The biomechanical response of persons with transfemoral amputation to variations in prosthetic knee alignment during level walking.
Ontology highlight
ABSTRACT:
SUBMITTER: Koehler-McNicholas SR
PROVIDER: S-EPMC5559886 | biostudies-other | 2016
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The walking pattern and comfort of a person with lower limb amputation are determined by the prosthetic foot's diverse set of mechanical characteristics. However, most design methodologies are iterative and focus on individual parameters, preventing a holistic design of prosthetic feet for a user's body size and walking preferences. Here we refined and evaluated the lower leg trajectory error (LLTE) framework, a novel quantitative and predictive design methodology that optimizes the mechanical function of a user's prosthesis to encourage gait dynamics that match their body size and desired walking pattern. Five people with unilateral below-knee amputation walked over-ground at self-selected speeds using an LLTE-optimized foot made of Nylon 6/6, their daily-use foot, and a standardized commercial energy storage and return (ESR) foot. Using the LLTE feet, target able-bodied kinematics and kinetics were replicated to within 5.2% and 13.9%, respectively, 13.5% closer than with the commercial ESR foot. Additionally, energy return and center of mass propulsion work were 46% and 34% greater compared to the other two prostheses, which could lead to reduced walking effort. Similarly, peak limb loading and flexion moment on the intact leg were reduced by an average of 13.1%, lowering risk of long-term injuries. LLTE-feet were preferred over the commercial ESR foot across all users and preferred over the daily-use feet by two participants. These results suggest that the LLTE framework could be used to design customized, high performance ESR prostheses using low-cost Nylon 6/6 material. More studies with large sample size are warranted for further verification.
| S-EPMC8964743 | biostudies-literature
Project description:Over 50% of individuals with lower limb amputation fall at least once each year. These individuals also exhibit reduced ability to effectively respond to challenges to frontal plane stability. The range of whole body angular momentum has been correlated with stability and fall risk. This study determined how lateral walking surface perturbations affected the regulation of whole body and individual leg angular momentum in able-bodied controls and individuals with unilateral transtibial amputation. Participants walked at fixed speed in a Computer Assisted Rehabilitation Environment with no perturbations and continuous, pseudo-random, mediolateral platform oscillations. Both the ranges and variability of angular momentum for both the whole body and both legs were significantly greater (p<0.001) during platform oscillations. There were no significant differences between groups in whole body angular momentum range or variability during unperturbed walking. The range of frontal plane angular momentum was significantly greater for those with amputation than for controls for all segments (p<0.05). For the whole body and intact leg, angular momentum ranges were greater for patients with amputation. However, for the prosthetic leg, angular momentum ranges were less for patients than controls. Patients with amputation were significantly more affected by the perturbations. Though patients with amputation were able to maintain similar patterns of whole body angular momentum during unperturbed walking, they were more highly destabilized by the walking surface perturbations. Individuals with transtibial amputation appear to predominantly use altered motion of the intact limb to maintain mediolateral stability.
| S-EPMC4408235 | biostudies-literature
Project description:Controlled trunk motion is crucial for balance and stability during walking. Persons with lower extremity amputation often exhibit abnormal trunk motion, yet underlying mechanisms are not well understood nor have optimal clinical interventions been established. The aim of this work was to characterize associations between altered lower extremity joint moments and altered trunk dynamics in persons with unilateral, transtibial amputation (TTA). Full-body gait data were collected from 10 persons with TTA and 10 uninjured persons walking overground (~1.4?m/s). Experimentally-measured trunk angular accelerations were decomposed into constituent accelerations caused by net joint moments throughout the body using an induced acceleration analysis. Results showed persons with TTA had similar ankle moment magnitude relative to uninjured persons (P?>?0.05), but greater trunk angular acceleration induced by the prosthetic ankle which acted to lean the trunk ipsilaterally (P?=?0.003). Additionally, persons with TTA had a reduced knee extensor moment relative to uninjured persons (P?<?0.001), resulting in lesser sagittal and frontal induced trunk angular accelerations (P?<?0.001). These data indicate kinetic compensations at joints other than the lumbar and hip contribute to altered trunk dynamics in persons with a unilateral TTA. Findings may inform development of new clinical strategies to modify problematic trunk motion.
| S-EPMC6706581 | biostudies-literature
Project description:BackgroundPersons with lower limb amputation often experience decreased physical capacity, difficulty walking, and increased fall risk. To either prevent or recover from a loss of balance, one must effectively regulate their stepping movements. It is therefore critical to identify how well persons with amputation regulate stepping. Here, we used a multi-objective control framework based on Goal Equivalent Manifolds to identify how persons with transtibial amputation (TTA) regulate lateral stepping while walking without and with lateral perturbations.Research questionWhen walking in destabilizing environments, do otherwise healthy persons with TTA exhibit greater difficulty regulating lateral stepping due to impaired control? Or do they instead continue to use similar strategies to regulate lateral stepping despite their amputation?MethodsEight persons with unilateral TTA and thirteen able-bodied (AB) controls walked in a virtual environment under three conditions: no perturbations, laterally oscillating visual field, and laterally oscillating treadmill platform. We analyzed step-to-step time series of step widths and absolute lateral body positions. We computed means, standard deviations and Detrended Fluctuation Analysis scaling exponents for each time series and computed how much participants directly corrected step width and position deviations at each step. We compared our results to computational predictions to identify the underlying causes of our experimental findings.ResultsAll participants exhibited significantly increased variability, decreased scaling exponents, and tighter direct control when perturbed. Simulations from our stepping regulation models revealed that people responded to the increased variability produced by the imposed perturbations by tightening their control of both step width and lateral position. Participants with TTA exhibited only a few minor differences from AB in lateral stepping regulation, even when subjected to substantially destabilizing lateral perturbations.SignificanceSince control of stepping is intrinsically multi-objective, developing effective interventions to reduce fall risk in persons with amputation will likely require strategies that adopt multi-objective approaches.
| S-EPMC7755758 | biostudies-literature
Project description:Locomotor adaptation is commonly studied using split-belt treadmill walking, in which each foot is placed on a belt moving at a different speed. As subjects adapt to split-belt walking, they reduce metabolic power, but the biomechanical mechanism behind this improved efficiency is unknown. Analyzing mechanical work performed by the legs and joints during split-belt adaptation could reveal this mechanism. Because ankle work in the step-to-step transition is more efficient than hip work, we hypothesized that control subjects would reduce hip work on the fast belt and increase ankle work during the step-to-step transition as they adapted. We further hypothesized that subjects with unilateral, trans-tibial amputation would instead increase propulsive work from their intact leg on the slow belt. Control subjects reduced hip work and shifted more ankle work to the step-to-step transition, supporting our hypothesis. Contrary to our second hypothesis, intact leg work, ankle work and hip work in amputees were unchanged during adaptation. Furthermore, all subjects increased collisional energy loss on the fast belt, but did not increase propulsive work. This was possible because subjects moved further backward during fast leg single support in late adaptation than in early adaptation, compensating by reducing backward movement in slow leg single support. In summary, subjects used two strategies to improve mechanical efficiency in split-belt walking adaptation: a CoM displacement strategy that allows for less forward propulsion on the fast belt; and, an ankle timing strategy that allows efficient ankle work in the step-to-step transition to increase while reducing inefficient hip work.
| S-EPMC5340589 | biostudies-literature
Project description:This meta-analysis compared the gait patterns of unicompartmental knee arthroplasty (UKA) patients and total knee arthroplasty (TKA) patients during level walking by evaluating the kinetics, kinematics, and spatiotemporal parameters. Studies were included in the meta-analysis if they assessed the vertical ground reaction force (GRF), joint moment at stance, flexion at initial contact, flexion at swing, overall range of motion (ROM), coronal knee angle at stance, walking speed, cadence, and stride length in UKA patients or TKA patients. Seven non-randomized studies met the criteria for inclusion in this meta-analysis. UKA patients and TKA patients were similar in terms of vertical GRF (95% CI: -0.36 to 0.20; P = 0.60), joint moment (95% CI: -0.55 to 0.63; P = 0.90), kinematic outcomes (95% CI: -0.72 to 1.02; P = 0.74), walking speed (95% CI: -0.27 to 0.81; P = 0.32), and cadence (95% CI: -0.14 to 0.68; P = 0.20). In contrast, the stride length (95% CI: 0.01 to 0.80; P = 0.04) differed significantly between groups. Subgroup analyses revealed that the pooled data were similar between the groups: 1st maximum (heel strike), -0.18 BW (P = 0.53); 1st minimum (mid-stance), -0.43 BW (P = 0.08); and 2nd maximum (toe off), -0.03 BW (P = 0.87). On gait analysis, there were no significant differences in vertical GRF, joint moment at stance, overall kinematics, walking speed, or cadence between UKA patients and TKA patients during level walking. However, the TKA group had significantly shorter stride length than UKA patients. Although the comparison was inconclusive in determining which types of knee arthroplasty offered the closest approximation to normal gait, we consider it important to provide better rehabilitation programs to reduce the abnormal stride length in TKA patients compared to UKA patients.
| S-EPMC6117028 | biostudies-literature
Project description:BackgroundKnee arthroplasty (KA) aims to restore normal gait, correct joint alignment, improve the quality of life and activities of daily living, and provide pain relief. Hence, the main purpose of this overview was to summarise data from published reviews exploring gait changes during unaided level walking post-KA, thereby providing for recommendations for future practice and research.MethodA systematic review of review (RoR) for articles published in English and since 2010, was conducted online using PubMed and Google Scholar, as per Preferred Reporting Items for Systematic reviews and Metaanalyses guidelines. Predefined eligibility criteria were applied, and the data thus compiled were analysed. Study quality was assessed using AMSTAR-2 checklist.ResultA total of 5 systematic reviews and meta-analysis consisting of 58 primary studies were included in the review. Based on the very limited evidence, it appears that though gait does not normalize post-KA, there seems to be an improvement in spatiotemporal gait parameters over mid to long term with some decline in gains over long term. Further reviews also suggest no benefits with unicompartmental KA in comparison to healthy controls or total KA patients. Further quality of the study was found to be of critically low confidence based on the AMSTAR-2 scale, suggesting that the results should be interpreted with great caution.ConclusionThe overview highlights the knowledge gap and limitations in gait assessment research post-KA with existing heterogeneity in methods and reporting amidst other factors within primary studies, establishing the need for further research.Supplementary informationThe online version contains supplementary material available at 10.1007/s43465-020-00342-w.
| S-EPMC8192636 | biostudies-literature
Project description:OBJECTIVE:Unilateral trans-tibial amputation signifies a challenge to locomotion. Prosthetic ankle-foot units are developed to mimic the missing biological system which adapts push-off power to walking speed in some new prosthetic ankle-foot designs. The first systematic review including the two factors aims to investigate push-off power differences among Solid Ankle Cushion Heel (SACH), Energy Storage And Return (ESAR) and Powered ankle-foot units (PWR) and their relation to walking speed. DATA SOURCES:A literature search was undertaken in the Web of Science, PubMed, IEEE xplore, and Google Scholar databases. The search term included: ampu* AND prosth* AND ankle-power AND push-off AND walking. STUDY APPRAISAL AND SYNTHESIS METHODS:Studies were included if they met the following criteria: unilateral trans-tibial amputees, lower limb prosthesis, reported analysis of ankle power during walking. Data extracted from the included studies were clinical population, type of the prosthetic ankle-foot units (SACH, ESAR, PWR), walking speed, and peak ankle power. Linear regression was used to determine whether the push-off power of different prosthetic ankle-foot units varied regarding walking speed. Push-off power of the different prosthetic ankle-foot units were compared using one-way between subjects' ANOVAs with post hoc analysis, separately for slower and faster walking speeds. RESULTS:474 publications were retrieved, 28 of which were eligible for inclusion. Correlations between walking speed and peak push-off power were found for ESAR (r = 0.568, p = 0.006) and PWR (r = 0.820, p = 0.000) but not for SACH (r = 0.267, p = 0.522). ESAR and PWR demonstrated significant differences in push-off power for slower and faster walking speeds (ESAR (p = 0.01) and PWR (p = 0.02)). CONCLUSION:Push-off power can be used as a selection criterion to differentiate ankle-foot units for prosthetic users and their bandwidth of walking speeds.
| S-EPMC6863538 | biostudies-literature
Project description:This paper presents the experimental validation of a novel control strategy that unifies the entire gait cycle of a powered knee-ankle prosthetic leg without the need to switch between controllers for different periods of gait. Current control methods divide the gait cycle into several sequential periods each with independent controllers, resulting in many patient-specific control parameters and switching rules that must be tuned for a specific walking speed. The single controller presented is speed-invariant with a minimal number of control parameters to be tuned. A single, periodic virtual constraint is derived that exactly characterizes the desired actuated joint motion as a function of a mechanical phase variable across walking cycles. A single sensor was used to compute a phase variable related to the residual thigh angle's phase plane, which was recently shown to robustly represent the phase of non-steady human gait. This phase variable allows the prosthesis to synchronize naturally with the human user for intuitive, biomimetic behavior. A custom powered knee-ankle prosthesis was designed and built to implement the control strategy and validate its performance. A human subject experiment was conducted across multiple walking speeds (1 to 3 miles/hour) in a continuous sequence with the single phase-based controller, demonstrating its adaptability to the user's intended speed.
| S-EPMC5381823 | biostudies-literature
Project description:The patellofemoral joint plays a crucial mechanical role during walking and running. It increases the knee extensor mechanism's moment arm and reduces the knee extension muscle forces required to generate the extension moment that supports body weight, prevents knee buckling and propels the centre of mass. However, the mechanical implications of moment arm variation caused by patellofemoral and tibiofemoral motion remain unclear. We used a data-driven musculoskeletal model with a 12-degree-of-freedom knee to simulate the knee extension moment arm during walking and running. Using a geometric method to calculate the moment arm, we found smaller moment arms during running than during walking in the swing phase. Overall, knee flexion causes differences between running and walking moment arms as increased flexion causes a posterior shift in the tibiofemoral rotation axis and patella articulation with the distal femur. Moment arms were also affected by knee motion direction and best predicted by separating by direction instead of across the entire gait cycle. Furthermore, we found high inter-subject variation in the moment arm that was largely explained by out-of-plane motion. Our results are consistent with the concept that shorter moment arms increase the effective mechanical advantage of the knee and may contribute to increased running velocity.
| S-EPMC8371375 | biostudies-literature