Trajectories of functional performance and muscle strength recovery differ after total knee and total hip replacement: a performance-based, longitudinal study.

Total joint replacement is indicated to alleviate pain and disability associated with hip and knee osteoarthritis. Arthroplasty outcomes are typically reported together, or anecdotal comparisons are made between total knee arthroplasty (TKA) and total hip arthroplasty (THA) recovery. Limited data quantifies differences in recovery trajectories, especially with respect to performance-based outcomes. Seventy-nine people undergoing total knee or THA were followed over 6 months. Functional performance was measured using the stair climb test, timed-up-and-go test, and 6-min walk test. Surgical limb isometric strength was also measured. All outcomes significantly declined 1 month after surgery. Participants in the TKA group showed a greater decline in climbing stairs (P < 0.001), timed-up-and-go (P = 0.01), and 6-min walk distance (P < 0.01). Further, the TKA group lost more strength (P < 0.001) and were weaker than those after THA (P < 0.001). Differences in postoperative outcomes between groups at 3 and 6 months were also observed. The TKA group experiences a greater decline in measured outcomes than the THA group, and muscle strength and functional recovery occurred differently in each group. These findings should be considered in rehabilitation priorities after arthroplasty surgery.