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

The groups were not randomly assigned to surgery type. The knee group came from control participants in two earlier randomized trials, and the hip group came from an observational study, so differences may reflect the original study designs rather than the surgeries alone. The hip group had a lower BMI and faster stair climb time than the knee group before surgery, which could favour the hip group in later performance tests. Physical therapy was not the same between groups. Knee replacement participants received five home visits and 10-12 outpatient visits, while hip replacement participants received surgeon-prescribed physical therapy that was not controlled. The paper reports different physical therapy amounts for the hip group: an average of four home visits and two outpatient visits in the methods, and 0-8 visits with an average of three home visits and two outpatient visits in the limitations. The outcome tests were chosen because they are common after knee replacement and rely heavily on quadriceps strength, so they may not fully capture hip-specific problems such as gluteal weakness or movement compensation. The study did not include patient self-report measures, so it cannot compare satisfaction, expectations, or perceived function. Participants were a convenience sample with exclusion criteria, so they may have been higher functioning than typical joint replacement patients.

The authors declared no conflicts of interest.

Do not conclude that hip replacement patients can recover without formal rehabilitation. The study compared recovery trajectories, not tested treatments, and the authors state that the early hip period may look easier but does not show the full picture of deficits or rehabilitative needs.