Hip replacement surgery is the routine treatment for severe hip osteoarthritis (OA), with over 450,000 procedures performed annually in the U.S. alone. Despite its popularity, randomized trials evaluating its effectiveness are lacking. To help close the knowledge gap, researchers in Denmark randomized 109 patients 50 and older (mean age 67.6 years) with severe hip OA to total hip replacement surgery or physical therapy (PT) that included resistance training. The primary outcome was the change in the Oxford Hip Score (scale 0 to 48 with higher scores indicating less pain and better function) at 6 months; the baseline score in both groups was 25. At study conclusion, increases in the Oxford score were significantly greater in the surgery group compared to the PT group (15.9 points vs 4.5 points, p<0.001). At 6 months, 9% of patients assigned to surgery had not received it, while 21% assigned to PT had undergone hip replacement (crossovers). Despite the significant number of crossovers in the PT group, surgery was still superior in the intention-to-treat analysis.

The main weakness of the study is the lack of blinding, which would have required a sham procedure in the control group. However, simulating hip replacement surgery would be difficult given the complexities and aftercare of such a major procedure, making a sham control impractical. While entirely objective evidence does not exist, most patients experience profound pain relief and improvement in mobility after joint replacement surgery, suggesting these procedures are highly effective.

Learn more about the effects of sham procedures and crossovers on study outcomes by taking our CME course, Medical Study Analysis.

• Hip Replacement vs PT for Severe OA, NEJM (2024) [PubMed abstract]
• Reviews of orthopedic studies