Assessment of knee flexion in young children with prosthetic knee components using dynamic time warping

Introduction: Analysis of human locomotion is challenged by limitations in traditional numerical and statistical methods as applied to continuous timeseries data. This challenge particularly affects understanding of how close limb prostheses are to mimicking anatomical motion. This study was the first to apply a technique called Dynamic Time Warping to measure the biomimesis of prosthetic knee motion in young children and addressed the following research questions: Is a combined dynamic time warping/root mean square analysis feasible for analyzing pediatric lower limb kinematics? When provided at an earlier age than traditional protocols dictate, can children with limb loss utilize an articulating prosthetic knee in a biomimetic manner? Methods: Warp costs and amplitude differences were generated for knee flexion curves in a sample of ten children five years of age and younger: five with unilateral limb loss and five age-matched typically developing children. Separate comparisons were made for stance phase flexion and swing phase flexion via two-way ANOVAs between bilateral limbs in both groups, and between prosthetic knee vs. dominant anatomical knee in age-matched pairs between groups. Greater warp costs indicated greater temporal dissimilarities, and a follow-up root mean square assessed remaining amplitude dissimilarities. Bilateral results were assessed by age using linear regression. Results: The technique was successfully applied in this population. Young children with limb loss used a prosthetic knee biomimetically in both stance and swing, with mean warp costs of 12.7 and 3.3, respectively. In the typically developing group, knee motion became more symmetrical with age, but there was no correlation in the limb loss group. In all comparisons, warp costs were significantly greater for stance phase than swing phase. Analyses were limited by the small sample size. Discussion: This study has established that dynamic time warping with root mean square analysis can be used to compare the entirety of time-series curves generated in gait analysis. The study also provided clinically relevant insights on the development of mature knee flexion patterns during typical development, and the role of a pediatric prosthetic knee

Design and preliminary evaluation of a new ankle foot orthosis on kinetics and kinematics parameters for multiple sclerosis patients

Background: The damage of the central nervous system due to Multiple Sclerosis (MS) leads to many walking disorders in this population. However, current ankle-foot orthoses prescribed for improving walking disorders for these patients are not clinically cost-efficient. Objective: This study aimed to design and fabricate a dynamic ankle foot orthosis and a new spring-damper joint mechanism that could adapt the walking problems of MS patients and evaluate the immediate effect of the new orthosis on the speed, range of motion, moment, total work and ground reaction force during walking. Material and Methods: In this case-series study, after the design and fabrication of a new orthosis, the kinetics and kinematics of walking of four patients with MS were assessed in a case series study. Results: Walking speed improved with the new orthosis in two participants. The sagittal range of motion (ROM) increased for most of the participants. The sagittal moments increased for hip, knee and ankle joints in most of the measurements. The total joint work showed noticeable difference in the ankle joint. The increased values of vertical component of the ground reaction force (VGRF) were negligible and the increase in the impulse of VGRF was noticeable for only one participant. Conclusion: The new orthosis had positive effects kinetic and kinematic parameters of walking such as the increased velocity by two subjects and also a more normal sagittal ROM, moment and work, suggesting the potential usefulness of the new orthotic device for MS population. © 2020, Shriaz University of Medical Sciences. All rights reserved

Pediatric Prosthetic Knee Angle Dataset for Dynamic Time Warping

Non-time-normalized knee joint angles from children with unilateral lower limb loss requiring a prosthetic knee joint (LL) and age-matched controls (C), in stance (first column per side) and swing (second column per side). Collected at the Biomechanics Laboratory at Georgia State University in Atlanta, GA

Evaluation of a Viscoelastic Ankle-Foot Prosthesis at Slow and Normal Walking Speeds on an Able-Bodied Subject

Objectives: This paper describes further improvement and preliminarily evaluation of a novel viscoelastic ankle-foot prosthesis prototype. The objective was to control the ankle hysteresis at slow and normal walking speeds. Methods: Inspired by the ankle biomechanics, in which the hysteresis differs based on the gait speeds, a manually damping control mechanism imbedded in the prosthesis for adjusting the ankle damping at slow and normal walking speeds. The prototype was then preliminarily tested on an able-bodied subject wearing an adaptor which simulates the amputee walking. The ankle joint kinetics and kinematics were measured in a gait analysis lab at different walking speeds. Results: The results suggest that the viscoelastic ankle foot prosthesis prototype could provide a smooth normal-like walking for most of the measured gait characteristics in slow and normal speeds. Discussion: Therefore, it is suggested to apply a controllable damping mechanism based on the gait speeds in the design of new prosthetic feet

Effects of Custom-mold Insole by Medial Heel Skive Technique on Physical Function in Flexible Flat Foot

Objectives: Flexible Flat Foot (FFF), a common foot deformity decreasing medial longitudinal arch height is often comorbid with subtalar joint pronation causing physical activity difficulties in this population. Among the orthotic insoles prescribed for improving foot function, foot orthoses with medial heel skive technique have a limited research background. The present study aimed to investigate the effects of the custom-mold insole with medial heel skive technique on physical function in FFF. Methods: Eighteen adults with FFF from the University of Social Welfare and Rehabilitation Sciences students and staff participated in this study. Custom-Mold insole with medial heel skive was fabricated for all research participants. Physical function in the activities of daily living and sports was assessed by the Foot and Ankle Ability Measure (FAAM), Activities of Daily Living (ADL) subscale (ADL-FAAM), and SPORT-FAAM questionnaires at the beginning of the study and 6 weeks after. Paired Samples t-test and nonparametric tests were used to compare the collected results. Results: After 6 weeks of using the insole with medial heel skive technique, scores in both ADL and SPORTS activities were significantly improved. Discussion: Foot function improvement was not found in all of the studies assessing foot function in flat feet after using different orthotic insoles, by different questionnaires or other systems. In this study, foot and ankle function was significantly improved per FAAM questionnaire- which had highly limited use in orthotic interventions in flat feet population- using medial heel skive technique; however, further studies are required to accentuate medial heel skive technique effect on flat feet function by comparing this technique with other positive cast modifications to control the flat foot. According to the present study results, custom-mold insole with medial heel skive may improve physical function in FFF and can be prescribed in this group

Original Article

Objectives: This paper describes further improvement and preliminarily evaluation of a novel viscoelastic ankle-foot prosthesis prototype. The objective was to control the ankle hysteresis at slow and normal walking speeds. Methods: Inspired by the ankle biomechanics, in which the hysteresis differs based on the gait speeds, a manually damping control mechanism imbedded in the prosthesis for adjusting the ankle damping at slow and normal walking speeds. The prototype was then preliminarily tested on an able-bodied subject wearing an adaptor which simulates the amputee walking. The ankle joint kinetics and kinematics were measured in a gait analysis lab at different walking speeds. Results: The results suggest that the viscoelastic ankle foot prosthesis prototype could provide a smooth normal-like walking for most of the measured gait characteristics in slow and normal speeds. Discussion: Therefore, it is suggested to apply a controllable damping mechanism based on the gait speeds in the design of new prosthetic feet

Walking and Balance in Children and Adolescents with Lower-limb Amputation: A Review of Literature

Background Children with lower limb loss face gait and balance limitations. Prosthetic rehabilitation is thus aimed at improving functional capacity and mobility throughout the developmental phases of the child amputee. This review of literature was conducted to determine the characteristics of prosthetic gait and balance among children and adolescents with lower-limb amputation or other limb loss. Methods Both qualitative and quantitative studies were included in this review and data were organized by amputation etiology, age range and level of amputation. Findings The findings indicated that the structural differences between children with lower-limb amputations and typically developing children lead to functional differences. Significant differences with respect to typically developing children were found in spatiotemporal, kinematic, and kinematic parameters and ground-reaction forces. Children with transtibial amputation place significantly larger load on their intact leg compared to the prosthetic leg during balance tasks. In more complex dynamic balance tests, they generally score lower than their typically developing peers. Interpretation There is limited literature pertaining to improving physical therapy protocols, especially for different age groups, targeting gait and balance enhancements. Understanding gait and balance patterns of children with lower-limb amputation will benefit the design of prosthetic components and mobility rehabilitation protocols that improve long-term outcomes through adulthood

Walking kinematics in young children with limb loss using early versus traditional prosthetic knee prescription protocols.

The traditional treatment protocol for young children with congenital or acquired amputations at or proximal to the knee prescribes a prosthesis without a working knee joint, based in part on the assumption that a child learning to walk cannot properly utilize a passively flexing prosthetic knee component. An alternative to this Traditional Knee (TK) protocol is an "Early Knee" (EK) protocol, which prescribes an articulating prosthetic knee in the child's first prosthesis, during development of crawling and transitioning into and out of upright positions. To date, no study has compared samples of children with limb loss at or proximal to the knee using TK and EK protocols. The purpose of this multi-site study was to examine kinematic outcomes during walking in separate groups of young children in an EK and a TK prosthesis protocol, along with a population of children without lower limb amputations. Eighteen children aged 12 months to five years were recruited for this study at two clinical sites, six in each of the three groups. Children in the two prosthesis groups had unilateral limb loss and had been treated either at one site with the TK protocol or at another with the EK protocol. Children in the EK group achieved swing phase prosthetic knee flexion averaging 59.8±8.4 degrees. Children wearing prosthetic limbs walked slower than age-matched peers. In most instances, walking speed and step length increased with age in the EK group, similar to the control group. However, this trend was not observed in the TK group. Clearance adaptations were present in both limb loss groups. Observed adaptations were twice as prevalent in the TK group versus the EK group; however, the groups differed in age and etiology. Children with limb loss provided with an articulating knee component in their first prosthesis incorporated knee flexion during swing phase and showed fewer gait adaptations than children in the TK protocol

Walking kinematics in young children with limb loss using early versus traditional prosthetic knee prescription protocols

The traditional treatment protocol for young children with congenital or acquired amputations at or proximal to the knee prescribes a prosthesis without a working knee joint, based in part on the assumption that a child learning to walk cannot properly utilize a passively flexing prosthetic knee component. An alternative to this Traditional Knee (TK) protocol is an “Early Knee” (EK) protocol, which prescribes an articulating prosthetic knee in the child’s first prosthesis, during development of crawling and transitioning into and out of upright positions. To date, no study has compared samples of children with limb loss at or proximal to the knee using TK and EK protocols. The purpose of this multi-site study was to examine kinematic outcomes during walking in separate groups of young children in an EK and a TK prosthesis protocol, along with a population of children without lower limb amputations. Eighteen children aged 12 months to five years were recruited for this study at two clinical sites, six in each of the three groups. Children in the two prosthesis groups had unilateral limb loss and had been treated either at one site with the TK protocol or at another with the EK protocol. Children in the EK group achieved swing phase prosthetic knee flexion averaging 59.8±8.4 degrees. Children wearing prosthetic limbs walked slower than age-matched peers. In most instances, walking speed and step length increased with age in the EK group, similar to the control group. However, this trend was not observed in the TK group. Clearance adaptations were present in both limb loss groups. Observed adaptations were twice as prevalent in the TK group versus the EK group; however, the groups differed in age and etiology. Children with limb loss provided with an articulating knee component in their first prosthesis incorporated knee flexion during swing phase and showed fewer gait adaptations than children in the TK protocol