Impact of plantar flexion resistive moment of dynamic ankle foot orthosis on measures of center of pressure and clinical gait outcomes in individuals with post-stroke hemiparesis.

BACKGROUND: An ankle-foot orthosis (AFO) with plantar flexion resistance (PFR) can improve the first rocker function during gait, but the incremental changes in the resistive moment on balance and gait have not been well identified. OBJECTIVES: To investigate the effect of changing the PFR moment of dynamic AFO (DAFO) on measures of the center of pressure (COP) and clinical gait outcomes in individuals with post-stroke hemiparesis. METHOD: In this randomized repeated measure study of 36 stroke individuals, the customized DAFO using foot drop ankle units set in three PFR situations (low, medium, and high) was evaluated. The balance parameters for COP measures were investigated by HUMAC® Balance & Tilt System. Gait parameters and ankle kinematics were recorded using the 3D motion analysis through force platform and optoelectronic system. The comparison was made using a parametric ANOVA test and the P value was set at 0.05 for statistical significance. RESULTS: Significant differences were observed for COP average velocity (1.30 ± 0.64, 1.10 ± 0.05, and 1.37 ± 0.43), COP path length (43.3 ± 4.6, 33.4 ± 4.3, and 36.3 ± 5.4), walking velocity (11.0 ± 3.1, 13.2 ± 4.4, and 9.9 ± 3.5), and cadence (31.5 ± 2.0, 33.0 ± 3.1, and 29.0 ± 1.6) respectively for low, medium and high PFR settings (P < 0.05). Except for the COP path length and cadence, posthoc multiple comparisons revealed significant differences between low and medium (P < 0.05) and medium and high (P < 0.05) PFR grades. PFR with medium resistance demonstrated near-normal maximal peak ankle dorsiflexion (mean deviation of 8 degrees, P < 0.05). CONCLUSION: Medium PFR grade should be encouraged since it can enhance balance parameters like path length and average velocity of COP, increase cadence and average velocity during gait, and improve maximal peak ankle dorsiflexion.

Efficacy of extension wrist hand orthosis on pain, grip strength and electromyographic activities in lateral epicondylitis: A randomized single-blind clinical trial.

BACKGROUND: Lateral epicondylitis (LE) is one of the most common work-related complications characterized by pain, decreased grip strength and dysfunction of upper limb. Although conservative management such as physiotherapy and orthosis is reported as first line of treatment, sufficient evidence to decide their effectiveness is lacking and remains controversial. PURPOSE: The current study evaluated and compared the efficacy of a custom-made extension wrist hand orthosis adjunct to usual physiotherapy and therapeutics alone for subjects with LE. STUDY DESIGN: Prospective randomized single-blinded clinical trial. METHODS: 62 subjects with LE were selected as samples using convenience method in this experimental study. They were randomly divided into two groups: usual physiotherapy only and its combination with orthosis. Pain and grip strength were measured using Visual Analog Scale and Jamar hydraulic digital hand dynamometer. Muscle activity of extensor carpi radialis brevis during hand gripping was measured using surface electro-myographic by PowerLab electromyography (AD Instruments, Castle Hill, Australia). Data analysis and comparison were performed for baseline and post-intervention (12weeks). RESULTS: After 12weeks of treatment, there were significant differences in mean scores of pain (1.22 ± 0.51, p = 0.001), maximum voluntary grip strength (5.82 ± 7.84, p = 0.04), and extensor carpi radialis brevis muscle activation (0.082 ± 0.094, p = 0.02) between the therapeutics alone group and the therapeutics plus orthosis group. Compared to therapeutics alone, those getting a combination of physiotherapy and orthosis had greater treatment efficacy (p < 0.05). CONCLUSIONS: Both postintervention (12-week) treatments could affect pain scores, grip strength, and extensor muscle activation. Custom-made extension wrist hand orthosis adjunct to usual physiotherapy is more effective than therapeutics alone in subjects with LE. Therefore, the use of wrist orthosis adjunct to physiotherapy should be recommended in rehabilitation settings for LE.

Design and analysis of polycentric prosthetic knee with enhanced kinematics and stability.

This paper describes a continuation of earlier work using the finite element method to conduct an engineering failure analysis of an existing polycentric prosthetic knee. The primary purpose of this work is to enhance the quality of the existing knee which has been reported with multiple cases of failure during its clinical practice in India. A modified design of the polycentric knee has been proposed based on the findings of failure analysis. Simulation-based comparative analysis of polycentric knees has been performed as per the ISO 10328:2016 standard in terms of stress distribution, total contour deformation, safety factor, and fatigue life. The upper extension lever is subjected to static and cyclic loads of 4130 and 1230 N, whereas the lower plate has a translational constraint. The modified polycentric knee prosthesis outperforms static and fatigue strength tests. The standard of the existing knee prosthesis has significantly improved as a result of design variations and integration of high-strength and lightweight aluminium 7075-T6 alloy. The modified polycentric knee prosthesis has a predicted maximum deformation of less than 0.7 mm and a minimum safety factor between 1.7 and 2 compared to 2.66 mm and 1.0 for the existing knee prosthesis. Based on the fatigue simulation results, it is predicted that the modified polycentric knee will have a lifespan of at least ten years indicating a safe design. It has improved alignment stability and kinematics, with a significant weight reduction of 33 g, and a high cost-benefit ratio to reach the maximum amputee population in low-income countries like India.

Conformity assessment with structural strength requirements of mechanical polycentric prosthetic knee used for amputee rehabilitation.

Prosthetic restoration is an important component of amputee rehabilitation which may be subjected to a static load of nearly five times of amputees' body weight and is continuously administered to cyclic or fatigue loads during its function. This study presents a structural strength analysis of polycentric mechanical prosthetic knee commonly used in National Institutes in India by finite element simulation and its experimental validation. Static and fatigue analyses have been performed to ensure its structural integrity as per the ISO 10328:2006 standard. Accurate dimensioning of knee components have been obtained using coordinate measuring machine and the 3 D CAD model has been generated by CATIA V5 from the 2 D geometry. The model is imported to the ANSYS 20.1 workbench to study stress distribution in the knee for ensuring its safety performance. The selection of reference planes, application of calculated loads, and position of load line have been done as per the ISO test procedure. Static and cyclic loadings of 4130 N and 1230 N are applied at the top and the bottom plate is given with translational constraints to limit its movement in any direction. Results indicate that the prosthetic knee model is moderately strong enough to outstrip the static strength test. However, the calculated strain and predicted fatigue life during the cyclic test suggest that this knee unit has poor fatigue strength. Validation results with an average error percentage of 3.44 and 10 show higher reliability based on previous study results and experimental tests, respectively.

Efficacy of prosthetic rehabilitation in rotationplasty following Ewing's sarcoma: A case study.

PURPOSE: Restoration of functional mobility including gait and balance are fundamental to prosthetic rehabilitation in children with rotationplasty. The literature to characterize and investigate the correlation between postural balance and gait following rotationplasty are scarce. This study examines the characteristics of balance and prosthetic gait in a subject with rotationplasty and checks whether any association exists between them. METHODS: A 14-year-old boy with rotationplasty following Ewing's sarcoma was fitted with a custom made prosthesis. Center of pressure (COP) measures using the HUMAC® Balance & Tilt System (CSMi, Stoughton, MA), temporal-spatial gait parameters, and energy expenditure measured by a 10 meter walk test were recorded using the new and old prosthesis. A control subject was used for comparison. RESULTS: The stability score, path length, and average velocity of COP improved in a new prosthesis for both standing conditions. Gait parameters were improved and energy expenditure was marginally reduced with the new prosthesis. However, overall prosthetic gait was significantly different compared to the control subject. CONCLUSION: This subject-centric approach successfully improved balance, gait parameters, and energy expenditure by providing better alignment, fit, and comfort with a custom prosthesis.

A systematic review on design technology and application of polycentric prosthetic knee in amputee rehabilitation.

The objective of this paper is to conduct a systematic review on design technology and clinical application of polycentric prosthetic knee joint in the rehabilitation of trans-femoral amputees. Relevant studies were identified using electronic database such as PubMed, EMBASE, SCOPUS and the Cochrane Controlled Trials Register (Rehabilitation and Related Therapies) up to February 2020. Screening of abstracts and application of inclusion and exclusion criteria were made. Design, modeling, material use, kinematic study, simulation technique and clinical application of polycentric knee models used in many developed and developing countries have been reviewed. Out of 516 potentially relevant studies, 43 articles were included. Specific variables on technical and clinical aspects were extracted and added to summary tables. The results reveal that polycentric knees have a variety of geometries but the methods for comparing their performances are rare. The data of structural analysis using different simulation techniques are validated with experimental results for determining model accuracy. Gait analysis using the polycentric knee components provides a valid tool to correlate with experimental results. There are well-designed studies on the technological development of polycentric knees, however, high-quality clinical researches are scarce. Conventional clinical knowledge had considerable gaps concerning the effects of polycentric knee and their mechanical characteristics on human functioning with a lower-limb prosthesis. Still, further research is needed to develop and implement standardized measures on prosthetic knee joints for their effective use, function, durability, and cost-effectiveness.