real-time feedback.AcknowledgmentThis study was funded by Medacta International (Castel San Pietro, Switzerland).

Lower limb joint loading during high-impact activities: implication for bone health.

Osteoporosis results in low-trauma fractures affecting millions globally, in particular elderly populations. Despite the inclusion of physical activity in fracture prevention strategies, the optimal bone-strengthening exercises remain uncertain, highlighting the need for a deeper understanding of lower limb joint loading dynamics across various exercise types and levels. This study examines lower limb joint loading during high-impact exercises across different intensities. A total of 40 healthy, active participants were recruited (mean ± SD: age of 40.3 ± 13.1yr; height 1.71 ± 0.08m; and mass 68.44 ± 11.67kg). Motion capture data and ground reaction forces of 6 different exercises: a self-selected level of walking, running, countermovement jump, squat jump, unilateral hopping, and bilateral hopping were collected for each participant. Joint reaction forces were estimated using lower body musculoskeletal models developed in OpenSim. Running and hopping increased joint forces compared to walking, notably at the hip (83% and 21%), knee (134% and 94%), and ankle (94% and 77%), while jump exercises reduced hip and ankle loading compared to walking (36% and 19%). Joint loading varied with exercise type and intensity, with running faster increasing forces on all joints, particularly at the hip. Sprinting increased forces at the hip but lowered knee and ankle forces. Higher jumps intensified forces on all joints, while faster hopping reduced forces. The wide variation of lower limb joint loading observed across the exercises tested in this study underscores the importance of implementing diverse exercise routines to optimize overall bone health and strengthen the musculoskeletal structure. Practitioners must therefore ensure that exercise programs include movements that are specifically suitable for their intended purpose.

Mechanical Ankle Joint Axis Point on a Hip-to-Calcaneus Long Leg View Correlates Significantly With SPECT/CT Activation in Symptomatic Asymmetric Ankle Osteoarthritis.

Asymmetric joint load is the main cause of development of ankle osteoarthritis (OA). Realignment surgery aims to transfer ankle joint load from the degenerative area toward the uninvolved area. Determination of the optimal shift is still challenging. When the degenerative area is correlated to the ankle joint mechanical axis establishing an optimal target angle for corrective surgery may become more feasible. The primary aim of our study was to investigate if the area of ankle joint activation on single-photon emission computed tomography and conventional computed tomography (SPECT/CT) imaging correlates with the mechanical ankle joint axis point (MAJAP). In this cross-sectional study, patients 18 years or older with symptomatic asymmetric ankle OA and a hip-to-calcaneus long leg view with SPECT/CT of the affected ankle were eligible for inclusion. Primary outcome was MAJAP divided into 3 alignment categories (medial shift, neutral, lateral shift). SPECT/CT activation was determined in 8 different areas of the ankle joint. A Spearman rho correlation coefficient was calculated to investigate the relationship between the alignment categories and SPECT/CT activation in the 8 areas. Forty-nine patients (mean age 58.8 [SD 10.0] years) with 52 ankles with moderate to severe asymmetric OA were included. A significantly (Spearman rho -0.379 [P = .006] and Spearman rho -0.279 [P = .045]) higher proportion of ankles with radioisotope uptake in the anteromedial ankle joint areas (zones 1 and 5) was seen in the medial shift category. A significantly (Spearman rho .312 (P = .025)) higher proportion of ankles with radioisotope uptake in the anterolateral ankle joint area (zone 8) was seen in the lateral shift category. We found in this patient group that the area of SPECT/CT uptake in asymmetric ankle OA was associated to MAJAP measured on hip-to-calcaneus weightbearing views, although the strength of the correlation is weak to moderate. Consequently, nonweightbearing metabolic SPECT/CT radiotracer uptake has the potential to help determine the area to unload in ankle joint-preserving alignment surgery.

Analysis of lumbar spine loading during walking in patients with chronic low back pain and healthy controls: An OpenSim-Based study.

Low back pain (LBP) is one of the most prevalent and disabling disease worldwide. However, the specific biomechanical changes due to LBP are still controversial. The purpose of this study was to estimate the lumbar and lower limb kinematics, lumbar moments and loads, muscle forces and activation during walking in healthy adults and LBP. A total of 18 healthy controls and 19 patients with chronic LBP were tested for walking at a comfortable speed. The kinematic and dynamic data of the subjects were collected by 3D motion capture system and force plates respectively, and then the motion simulation was performed by OpenSim. The OpenSim musculoskeletal model was used to calculate lumbar, hip, knee and ankle joint angle variations, lumbar moments and loads, muscle forces and activation of eight major lumbar muscles. In our results, significant lower lumbar axial rotation angle, lumbar flexion/extension and axial rotation moments, as well as the muscle forces of the four muscles and muscle activation of two muscles were found in patients with LBP than those of the healthy controls (p < 0.05). This study may help providing theoretical support for the evaluation and rehabilitation treatment intervention of patients with LBP.

Influence of Walking Over Unexpected Uneven Terrain on Joint Loading for Individuals With Transtibial Amputation.

Individuals with transtibial amputation (TTA) experience asymmetric lower-limb loading which can lead to joint pain and injuries. However, it is unclear how walking over unexpected uneven terrain affects their loading patterns. This study sought to use modeling and simulation to determine how peak joint contact forces and impulses change for individuals with unilateral TTA during an uneven step and subsequent recovery step and how those patterns compare to able-bodied individuals. We expected residual limb loading during the uneven step and intact limb loading during the recovery step would increase relative to flush walking. Further, individuals with TTA would experience larger loading increases compared to able-bodied individuals. Simulations of individuals with TTA showed during the uneven step, changes in joint loading occurred at all joints except the prosthetic ankle relative to flush walking. During the recovery step, intact limb joint loading increased in early stance relative to flush walking. Simulations of able-bodied individuals showed large increases in ankle joint loading for both surface conditions. Overall, increases in early stance knee joint loading were larger for those with TTA compared to able-bodied individuals during both steps. These results suggest that individuals with TTA experience altered joint loading patterns when stepping on uneven terrain. Future work should investigate whether an adapting ankle-foot prosthesis can mitigate these changes to reduce injury risk.

Joint kinematics and SPM analysis of gait in children with and without Down syndrome

BackgroundIndividuals with Down syndrome (DS) walk with altered gait patterns compared to their typically developing (TD) peers. While walking at faster speeds and with external ankle load, preadolescents with DS demonstrate spatiotemporal and kinetic improvements. However, evidence of joint kinematic adjustments is unknown, which is imperative for targeted rehabilitation design. Research questionHow does increasing walking speed and adding ankle load affect the joint kinematics of children with and without DS during overground walking? MethodsIn this cross-sectional observational study, thirteen children with DS aged 7–11 years and thirteen age- and sex-matched TD children completed overground walking trials. There were two speed conditions: normal speed and fast speed (as fast as possible without running). There were two load conditions: no load and ankle load (2% of body mass added bilaterally above the ankle). A motion capture system was used to register the ankle, knee, and hip joint angles in the sagittal plane. Peak flexion/extension angles, range of motion, and timing of peak angles were identified. In addition, statistical parametric mapping (SPM) was conducted to evaluate the trajectory of the ankle, knee, and hip joint angles across the entire gait cycle. Results and significanceSPM analysis revealed the DS group walked with greater ankle, knee, and hip flexion compared to the TD group for most of the gait cycle, regardless of condition. Further, increasing walking speed led to improved ankle joint kinematics in both groups by shifting peak plantarflexion closer to toe-off. However, knee extension during stance was challenged in the DS group. Adding ankle load improved hip and knee kinematics in both groups but reduced peak plantarflexion around toe-off. The kinematic adjustments in the DS group suggest specific motor strategies to accommodate their neuromuscular deficits, which can provide a foundation to design targeted gait-based interventions for children with DS.

The association between obesity, knee pain, and gait during stair descent in older adults with knee osteoarthritis

BackgroundObesity and knee osteoarthritis adversely affect activities of daily living in older adults. Together, the complexities of their interaction on mobility, including stair negotiation, are unresolved. The purpose of this study was to determine the relationship between obesity, pain, and stair negotiation in older adults with knee osteoarthritis. MethodsOlder adults with symptomatic knee osteoarthritis and overweight or obesity participated in the study (n = 28; age range = 57.0–78.0 yrs.; body mass index range = 26.6–42.8 kg•m−2). The Western Ontario and McMaster Universities Osteoarthritis Index pain subscale was used to measure knee pain. Measurements included a three-dimensional biomechanical analysis during descent on a set of force plate-instrumented stairs and a timed stair descent test. Pearson's r was used to determine associations between body mass index and pain, stair descent weight-acceptance phase vertical ground reaction force (vGRF) variables and lower extremity joint kinematics and kinetics, and timed stair descent performance. FindingsSignificant correlations existed between body mass index and pain (r = 0.41; p = 0.03), peak vGRF (r = 0.39; p = 0.04), vertical impulse (r = 0.49; p = 0.008), and peak ankle plantar flexor moments (r = 0.50; p = 0.007) in older adults with knee osteoarthritis. InterpretationGreater obesity in older adults with knee osteoarthritis was associated with greater knee pain and higher ankle joint loads during stair descent. These results support the recommendations of osteoarthritis treatment guidelines for weight-loss as a first-line of treatment for older adults with obesity and knee osteoarthritis.

A framework based on subject-specific musculoskeletal models and Monte Carlo simulations to personalize muscle coordination retraining

Excessive loads at lower limb joints can lead to pain and degenerative diseases. Altering joint loads with muscle coordination retraining might help to treat or prevent clinical symptoms in a non-invasive way. Knowing how much muscle coordination retraining can reduce joint loads and which muscles have the biggest impact on joint loads is crucial for personalized gait retraining. We introduced a simulation framework to quantify the potential of muscle coordination retraining to reduce joint loads for an individuum. Furthermore, the proposed framework enables to pinpoint muscles, which alterations have the highest likelihood to reduce joint loads. Simulations were performed based on three-dimensional motion capture data of five healthy adolescents (femoral torsion 10°–29°, tibial torsion 19°–38°) and five patients with idiopathic torsional deformities at the femur and/or tibia (femoral torsion 18°–52°, tibial torsion 3°–50°). For each participant, a musculoskeletal model was modified to match the femoral and tibial geometry obtained from magnetic resonance images. Each participant’s model and the corresponding motion capture data were used as input for a Monte Carlo analysis to investigate how different muscle coordination strategies influence joint loads. OpenSim was used to run 10,000 simulations for each participant. Root-mean-square of muscle forces and peak joint contact forces were compared between simulations. Depending on the participant, altering muscle coordination led to a maximum reduction in hip, knee, patellofemoral and ankle joint loads between 5 and 18%, 4% and 45%, 16% and 36%, and 2% and 6%, respectively. In some but not all participants reducing joint loads at one joint increased joint loads at other joints. The required alteration in muscle forces to achieve a reduction in joint loads showed a large variability between participants. The potential of muscle coordination retraining to reduce joint loads depends on the person’s musculoskeletal geometry and gait pattern and therefore showed a large variability between participants, which highlights the usefulness and importance of the proposed framework to personalize gait retraining.

Muscle contributions to reduced ankle joint contact force during drop vertical jumps in patients with chronic ankle instability

Chronic ankle instability is a condition linked to progressive early ankle joint degeneration. Patients with chronic ankle instability exhibit altered biomechanics during gait and jump landings and these alterations are believed to contribute to aberrant joint loading and subsequent joint degeneration. Musculoskeletal modeling has the capacity to estimate joint loads from individual muscle forces. However, the influence of chronic ankle instability on joint contact forces remains largely unknown. The objective of this study was to compare tri-axial (i.e., compressive, anterior-posterior, and medial–lateral) ankle joint contact forces between those with and without chronic ankle instability during the ground contact phase of a drop vertical jump. Fifteen individuals with and 15 individuals without chronic ankle instability completed drop vertical jump maneuvers in a research laboratory. We used those data to drive three-dimensional musculoskeletal simulations and estimate muscle forces and tri-axial joint contact force variables (i.e., peak and impulse). Compared to those without chronic ankle instability, the ankles of patients with chronic ankle instability underwent lower compressive ankle joint contact forces as well as lower anterior-posterior and medial–lateral shearing forces during the weight acceptance phase of landing (p <.05). These findings suggest that patients with chronic ankle instability exhibit lower ankle joint loading patterns than uninjured individuals during a drop vertical jump, which may be considered in rehabilitation to potentially reduce the risk of early onset of ankle joint degeneration.

Dynamic gait stability in children with and without Down syndrome during overground walking

BackgroundChallenging children with Down syndrome to walk fast and with external ankle load has demonstrated acute adjustments, such as increased step length and decreased step width, and improved joint stability. However, it is unknown to what extent these task constraints affect gait stability. Assessing dynamic gait stability through margin-of-stability not only quantifies adjustments related to balance control, but also informs safety considerations. MethodsTwenty-four children with and without Down syndrome participated in this study. Subjects walked overground at two speed conditions: self-selected (normal) and as fast as possible (fast); and two ankle load conditions: no load and ankle load of 2% body mass. We assessed margin-of-stability in the anteroposterior and mediolateral directions, separately, at three gait events of toe-off, mid-swing, and heel strike. FindingsChildren with Down syndrome walked with greater mediolateral margin-of-stability than typically developing children. Children with Down syndrome demonstrated less anteroposterior margin-of-stability than typically developing children only before heel-strike at normal speed but increased anteroposterior margin-of-stability at fast speed. The ankle load increased the mediolateral margin-of-stability in both groups but did not impact the anteroposterior margin-of-stability. In addition, children with Down syndrome took shorter and wider steps for more lateral placement of mediolateral margin-of-stability. InterpretationChildren with Down syndrome were capable of adjusting their margin-of-stability for fast walking and ankle-load conditions. However, children with Down syndrome walked with less mediolateral stability and anteroposterior mobility than typically developing children. Children with Down syndrome overcompensate the mediolateral foot placement to recapture their margin-of-stability and maintain gait stability.

Articular ankle joint loading during dynamic activities

Articular ankle joint loading during dynamic activities

Intelligent prediction of lower extremity loadings during badminton lunge footwork in a lab-simulated court.

Introduction: Playing badminton has been reported with extensive health benefits, while main injuries were documented in the lower extremity. This study was aimed to investigate and predict the knee- and ankle-joint loadings of athletes who play badminton, with "gold standard" facilities. The axial impact acceleration from wearables would be used to predict joint moments and contact forces during sub-maximal and maximal lunge footwork. Methods: A total of 25 badminton athletes participated in this study, following a previously established protocol of motion capture and musculoskeletal modelling techniques with the integration of a wearable inertial magnetic unit (IMU). We developed a principal component analysis (PCA) statistical model to extract features in the loading parameters and a multivariate partial least square regression (PLSR) machine learning model to correlate easily collected variables, such as the stance time, approaching velocity, and peak accelerations, with knee and ankle loading parameters (moments and contact forces). Results: The key variances of joint loadings were observed from statistical principal component analysis modelling. The promising accuracy of the partial least square regression model using input parameters was observed with a prediction accuracy of 94.52%, while further sensitivity analysis found a single variable from the ankle inertial magnetic unit that could predict an acceptable range (93%) of patterns and magnitudes of the knee and ankle loadings. Conclusion: The attachment of this single inertial magnetic unit sensor could be used to record and predict loading accumulation and distribution, and placement would exhibit less influence on the motions of the lower extremity. The intelligent prediction of loading patterns and accumulation could be integrated to design training and competition schemes in badminton or other court sports in a scientific manner, thus preventing fatigue, reducing loading-accumulation-related injury, and maximizing athletic performance.

Effect of unilateral ankle loading on gait symmetry in young adults

BackgroundWalking requires constant adjustments to the changing environment. An asymmetrical perturbation can affect the gait symmetry, cause gait adaptations, and potentially induce retention of the adapted gait after removal of the perturbation. A unilateral ankle load has the potential to create asymmetry and facilitate the emergence of new gait patterns. However, few studies have examined the effect of unilateral loading on muscular adjustments during walking. The purpose of this study was to investigate gait adaptations and muscular adjustments after unilaterally loading or unloading the ankle. Research questionWhat are the effects of unilateral loading and unloading on gait spatiotemporal parameters and muscle activation in young adults? MethodsTwenty young adults (10 M/10 F) walked on a treadmill at their preferred walking speeds in 3 conditions: 1) a 2-minute baseline trial; 2) three 5-minute trials with a load (3 % of bodyweight) on the dominant ankle (Loading); and 3) one 5-minute trial with the load removed (Unloading). Inertial measurement units (IMUs) and electromyography sensors (EMGs) were used for data collection. Early and late adaptation and post-adaptation were assessed using the first 5 strides and the last 30 strides of loading and unloading conditions. Outcome measures included symmetry index (SI) of spatiotemporal parameters, range-of-motion (ROM) of the lower body joints, and EMG integrals of leg muscles. Repeated measures ANOVA was conducted for statistical analysis (α = 0.05). ResultsSI of swing phase percentage demonstrated rapid adaptation after unilateral loading or unloading. Stride length demonstrated an aftereffect following unloading. Young adults reduced ankle ROMs bilaterally in early adaptation and increased loaded-side knee and hip ROMs in late adaptation. Additionally, they increased the tibialis anterior activity bilaterally immediately after unilateral loading. SignificanceYoung adults showed an aftereffect in some variables after unilateral unloading, signifying that unilateral ankle loading can induce short term learning of a new gait pattern.

A forefoot strike pattern during 18° uphill walking leads to greater ankle joint and plantar flexor loading

BackgroundThe ankle joint is one of the most involved joints in uphill walking. Furthermore, it is well known that toe walking increases the external dorsiflexion moment in the first half of stance during level walking. However, the effects of different foot-strike patterns on plantar flexor muscle forces, ankle joint forces, and other lower limb joint and muscle forces are unknown. Research questionDo foot-strike patterns during 18° uphill walking affect lower limb sagittal joint angles and moments, as well as joint contact and muscle forces? MethodsThis study was based on a data subset from previous publications, analysing uphill walking on an 18° ramp at a preset speed of 1.1 m/s in 18 male participants (34 limbs analyzed, 27 ± 5 years). Participants were divided into two groups based on their foot-strike pattern at initial contact: heel (HC) and forefoot (FC). Lower limb sagittal joint angles and moments as well as joint contact and muscle forces were assessed. Differences between the groups were assessed using two-sample t-tests. ResultsFC showed increased soleus and gastrocnemius muscle forces as well as ankle joint forces during loading response and mid stance compared to HC. The soleus muscle force impulse was 51.1% higher in the FC group than in the HC group (p < 0.001). On the other hand, FC had a lower absolute centre of mass vertical displacement and reduced knee and hip joint, as well as iliopsoas and hamstring muscle force impulses. SignificanceIn terms of plantar flexor and ankle joint loading, it is advantageous to exhibit a heel strike pattern. The current results can be used to recommend foot-strike patterns for uphill walking, particularly in the presence or prevention of musculoskeletal issues.

Effect of body position and external ankle load on the pendulum test in adults

BackgroundThe pendulum test is commonly used to measure passive stiffness about the knee in healthy and clinical populations. While most studies used an upright position, some studies explored different body positions, particularly with children. Additionally, including external ankle load increases the passive motion of the lower leg in children with Down syndrome. Does combining body position and ankle loading affect joint kinematics and muscle activity of the knee extensors during the pendulum test? MethodsTwenty young adults participated in this study. Three body positions were included: 90-dgree upright, 45-degree incline, and 0-degree supine. Three load conditions were tested: no load (0%), and ankle loads equal to 3% and 6% of the subject’s body mass. This resulted in a total of 9 conditions. Five trials were collected for each condition. ResultsThe upright position elicited a greater number of leg swings and a longer duration of the first knee flexion, while the incline position produced a higher relaxation index. Both ankle load conditions (3% and 6%) increased the magnitude of the first flexion excursion and relaxation index, and the 6% condition produced greater kinematic variables than the 3% load condition. Neither body position nor ankle load elicited muscle activity of the quadriceps. ConclusionsBody position and external ankle load can affect the kinematics of leg swing during the pendulum test in healthy young adults. Particularly, ankle loads may increase passive motion about the knee. However, we wonder whether small differences across body positions would be clinically relevant.

Differences in Muscle Demand and Joint Contact Forces Between Running and Skipping

Skipping has been proposed as a viable cross-training exercise to running due to its lower knee contact forces and higher whole-body energy expenditure. However, how individual muscle forces, energy expenditure, and joint loading are affected by differences in running and skipping mechanics remains unclear. The purpose of this study was to compare individual muscle forces, energy expenditure, and lower extremity joint contact forces between running and skipping using musculoskeletal modeling and simulations of young adults (n = 5) performing running and skipping at 2.5m·s-1 on an instrumented treadmill. In agreement with previous work, running had greater knee and patella contact forces than skipping which was accompanied by greater knee extensor energetic demand. Conversely, skipping had greater ankle contact forces and required greater energetic demand from the uniarticular ankle plantarflexors. There were no differences in hip contact forces between gaits. These findings further support skipping as a viable alternative to running if the primary goal is to reduce joint loading at the commonly injured patellofemoral joint. However, for those with ankle injuries, skipping may not be a viable alternative due to the increased ankle loads. These findings may help clinicians prescribe activities most appropriate for a patient's individual training or rehabilitation goals.

Ankle joint contact force profiles differ between those with and without chronic ankle instability during walking

BackgroundIndividuals with chronic ankle instability (CAI) exhibit aberrant gait biomechanics relative to uninjured controls. Altered gait biomechanics likely contribute aberrant joint loading and subsequent early onset ankle joint degeneration. Joint (i.e. cartilage) loading cannot be directly measured without invasive procedures but can be estimated via joint contact forces (JCF) generated from musculoskeletal modeling. However, no investigation has quantified JCF in those with CAI during walking despite the link between ligamentous injury and ankle post-traumatic ankle osteoarthritis. Research questionDo patients with CAI exhibit altered ankle compressive and shear JCF profiles during the stance phase of walking compared to those without CAI? MethodsTen individuals with CAI and 10 individuals without a history of ankle sprain completed a gait assessment at their self-selected speed on an instrumented treadmill. Musculoskeletal modeling was applied to estimate ankle JCF variables within a generic model. Variables included the peak, impulse, and loading rates for compressive, anteroposterior shear, and mediolateral shear JCF. ResultsThose with CAI had significantly different JCF forces, relative to uninjured controls, in all directions. More specifically, lower compressive peak and impulse values were noted while higher anteroposterior shearing forces (1 st peak, impulse, loading late) were observed in those with CAI. Those with CAI also demonstrated higher mediolateral shearing forces (1 st peak and impulse). SignificanceOur finding suggests that those with CAI exhibit different ankle joint loading patterns than uninjured controls. Directionality of the identified differences depends on the axis of movement.

Assessment of the effect of a total contact cast on lower limb kinematics and joint loading

BackgroundTotal contact casts (TCCs) are used to immobilize and unload the foot and ankle for the rehabilitation of ankle fractures and for the management of diabetic foot complications. The kinematic restrictions imposed by TCCs to the foot and ankle also change knee and hip kinematics, however, these changes have not been quantified before. High joint loading is associated with discomfort and increased risk for injuries. To assess joint loading, the effect of the muscle forces acting on each joint must also be considered. This challenge can be overcome with the help of musculoskeletal modelling. Research questionHow does a TCC affect lower extremity joint loading? MethodsTwelve healthy participants performed gait trials with and without a TCC. Kinematic and kinetic recordings served as input to subject-specific musculoskeletal models that enabled the computation of joint angles and loading. Cast-leg interaction was modelled by means of reaction forces between a rigid, zero-mass cast segment and the segments of the lower extremity. Resultsand Significance: Reduced ankle, knee and hip range of motion was observed for the TCC condition. Statistical parametric mapping indicated decreased hip abduction and flexion moments during initial contact with the TCC. The anterior knee force was significantly decreased during the mid and terminal stance and the second peak of the compressive knee force was significantly reduced for the TCC. As expected, the TCC resulted in significantly reduced ankle loading. SignificanceThis study is the first to quantify the effect of a TCC on lower limb joint loading. Its results demonstrate the efficiency of a TCC in unloading the ankle joint complex without increasing the peak loads on knee and hip. Future studies should investigate whether the observed knee and hip kinematic and kinetic differences could lead to discomfort.

Energy Absorption Contribution Deficits in Participants Following Anterior Cruciate Ligament Reconstruction: Implications for Second Anterior Cruciate Ligament Injury.

Lower-extremity loading patterns change after anterior cruciate ligament reconstruction (ACLR). However, there is limited research regarding energy absorption contribution (EAC) of athletes following ACLR who reinjure their ACL and those who do not. EAC can be utilized as a measure of joint loading during tasks. Cross-sectional study. Three groups of individuals (13 in each group) with matched age, sex, height, weight, and sports were enrolled. Data were collected at time of return-to-sport testing for the 2 ACLR groups. An 8-camera 3D motion capture system with a sampling rate of 120Hz and 2 force plates capturing at 1200Hz were used to capture joint motions in all 3 planes during a double-limb jump landing. Participants in the ACLR no reinjury and ACLR reinjury groups had significantly greater hip EAC (55.8 [21.5] and 56.7 [21.2]) compared with healthy controls (19.5 [11.1]), P < .001 and P < .001, respectively. The ACLR no reinjury and ACLR reinjury groups had significantly lower knee EAC (24.6 [22.7] and 27.4 [20.8]) compared with healthy controls (57.0 [12.2]), P < .001 and P < .001, respectively. However, the ACLR reinjury group had significantly lower ankle EAC (15.9 [4.6]) than healthy controls (23.5 [6.6]), whereas there was no statistical difference between the ACLR no reinjury group (19.7 [7.8]) and healthy controls. Athletes who had a second ACL injury after ACLR, and those without second ACL injury, appear to have similar hip, knee, and ankle joint loading of the surgical limb at return-to-sport testing. Nevertheless, joint loading patterns were significantly different from healthy controls. The study suggests that EAC as a measure of joint loading during a double-limb jump landing at time of return to sport may not be a strong predictor for second injury following ACLR.