The role of exercise testing in predicting successful ambulation with a lower extremity prosthesis: a systematic literature review and clinical practice guideline

An enhancement of the Genium™ microprocessor-controlled knee improves safety and different aspects of the perceived prosthetic experience for unilateral and bilateral users

Introduction

Bilateral microprocessor-controlled prosthetic knee (MPK) users have unique needs in traversing environmental barriers compared to unilateral users. An enhancement to the Genium™/Genium X3™ MPK which included an updated ruleset, hydraulics, and new bilateral parameter presets was made to improve safety while stumbling and the smoothness of gait for all users while also improving the experience of bilateral users. The purpose of the study was to evaluate the effectiveness of the enhancements in a sample with unilateral and bilateral amputation.

Methods

A convenience sample of MPK users was recruited from two sites in the USA in two phases. Assessments included the L-Test of Functional Mobility, Activity-specific Balance Confidence Scale, Prosthetic Limb User Survey of Mobility, a study-specific questionnaire, and the Comparative Activities of Daily Living (ADL) Questionnaire. Statistical significance of extracted data was tested with the Wilcoxon Rank-Sum Test for independent data and Wilcoxon Signed-Rank for paired data with an a priori significance level of p < 0.05. Unilateral subjects were age-matched to the group of bilateral subjects for between-groups and within-groups analyses.

Results

Twenty-six subjects (n = 26) were enrolled. Stumble frequency reduced 85% from 16.0 ± 39.7 to 2.4 ± 2.3 (p = 0.008) between baseline and final assessment overall. The bilateral group reported 50% (p = 0.009) and 57% (p = 0.009) greater relative improvement in patient-reported ease and safety, respectively, of completing ADLs compared to the unilateral group. The unilateral group reported residual limb pain and low back pain reduced from 2.3 to 1.4 (p = 0.020) and 3.8 to 1.8 (p = 0.027), respectively, whereas the bilateral group did not.

Discussion

Substantial reductions in stumbles, residual limb pain, and back pain were shown overall. These reductions were driven by the unilateral group who also showed improvements in comfort, exertion, and concentration while walking. The enhancements to the knee likely reduced some gait asymmetry for unilateral users. Improvements in patient-reported ease and safety of completing ADLs were shown overall and were driven by the bilateral group. This study shows further improvement in patient experience is achievable through innovation in MPK technology even for patients who appear to be functioning well.

The C-Brace® microprocessor controlled stance and swing orthosis improves safety, mobility, and quality of life at one year: Interim results from a prospective registry

Introduction

The C-Brace microprocessor-controlled stance and swing control orthosis has been shown to improve function, mobility, and quality of life. A systematic registry to gather long-term, real-world safety and effectiveness data in patients fit with a C-Brace has not been performed.

Methods

International multicenter registry. Patients undergoing routine C-Brace fittings were assessed at baseline and 1 year after fitting. Primary outcomes were fast walking speed (FWS) measured by 25-foot or 10-meter walk test, Timed Up and Go (TUG) and the Activity-specific Balance Confidence (ABC) Scale. Secondary and exploratory outcomes included the Patient-specific Functional Scale (PSFS), falls, pain, PROMIS Pain Interference (PI), and quality of life.

Results

48 subjects with 1-year baseline and follow up data were analyzed. With the C-Brace, FWS improved by + 0.26 ± 0.33 m/s (p < .0001), TUG by -8.1 ± 14.6 sec (p < .0001), and ABC by + 24.9 ± 25.8% (p < .0001). Mean falls reduced from 33 ± 77 to 3.0 ± 5.6 (p = .0005). PSFS increased by 3.60 ± 2.34 points (p < .0001). Outcomes for pain, PI and quality of life showed significant improvements with the C-Brace.

Conclusion

The C-Brace is an effective option to improve safety, mobility, and quality of life for patients needing a KAFO for ambulation.

[Objective measurement tools that predict success in the fitting of major unilateral lower limb amputations patients]

The profile of the patient who most frequently suffers lower limb amputations is usually an elderly patient with high comorbidity. Physiatrists need objective tools in the assessment of these patients that predict the results of prosthetic programs to increase patient safety and efficiency of prosthetic rehabilitation programs. Given the need to update scientific knowledge in this field, we have carried out a review of the literature with the aim of defining a proposal for tools that facilitate decision-making in the indication of prosthetic rehabilitation in these patients. A bibliographic search strategy has been carried out using the scientific databases PubMed, Web of Science, Scopus and Cochrane Library. The quality of the selected articles has been assessed according to the tools proposed by CASPe.

Interobserver and intraobserver reliabilities of determining the ventilatory thresholds in subjects with a lower limb amputation and able-bodied subjects during a peak exercise test on the combined arm-leg (Cruiser) ergometer

The first (VT1) and second ventilator (VT2) (anaerobic) thresholds are used to individually prescribe exercise training programs. The purpose of this research was to analyze inter- and intraobserver reliabilities of determining VT1 and VT2 in subjects with lower limb amputation (LLA) and able-bodied (AB) subjects during a peak exercise test on the arm-leg (Cruiser) ergometer. Previously published data of exercise tests on the Cruiser ergometer of subjects with LLA ( n = 17) and AB subjects ( n = 30) were analyzed twice by two observers. The VT1 and VT2 were determined based on ventilation plots. Differences in determining the VT1 and VT2 between the observers for the first and second analyses were analyzed. To quantify variation in measurement a variance component analysis was performed. Bland-Altmann plots were made, and limits of agreement were calculated. The number of observations in which thresholds could not be determined differed significantly between observers and analysis. Variation in VT1 between and within observers was small (0-1.6%) compared with the total variation, for both the subjects with an LLA and AB subjects. The reliability coefficient for VT1 was more than 0.75, and the limits of agreement were good. In conclusion, based on the results of this study on a population level, VT1 can be used to prescribe exercise training programs after an LLA. In the current study, the determination of VT2 was less reliable than VT1. More research is needed into the clinical application of VT1 and VT2 during a peak exercise test on the Cruiser ergometer.

Establishing K-levels and prescribing transtibial prostheses using six-minute walk test and one-leg standing test on prosthesis: a retrospective audit

Rehabilitation programs after amputation often include fitting a prosthesis, but prescriptions vary under similar circumstances. The US Medicare Functional Classification Level (K-level) is a scale for describing functional abilities of persons after lower-limb amputation (from 0 = no ability or potential to ambulate, to 4 = prosthetic demands of a child/active adult/athlete). Different outcome measures are used to assess K-level, including six-minute walk test (6MWT). We attempted to predict the assigned K-level of unilateral transtibial prosthesis users from their results of 6MWT and one-leg standing test on prosthesis (OLSTP). Outpatients who had been rehabilitated and fitted with transtibial prosthesis at the University Rehabilitation Institute in Ljubljana in 2014 were included in a retrospective audit. The data were analysed using receiver-operating-characteristics curves, linear discriminant analysis, classification trees and ordinal logistic regression. Among the 120 patients (aged 39-90, mean 67 years; 79% men), eight belonged to K1 level, 94 to K2, and 18 to K3 or K4; 61 could not stand on the prosthesis, eight stood on it for 1 s, and 51 stood on it for 2 s or more. With a simple classification rule based only on 6MWT (130 m threshold for K2/K3/K4 vs. K1, 340 m for K3/K4 vs. K1/K2), we observed sensitivity and specificity close to 90%. The more sophisticated statistical approaches yielded substantially similar and comparably accurate results. 6MWT and OLST could therefore be used as predictors for transtibial prosthesis prescription in clinical practice.