Hip Replacement Outperformed Strength Training for Severe Hip Osteoarthritis

CATEGORY: MOBILITY, BONES & JOINTS

A hip can deteriorate until an operation is genuinely on the table, and the person living with it then has to weigh that operation against a program of supervised exercise. No randomized trial had ever compared the two. One finally has. Six months after treatment began, patients given a hip replacement had gained an average of 15.9 points on a standard 48-point score of hip pain and daily function, while those given strength training had gained 4.5.¹

The Common Operation Nobody Had Randomized

Hip replacement removes the damaged ball-and-socket joint and puts an artificial one in its place. It ranks among the most common operations in medicine, routinely offered once osteoarthritis, the wear-related breakdown of the cartilage that cushions a joint, turns severe. Yet the study’s authors point out that nobody had ever tested it against a nonsurgical alternative in a randomized trial. The PROHIP trial, run across Danish hospitals, was built for that one comparison. It enrolled 109 patients aged 50 or older, average age 68, whose hip osteoarthritis was already severe enough for surgery to be indicated. A random allocation, not a preference, decided who got the operation and who got progressive resistance training.

Socks, Stairs and a Forty-Eight-Rung Ladder

Both groups were scored on the Oxford Hip Score. It asks about the realities of a bad hip: how much it hurts, whether you can pull on your own socks, climb stairs, get in and out of a car. Scores run from 0 to 48, with higher numbers meaning less pain and better function, so the scale works like a ladder of 48 rungs. Over six months the surgery group climbed about sixteen of them. The group doing resistance training, which meant supervised hip and leg strength work such as squats and step-ups with the effort raised as strength builds, climbed about four and a half. That left a gap of 11.4 points (95% confidence interval, 8.9 to 14.0). The authors call the difference clinically important, meaning large enough to be felt in daily life rather than only seen in the statistics.

One in Five Exercisers Had the Operation Anyway

The crossovers tell their own story. By the six-month mark, 12 of the 56 patients assigned to exercise, or 21%, had gone ahead and had the hip replaced. Five of the 53 assigned to surgery, 9%, had not yet had the operation. Serious adverse events occurred at a similar rate on both sides, and that similarity has a cause worth understanding: because some exercisers had already crossed over, their adverse-event totals included the same surgical complications counted in the surgery group. Real surgical risk arrives alongside the operation’s clear benefit. Follow-up stopped six months after treatment began, so the trial describes the first half-year and nothing beyond it.

Four Out of Five Exercisers Stayed With Exercise

The exercise group did improve, modestly. Four out of five of its members had not moved to surgery by six months. Treatment guidelines generally put exercise first in hip osteoarthritis and reserve surgery for people whose symptoms persist, and nothing in this trial overturns that order. Everyone enrolled had already reached the stage where surgery was indicated. What the trial supplies, where randomized evidence simply did not exist, is the size of the difference at that stage. For severe disease, the operation delivered a far larger improvement than a structured strength program did.

Key Takeaways

• Six months after treatment began, hip replacement had improved pain and daily function by an average of 15.9 points on a 48-point score, against 4.5 points with supervised resistance training, among patients whose hip osteoarthritis already qualified them for surgery.
• One in five patients assigned to exercise crossed over to surgery within six months, while the majority who stayed with exercise saw modest gains.
• Serious adverse events were similarly common in the two groups, partly because the exercisers who crossed over carried surgical complications into their group’s totals.
• Everyone in the trial already qualified for surgery and was followed for six months, so the result does not describe milder disease or longer horizons.

References

1. Frydendal T, Christensen R, Mechlenburg I, et al. Total Hip Replacement or Resistance Training for Severe Hip Osteoarthritis. N Engl J Med. 2024;391(17):1610–1620. link