The Effect of Knee Flexion Contracture Following Total Knee Arthroplasty on the Energy Cost of Walking

This study evaluated the energy cost of walking (C_w) with knee flexion contractures (FC) simulated with a knee brace, in total knee arthroplasty (TKA) recipients (n = 16) and normal controls (n = 15), and compared it to baseline (no brace). There was no significant difference in C_w between the groups at baseline but TKA recipients walked slower (P = 0.048) and with greater knee flexion in this condition (P = 0.003). Simulated FC significantly increased C_w in both groups (TKA P = 0.020, control P = 0.002) and this occurred when FC exceeded 20° in the TKA group and 15° in the controls. Reported perceived exertion was only significantly increased by FC in the control group (control P < 0.001, TKA P = 0.058). Simulated knee FCs less than 20° do not increase C_w or perceived exertion in TKA recipients.