Biomechanical assessment of persons with bilateral transfemoral/through-knee amputations using stubby prostheses: A pilot study.

BACKGROUND: Stubby prostheses are nonarticulated prostheses used by persons with bilateral transfemoral/through-knee amputations (BTF) either exclusively or alongside full-length articulated prostheses. The implications of stubby prosthesis use on musculoskeletal function and movement patterns are unclear. This study aims to provide insights into the biomechanics of walking with stubbies. METHODS: Gait data were collected using a 10-camera motion capture system from 4 male traumatic BTF who exclusively use stubbies and 4 male traumatic BTF who use multiple prostheses, including stubbies and full-length articulated prostheses. Both cohorts completed level-ground walking trials wearing stubby prostheses. Muscle parameters were quantified through high-resolution magnetic resonance imaging scans. RESULTS: Compared with BTF who use multiple prostheses, stubbies-only users showed lower walking speeds by 15% (0.79 vs 0.93 m/s), lower cadence by 20% (91.2 vs 114.7 steps/min), lower peak hip flexion angles by 45% (19.7° vs 35.9°), and larger peak-to-peak anterior pelvic tilt by 103% (15.8° vs 7.8°). Stubbies-only users presented lower overall muscle volume and physiological cross-sectional area. CONCLUSION: In this small cohort, full-time stubby users presented signs of muscle weakness that were not observed in those using full-length articulated prostheses. This may affect current and future functional abilities.