Sound Limb Research Articles

Alpha-band activity in parietofrontal cortex predicts future availability of vibrotactile feedback in prosthesis use.

Prosthesis disuse and abandonment is an ongoing issue in upper-limb amputation. In addition to lost structural and motor function, amputation also results in decreased task-specific sensory information. One proposed remedy is augmenting somatosensory information using vibrotactile feedback to provide tactile feedback of grasping objects. While the role of frontal and parietal areas in motor tasks is well established, the neural and kinematic effects of this augmented vibrotactile feedback remain in question. In this study, we sought to understand the neurobehavioral effects of providing augmented feedback during a reach-grasp-transport task. Ten persons with sound limbs performed a motor task while wearing a prosthesis simulator with and without vibrotactile feedback. We hypothesized that providing vibrotactile feedback during prosthesis use would increase activity in frontal and parietal areas and improve grasp-related behavior. Results show that anticipation of upcoming vibrotactile feedback may be encoded in motor and parietal areas during the reach-to-grasp phase of the task. While grasp aperture is unaffected by vibrotactile feedback, the availability of vibrotactile feedback does lead to a reduction in velocity during object transport. These results help shed light on how engineered feedback is utilized by prostheses users and provide methodologies for further assessment in advanced prosthetics research.

Effects of walking speed and prosthetic knee control type on external mechanical work in transfemoral prosthesis users

During human locomotion, each limb performs step-to-step work on the body center of mass to maintain forward walking. This energy exchange relies on physiological mechanisms which are altered or impaired in transfemoral prosthesis users (TFPUs). Exploring step-to-step energy exchange modifications displayed by TFPUs at greater walking speeds may provide insight into their means for improving gait efficiency. The primary aim of this study was to characterize the effects of walking speed on mechanical work in unilateral TFPUs. The secondary aim assessed the effect of prosthetic knee (microprocessor, mechanical passive) on limb collision work. Twenty-five TFPUs walked with their customary prosthesis on a split-belt instrumented treadmill at eight speeds (0.55–1.53 m/s range), and collision, midstance, and push-off work were calculated for each limb. TFPUs displayed a significant (p < 0.001) bilateral increase in collision work with increased walking speed, but midstance and push-off work increased only for the sound limb and remained nearly constant for the prosthetic limb. TFPUs displayed significantly (p < 0.001) less push-off work generated by the prosthetic limb across all speeds. A microprocessor knee was associated with reduced sound limb collision work across speeds with the peak (negative) power being significantly greater for mechanical knees (p = 0.032). Results suggest that TFPU gait inefficiency may be related to a near complete loss of energy transfer on the prosthetic limb, relying on the sound limb to drive energy changes. Such reliance emphasizes need for attention to the long-term effects on sound limb health and possible benefit of microprocessor knees to offset that impact.

Residual and sound limb hip strength distinguish between sedentary and nonsedentary adults with transtibial amputation.

Following a transtibial amputation (TTA), physical activity has known benefits for health and quality of life. Adults post-TTA, however, demonstrate reduced physical activity, predisposing them to adverse health outcomes. Identifying adults at the risk of sedentarism post-TTA via commonly used, objective clinical measures may enhance clinical decisions, including prosthesis prescription. The study's purpose was to determine whether residual and sound limb hip strength distinguishes between sedentary and nonsedentary adults post-TTA. A secondary analysis of a cross-sectional dataset (n = 44) was conducted. Participant residual and sound limb hip flexion, extension, abduction and adduction strength were assessed via handheld dynamometry. Physical activity was monitored for 7 days and participants were classified as sedentary (<5000 steps/day; n = 13) or nonsedentary (≥5000 steps/day; n = 31). Receiver operating curves revealed that residual and sound limb hip extension, abduction and adduction strength distinguished between sedentary and nonsedentary adults post-TTA (P < 0.050). Preliminary cut-points for hip strength measures to classify adults at the risk of sedentarism were determined. A hip strength composite score (0-6) estimates a 2.2× increased odds of being sedentary with each additional hip strength deficit. Post-TTA, residual and sound limb hip strength can help identify adults at risk of sedentarism to aid clinical decision making, including prosthesis prescription.

EEG based cortical investigation for the limit of stability analysis in transfemoral amputees: A comparison with able-bodied individuals

BackgroundThe evidences for demonstrating the contributions of the cerebral cortex in human postural control is increasing. However, there remain little insights about the cortical correlates of balance control in lower-limb amputees. The present study aimed to investigate the cortical activity and balance performance of transfemoral amputees in comparison to healthy individuals during a continuous balance task (CBT). MethodsThe postural stability of the participants was defined with limit of stability parameter. Electroencephalography (EEG) data were recorded in synchronization with the center of pressure (CoP) data from eighteen individuals (including eight unilateral transfemoral amputees). We anticipated that, due to the limb loss, the postural demand of transfemoral amputees increases which significantly modulates the spectral power of intrinsic cortical oscillations. FindingsUsing the independent components from the sensorimotor areas and supplementary motor area (SMA), our results present a well-pronounced drop of alpha spectral power at sensorimotor area contralateral to sound limb of amputees in comparison to SMA and the sensorimotor area contralateral to prosthetic limb. Following this, we found significantly higher (p < 0.05) limit of stability (LOS) at their sound limb than at the prosthetic limb. Healthy individuals have similar contribution from both the limbs and the EEG alpha spectral power was similar across the three regions of the cortex during the balance control task as expected. Overall, a decent correlation was found between the LOS and alpha spectral power in both amputee and healthy individuals (Pearson’s correlation coefficient > 0.5). InterpretationBy externally stimulating the highlighted cortical regions, neuroplasticity might be promoted which helps to reduce the training time for the efficient rehabilitation of amputees. Additionally, this new knowledge might benefit in the designing and development of innovative interventions to prevent falls due to lower limb amputation.

Quantitative assessment of postural balance in patients with chronic anterior cruciate ligament injury- A controlled study

PurposeEvaluation of single and double limb support postural balance in patients with Anterior cruciate ligament (ACL)injury and comparison of the postural strategy adopted after ACL injury/deficiency(ACLD) with that of an age-matched healthy individual. MethodsThe study group that included 33 subjects confirming inclusion criteria had undergone postural balance assessment using the HUMAC Balance system. The parameters of the center of pressure excursion were recorded on a force plate and compared with age, BMI matched 66 healthy volunteers of control group. The center of pressure excursions was monitored using dependable variables such as sway path length(cm), the average velocity of sway(cm/sec), and the mean COP stability score(%). The mobility component was recorded as the percentage (%) of time spent on each target. ResultA decrease in postural balance in the injury group was evidenced by a statistically significant decrease of stability score(p = 0.015), increase in path length(p = 0.002) and decrease on time on target mean score (p= <0.001),. Although, the stability score path length and average sway velocity scores in the sound limb of the ACLD group showed impaired balance, the differences were not statistically significant (p = 0.180, p = 0.561, and p = 0.639 respectively) when compared with the dominant limb of the control group. ConclusionHUMAC balance system is an effective and simplified measure for quantifying postural balance. Although overall postural stability in ACL injury is impaired, static postural balance is maintained by the compensatory of strategy of sound limb. However, the quantitative parameters of postural stability for the sound limb, despite of a lower mean value, did not show statistically significant differences from the dominant limb of the controlled group.

Evaluating the Ability of Congenital Upper Extremity Amputees to Control a Multi-Degree of Freedom Myoelectric Prosthesis

To determine whether children and adults with unilateral congenital upper limb amputation can control myoelectric prostheses with multiple degrees of freedom (DOF) using pattern recognition (PR) technology. Seven participants (age 9-62 years) with unilateral congenital transradial amputation were tested on both their residual and sound side limbs to determine proficiency in controlling a virtual prosthesis using electromyographic signals captured by an array of surface electrodes that were processed using PR technology. Proficiency was measured through a virtual environment game called the target achievement control test, in which the testing protocol asked participants to match increasingly complex prosthesis postures with 1,2, and 3 DOF. All the participants successfully created a PR calibration at 1, 2, and 3 DOF with their residual limb during testing, and no differences in calibration accuracy were observed when comparing the residual versus sound upper limbs. No differences were noted in the mean completion rate on the target achievement control test between the residual and sound limbs. Participants with a congenital upper limb amputation achieved PR control calibration of multi-DOF prostheses with proficiency and quality results of PR calibration that were comparable to those of their sound limb. This capability was observed in children as well as in adults. This demonstrates the potential for children and adults with a unilateral congenital transradial amputation to benefit from myoelectric prostheses with PR control. The results from this study highlight the potential for patients in this population to benefit from myoelectric prostheses with PR control. Persons with unilateral congenital upper limb amputations can be considered for provision of this technology andenrollment in future research activities.

Vibration Sensitivity Is Associated With Functional Balance After Unilateral Transtibial Amputation

ObjectivesTo evaluate differences in vibration perception thresholds between adults with transtibial amputation and age-matched adults without amputation and to examine associations between vibration perception thresholds and balance performance. We hypothesized that adults with transtibial amputation would demonstrate lower thresholds compared with adults without amputation and that lower thresholds would be associated with better functional balance. DesignProspective cross-sectional study. SettingNational conference, clinical practice, and university laboratory. ParticipantsAdults (N=34) with a nondysvascular, unilateral, transtibial amputation and 43 age-matched controls without amputation. InterventionsParticipants’ vibration perception thresholds were evaluated bilaterally by applying a vibration stimulus to the midpatella and recording their verbal response to conscious perception of stimulus. Functional balance was assessed with the Berg Balance Scale and the Four Square Step Test. Main Outcome MeasuresResidual and sound limb (right and left for controls) vibration perception thresholds, Berg Balance Scale, and Four Square Step Test. ResultsFor participants with transtibial amputation and controls, there were no significant between-group (P=.921) or interlimb (P=.540) differences in vibration perception thresholds. Overall, robust regression models explained 35.1% and 19.3% variance in Berg Balance Scale scores and Four Square Step Test times, respectively. Among adults with transtibial amputation, vibration perception thresholds were negatively associated with Berg Balance Scale scores (P=.009) and positively associated with Four Square Step Test times (P=.048). Among controls, average vibration perception thresholds were not significantly associated with functional balance (P>.050). ConclusionsAdults with nondysvascular, transtibial-level amputation demonstrated similar vibration detection compared with adults with intact limbs, indicating that vibration detection is preserved in the amputated region postamputation. These findings suggest a unique relationship between vibration perception and functional balance post-transtibial amputation.

Do Upper Limb Loss and Prosthesis Use Affect Lower Limb Gait Dynamics?

Intentional interruption of upper and lower limb coordination of able-bodied subjects alters their gait biomechanics. However, the effect of upper-limb loss (ULL) on lower-limb gait biomechanics is not fully understood. The aim of this secondary study was to perform a follow-up analysis of a previous dataset to characterize the spatiotemporal parameters and lower-limb kinematics and kinetics of gait for persons with ULL when wearing and not wearing an upper limb prosthesis (ULP). We were particularly interested in quantifying the effects of matching the mass and inertia of the prosthetic limb to the sound limb. Ten persons with unilateral ULL walked at a self-selected speed under three randomly presented conditions: 1) not wearing a prosthesis, 2) wearing their customary prosthesis, and 3) wearing a mock prosthesis that can be adjusted to match the length, mass, and inertial properties of each subject's sound limb. Walkway-embedded force plates and a 12-camera digital motion capture system recorded ground reaction forces (GRFs) and retroreflective marker position data, respectively. Average spatiotemporal (walking speed, cadence, stance time, swing time, step length, double support time), lower-limb kinematic (joint angles), and lower-limb kinetic (ground forces, joint moments and powers) data were processed and their statistical significance were analyzed. Walking speed for each condition was nearly equivalent (1.20±0.01 m/s) and differences between condition were non-significant (p=0.769). The interaction effect (side× prosthesis) was significant for peak hip extension (p=0.01) and second peak (propulsive) vertical GRF (p=0.028), but separate follow-up analyses of both main effects were not significant (p≥0.099). All other main effect comparisons were not significant (p≥0.102). Although the sample cohort was small and heterogeneous, the results of this study suggest that persons with unilateral ULL did not display significant limb side asymmetry in lower-limb gait spatiotemporal, kinetic, and kinematic parameters, regardless of ULP use.

Symmetry function - An effective tool for evaluating the gait symmetry of trans-femoral amputees.

Prostheses can help persons with trans-femoral amputation (TFA) regain normal function, but such individuals still exhibit gait deviations expressed in gait asymmetries. We apply a specialised tool, the Symmetry Function (SF), to evaluate the symmetry of walking in terms of kinematic and dynamic variables and to identify areas with large side deviations (exceeding defined ±5% threshold) in the movement cycle. Which movements and joints or GRF components revealed the most significant side deviations in the movement cycle? When exactly are they located in the gate cycle? In this retrospective observational study, an instrumented motion analysis system was used to register the gait of fourteen patients after unilateral TFA. Measurements involved evaluating the time series of gait variables characterising a range of motion and the ground reaction force components. Comparison of the prosthetic (involved) limb with the sound (uninvolved) limb in TFA patients was carried out on the basis of the Symmetry Function values. The Symmetry Function proved to be an effective tool to localise the regions of asymmetry and limb dominance in the full gait cycle. The difference between sides revealed by the Symmetry Function was the highest for the pelvis and the hip. In the sagittal plane, the pelvis was asymmetrically tilted, reaching the highest SF value of more than 25 % at 60 % cycle time. In the transverse plane, the pelvis was even more asymmetrically positioned throughout the entire gait cycle (50 % difference). The hip in the frontal plane reached a 60 % difference throughout the single support phase for the involved and then for the uninvolved limb. The Symmetry Function allows for the detection of gait asymmetries, temporal shifts in the gait phases and may assess the precise in time adaptation of prostheses and rehabilitation monitoring, especially in unilateral impairments.

Evaluation of Donor Ankle Stability, Function and Body Balance Following Anterior Cruciate Ligament Reconstruction with Peroneus Longus Tendon Graft -A Prospective Cohort Study

Background: The effect of harvesting peroneus longus tendon graft (PLTG) for anterior Cruciate ligament reconstruction (ACLR) on donor ankle stability and function and its effect on overall body balance is not yet investigated. PLT is thought to play some role in the proprioceptive regulation of the ankle joint. ACL too has a vital role in the postural control of the knee joint. This study evaluates and compares the affected and sound limb balance and function in subjects following ACLR with autologous PLTG.Methods: A total of 44 eligible participants were assessed for balance using the HUMAC balance system and function with the Foot Ankle Ability Measure (FAAM) scale at 6week, 3month, and 6month after ACLR with PLTG. Outcome measures were stability score, path length, average velocity, time on target, and FAAM score.Results: There was statistically significant improvement in all the parameters of bilateral or unilateral standing balance at 6month post-op [Bilateral: stability score: p=0.001; path length: p=0.000; average velocity: p=0.000; time on target: p=0.006]; [unilateral-affected/sound: path length: p=0.000, p=0.003; average velocity: p=0.000, p=0.009). The difference between affected and sound limb balance was insignificant. Median of FAAM score at 6week, 3month, &amp; 6month were 97.368, 98.809 and 100 respectively.Conclusion: Balance of the whole body or any single leg stability is impaired after ACLR with PLTG, but it may improve to an optimal level with due time and recover fully by six months. Donor ankle function also restores to 100% at 6month.

Para Surfing Performance in Athletes With Lower Limb Amputations - A Cross-Sectional Study

<h3>Research Objectives</h3> To investigate para surfing performance in athletes with above knee amputations compared to below knee amputations. To investigate prior para surfing experiences with performance in athletes with lower limb amputations. <h3>Design</h3> Cross-sectional comparative study design. <h3>Setting</h3> Data collected from archived classification records and archived certified judged wave scores from two international Para Surfing competitions. <h3>Participants</h3> Twenty (2 female and 18 male) international Para Surfers with amputations (n=6 AKA and n=14 BKA). <h3>Interventions</h3> Data from classification records was reviewed for athletes classified with the eligible impairment of limb deficiency with an AKA or BKA and judged waves scores. <h3>Main Outcome Measures</h3> The residual limb of all athletes with amputations was measured in centimeters and described by percentage length of the residual limb compared to sound limb. The following information was retrieved classification forms: gender, age, diagnosis, lower extremity limb measurements, and surf history. <h3>Results</h3> No significant difference of demographics between the groups except for the percentage of remaining leg length with athletes with AKA compared to athletes with BKA. There were significant differences in the surfing scores between the groups. The significant difference persists even after performing the analysis using the percentage of the remaining leg length as a covariate (AKA versus BKA total score at 2019) F(1,9)= 8.10, p=.019; score at 2020 F (1,10) =7.73, p=.019). Subgroup analysis on surfers with AKA who performed in kneeling (n=3) and standing (n=3) did not have any significant differences in the surfing scores (2019 Score U=2.0; p=.564. 2020 score U=1.0; p=.248). No significant correlation between the duration of adaptive surfing experience or duration of competing with any surfing performance scores. results accepted primary hypothesis and rejected secondary hypothesis. <h3>Conclusions</h3> AKA performed better than athletes with BKA in Para Surfing. Results may provide beneficial evidence to contribute to the newly designed Para Surfing classification system. Understanding how different levels of amputations are limiting sports performance is fundamental for evidence-based classification. <h3>Author(s) Disclosures</h3> Primary author is Director of Para Surfing Classification, Second author is a para surfing classifier.

Reducing stiffness of shock-absorbing pylon amplifies prosthesis energy loss and redistributes joint mechanical work during walking

BackgroundA shock-absorbing pylon (SAP) is a modular prosthetic component designed to attenuate impact forces, which unlike traditional pylons that are rigid, can compress to absorb, return, or dissipate energy. Previous studies found that walking with a SAP improved lower-limb prosthesis users’ comfort and residual limb pain. While longitudinal stiffness of a SAP has been shown to affect gait kinematics, kinetics, and work done by the entire lower limb, the energetic contributions from the prosthesis and the intact joints have not been examined. The purpose of this study was to determine the effects of SAP stiffness and walking speed on the mechanical work contributions of the prosthesis (i.e., all components distal to socket), knee, and hip in individuals with a transtibial amputation.MethodsTwelve participants with unilateral transtibial amputation walked overground at their customary (1.22 ± 0.18 ms−1) and fast speeds (1.53 ± 0.29 ms−1) under four different levels of SAP stiffness. Power and mechanical work profiles of the leg joints and components distal to the socket were quantified. The effects of SAP stiffness and walking speed on positive and negative work were analyzed using two-factor (stiffness and speed) repeated-measure ANOVAs (α = 0.05).ResultsFaster walking significantly increased mechanical work from the SAP-integrated prosthesis (p < 0.001). Reducing SAP stiffness increased the magnitude of prosthesis negative work (energy absorption) during early stance (p = 0.045) by as much as 0.027 Jkg−1, without affecting the positive work (energy return) during late stance (p = 0.159), suggesting a damping effect. This energy loss was partially offset by an increase in residual hip positive work (as much as 0.012 Jkg−1) during late stance (p = 0.045). Reducing SAP stiffness also reduced the magnitude of negative work on the contralateral sound limb during early stance by 11–17% (p = 0.001).ConclusionsReducing SAP stiffness and faster walking amplified the prostheses damping effect, which redistributed the mechanical work, both in magnitude and timing, within the residual joints and sound limb. With its capacity to absorb and dissipate energy, future studies are warranted to determine whether SAPs can provide additional user benefit for locomotor tasks that require greater attenuation of impact forces (e.g., load carriage) or energy dissipation (e.g., downhill walking).

A Case Series of Five Horses with Superficial Digital Flexor Tendon Lesions in the Carpal Canal

This case series discusses the clinical presentation, ultrasonographic findings, treatment, and outcome of 5 horses with superficial digital flexor tendon (SDFT) lesions within the carpal canal. The horses’ ages ranged from 11-28 years, and presented with an acute, unilateral forelimb lameness which worsened following proximal limb flexion. The presence of a lesion within the SDFT of the carpal canal was accompanied by a mild swelling of the palmar carpal region in most cases. Diagnostic anesthesia of the ulnar nerve, when performed, abolished the lameness. Ultrasound evaluation revealed an increased cross-sectional area (CSA) of the superficial digital flexor tendon compared to the contralateral, sound limb and a loss of tendon fiber architecture within the palmar aspect of the affected tendon, most readily identifiable upon longitudinal ultrasound images. Three out of the five horses returned to their previous level of performance, and two were euthanized. A back at the knee carpal region conformation was associated with a poorer prognosis in these cases. An intratendinous fibroma was identified on histopathological analysis of one-horse following euthanazia, which has been recorded in a complementary short communication.

Evidence-based Customized Ankle-Foot Orthosis with Energy Storage

Three-dimensional printed ankle-foot orthoses (AFO) have been used in stroke patients recently, but there was little evidence of gait improvement. Here, we designed a novel customized AFO with energy storage, named Energy-Storage 3D Printed Ankle-Foot Orthosis (ESP-AFO), and investigated its effects on gait improvement in stroke patients. 12 stroke survivors were recruited (9 females/3 males, age: 55.58 ± 5.9 y/o). Participants were instructed to walk (1) bare foot (BF), with (2) anterior AFO (AAFO), and with (3) ESP-AFO, respectively. Gait analysis by the motion capture system was performed bilaterally (SL: Sound limb; AL: Affected limb). Participant satisfaction and fatigue were also compared. We found that the ESP-AFO significantly increased bilateral gait velocity (SL: ESP-AFO 52.62 ± 19.18 cm/s, BF 47.61 ± 22.78 cm/s; AL: ESP-AFO 52.78 ± 19.57 cm/s, BF 47.31 ± 23.27 cm/s), stride length (SL: ESP-AFO 78.96 ± 19.16 cm, BF 74.89 ± 21.92 cm; AL: ESP-AFO 79.06 ± 17.82 cm, BF 74.08 ± 21.31 cm). ESP-AFO reversed drop-foot in swing phase and created a higher ankle moment at terminal stance. Patients also reported more satisfaction with the ESP-AFO (total satisfaction: ESP-AFO 4.3 ± 0.47, AAFO 3.3 ± 0.62). We demonstrated that the novel custom-made ESP-AFO improved the gait performance with better satisfaction than traditional AFOs did. (Registry number of clinical trial: A-BR-106-005)

Cortical representations of phantom movements in lower limb amputees.

Understanding how sensorimotor cortex (SMC) organization relates to limb loss has major clinical implications, as cortical activity associated with phantom hand movements has been shown to predict phantom pain reports. Critically, earlier studies have largely focused on upper limb amputees; far less is known regarding SMC activity in lower limb amputees, despite the fact that this population comprises the majority of major limb loss cases. We aimed to characterize BOLD fMRI responses associated with phantom and sound limb movements to test the hypothesis that SMC organization is preserved in individuals with lower limb loss. Individuals with unilateral or bilateral lower limb loss underwent fMRI scans as they performed simple movements of their sound or phantom limbs. We observed that voluntary movements of the sound and phantom ankles were associated with BOLD signal changes in medial and superior portions of the precentral and postcentral gyri. In both hemispheres, contralateral limb movements were associated with greater signal changes compared to ipsilateral limb movements. Hand and mouth movements were associated with distinct activation patterns localized to more lateral SMC regions. We additionally tested whether activations associated with phantom movements related to self-report assessments indexing phantom pain experiences, nonpainful phantom sensations and phantom movement capabilities. We found that responses during phantom ankle movements did not correlate with any of the composite phantom limb indices in our sample. Our collective results reveal that SMC representations of the amputated limb persist and that traditional somatotopic organization is generally preserved in individuals suffering from lower limb loss.

Bodyweight distribution between limbs, muscle strength, and proprioception in traumatic transtibial amputees: a cross-sectional study

OBJECTIVES:To evaluate how transtibial amputation (TT) affects bodyweight distribution, voluntary knee joint position sense (JPS), and quadriceps (QUA) and hamstrings (HAM) strength in prosthetized patients.METHODS:Only TT patients who had been prosthetized for more than one year were included, and an age-paired able-bodied group was used as control. The participants stood on force plates with their eyes open to measure bodyweight distribution between the limbs. Knee voluntary JPS was assessed by actively reproducing a set of given arbitrary joint angles using a video analysis approach, and QUA and HAM strength were assessed isometrically with a hand-held dynamometer.RESULTS:Sixteen TT subjects (age: 39.4±4.8 years) and sixteen age-paired control subjects (age: 38.4±4.3 years) participated in the study. The amputees supported their bodyweight majorly on the sound limb (54.8±8.3%, p<0.001). The proprioceptive performance was similar between the amputated (absolute error (AE): 2.2±1.6°, variable error (VE): 1.9±1.6°, constant error (CE): -0.7±2.0°) and non-amputated limbs (AE: 2.6±0.9°, VE: 2.1±0.9°, CE: 0.02±2.3°), and was not different from that of control subjects (AE: 2.0±0.9°, VE: 1.4±0.4°, CE: -1.1±1.7°). There was a considerable weakness of the QUA and HAM in the amputated limb compared with the sound limb and control subjects (p<0.001 both).CONCLUSIONS:The asymmetric bodyweight distribution in the transtibial amputees was not accompanied by a reduction in knee proprioception. There was significant weakness in the amputated limb, which could be a potential issue when designing rehabilitation programs.

Evaluation of Donor Ankle Function after Harvesting Peroneus Longus Tendon Graft for Anterior Cruciate Ligament Reconstruction- A Prospective Cohort Study

Introduction: Primary full thickness Peroneus Longus Tendon Graft (PLTG) for Anterior Cruciate Ligament Reconstruction (ACLR) has been used with good clinical outcome. Recently, it is designated as a promising graft option for ACLR. The effect of harvesting PLTG on donor ankle function is still not completely understood. Peroneus Longus Tendon (PLT) is thought to play a major role in proprioceptive regulation of the ankle joint. All the studies till date did cross-sectional assessments of ankle and foot function at or after 6 months that might have overlooked the timely detection of donor site morbidities. Aim: To evaluate the ankle function and compare the affected and sound limb function in subjects with an ACLR with autologous PLTG starting at an early postoperative visit upto six months. Materials and Methods: A prospective cohort study was conducted at a tertiary rehabilitation centre from March 2019 to March 2021 including the follow-up evaluation. As per the inclusion criteria, 63 participants after ACLR with PLTG were considered for assessment using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hind foot scale and Foot and Ankle Ability Measure (FAAM) scale at 6 weeks, 3 months and 6 months post-ACLR follow-up. Comparison between sound and affected limbs was done during all follow-ups. The statistical analysis was done using Statistical Package for the Social Sciences (SPSS) version 18.0. Both FAAM and AOFAS ankle and foot scores were analysed with non parametric tests. Results: Mean age of 63 participants were 29.25 years. Median of AOFAS and FAAM score at 6 week, 3 month, and 6 month post- ACLR follow-ups were (88, 98 and 100) and (97.22, 98.80 and 100), respectively. Statistically significant increase in AOFAS and FAAM scores were observed at 3 month and 6 month as compared to 6 week follow-ups with p=0.001 and p-value=0.001 respectively. The group comparison between the affected and sound side functional scores at different study visits showed statistically significant greater values for the sound ankle than the affected ankle (FAAM: 6 week: p-value=0.001; 3 month: p-value=0.001; 6 month: p-value=0.001 and AOFAS p-value=0.001; p-value=0.001; p-value=0.001, respectively). Conclusion: The evaluation of functional outcomes showed gradual and linear improvement at subsequent postoperative visits and restores fully to 100% at 6 month indicating a near- normal to normal donor ankle function following ACLR with PLTG by 6 months. The group comparison showed only marginal but significant difference between affected and sound ankle function.

Investigating the Effect of Vibrotactile Feedback in Transfemoral Amputee With and Without Movable Ankle Joint.

The loss of somatosensory feedback after transfemoral amputation imposes a serious challenge in achieving postural stability. In the recent past, weight shifting exercises with fixed ankle joint have been reported useful in boosting the limit of stability (LOS) only in the sound limb; the LOS on the prosthetic limb did not improve. A fixed ankle joint restricts movement in the anterior-posterior direction at the ankle level. Thus, it may suppress the ability to move forward LOS despite awareness of center of pressure (COP) due to vibrotactile feedback. Therefore, it could have limited the improvement in the LOS of a prosthetic limb in previous studies. This article investigates this hypothesis by evaluating the effect of vibrotactile feedback in the LOS of transfemoral amputees with fixed as well as movable ankle joints. This evaluation is done during weight shifting exercises. Firstly, we developed an in-house COP guided vibrotactile sensory feedback system. Next, we recruited five transfemoral amputees to perform a weight-shifting exercise with a) fixed ankle joint (single-axis cushion heel (SACH) foot) and b) movable ankle joint (single-axis foot). Finally, we analyzed the recorded center of pressure trajectory signals for the limit of stability. The findings of repeated measures ANOVA showed a marginally significant interaction ( [Formula: see text], [Formula: see text], [Formula: see text]) between ankle joint and feedback conditions during backward shifting in weight shifting exercise. Further analysis showed that during the backward shifting fixed ankle joint did not improve in the presence of vibrotactile feedback, while a marginally significant ( [Formula: see text]) improved LOS was observed in the movable ankle joint with feedback. The findings conclude that the vibrotactile feedback is more effective in transfemoral amputees with movable ankle joint compared with fixed ankle joint.

Effects of vibrotactile feedback on postural sway in trans-femoral amputees: A wavelet analysis

Loss of somatosensory feedback after amputation inflicts a serious challenge to achieve postural stability. Improving motor skills by incorporating sensory feedback in rehabilitation protocols for persons with lower limb amputation has been gaining traction over time. However, the control mechanisms involved in this regarding time–frequency analysis have not been investigated yet. The purpose of this study was to explore the frequencies/time-scales responsible for postural stability in trans-femoral amputees with vibrotactile feedback. Center of Pressure (COP) signals were collected from 5 trans-femoral amputees and 10 healthy subjects during weight shifting balance tasks. A customized foot insole was used to estimate the COP for actuation of vibratory feedback. The evaluation of postural sway fluctuations by means of COP excursions with vibrotactile feedback was computed by wavelet transform method. Vibrotactile feedback was found to be effective in controlling low frequency postural sway in amputees. We found significantly higher energy (p = 0.004, 0.0007) at shorter time-scales (j = 6,7, freq. = 0.6–1.25 Hz) and lower energy (p = 0.0006) at longer time-scale (j = 10, freq. = 0.078 Hz) in amputees with vibrotactile feedback in comparison to healthy subjects using Coif 1 wavelet. We also found significant increase in energy (p = 0.003) during forward weight shifting with vibrotactile feedback in the sound limb of amputees in comparison to no feedback session at frequency/time-scales corresponding to somatosensory acuity (j = 6–8, freq. = 0.3–1.5 Hz) using Haar wavelet. These findings reflect the higher contribution of somatosensory receptors in amputees with vibrotactile feedback and may provide a better understanding of the mechanisms associated with standing balance in terms of time–frequency analysis.

Effects on ankle power and sound limb load with an active prosthetic foot

Abstract The performance of conventional prosthetic feet depends on material and construction principles. Certain powered feet can even generate net positive mechanical work in order to provide an active push-off. The aim of this study was to evaluate the influence of ankle power on the gait of transfemoral amputees. For this purpose level walking of six transfemoral amputees was analysed with a basic and an active foot and three different power settings of the latter. The results show clear advantages of the active foot in comparison with a basic foot. However, a strong relation of the sound side knee loading parameters with the varied ankle power outputs of the active foot couldn’t be shown.