Central imaging based on near-infrared functional imaging technology can be useful to plan management in patients with chronic lateral ankle instability.

BACKGROUND: Near infrared brain functional imaging (FNIRS) has been used for the evaluation of brain functional areas, the imaging differences of central activation of cognitive-motor dual tasks between patients with chronic lateral ankle instability (CLAI) and healthy population remain unclear. This study aimed to evaluated the role of central imaging based on FNIRS technology on the plan management in patients with CLAI, to provide insights to the clinical treatment of CLAI. METHODS: CLAI patients treated in our hospital from January 1, 2021 to June 31, 2022 were selected. Both CLAI patients and health controls were intervened with simple task and cognitive-motor dual task under sitting and walking conditions, and the changes of oxygenated hemoglobin concentration in bilateral prefrontal cortex (PFC), premotor cortex (PMC) and auxiliary motor area (SMA) were collected and compared. RESULTS: A total of 23 participants were enrolled. There were significant differences in the fNIRS ΔHbO2 of barefoot subtractive walking PFC-R and barefoot subtractive walking SMA-R between experimental and control group (all P < 0.05). There was no significant difference in ΔHbO2 between the experimental group and the control group in other states (P > 0.05). There was no significant difference in ΔHbO2 between the experimental group and the control group in each state of the brain PMC region. CONCLUSION: Adaptive alterations may occur within the relevant brain functional regions of individuals with CLAI. The differential activation observed between the PFC and the SMA could represent a compensatory mechanism emerging from proprioceptive afferent disruptions following an initial ankle sprain.

Factors associated with clinical severity in chronic venous disease: The role of functional parameters.

INTRODUCTION: Chronic venous disease (CVD) is a highly prevalent disease that presents a wide spectrum of clinical expressions due to abnormalities in the venous system. Patients often have major functional changes that can limit daily activities. However, the functional factors associated with the severity of the disease remain poorly understood. OBJECTIVE: To identify the functional factors associated with CVD severity. METHODS: Seventy-five patients with CVD (92.0% females, 49.6 ± 13.3 years) were evaluated through clinical examination, lower limb perimetry, ankle range of motion (AROM), and lower limb muscle strength by the Heel Rise test, and Sit-to-stand test. Patients were stratified according to the disease severity as mild (telangiectasia, varicose veins, or edema in the lower limbs) or severe CVD (trophic changes or venous ulcer). RESULTS: Patients with severe CVD (n = 13) were older (p = 0.002), predominantly male (p = 0.007), with reduced AROM in dorsiflexion (p = 0.028) and inversion (p = 0.009), reduced lower limb strength by the Heel Rise test (p = 0.040), and greater circumference of the calf (p = 0.020), ankle (p = 0.003), and plantar arch (p = 0.041) when compared to mild CVD (n = 62). Advanced age, male sex, lower ankle range of motion in dorsiflexion, and greater ankle and plantar arch circumferences were associated with CVD severity. However, the ankle circumference (OR 1.258, 95% CI: 1.008-1.570; p = 0.042), together with advanced age and male sex, was the only functional variable that remained independently associated with CVD severity. CONCLUSION: The increased ankle circumference was a determinant of the CVD severity and may assist in risk stratification and guide treatment goals in this population.

Single-legged landing behavior of high school basketball players with chronic ankle instability.

OBJECTIVES: Anterior cruciate ligament injury is one of the most serious ligamentous injuries. The purpose is to compare the impact of the ankle joint on the knee during landing between athletes with chronic instability and a control group (coper group) and to verify the effects of the kinetic chain from other joints. DESIGN: Prospective study. SETTING: High school basketball. PARTICIPANTS: Participants were 62 female high school basketball players who had participated in team sports for >6 months. MAIN OUTCOME MEASURES: Player joint angles, movements, and moments. RESULTS: The knee valgus moment was significantly higher in the chronic ankle instability group than in the coper group (20%-60% [p < 0.01]; 80%-100% [p < 0.05]) during landing motion. The knee valgus moment was also significantly higher during the change from the maximum knee joint flexion position to the maximum extension (p < 0.05). In addition, the landing motions of the chronic instability group may have utilized suboptimal compensatory motor strategy on the sagittal plane, depending heavily on the knee joint's abduction moment. CONCLUSIONS: Our findings indicate that the chronic ankle instability group uses a different landing strategy pattern than the coper group by changing the joint moment and joint angle during landing, which may increase the risk of anterior cruciate ligament injury.

Effects of ankle joint mobilization on dynamic balance muscle activity and dynamic balance in persons with chronic ankle instability - Feasibility of a cross-over study.

INTRODUCTION: Studies with focus on effects of manual therapy techniques on postural control and muscle activity in patients with chronic ankle instability (are lacking. The purpose of this study was to evaluate the feasibility of a planned cross-over study to assess efficacy of manual therapy techniques applications in patients with chronic ankle instability. METHODS: This feasibility study used a randomized controlled, blinded assessor cross-over design. Criteria of success under evaluation were adherence and attrition rates and adverse events. while preliminary treatment effects of manual therapy techniques on muscular activity (measured by surface electromyography) and on dynamic balance (measured by time to stabilization test) were secondary aims. RESULTS: Thirteen participants (mean age: 24.4 ± 3.8 years) with chronic ankle instability volunteered in this feasibility study. Success criteria showed a high adherence (98.7%) and low attrition (0%). No missing data were reported but four out of 26 data sets could not be used for statistical analysis because of non-readability of the recorded data. Preliminary treatment effect showed divergent results for surface electromyography and time to stabilization. One significant result (p = 0.03, ES = 1.48) in peroneus longus muscle activity after jump landing between 30 and 60 ms could be determined. CONCLUSIONS: This study showed that the study protocol is feasible but should be modified by offering participants the opportunity to familiarize to the jumps and to the test repetitions. This study generates better understanding of manual therapy techniques for patients with chronic ankle instability.

Lower extremity inter-joint coupling angles and variability during gait in pediatric hypermobility spectrum disorder.

Complex musculoskeletal complications in children with hypermobility spectrum disorder (HSD) include pain, proprioception deficits, and joint instability, which may result in movement dysfunction during walking. However, no studies have explored the inter-joint coordination deficits in children with HSD. The purpose of this study was to determine the lower extremity inter-joint coupling angles, patterns, and variability during walking in children with HSD compared to children without HSD (non-HSD). Ankle, knee, and hip kinematics during the stance phase of walking in 18 children with HSD and 18 children without HSD were measured using three-dimensional motion analysis. Coupling angles, patterns, and variability of hip-knee, hip-ankle, and knee-ankle were quantified in the sagittal, frontal, and transverse planes using vector coding techniques. Statistical modeling of coupling angles on sine and cosine scales and bootstrapped standard errors were used to compare coupling angles between HSD and non-HSD groups. Permutational multivariate analysis of variance and statistical non-parametric mapping two-sample t-tests were used to compare the coupling patterns and variability between HSD and non-HSD groups, respectively. Our results indicated that coupling angles, patterns, and variability were not significantly different between the groups. These findings suggest that lower extremity inter-joint coordination and its variability during walking might not be a promising area for further research or intervention in children with HSD. Further research could use other biomechanical methods to investigate coordination deficits in pediatric patients with HSD, and how aging and disease progression are associated with coordination deficits in individuals with HSD.

Outcomes comparison of elastic bandage versus lower-leg cast immobilization after anterior talofibular ligament repair.

PURPOSE: The aim of this study was to compare the clinical outcomes between patients with chronic ankle instability (CAI) undergoing arthroscopic anterior talofibular ligament (ATFL) repair who received elastic bandage treatment and those who received lower-leg cast immobilization. METHODS: CAI patients with isolated ATFL injury undergoing arthroscopic ATFL repair from January 2017 and August 2019 were included in the study. The visual analogue scale (VAS) at rest and during activities, American Orthopedic Foot and Ankle Society (AOFAS) score, Karlsson Ankle Functional Score (Karlsson score), and time of returning to walk, walk normally, work and sports were evaluated preoperatively, and at 6 months and 12 months follow-up. RESULTS: A total of 41 patients were included in this study. Among them, 24 patients accepted lower-leg cast fixation, and the other 17 patients were immobilized with elastic bandage. Compared to patients with lower-leg immobilization, patients with elastic bandage fixation had significantly lower VAS during activities (P = 0.021) and higher AOFAS score (P = 0.015) at 12 months follow-up. The Karlsson score at 6 months follow-up were significantly higher in elastic bandage group than those in lower-leg group (P = 0.011). However, no significant difference was observed in time of returning to walk, work and sports between the two groups. CONCLUSION: Elastic bandage treatment was better than lower-leg cast immobilization in terms of eliminating pain symptom at 12 months follow-up, and improving ankle functional outcome at 6 months follow-up. Moreover, the present study emphasized that lower-leg cast immobilization offered no advantages in arthroscopic ATFL repair postoperative immobilization. STUDY DESIGN: Cohort study; Level of evidence, 3.

Change of Segmental Motion Following Total Ankle Arthroplasty Using a 3-Dimensional Multi-segment Foot Model.

Background: Total ankle arthroplasty (TAA) enhances patients' subjective outcomes with respect to pain and function. The aim of this study was to analyze the biomechanical changes of the affected limb following TAA using gait analysis with a 3-dimensional multi-segment foot model (3D MFM). Methods: We reviewed medical records, simple radiographs, and gait analyses using a 3D MFM of patients who underwent TAA for severe varus ankle arthritis. Preoperative and postoperative gait data of 24 patients were compared. Postoperative gait analyses were done at least 1 year after surgery. Results: TAA significantly increased stride length (p = 0.024). The total range of motion of all planes in the hindfoot and forefoot showed no significant changes between preoperative and postoperative states. Hindfoot was significantly plantarflexed and pronated after TAA, while forefoot was significantly supinated in all phases. After appropriate calculations, the genuine coronal motion of the hindfoot showed no changes after TAA in all phases. Conclusions: TAA did not result in biomechanical improvements of segmental motions in the forefoot and hindfoot, except for changes to the bony structures. Therefore, it is important to point out to patients that TAA will not result in significant improvement of ankle function and range of motion. Clinicians can consider this information during preoperative counseling.

Inhibitory kinesiotaping has no effect on post-stroke spasticity: Prospective, randomised, controlled study.

OBJECTIVE: Motor neuron pool activity is high in spasticity. The effect of inhibitory kinesiotaping (KT) on spasticity is unclear. The aim of this study is to investigate the effect of inhibitory KT on spasticity after stroke. METHODS: Fifty stroke patients with ankle plantarflexor spasticity were randomised to intervention (27) and control (23) groups. Inhibitory KT was applied to the triceps surae muscle in the intervention group and sham KT to the Achilles tendon in the control group. Inhibitory and sham KT were applied for 72 h with a combined conventional rehabilitation programme. Spasticity was assessed at baseline and 72 h after KT using three instruments: Modified Ashworth Scale (MAS), Homosynaptic Post-Activation Depression (HPAD) reflecting the level of motor neuron pool activity, and joint torque as a measure of resistance to passive ankle dorsiflexion. RESULTS: The baseline MAS score, HPAD levels and dorsiflexion torque of the two groups were not significantly different. The change in MAS score was -3.7 ± 17.5 (p = 0.180) in the intervention group and 3.6 ± 33.3 (p = 0.655) in the control group. The change in dorsiflexion torque was -0.3 ± 16.1 kg m (p = 0.539) in the intervention group and 8.0 ± 24.1 kg m (p = 0.167) in the control group. The change in mean HPAD was 8.7 ± 34.7 (p = 0.911) in the intervention group and 10.1 ± 41.6 (p = 0.609) in the control group. CONCLUSIONS: The present study showed that inhibitory KT has no antispastic effect in stroke patients.

Accuracy to identify young adults with chronic ankle instability using a virtual reality - Balance error scoring system: A cross-sectional study.

INTRODUCTION: The Balance Error Scoring System (BESS) assesses the ability to control postural stability by performing 3 different stances on two-type surfaces during closed eyes. Virtual reality technology combined with the BESS test (VR-BESS) may be used to disrupt visual inputs instead of closing the eyes, which may improve the sensitivity of diagnosing patients with chronic ankle instability (CAI). OBJECTIVE: This study aimed to evaluate the accuracy to identify individuals with CAI of the VR-BESS test comparing with the original BESS test. METHODS: The BESS and VR-BESS tests were administered to 68 young adults (34 participants with CAI and 34 without CAI). Frontal and lateral video views were used to measure the participant's performance errors. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was computed to determine the diagnostic test's overall accuracy. RESULTS: The total score of the BESS test and the VR-BESS test were statistically significant in comparison to the AUC of no discrimination at 0.5, with AUC values of 0.63 and 0.64, respectively. The cut-off scores for the BESS and VR-BESS tests were 12 and 15, respectively. There was no significant difference between the ROC curves of the BESS and the VR-BESS test for identifying individuals with CAI. CONCLUSION: The BESS and VR-BESS tests may be utilized interchangeably to identify individuals with CAI.

Neuromuscular and trunk control mediate factors associated with injury in fatigued runners.

This study aimed to determine how fatigue affects factors associated with injury, neuromuscular activity, and control in recreational runners. Previously identified injury risk factors were defined as peak vertical instantaneous loading rates (pVILR) for tibial stress fracture (TSF) and peak hip adduction (pHADD) for patellofemoral pain syndrome and iliotibial band syndrome. Kinematics, kinetics, and electromyography data were collected from 11 recreational runners throughout a fatiguing run. Three trials were collected in the first and final minutes of the run. Coactivation was quantified about the knee and ankle for the entire stance phase and anticipatory, weight acceptance (WA), and propulsion sub-phases of stance. Trunk control was quantified by the peak mediolateral lean, peak forward lean, and flexion range of motion (ROM). There were significant increases in pHADD and pVILR when fatigued. Significant decreases in coactivation around the knee were found over the entire stance phase, in the anticipatory phase, and WA phase. Coactivation decreased about the ankle during WA. Lateral trunk lean significantly increased when fatigued, but no significant changes were found in flexion ROM or lean. Mediation analyses showed changes in ankle coactivation during WA, and lateral trunk lean are significant influences on pVILR, a measure associated with TSF. Fatigue-induced adaptations of decreasing ankle coactivation during WA and increased lateral trunk lean may increase the likelihood of TSF. In this study, a fatiguing run influenced changes in control in recreational runners. Further investigation of causal fatigue-induced injuries is necessary to better understand the effects of coactivation and trunk control.

Articulated ankle-foot-orthosis improves inter-limb propulsion symmetry during walking adaptability task post-stroke.

BACKGROUND: Community ambulation involves complex walking adaptability tasks such as stepping over obstacles or taking long steps, which require adequate propulsion generation by the trailing leg. Individuals post-stroke often have an increased reliance on their trailing nonparetic leg and favor leading with their paretic leg, which can limit mobility. Ankle-foot-orthoses are prescribed to address common deficits post-stroke such as foot drop and ankle instability. However, it is not clear if walking with an ankle-foot-orthosis improves inter-limb propulsion symmetry during adaptability tasks. This study sought to examine this hypothesis. METHODS: Individuals post-stroke (n = 9) that were previously prescribed a custom fabricated plantarflexion-stop articulated ankle-foot-orthosis participated. Participants performed steady-state walking and adaptability tasks overground with and without their orthosis. The adaptability tasks included obstacle crossing and long-step tasks, leading with both their paretic and nonparetic leg. Inter-limb propulsion symmetry was calculated using trailing limb ground-reaction-forces. FINDINGS: During the obstacle crossing task, ankle-foot-orthosis use resulted in a significant improvement in inter-limb propulsion symmetry. The orthosis also improved ankle dorsiflexion during stance, reduced knee hyperextension, increased gastrocnemius muscle activity, and increased peak paretic leg ankle plantarflexor moment. In contrast, there were no differences in propulsion symmetry during steady-state walking and taking a long-step when using the orthosis. INTERPRETATION: Plantarflexion-stop articulated ankle-foot-orthoses can improve propulsion symmetry during obstacle crossing tasks in individuals post-stroke, promoting paretic leg use and reduced reliance on the nonparetic leg.

Activity-Dependent Compensation at the Hip and Ankle at 8 Years After the Reconstruction of Isolated and Combined Posterior Cruciate Ligament Injuries.

BACKGROUND: After posterior cruciate ligament reconstruction (PCLR), functional deficits at the knee can persist. It remains unclear if neighboring joints compensate for the knee during demanding activities of daily living. PURPOSE: To assess long-term alterations in lower limb mechanics in patients after PCLR. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 28 patients who had undergone single-bundle unilateral isolated or combined PCLR performed stair navigation, squat, sit-to-stand, and stand-to-sit tasks at 8.2 ± 2.2 years after surgery. Motion capture and force plates were used to collect kinematic and kinetic data. Then, 3-dimensional hip, knee, and ankle kinematic data of the reconstructed limb were compared with those of the contralateral limb using statistical parametric mapping. RESULTS: Side-to-side differences at the knee were primarily found during upward-driven movements at 8 years after surgery. The reconstructed knee exhibited lower internal rotation during the initial loading phase of stair ascent versus the contralateral knee (P = .005). During the sit-to-stand task, higher flexion angles during the midcycle (P = .017) and lower external rotation angles (P = .049) were found in the reconstructed knee; sagittal knee (P = .001) and hip (P = .016) moments were lower in the reconstructed limb than the contralateral limb. In downward-driven movements, side-to-side differences were minimal at the knee but prominent at the ankle and hip: during stair descent, the reconstructed ankle exhibited lower dorsiflexion and lower external rotation during the midcycle versus the contralateral ankle (P = .006 and P = .040, respectively). Frontal hip moments in the reconstructed limb were higher than those in the contralateral limb during the stand-to-sit task (P = .010); during squats, sagittal hip angles in the reconstructed limb were higher than those in the contralateral limb (P < .001). CONCLUSION: Patients after PCLR exhibited compensations at the hip and ankle during downward-driven movements, such as stair descent, squats, and stand-to-sit. Conversely, residual long-term side-to-side differences at the knee were detected during upward-driven movements such as stair ascent and sit-to-stand. CLINICAL RELEVANCE: After PCLR, side-to-side differences in biomechanical function were activity-dependent and occurred either at the knee or neighboring joints. When referring to the contralateral limb to assess knee function in the reconstructed limb, concentric, upward-driven movements should be prioritized. Compensations at the hip and ankle during downward-driven movements lead to biases in long-term functional assessments.

Effects of Homologous instrument assisted mobilization (HIM) on ankle movement, gait-related muscle activation, and plantar pressure distribution in ankle dorsiflexion syndrome: A randomized single control trial.

BACKGROUND: While the limited ankle dorsiflexion syndrome (ADS) is common in neuro-musculoskeletal conditions, the instrument-assisted mobilization focused on the shortened gastro-soleus myofascial structure (IMI) rather than the homologous structure (both gastrosoleus and tibiliais anterior muscles, HIM). OBJECTIVE: We aimed to compare the immediate therapeutic effects between IMH and IMI treatment groups on the ankle dorsiflexion angle, muscle activation and foot pressure distribution during dynamic gait in ADS. METHODS: Neuromechanical tests including kinematics (ankle mobility), kinetics (center of pressure distribution), and electromyography were used to determine the immediate therapeutic effects between HIM and IMI treatment groups in 24 participants with ADS. RESULTS: The ankle joint angle analysis demonstrated a more improved active DF angle in the group who received HIM intervention when compared to the group who received IMI intervention. (11.26% and 3.58%, respectively) EMG analysis showed more decreased mean and peak TA activation amplitudes in the group who received HIM intervention (9.1% and 9%) when compared to the group who received IMI intervention (11.48% and 1.48%). Plantar pressure distribution analysis showed difference that the forefoot/area decreased in the group who received HIM intervention (8.1%), but rather increased in the group who received IMI intervention (14.3%). CONCLUSIONS: Our neuromechanical results demonstrated promising positive effects on ankle joint mobility, muscle activation and foot pressure distribution during gait in ADS.

Differences in ankle and knee muscle architecture and plantar pressure distribution among women with knee osteoarthritis.

BACKGROUND: The aim of this study was to compare the plantar pressure distribution and knee and ankle muscle architecture in women with and without knee osteoarthritis (OA). METHODS: Fifty women with knee OA (mean age = 52.11 ± 4.96 years, mean Body mass index (BMI) = 30.94 ± 4.23 kg/m2) and 50 healthy women as a control group (mean age = 50.93 ± 3.78 years, mean BMI = 29.06 ± 4.82 kg/m2) were included in the study. Ultrasonography was used to evaluate knee and ankle muscles architecture and femoral cartilage thickness. The plantar pressure distribution was evaluated using the Digital Biometry Scanning System and Milleri software (DIASU, Italy). Static foot posture was evaluated using the Foot Posture Index (FPI), and pain severity was assessed using the Visual Analog Scale. RESULTS: The OA group exhibited lower muscle thickness in Rectus Femoris (RF) (p = 0.003), Vastus Medialis (VM) (p = 0.004), Vastus Lateralis (p = 0.023), and Peroneus Longus (p = 0.002), as well as lower Medial Gastrocnemius pennation angle (p = 0.049) and higher Fat thickness (FT) in RF (p = 0.033) and VM (p = 0.037) compared to the control group. The OA group showed thinner femoral cartilage thickness (p = 0.001) and higher pain severity (p = 0.001) than the control groups. FPI scores were higher (p = 0.001) in OA group compared to the control group. The plantar pressure distribution results indicated an increase in total surface (p = 0.027), total load (p = 0.002), medial load (p = 0.005), and lateral load (p = 0.002) on dominant side in OA group compared to the control group. CONCLUSIONS: Knee and ankle muscle architecture, knee extensor muscle FT, and plantar pressure distribution in the dominant foot differed in individuals with knee OA compared to the control group.

The applicability of markerless motion capture for clinical gait analysis in children with cerebral palsy.

The aim of this comparative, cross-sectional study was to determine whether markerless motion capture can track deviating gait patterns in children with cerebral palsy (CP) to a similar extent as marker-based motion capturing. Clinical gait analysis (CGA) was performed for 30 children with spastic CP and 15 typically developing (TD) children. Marker data were processed with the Human Body Model and video files with Theia3D markerless software, to calculate joint angles for both systems. Statistical parametric mapping paired t-tests were used to compare the trunk, pelvis, hip, knee and ankle joint angles, for both TD and CP, as well as for the deviation from the norm in the CP group. Individual differences were quantified using mean absolute differences. Markerless motion capture was able to track frontal plane angles and sagittal plane knee and ankle angles well, but individual deviations in pelvic tilt and transverse hip rotation as present in CP were not captured by the system. Markerless motion capture is a promising new method for CGA in children with CP, but requires improvement to better capture several clinically relevant deviations especially in pelvic tilt and transverse hip rotation.

Three-Dimensional Printed Total Talus Replacement with a Concurrent Total Ankle Arthroplasty as a Personalized Approach for Advanced Ankle Osteoarthritis A Case Repor.

Ankle arthritis is becoming more common and can be pain-ful and debilitating. As the disease progresses, degenera-tive cystic changes may be found in the distal fibula, distal tibia, and talus. After failure of non-operative modalities, arthrodesis is often considered the surgical intervention of choice, but this leaves the patient with reduced range of motion, altered gait, and can negatively impact adjacent joints of the foot. Total ankle arthroplasty has been found to be an effective surgical option for ankle arthritis but is contraindicated in patients with talar collapse. When this is the case, a more personalized approach for preserving ankle motion is necessary. We present the case of a 65-year-old male with severe right ankle arthritis and talar collapse treated with a custom three-dimensionally printed talus and concurrent total ankle replacement with 2-year follow-up.

Knee and ankle range of motion and spasticity from childhood into adulthood: a longitudinal cohort study of 3,223 individuals with cerebral palsy.

BACKGROUND AND PURPOSE: Reduced range of motion (ROM) and spasticity are common secondary findings in cerebral palsy (CP) affecting gait, positioning, and everyday functioning. These impairments can change over time and lead to various needs for intervention. The aim of this study was to analyze the development path of the changes in hamstring length, knee extension, ankle dorsiflexion, and spasticity in hamstrings and gastrosoleus from childhood into adulthood in individuals with CP at the Gross Motor Function Classification System (GMFCS) levels I-V. METHODS: A longitudinal cohort study was undertaken of 61,800 measurements in 3,223 individuals with CP, born 1990-2017 and followed for an average of 8.7 years (range 0-26). The age at examination varied between 0 and 30 years. The GMFCS levels I-V, goniometric measurements, and the modified Ashworth scale (MAS) were used for repeated assessments of motor function, ROM, and spasticity. RESULTS: Throughout the follow-up period, knee extension and hamstring length exhibited a consistent decline across all individuals, with more pronounced decreases evident in those classified at GMFCS levels III-V. Ankle dorsiflexion demonstrated a gradual reduction from 15° to 5° (GMFCS I-IV) or 10° (GMFCS V). Spasticity levels in the hamstrings and gastrosoleus peaked between ages 5 and 7, showing a propensity to increase with higher GMFCS levels. CONCLUSION: Passive ROM continues to decrease to 30 years of age, most pronouncedly for knee extension. Conversely, spasticity reached its peak at a younger age, with a more notable occurrence observed in the gastrosoleus compared with the hamstrings. Less than 50% of individuals had spasticity corresponding to MAS 2-4 at any age.

A finite element model of human hindfoot and its application in supramalleolar osteotomy.

BACKGROUND: The majority of the ankle osteoarthritis cases are posttraumatic and affect younger patients with a longer projected life span. Hence, joint-preserving surgery, such as supramalleolar osteotomy becomes popular among young patients, especially those with asymmetric arthritis due to alignment deformities. However, there is a lack of biomechanical studies on postoperative evaluation of stress at ankle joints. We aimed to construct a verifiable finite element model of the human hindfoot, and to explore the effect of different osteotomy parameters on the treatment of varus ankle arthritis. METHODS: The bones of the hindfoot are reconstructed using normal CT tomography data from healthy volunteers, while the cartilages and ligaments are determined from the literature. The finite element calculation results are compared with the weight-bearing CT (WBCT) data to validate the model. By setting different model parameters, such as the osteotomy height (L) and the osteotomy distraction distance (h), the effects of different surgical parameters on the contact stress of the ankle joint surface are compared. FINDINGS: The alignment and the deformation of hindfoot bones as determined by the finite element analysis aligns closely with the data obtained from WBCT. The maximum contact stress of the ankle joint surface calculated by this model increases with the increase of the varus angle. The maximum contact stresses as a function of the L and h of the ankle joint surface are determined. INTERPRETATION: The relationship between surgical parameters and stress at the ankle joint in our study could further help guiding the planning of the supramalleolar osteotomy according to the varus/valgus alignment of the patients.

Effects of ankle-foot orthosis with dorsiflexion resistance on the quasi-joint stiffness of the ankle joint and spatial asymmetry during gait in patients with hemiparesis.

BACKGROUND: Reduced ankle quasi-joint stiffness affects propulsion in the paretic side of patients with hemiparesis, contributing to gait asymmetry. We investigated whether the use of an ankle-foot orthosis with dorsiflexion resistance to compensate for reduced stiffness would increase quasi-joint stiffness and spatiotemporal symmetry in patients with hemiparesis. METHODS: Seventeen patients walked along a 7-m walkway in both ankle-foot orthosis with dorsiflexion resistance and control (i.e., ankle-foot orthosis) conditions. Dorsiflexion resistance by spring and cam was set to increase linearly from zero-degree ankle dorsiflexion. Gait data were analyzed using a three-dimensional motion analysis system. FINDINGS: Ankle-foot orthosis with dorsiflexion resistance significantly increased the quasi-joint stiffness in the early and middle stance phase (P = 0.028 and 0.040). Furthermore, although ankle power generation in the ankle-foot orthosis with dorsiflexion resistance condition was significantly lower than in the control condition (P = 0.003), step length symmetry significantly increased in the ankle-foot orthosis with dorsiflexion resistance condition (P = 0.016). There was no significant difference in swing time ratio between conditions. INTERPRETATION: Applying dorsiflexion resistance in the paretic stance phase increased quasi-joint stiffness but did not lead to an increase in ankle power generation. On the other hand, applying dorsiflexion resistance also resulted in a more symmetrical step length, even though the ankle joint power generation on the paretic side did not increase as expected. Future research should explore whether modifying the magnitude and timing of dorsiflexion resistance, considering the biomechanical characteristics of each patients' ankle joint during gait, enhances ankle joint power generation.

Frequency analysis of ankle joint quasi-stiffness during quiet unperturbed standing in Chiari Malformation.

Chiari Malformation (Chiari) is a congenital condition occurring from an inferior herniation of the cerebellar tonsils into the foramen magnum. Given the role of the cerebellum in postural control, it is reasonable to expect joint motion to be affected in this patient population. In fact, joint stiffness is a common self-reported symptom of Chiari, however it has never been assessed in these individuals. This study aimed to examine if ankle joint quasi-stiffness is correlated with Chiari severity. The human body was considered as an inverted oscillating pendulum without damping. A Fast Fourier Transform was used to extract natural frequency from the center of pressure trajectories during upright standing. Ankle joint quasi-stiffness was then calculated using the relationship between natural frequency and moment of inertia. Twelve Chiari participants (Chiari), six with decompression surgery (Chiari-D) and six without (Chiari-ND), and eight control individuals (Control) participated. Participants completed three, 30-second quiet standing trials on a force plate, focused on a target three meters in front of them. Chiari, regardless of surgery, had significantly lower quasi-stiffness than controls (Chiari-D vs. Control p = 0.0011, Chiari-ND vs. Control, p < 0.001). The proposed method is advantageous as it incorporates the entire center of pressure signal, minimizes error from instantaneous muscular dynamics, and does not require motion capture.