Lower extremity kinematic and kinetic adaptations in unilateral below-knee amputees during walking

The aim of this project was to explore the nature of gait accommodations by unilateral below-knee amputees during walking. Lower extremity kinematic and kinetic data for two groups of subjects, 6 below-knee amputees (both prosthetic and intact limbs) and 6 able-bodied individuals (a single limb), were computed as subjects walked at 1.2 and 1.6 m/s. Kinematic profiles were similar for all three limb conditions. The largest difference between limbs occurred late in stance at the ankle joint when the prosthetic limb displayed substantially less planter flexion because of its passive response to unloading. Joint kinetic differences between limbs were most apparent at the knee. Whereas the net ankle and hip moments were similar for all three limb conditions, the net knee moment for the prosthetic leg deviated from the amputee intact and non-amputee limbs by remaining flexor throughout the stance phase. This response was attributed to an effort to reduce loading on and about the knee joint and stump of the prosthetic limb. Despite the absence of an extensor contribution from the prosthetic knee, the overall support moment on the prosthetic side was sufficient to provide a normal support function.