Total hip arthroplasty (THA) improves patient-reported pain and function more than progressive resistance training (PRT) in severe hip osteoarthritis, but whether it provides greater improvements in objectively measured physical activity remains unclear.

To evaluate whether THA resulted in a higher number of daily steps compared with PRT at 6 months after treatment initiation in individuals aged ≥50 years who had severe hip osteoarthritis and an indication for surgery.

Secondary analysis of a multicenter randomized trial. Participants were enrolled from September 2, 2019, to June 30, 2021, from 4 orthopedic departments in Denmark and randomly assigned to undergo THA or participate in a supervised PRT program. For these secondary analyses, the primary outcome was the number of daily steps at 6 months, assessed using tri-axial accelerometry, with data being post-processed using a validated algorithm. Analyses were based on a modified intention-to-treat population, excluding participants with baseline data containing fewer than 3 days and 10 hours of measurement.

A total of 101 participants (mean age, 67.6 years, 51% females) provided valid tri-axial accelerometry data at baseline, with 47 being randomized to THA and 54 to PRT. In a modified intention-to-treat analysis, the mean number of daily steps at 6 months was 8 155 in participants assigned to THA and 6 760 in those assigned to PRT (between-group difference, 1 394 steps; 95% confidence interval 466 to 2322; P  = 0.004). At 6 months, the 2 treatment groups did not differ in the number of daily sit-to-stand transfers, but participants assigned to THA had more daily short walking bouts than those assigned to PRT.

We found that THA resulted in more daily steps and short walking bouts, while there was no difference in the number of daily sit-to-stand transfers, as compared with PRT at 6-month follow-up.