Transfemoral amputee intact limb loading and compensatory gait mechanics during down slope ambulation and the effect of prosthetic knee mechanisms

Intact limb knee osteoarthritis is a prevalent secondary disability in transfemoral amputees. Walking down a ramp may increase this risk due to excessive limb loading. We sought to determine whether intact limb loading differed between transfemoral amputees and controls during down slope ambulation, and the compensatory strategies transfemoral amputees used to modify intact limb loading. Secondarily, we sought to determine the effect of prosthetic knee type. Five unilateral transfemoral amputees and five non-amputee controls walked down a ramp and the following outcome measures were compared between amputees and controls and across prosthetic knee type (C-leg versus Power Knee): step length, walking speed, leading limb ground reaction forces, and trailing and leading limb ankle and knee energy absorption. Linear mixed effects regression was used to test for association between gait variables and limb. There were no significant differences in intact limb loading between amputees and controls or between prosthetic knee types. Transfemoral amputees walked slower (C-leg - control = −0.29 m/s; P = 0.008, Power Knee – control = −0.38 m/s; P