Prosthetic gait of unilateral lower-limb amputees with current and novel prostheses

BACKGROUND: Novel lower-limb prostheses aim to improve the quality of locomotion of individuals with an amputation. This study evaluates the biomechanics of a novel bionic foot during walking.

METHODS: Able-bodied individuals (n = 7) and individuals with a transfemoral (n = 6) or transtibial amputation (n = 6) were included. Able-bodied individuals conducted one experimental trial, whereas individuals with transtibial and transfemoral amputations conducted a familiarization (with current prosthesis) and two experimental trials using a passive and bionic prosthesis. Each trial consisted of 3 bouts of 2 min of treadmill walking at different speeds. Biomechanical data were gathered using a force platform and motion capture system and analysed using Statistical Parametric Mapping and (non)-parametric tests.

FINDINGS: Conventional prosthetic feet alter gait patterns and induce locomotion difficulties. While walking at a normal speed with the passive prosthesis, transtibial amputees display reduced maximum heel forces, increased ankle and trunk angular velocities at midstance, and increased knee angle during stance and swing phases on their effected side (P ≤ 0.026). Improved lower-limb kinematics was demonstrated during slow and normal speed walking with the bionic prosthesis; however, dynamic trunk stability was negatively impacted during this condition. The bionic prosthesis did not benefit transfemoral amputees at any walking speed.

INTERPRETATION: Transtibial amputees can better approximate typical movement patterns at slow and normal walking speeds using the novel bionic prosthesis; however the same benefit was not observed in transfemoral amputees.