THR beats resistance training for hip osteoarthritis pain, function

For people with severe symptomatic hip osteoarthritis, total hip replacement (THR) relieves hip pain and improves function much more effectively than a resistance training program supervised by a physical therapist, according to the results of a randomized, controlled clinical trial.

In the PROHIP studymean increases in Oxford Hip Scores from baseline to 6 months were 15.9 points for THR and 4.5 points for resistance training. The 11.4-point difference in scores was both statistically and clinically significant, the study researchers said report in the New England Journal of Medicine.

“Our results are clear: surgery is superior to exercise in patients with hip osteoarthritis and indication for surgery, and now we have finally proven that with the highest level of evidence,” said corresponding author Thomas Frydendal, PT, PhD, MSc. Medscape Medical News.

Frydendal, who was involved in the research while working on his PhD at Vejle Hospital in Denmark, the main center for the trial, is now a postdoctoral researcher at Aarhus University’s Department of Clinical Medicine and the Department of Orthopedic Surgery at the Aarhus University Hospital. .

“We believe that our findings are quite robust,” Frydendal added. “I think if anyone in the world does a process similar to ours, they will find fairly close or consistent findings. regardless of the type of exercise they choose.”

The PROHIP study

THR is routinely recommended for the treatment of severe hip osteoarthritis, but since there is no clinical trial data on the effectiveness of this procedure compared to first-line treatment such as resistance training, the PROHIP study was designed.

The study was conducted in four Danish orthopedic centers and was designed as a superiority study, hypothesizing that THR would be better at relieving self-reported hip pain and improving hip function than resistance training.

Of a possible 1474 persons with a clinical suspicion of hip osteoarthritis, 791 were eligible for inclusion in the study. Inclusion criteria were being 50 years or older and having an indication for THR based on the presence of hip pain and clinical and radiographic findings.

However, the majority (86%) declined to participate in the study, with almost half (43%) deciding to undergo THR and enroll in a parallel observational cohort. This meant that only 110 (14%) individuals agreed to participate and underwent randomization, which does limit the generalizability of the study, the PROHIP researchers acknowledged.

Design and study population

The change in Oxford Hip Score from baseline to 6 months was selected as the primary outcome measure based on the findings of a prior qualitative research. This 12-item, patient-reported outcome measure provides a score ranging from 0 to 48, with higher scores indicating less hip pain and better hip function. The estimated minimal clinically important difference is a change of 5 points.

After a baseline assessment, 53 of 109 subjects were randomly assigned to undergo THR and 56 to participate in the resistance training program. Overall, the average age of participants was 67.6 years, and half were female. The average duration of hip pain was 1.7 years on average.

The median time to receipt of assigned treatment was 2.8 months in the THR group and 0.5 months in the resistance training group.

Those assigned to the THR group also underwent a ‘fast track’ program that included patient education, pain management and early mobilization.

The resistance training group received 12 weeks of exercise under the supervision of a physical therapist and was then offered 12 weeks of additional exercise performed independently. The exercise sessions under the supervision of the physiotherapist took place twice a week and lasted 1 hour. These started with a 10-minute warm-up on a stationary bike, followed by a standard series of resistance-based exercises, including a leg press, hip extension, hip flexion and hip abduction.

‘Reassuring’ results

Comment for Medscape Medical NewsConsultant orthopedic surgeon Antony Palmer, MA, BMBCh, DPhil, said: “It is reassuring that patients with advanced symptomatic osteoarthritis do well with hip replacements.”

THR of course carries the potential risk of complications, but “the speed of this is what you would expect for that procedure,” said Palmer, who works for the Nuffield Orthopedic Centre, Oxford University Hospital NHS Foundation Trust, and a senior clinical researcher at the University of Oxford in England.

There was one case of prosthetic joint infection in the THR arm hip dislocationtwo revision operations, one copy of drop footand one case of gastroesophageal reflux. Meanwhile, in the resistance training group, there was one hip dislocation, one pelvic fracturea case of atrial fibrillationand one urinary tract and kidney infection.

Overall, every serious adverse event was reported in six (12%) of 48 patients in the THR arm versus five (9%) of 55 participants in the resistance training group, of which only one, which occurred in the resistance training group, resulted in termination of the program.

Resistance training role

A notable finding was that after six months, five (9%) people assigned to the THR arm had not undergone surgery, and 12 (21%) people in the resistance training group had undergone THR.

This could suggest two things, Palmer suggested in the interview. The first is that there may be a small proportion of people assigned to THR who may not need the surgery and who can perform exercise therapy well. And conversely, there may be people who would do well to undergo surgery without first going through the intermediate phase of physiotherapy.

It’s a suggestion that “we may need to refine that a little bit more and identify the patients who really benefit from physical therapy and who therefore may not need hip replacement,” Palmer said.

Or in other words, “should all patients undergo a physical therapy program before considering surgery?” he added.

Author’s view

The PROHIP researchers conclude: “These results support current recommendations for the treatment of hip osteoarthritis and can be used to inform and guide shared decision-making in clinical practice.”

Furthermore, the results “do not argue against the use of resistance training as initial treatment,” the authors say.

Frydendal emphasized this in his interview with Medscape Medical News that nearly three out of four patients reported not having done any form of guided exercise before participating in the study, which is a first-line option recommended by guidelines.

“If a patient tells me, ‘I’ve never exercised before,’ I would say, ‘Let’s start by completing a six- to 12-week exercise program tailored to your individual needs and then evaluate your symptoms,’” he said.

“But we should refer the patient if our first-line treatment does not produce any improvement in the patient’s symptoms, because total hip replacement surgery is clearly a very good treatment option,” Frydendal said.

The research was funded by, among others, the Danish Rheumatism Association. Frydendal and Palmer reported no relevant financial relationships.

Sara Freeman is a freelance medical journalist based in London, England.