Subtalar Inversion Research Articles

Influence of Isolated Talonavicular and Subtalar Joint Arthrodesis on Hindfoot Kinematics and Range of Motion During Cadaveric Gait Simulation.

Isolated subtalar and talonavicular joint arthrodeses have been associated with adjacent joint arthritis and altered hindfoot kinematics during simplified loading scenarios. However, the effect on kinematics during dynamic activity is unknown. This study assessed changes in subtalar and talonavicular kinematics after isolated talonavicular (TNiso) and subtalar (STiso) arthrodesis, respectively, during stance simulations. Fourteen midtibia specimens received either a TNiso or STiso arthrodesis, with 7 randomized to each group. A 6-degree-of-freedom robot sequentially simulated the stance phase for the intact and arthrodesis conditions. Bootstrapped bias-corrected 95% CIs of the talonavicular and subtalar joint kinematics were calculated and compared between conditions. The TNiso decreased subtalar inversion, adduction, and plantarflexion in late stance (P < .05). The subtalar range of motion in the sagittal and coronal planes decreased by 40% (P = .009) and 46% (P = .002), respectively. No significant changes in talonavicular joint kinematics were observed after isolated subtalar arthrodesis; however, the range of motion was reduced by 61% (P = .007) and 50% (P = .003) in the coronal and axial planes, respectively. In this model for arthrodesis, changes in subtalar kinematics and motion restriction were observed after isolated talonavicular arthrodesis, and motion restriction was observed after isolated subtalar arthrodesis. Surprisingly, talonavicular kinematics did not appear to change after isolated subtalar arthrodesis. Both joint fusions substantially decrease the motion of the reciprocal adjacent joint. Surgeons should be aware that the collateral costs with talonavicular fusion appear higher, and it has a significant effect on subtalar kinematics during the toe-off phase of gait.

Influence of Talar and Calcaneal Morphology on Subtalar Kinematics During Walking.

Cadaver biomechanical testing suggests that the morphology of articulating bones contributes to the stability of the joints and determines their kinematics; however, there are no studies examining the correlation between bone morphology and kinematics of the subtalar joint. The purpose of this study was to investigate the influence of talar and calcaneal morphology on subtalar kinematics during walking in healthy individuals. Forty ankles (20 healthy subjects, 10 women/10 men) were included. Participants walked at a self-selected pace while synchronized biplane radiographs of the hindfoot were acquired at 100 images per second during stance. Motion of the talus and calcaneus was tracked using a validated volumetric model-based tracking process, and subtalar kinematics were calculated. Talar and calcaneal morphology were evaluated using statistical shape modeling. Pearson correlation coefficients were used to assess the relationship between subtalar kinematics and the morphology features of the talus and calcaneus. This study found that a shallower posterior facet of the talus was correlated with the subtalar joint being in more dorsiflexion, more inversion, and more internal rotation, and higher curvature in the posterior facet was correlated with more inversion and eversion range of motion during stance. In the calcaneus, a gentler slope of the middle facet was correlated with greater subtalar inversion. The morphology of the posterior facet of the talus was found to a primary factor driving multiplanar subtalar joint kinematics during the stance phase of gait. This new knowledge relating form and function in the hindfoot may assist in identifying individuals susceptible to subtalar instability and in improving implant design to achieve desired kinematics after surgery.

Integrating an LSTM framework for predicting ankle joint biomechanics during gait using inertial sensors

The ankle joint plays a crucial role in gait, facilitating the articulation of the lower limb, maintaining foot-ground contact, balancing the body, and transmitting the center of gravity. This study aimed to implement long short-term memory (LSTM) networks for predicting ankle joint angles, torques, and contact forces using inertial measurement unit (IMU) sensors. Twenty-five healthy participants were recruited. Two IMU sensors were attached to the foot dorsum and the vertical axis of the distal anteromedial tibia in the right lower limb to record acceleration and angular velocity during running. We proposed a LSTM-MLP (multilayer perceptron) model for training time-series data from IMU sensors and predicting ankle joint biomechanics. The model underwent validation and testing using a custom nested k-fold cross-validation process. The average values of the coefficient of determination (R2), mean absolute error (MAE), and mean squared error (MSE) for ankle dorsiflexion joint and moment, subtalar inversion joint and moment, and ankle joint contact forces were 0.89 ± 0.04, 0.75 ± 1.04, and 2.96 ± 4.96 for walking, and 0.87 ± 0.07, 0.88 ± 1.26, and 4.1 ± 7.17 for running, respectively. This study demonstrates that IMU sensors, combined with LSTM neural networks, are invaluable tools for evaluating ankle joint biomechanics in lower limb pathological diagnosis and rehabilitation, offering a cost-effective and versatile alternative to traditional experimental settings.

Collegiate Dancers With Chronic Ankle Instability Possess Altered Strength and saut de chat Leap Landing Mechanics.

Ankle sprains are among the most common injuries in dancers. Following one or more severe sprains, some individuals will experience residual mechanical and functional deficits, otherwise known as chronic ankle instability (CAI). Dancers who suffer from CAI may have weaker musculature surrounding the ankle and altered landing mechanics. The purpose of this study was to compare ankle strength and saut de chat landing mechanics between dancers with and without CAI. Dancers with and without CAI, defined by the Identification of Functional Ankle Instability (IdFAI), participated in the study (CAI n = 8; IdFAI = 18.75 ± 5.50 points; age = 20 ± 1.5 years; training = 15.5 ± 3.5 years) (Control n = 8; IdFAI = 7.13 ± 3.40 points; age = 19 ± 0.6 years; training = 15.9 ± 2.5 years). Strength and leap landing mechanics were measured on the affected ankle for the CAI group and on the preferred landing leg of a leap for the control group. Concentric and eccentric ankle plantar flexion, and subtalar inversion and eversion strength were determined with dynamometry set at an angular velocity of 60°•s-1. Force plates and motion capture cameras were used to calculate lower extremity kinematic and kinetic data as participants performed 3 saut de chat leaps. Independent t-tests were calculated to determine differences between groups. Compared to dancers without CAI, dancers with CAI had lower eccentric plantar flexor strength, landed with higher vertical ground reaction forces, and absorbed greater power at the knee-joint during landing. Whether dancers who are weaker are more prone to injury or ankle-joint injury leads to muscular weakness is unknown. Dancers with CAI appear to lack control during leap landing while concomitantly shifting loads proximally away from the ankle-joint. We encourage dancers with and without CAI to engage in additional training that enhances ankle strength.

Kinematic Analysis of Sequential Partial-Midfoot Arthrodesis in Simulated Gait Cadaver Model.

Primary tarsometatarsal (TMT) arthrodesis is gaining popularity in the surgical treatment of Lisfranc injuries. However, few studies have evaluated biomechanical effects of TMT arthrodesis. The purpose of this study was to compare the kinematics of joints adjacent to the midfoot during simulations of stance before and after sequential arthrodesis of the first, second, and third TMT joints. Ten midtibia cadaveric specimens were loaded on a 6-degree-of-freedom robotic gait simulator. Motion capture cameras were used to collect joint kinematics throughout simulations of the stance phase. Simulations were performed for the intact and sequential arthrodesis conditions of the first, second, and third TMT joints. The sagittal, coronal, and transverse plane rotational kinematics of the intact condition were compared to kinematics after each sequential arthrodesis condition. Sequential arthrodesis of the first and second TMT joints had no significant effect on ankle, subtalar, talonavicular, and first metatarsophalangeal joint motion during simulated stance when compared to the intact condition. In contrast, inclusion of the third TMT joint into the sequential arthrodesis significantly increased subtalar inversion (P = .032) in late stance and increased range of motion values in the ankle and subtalar joints by 2.1 degrees (P = .009) and 2.8 degrees (P = .014), respectively. Sequential primary arthrodesis induced changes to ankle and adjacent joint kinematics during stance phase simulations, although not until the third TMT joint was included into the primary arthrodesis. The significant changes to kinematics due to arthrodesis of the first, second, and third TMT joints were small. The minimal changes in sagittal, coronal, and transverse plane rotational kinematics support the positive clinical outcomes reported in the literature for primary partial arthrodesis of Lisfranc injuries. The inclusion of the third TMT joint should be done judiciously.

Kinematic analysis of ankle joint during gait in drop foot patients wearing passive Ankle-Foot Orthosis *

The term ‘drop-foot’ refers to an uncommon presentation of degenerative diseases, derived from neurological, muscular or anatomical complications, resulting in difficulties in performing foot dorsiflexion. This causes an abnormal gait pattern, characterized by two complications: the ‘foot slap’ at the initial contact with the ground, and the ‘toe-drag’ during the swing phase. In order to support gait, a common non-surgical treatment is the use of lightweight ‘L’ shaped ankle-foot orthosis (AFO). In this study we combine gait analysis and biomechanical modeling tools to analyse the kinematics of ankle joint in gait with and without the support of a passive AFO, namely the ‘Codivilla’ spring. The study was conducted on a population of eighteen adult subjects suffering from unilateral drop-foot (7 females, age 58.1 ± 14.5 years, BMI 23.4 ± 4.60). The infrared multicamera system SMART DX by BTS Bioengineering (Milan, Italy), was used to acquire data relating the 3D position of 22 markers placed on patient’s body, following the Davis protocol, during walking trials performed in two conditions: barefoot and with the AFO mounted on the affected limb. Data were then imported in OpenSim (SimTK software) and used to solve an inverse kinematic problem in order to reproduce walking and compute the evolution of body joints angles. Ankle dorsiflexion and subtalar inversion signals were analysed using MATLAB (2022a) to compute the following metrics for each angle: Range of Motion (RoM), angle at Heel Strike (HS) and angle at Toe Off (TO). The two-way ANOVA statistical test was used to analyse the effects of two factors: walking condition (with versus without AFO) and limb (affected versus contralateral). The interaction factor (condition*limb) was also analysed. Fig. 1 shows the evolution over the gait cycle of the ankle and subtalar angles in the two walking conditions for each foot. Solid lines are obtained as the mean value of subjects’ averaged step. Shaded areas represent the variability among subjects. Table 1 reports the results of the two-way ANOVA test in terms of p-value. Results show that the AFO ‘Codivilla’ spring acts on the kinematics of ankle by reducing the RoM during walking, as it limits the plantar flexion of drop foot. However, it does not significantly affect the ankle angle at HS and TO, although the first is lower in the affected foot. Results also show that the evolution of subtalar angle in the affected foot is altered, not in the RoM, rather in values, in particular at the initial phases of gait cycle. However, the considered orthosis does not produce improvements in the kinematics of subtalar angle. This is probably due to the L-shape of the device, which does not limit ankle inversion/eversion. In conclusion our study confirms the alterations of the drop foot in the kinematics of the ankle joint, particularly at Heel Strike in which both the ankle and the subtalar angle are altered compared to the contralateral foot. The use of Codivilla spring results in a more physiological dorsiflexion of the ankle but has no significant effect on the kinematics of the subtalar joint.

Differences between men and women in coupled subtalar and tibiofemoral joint kinematics during gait revealed through dynamic biplane radiography

It has been suggested that subtalar and tibiofemoral kinematics are coupled, such that abnormal subtalar inversion during the impact and push-off portions of stance may affect tibial rotation, leading to abnormal compensatory knee motion. This study aimed to characterize tibiofemoral and subtalar coupled motion and to determine if sex-dependent differences exist in lower extremity coupled motion. Twenty young adults were imaged at 100 frames/s using dynamic biplane radiography while walking. Lower extremity CT scans were obtained and segmented into subject-specific 3D bone models. Digitally reconstructed radiographs generated from the models were matched to the biplane radiographs via a validated tracking process to obtain tibiofemoral and subtalar joint kinematics. Subtalar inversion/eversion was strongly associated with tibiofemoral internal/external rotation and tibiofemoral ab/adduction during impact and push-off (P < 0.001). Men reached neutral subtalar and tibiofemoral orientation at midstance, while women remained more inverted at the subtalar joint and more externally rotated at the tibiofemoral joint. The rate of tibiofemoral ab/adduction to subtalar eversion differed between sexes during push-off (P = 0.005). Women underwent subtalar inversion, as well as tibiofemoral internal rotation and adduction during push-off, while men underwent only subtalar inversion and tibiofemoral internal rotation, with effectively no tibiofemoral adduction. These results provide the first quantitative evidence characterizing subtalar and tibiofemoral coupled motion. Differences in coupled motion trajectories between men and women may be associated with the higher incidence of knee-related pathology in women. These novel findings may serve as a standard for comparison when evaluating patients with patellofemoral pain.

An open-source OpenSim® ankle-foot musculoskeletal model for assessment of strains and forces in dense connective tissues

BackgroundThe ankle and foot are among the most critical load-bearing joints in the human anatomy. Anatomically accurate human body models are imperative to understanding the mechanics of injury and musculoskeletal disorders. A typical human ankle-foot anatomy consists of 25 DOFs, 112 dense connective tissues (DCTs) (92 ligaments, one capsule and 19 fasciae), 30 tendons, and 65 muscles. Existing models possess less than half of the DOFs and physiological elements. In this work, we have developed an ankle-foot joint complex musculoskeletal model for the OpenSim® platform by incorporating 24 degrees of freedom (DOF) comprising of 66 DCTs (46 ligaments, one 1 capsule and 19 fasciae), 30 tendons, and 65 muscles. MethodsComputed tomography (CT) data of human ankle joint-foot complex was segmented using Mimics ® (Version 17.0, Materialise, Belgium) to obtain models of the cartilages and bones of the ankle joint-foot complex. The position and resting lengths of the DCTs were attained from the MRI data and literature. Five joints, namely, tibiotalar, subtalar, chopart, tarsometatarsal (TMT), and metatarsophalangeal (MTP) joints and their joint axes were formulated to yield 24 DOFs. A forward simulation was carried out at each joint of the ankle-foot complex within their respective range of motions. The strains, instantaneous strain rates, and forces developed in the ligaments during the simulation were studied. ResultsDuring plantar-dorsiflexion of the tibiotalar joint, the anterior tibio-talar ligament (aTTL) yielded the maximum strain compared to all other ligaments. Anterior tibio-fibular ligament (aTFL) experienced extreme strain during subtalar inversion. Hence, the coupled kinematics of subtalar inversion and plantar flexion are failure-prone activities for aTFL. The chopart, TMT, and MTP joints yielded maximum strains or forces for several bundles at the extremes of the range of motion. This signifies that rotations of these joints to their extreme range of motion are prone to failure for the bundles attached to the joint complex. ConclusionThe results illustrate the potential application of the proposed OpenSim® ankle-foot model in understanding the ligament injury mechanism during sports activity and its prevention. Researchers can use the proposed model or customise it to study complex kinematics, understanding injury mechanisms, testing fixtures, orthosis or prosthesis, and many more in the domain of musculoskeletal research.

Anterior Capsule Reconstruction in the Setting of PVNS.

Pigmented villonodular synovitis (PVNS) is a benign proliferative disease affecting tendon sheaths and synovial tissue. Pigmented villonodular synovitis in the foot and ankle has a high rate of recurrence, which can be destructive if incompletely removed. This case series analyzes functional outcomes after PVNS operative resection with an anterior ankle capsular reconstruction, using a novel technique. Three patients with PVNS underwent surgery between 2010 and 2020. The operative technique involved a posterior, midline approach for PVNS resection of the affected ankle joint, followed by a standard anterior approach for capsular excision. Subsequent anterior capsular reconstruction was performed with a regenerative tissue matrix and a bioresorbable anchoring system. Preoperative and postoperative range of motion for the ankle and subtalar joints, visual analog scale (VAS) for pain, and return to daily activities was assessed along with appropriate radiographs and magnetic resonance imaging (MRI) imaging. All 3 surgeries had a mean follow-up period of 52.3 (range, 4-123) months and resulted in successful recovery as assessed by the VAS and self-reported activity. Preoperative ankle dorsiflexion and plantarflexion along with subtalar inversion and eversion range of motion were all normal. Postoperative ankle motion and subtalar motion were not statistically different. No complications or recurrence of PVNS was observed. Further investigation is warranted to better understand the clinical outcomes of this technique designed to successfully eliminate PVNS recurrence. IV- Retrospective case series.

Short-term results of gait analysis with the Heidelberg foot measurement method and functional outcome after operative treatment of ankle fractures

BackgroundAnkle fractures are common fractures in trauma surgery. Several studies have compared gait patterns between affected patients and control groups. However, no one used the Heidelberg Foot Measurement Method in combination with statistical parametric mapping of the entire gait cycle in this patient cohort. We sought to identify possible mobility deficits in the tibio-talar joint and medial arch in patients after ankle fractures as a sign of stiffness and pain that could result in a pathological gait pattern. We focused on the tibio-talar flexion as it is the main movement in the tibio-talar joint. Moreover, we examined the healing progress over time.MethodsFourteen patients with isolated ankle fractures were included prospectively. A gait analysis using the Heidelberg Foot Measurement Method was performed 9 and 26 weeks after surgery to analyse the tibio-talar dorsal flexion, the foot tibia dorsal flexion, the subtalar inversion and the medial arch as well as the cadence, the walking speed and the ground reaction force. The American Orthopedic Foot & Ankle Society ankle hindfoot score was used to obtain clinical data. Results were compared to those from 20 healthy participants. Furthermore, correlations between the American Orthopedic Foot & Ankle Society hindfoot score and the results of the gait analysis were evaluated.ResultsStatistical parametric mapping showed significant differences for the Foot Tibia Dorsal Flexion for patients after 9 weeks (53–75%: p = 0.001) and patients after 26 weeks (58–70%: p = 0.011) compared to healthy participants, respectively. Furthermore, significant differences regarding the tibio-talar dorsal flexion for patients 9 weeks after surgery (15–40%: p < 0.001; 56,5–70%: p = 0.007; 82–88%: p = 0.033; 97–98,5%: p = 0.048) as well as patients after 26 weeks (62,5–65%: p = 0.049) compared to healthy participants, respectively. There were no significant differences looking at the medial arch and the subtalar inversion. Moreover, significant differences regarding the ground reaction force were found for patients after 9 weeks (0–17%: p < 0.001; 21–37%: p < 0.001; 41–54%: p < 0.001; 60–64%: p = 0.013) as well as patients after 26 weeks (0–1,5%: p = 0.046; 5–15%: p < 0.001; 27–33%: p = 0.001; 45–49%: p = 0.005; 57–59%: p = 0.049) compared to healthy participants, respectively. In total, the range of motion in the tibio-talar joint and the medial arch was reduced in affected patients compared to healthy participants. Patients showed significant increase of the range of motion between 9 and 26 weeks.ConclusionsThis study shows, that patients affected by ankle fractures show limited mobility in the tibio-talar joint and the medial arch when compared to healthy participants. Even though the limitation of motion remains at least over a period of 26 weeks, a significant increase can be recognized over time. Furthermore, if we look at the absolute values, the patients’ values tend to get closer to those of the control group.Trial registrationThis study is registered at the German Clinical Trials Register (DRKS00023379).

The Effect of Lower Limb Muscle Fatigue on Running Tempo- Spatial Parameters and Joint Excursion in Individuals with Pes Planus

Context: The relation between running kinematics parameters and lower limb muscle fatigue in association with low longitudinal arch (LLA) is not well understood. Objective: The purpose of the present study was to examine the effects of fatigue on running kinematics in Subjects who had a low longitudinal arch. Design: Quasi- Experimental study. Setting: Clinical Biomechanics Laboratory. Participants: forty four subjects were equally divided into two groups, a healthy one and a group with LLA. Main Outcome Measures: The kinematics parameter of running includes tempo-spatial parameters and joint angles, which were calculated by Vicon Nexus 1.8.5 software. A two-way repeated measure ANOVA (group x fatigue) was used to compare the data between the two groups. Results: In the unfatigued conditions, running speed, ankle plantar flexion/ dorsiflexion, and ankle external rotation, knee flexion and hip flexion/extension in the low arch subjects are significantly different than those in the healthy subjects (P&lt;0.05). Induced fatigue increased Step time (p=0.014) and Subtalar inversion (p=0.034); too decreased Step length (p=0.027) in LLA. The observed Induced fatigue decreased running speed and ankle plantar flexion, and increased Knee flexion, Knee abduction, Knee Internal rotation, Knee external rotation, Hip flexion, Hip adduction, hip Internal rotation and hip external rotation in both groups (p≤0.05). A significant interaction between group and time was found for Step time, ankle plantar flexion, hip extension and hip adduction (p≤0.05). Conclusion: Patients suffering from low arches will respond differently to lower extremity fatigue. Individuals with flat feet arches appear to be more prone to the risk of injury to the lower extremities at exhausting activities.

Anterior Capsule Reconstruction in the Setting of PVNS

Category:Ankle; OtherIntroduction/Purpose:Pigmented villonodular synovitis (PVNS) is a rare benign proliferative disease affecting tendon sheaths and synovial tissue. Most cases of PVNS arise in the hip and knee joints, while < 5% of total cases occur in the foot and ankle. PVNS of the ankle has a high rate of recurrence and can be destructive to the affected joints if incompletely removed. This case series analyzes functional outcomes after PVNS surgical resection and anterior ankle capsular reconstruction, using a novel technique.Methods:This case series included three patients who underwent surgery between 2010 and 2020 for their ankle pain and swelling caused by PVNS. The surgical technique involved a posterior, midline approach for PVNS resection of the affected ankle joint, followed by a standard anterior approach for capsular excision. Subsequent anterior capsular reconstruction was performed with a regenerative tissue matrix and a bioresorbable anchoring system. Preoperative and postoperative range of motion testing for the ankle and subtalar joints were assessed along with appropriate radiographs and MRI imaging.Results:All three surgical procedures for PVNS of the ankle resulted in successful recovery and promising clinical outcomes. The mean cohort age was 43.7 (R:36-58) years and follow-up period was 52.3 (R:4-123) months. Preoperative ankle dorsiflexion and plantarflexion along with subtalar inversion and eversion range of motion were all normal. Postoperative ankle motion and subtalar motion were recorded at final follow up and found to be unchanged. No complications or recurrence of PVNS occurred.Conclusion:This case series demonstrates that PVNS surgical resection and anterior ankle capsular reconstruction is a safe and effective treatment modality that allows for maintenance of pre-operative motion. Further investigation is warranted to better understand the clinical outcomes of this surgical technique on PVNS recurrence.

Year-Long Use of Ankle-Foot Orthosis–Footwear Combination with Talar Flange Modification in an Adult Poststroke

ABSTRACT Introduction There are limited examples in the literature of detailed orthotic management related to triplanar control of the ankle-foot complex. The aim of this case report was to describe year-long use of an ankle-foot orthosis–footwear combination (AFO-FC) augmented with a talar flange that aimed to stabilize the subtalar joint during gait in an individual with poststroke hemiplegia who presented with both knee hyperextension and an unstable subtalar joint. Materials and Methods A 40-year-old woman 1-year poststroke with right hemiplegia presented with right equinovarus and knee hyperextension, with complaint of pain in the ankle and knee. Her right talocrural joint measured 15° plantarflexion with clinically significant inversion instability. Results A right solid AFO-FC, designed using published algorithms, was provided. In addition, a talar flange modification was incorporated to control subtalar inversion. During year-long use of the AFO-FC, the patient was able to return to community ambulation without pain. Successful orthotic intervention required that the device met not only biomechanical goals but also broader patient goals, which changed over time. Therapy with the device was also important for successful orthotic intervention. Conclusions This case illustrates use of a talar flange in an AFO-FC to provide triplanar control of the ankle-foot complex and improve gait in a person poststroke.

Evertor muscle fatigue decreases the passive inversion joint position sense in female volleyball players

IntroductionThe study aimed to investigate the effect of evertor muscle fatigue on passive inversion joint position sense in female volleyball players.MethodsA cross-sectional design was implemented in this study. The passive inversion joint position sense of 25 college-age female volleyball players was assessed in fatigue and non-fatigue conditions. A 10° subtalar inversion was used as a target angle for position sense evaluation. The assessment of position sense and the induction of fatigue were performed with a Biodex System isokinetic device. The average error of joint position sense was measured in both fatigue and non-fatigue conditions.ResultsThere was a significant reduction in passive inversion joint position sense when the evertor muscles were fatigued (&lt;i&gt;p&lt;/i&gt; &lt; 0.001).ConclusionsPeroneal muscle fatigue declines the subtalar joint inversion position sense in female volleyball players.

Healthy ankle and hindfoot kinematics during gait: Sex differences, asymmetry and coupled motion revealed through dynamic biplane radiography

The aims of this study were to compare male versus female and dominant versus non-dominant kinematics in the ankle and hindfoot, and to characterize coupled motion between the subtalar and tibiotalar joints during the support phase of gait. Twenty healthy adults walked on a laboratory walkway while synchronized biplane radiographs of the ankle and hindfoot were collected at 100 frames/s. A validated tracking technique was used to measure tibiotalar and subtalar kinematics. Differences between male and female range of motion (ROM) were observed only in tibiotalar (AP and ML) and subtalar (ML) translation (all differences<1 mm and all p < 0.04). Statistical parametric mapping identified differences between kinematics waveforms of males and females in tibiotalar translation (AP and ML) and eversion, and subtalar ML translation. No differences between dominant and non-dominant sides were observed in ROM or kinematics waveforms. The average absolute side-to-side difference in the kinematics waveforms was 4.1° and 1.5 mm or less for all rotations and translations, respectively. Tibiotalar plantarflexion was coupled to subtalar inversion and eversion during the impact and push-off phases of stance (r = 0.90 and r = 0.87, respectively). This data may serve as a guide for evaluating ankle kinematics waveforms, ROM, symmetry, and restoration of healthy coupled motion after surgical intervention or rehabilitation. The observed kinematics differences between males and females may predispose females to higher rates of ankle and knee injury and suggest sex-dependent ankle reconstruction techniques may be beneficial.

Estimating the stabilizing function of ankle and subtalar ligaments via a morphology-specific three-dimensional dynamic model

Knowledge of the stabilizing role of the ankle and subtalar ligaments is important for improving clinical techniques such as ligament repair and reconstruction. However, this knowledge is incomplete. The goal of this study was to expand this knowledge by investigating the stabilizing function of the ligaments using multiple morphologically subject-specific computational models.Nine models were created from the lower extremities of nine donors. Each model consisted of the articulating bones, articular cartilage, and ligaments. Simulations were conducted in ADAMS™ – a dynamic simulation program. During simulation, tibia and fibula were fixed while cyclic moments in all three anatomical planes were applied to the calcaneus one-at-a-time. The resulting displacements between the bones and the forces in each ligament were computed. Simulations were conducted with all ligaments intact and after simulated ligament serial sectioning. Each model was validated by comparing the simulation results to experimental data obtained from the specimen used to construct the model. From the results the stabilizing role of each ligament was established and the effect of ligament sectioning on Range of Motion and Overall Laxity was identified.On the lateral side, ATFL provided stabilization in supination, CFL restrained inversion, external rotation and dorsiflexion and PTFL limited dorsiflexion and external rotation. On the medial side, PTTL restrained dorsiflexion and internal rotation, ATTL limited plantarflexion and external rotation, and TCL limited dorsiflexion, eversion and external rotation. At the subtalar joint, ITCL limited plantarflexion and its posterior-lateral bundle restrained subtalar inversion. CL restrained plantarflexion/dorsiflexion, and internal and external rotation.The large inter-model variability observed in the results indicate the importance of using multiple subject-specific models rather than relying on one “representative” model.

Effects of an ankle brace on the in vivo kinematics of patients with chronic ankle instability during walking on an inversion platform

BackgroundAs in vivo tibiotalar and subtalar joint kinematics are not currently known following the application of an ankle brace, an investigation of these kinematics may provide insight into the mechanisms of ankle braces. Research questionThis study aimed to determine the effect of an ankle brace on in vivo kinematics of patients with chronic ankle instability. MethodsEleven patients with chronic ankle instability were recruited in this study. A dual fluoroscopic imaging system and a solid modeling software were utilized to calculate the joint positions of the participants as they walked barefooted on a level platform, walked barefooted on a 15° inversion platform, and walked with an ankle brace on a 15° inversion platform. The joint positions during the three walking conditions were compared. ResultsTibiotalar joints were more inverted (pose 2, p = .004), and subtalar joints were more anteriorly translated (pose 2–6, p = .003), more plantarflexed (pose 2, p = .008; pose 3, p = .013; pose 5, p = .008; pose 6, p = .016) and more inverted (pose 1–5, p = .003; pose 6, p = .013) during barefooted walking on the inversion platform than during walking on the level platform. The inversion of subtalar joints was decreased after the brace application (pose 2–4, p = .003; pose 5, p = .004; pose 7, p = .016). SignificanceBrace application reduced the increased subtalar inversion induced by the inversion platform. Nevertheless, increased subtalar anterior translation and plantarflexion persisted after brace application. The ankle brace might be beneficial for clinical populations with increased subtalar inversion.

Midfoot osteoarthritis: potential phenotypes and their associations with demographic, symptomatic and clinical characteristics

To investigate the demographic, symptomatic, clinical and structural foot characteristics associated with potential phenotypes of midfoot osteoarthritis (OA). Cross-sectional study of 533 community-dwelling adults aged ≥50 years with foot pain in the past year. Health questionnaires and clinical assessments of symptoms, foot structure and function were undertaken. Potential midfoot OA phenotypes were defined by the pattern of radiographic joint involvement affecting either the medial midfoot (talonavicular, navicular-1st cuneiform, or cuneiform-1st metatarsal joint), central midfoot (2nd cuneiform-metatarsal joint), or both medial and central midfoot joints. Multivariable regression models with generalised estimating equations were used to investigate the associations between patterns of midfoot joint involvement and symptomatic, clinical and structural characteristics compared to those with no or minimal midfoot OA. Of 879 eligible feet, 168 had medial midfoot OA, 103 central midfoot OA, 76 both medial and central midfoot OA and 532 no/minimal OA. Having both medial and central midfoot OA was associated with higher pain scores, dorsally-located midfoot pain (OR 2.54, 95%CI 1.45, 4.45), hallux valgus (OR 1.76, 95%CI 1.02, 3.05), flatter foot posture (β 0.44, 95%CI 0.12, 0.77), lower medial arch height (β 0.02, 95%CI 0.01, 0.03) and less subtalar inversion and 1st MTPJ dorsiflexion. Isolated medial midfoot OA and central midfoot OA had few distinguishing clinical characteristics. Distinct phenotypes of midfoot OA appear challenging to identify, with substantial overlap in symptoms and clinical characteristics. Phenotypic differences in symptoms, foot posture and function were apparent in this study only when both the medial and central midfoot were involved.

Microfracture of subchondral bone leads to persistent subchondral sclerosis and poorer functional outcomes following distraction arthroplasty of the ankle joint while biologic augment may improve recovery times

Category: Ankle Arthritis Introduction/Purpose: Treatment of ankle osteoarthritis (OA) continues to remain a challenge. Previous reports have demonstrated the short-term benefits of using joint distraction for the treatment of ankle (OA), however, its efficacy in long term clinical outcomes and its role in preserving the joint space remains controversial. The purpose of this study is to establish whether microfracture or biologics improve the outcomes of ankle distraction. Methods: Records of patients that underwent an ankle distraction procedure between January 2009-December 2013 were retrospectively reviewed. Four groups were identified: Group 1: distraction with no additional treatment, Group 2: distraction with microfracture, Group 3: distraction with microfracture and BMAC/PRP, Group 4: distraction with BMAC/PRP. Demographic data was recorded. Pre-and-postoperative range of motion, Foot and Ankle Outcome Scores (FAOS), complication rate, and return to activity were evaluated. Radiographic images were used to assess the joint space changes pre-operatively and post-operatively. Global comparisons were performed using chi square testing, while individual between-group comparisons were made using robust, resistant regression and Wald tests. Results: Eighty-one patients with a mean age of 47 (range, 37-69) underwent ankle distraction with a mean follow up of 5 years (range, 3-6). All treatment strategies resulted in statistically significant improvements in FAOS (&lt;0.001). Groups that underwent microfracture had a statistically significant decrease in post-operative plantarflexion, dorsiflexion, subtalar inversion and subtalar eversion (p=0.003) as well as an overall decrease in joint space (0.002) with persistence of subchondral bone sclerosis. Patients who underwent distraction with no microfracture treatment resulted in a significant increase in post-operative joint space (p=0.001) and decreased sclerosis in the subchondral bone. Average return to activity was 6 months in patients who received BMAC/PRP with ankle distraction compared to 12 months in patients who were treated with ankle distraction and microfracture (p&lt;0.01). Conclusion: Distraction arthroplasty results in good functional outcomes at medium term follow up. The addition of microfracture seems to create functional outcome deterioration, whereas the addition of a biologic agent either BMAC or PRP appears to benefit earlier return to function. Longer-term studies will be required to see if these effects are sustained.

The Role of the Midfoot in Drop Landings.

The midfoot is instrumental to foot function; however, quantifying its roles in human movement has been difficult. A forceful dynamic activity like landing may help elucidate the midfoot's contribution to foot energetics and function. The main purpose of this study was to measure midtarsal joint kinematics and kinetics during a barefoot single-leg landing task. A secondary aim of this study was to explore the relationship between static foot posture and dynamic midfoot function. In a cross-sectional study design, 48 females (age = 20.4 ± 1.8 yr, body mass index = 21.6 ± 1.7 kg·m) performed drop landings from a height of 0.4 m onto split force platforms. Subjects hung from wooden rings and landed on their dominant leg. Midtarsal joint kinematic and kinetic data were recorded using a 14-camera optical motion capture system in conjunction with two in-ground force platforms and a custom kinetic three-segment foot model. Foot structure was measuring using the arch height index (AHI) and the static midtarsal joint angle from motion capture. Kinematic data revealed an average sagittal plane midtarsal joint range of motion of 27° through the landing phase. Kinetic data showed that between 7% and 22% of the total lower extremity joint, work during the landing was performed by the midtarsal joint. Both standing AHI and static midtarsal joint angle (static MA) were correlated with sagittal plane midtarsal joint range of motion (standing AHI: r = -0.320, P = 0.026; static MA: r = 0.483, P < 0.001) and with midtarsal joint work (standing AHI: r = 0.332, P = 0.021; static MA: r = -0.323, P = 0.025). The midfoot contributes substantially to landing mechanics during a barefoot single-leg landing task. Static foot posture measures have limited value in predicting midfoot kinematics and kinetics during sportlike landings.