Falls and diminished walking capacity are impairments common in persons with transfemoral amputation (TFA). Reducing falls and optimizing walking capacity through such means as achieving a more normal gait speed and community ambulation should be considered when formulating the prosthetic prescription. Because walking capacity and balance confidence are compromised with TFA, these outcomes should be considered when evaluating interfaces for transfemoral prosthetic users. The purpose of this study was to compare the effect of TFA interface design on walking capacity and balance confidence A retrospective cohort design was utilized involving unilateral TFA patients who used ischial ramus containment (IRC) and High-Fidelity (HiFi) interfaces (independent variables). Dependent variables included the Activity-specific Balance Scale (ABC) and the two-minute walk test (2MWT). Complete records were available for 13 patients (n = 13). The age range was 26 to 58 years. Three patients functioned at the K4 activity level, whereas all others functioned at the K3 level. Mean ABC scores were significantly different (p ≤ 0.05) at 77.2 (±16.8; 35.6 to 96.9) for IRC and 90.7 (±5.7; 77.5 to 98.7) for HiFi. The mean distance walked on the 2MWT was 91.8 m (±22.0, 58.3 to 124.7) for IRC compared to 110.4 m (±28.7; 64.7 to 171.1) for the HiFi socket (p ≤ 0.05). Alternative transfemoral interface design, such as the HiFi socket, can improve walking capacity and balance confidence in higher-functioning TFA patients.

Introduction The High-Fidelity (HiFi) interface is an emerging transfemoral interface technology. However, no comparison of this interface to traditional transfemoral interface designs is currently available. The purpose of this study is to measure the effects of the HiFi system on gait and perceived disability compared with a traditional socket design in a subject with transfemoral amputation. Methods The subject was first tested with a traditional ischial containment socket, then fit with the HiFi system, and tested again after a 30-day accommodation period. Three-dimensional motion analysis was performed using an 8-camera Vicon Motion Capture system. The Oswestry Low Back Pain Disability Questionnaire v2.0 and Western Ontario and McMaster University Osteoarthritis index were administered at initial and secondary testing to evaluate perceived disability. A one-way analysis of variance and Fischer's least significant difference were used to determine statistical difference between conditions. The level of significance for all tests was set at P ≤ 0.05. Results Notable results included an increase in self-selected gait velocity, prosthetic hip adduction, and hip extension. Reductions in lateral center of mass deviation during gait and in perceived disability was also shown with use of the HiFi condition. Discussion This study analyzed the effects of the HiFi Interface System on biomechanical parameters of gait and perceived disability compared with a baseline IRC condition in this elderly subject with history of TF amputation. Several improvements and markers of increased stability with use of the HiFi were noted. Perceived disability was also greatly improved comparatively. Conclusions The HiFi Interface System presented some biomechanical advantages to traditional IRC socket designs in this case, which may allow for increased stability in patients utilizing a TF prosthesis. Further research with larger samples is warranted.