Comparison of clinical outcomes between total hip replacement and total knee replacement.

Background: Total hip replacements (THR) and total knee replacements (TKR) are effective treatments for severe osteoarthritis (OA). Some studies suggest clinical outcomes following THR are superior to TKR, the reason for which remains unknown. This study compares clinical outcomes between THR and TKR.

Aim: To compare the clinic outcomes of THR anad TKR using a comprehensive range of patient reported outcome measures (PROMs).

Methods: A prospective longitudinal observational study of patients with OA undergoing THR and TKR were evaluated using a comprehensive range of generic and joint specific PROMs pre- and post-operatively.

Results: A total of 131 patients were included in the study which comprised the THR group (68 patients) and the TKR group (63 patients). Both groups demonstrated significant post-operative improvements in all PROM scores ( < 0.001). There were no significant differences in post-operative PROM scores between the two groups: Hip and Knee Osteoarthritis Outcome scores ( = 0.140), Western Ontario and McMaster Universities Osteoarthritis Index pain ( = 0.297) stiffness ( = 0.309) and function ( = 0.945), Oxford Hip and Knee Score ( = 0.076), EuroQol-5D index ( = 0.386) and Short-Form 12-item survey physical component score ( = 0.106). Subgroup analyses showed no significant difference ( > 0.05) between cruciate retaining and posterior stabilised prostheses in the TKR group and no significant difference ( > 0.05) between cemented and uncemented fixation in the THR group. Obese patients had poorer outcomes following TKR but did not significantly influence the outcome following THR.

Conclusion: Contrary to some literature, THR and TKR are equally efficacious in alleviating the pain and disability of OA when assessed using a comprehensive range of PROMs. The varying knee prosthesis types and hip fixation techniques did not significantly influence clinical outcome. Obesity had a greater influence on the outcome following TKR than that of THR.