Study Casts Doubt on Common PT Regimen for Hip OA
Patients who participated in physical therapy improved, but so did those who received “sham” treatment.
When patients with hip osteoarthritis (OA) have difficulty with pain and movement, doctors sometimes prescribe physical therapy. The conservative therapy – which often includes a combination of manual therapy (the use of hands to manipulate joints and put pressure on muscles), therapeutic exercises (targeting strength, flexibility and balance), massage and education under the direction of a trained physical therapist – offers minimal risk and is often covered to some extent by insurance plans. But while physical therapy is a well-accepted approach in the United States as well as internationally, and studies have shown the benefits of exercise and of manual therapy individually, no placebo-controlled trial has examined the effectiveness of a combined physical therapy program.
To close this evidence gap, a team of researchers in Australia, led by Kim L. Bennell, PhD, director of the Centre for Health, Exercise and Sports Medicine at the School of Health Sciences at the University of Melbourne, designed a study to measure how well physical therapy works. The results? The patients on a physical therapy program did improve in terms of pain and function – but those who had placebo (sham) physical therapy treatments improved just as much, and even a little more in some cases. Their findings appeared recently in The Journal of the American Medical Association (JAMA).
About 25 percent of adults in the U.S. will develop hip arthritis in their lifetime, according to the Centers for Disease Control and Prevention (CDC). No currently available therapy slows down or reverses the cartilage wear that occurs in the disease, so treatments focus on improving pain and function as well as delaying or preventing joint replacement. Many doctors and professional organizations – including the American College of Rheumatology (ACR), the European League Against Rheumatism (EULAR) and the Osteoarthritis Research Society International (OARSI) – recommend daily exercise, such as walking or swimming, to relieve symptoms and maintain mobility in arthritis patients. Some, including the ACR and OARSI, also recommend physical therapy.
Bennell and her colleagues recruited 102 people with moderate OA-related hip pain and followed them for nine months between 2010 and 2013. All were 50 years of age or older and none had undergone physical therapy or exercised more than 30 minutes per day for the previous six months.
Study participants were randomly assigned to either an active or a sham treatment group. Those in the active group had 10 physical therapy treatments with experienced therapists during a 12-week period. Treatments included hands-on manipulation of the hip and, massage, education and instruction on the proper use of a cane, if needed. Additionally, they were given exercises to perform at home several times a week. The placebo group received fake ultrasound treatments using an inactive gel but no manual therapy, exercise instruction or other intervention.
After 12 weeks of treatment the participants in both groups were followed for an additional six months. During that time, the active group continued the prescribed exercises on their own and the placebo group continued to apply the inactive gel three times per week.
Participants were assessed for pain and physical function before the study (at baseline) and at 13 and 36 weeks after the start of the study. Pain was measured using the visual analog scale (VAS), where 0 represents no pain and 100 is the worst pain imaginable. Physical function was measured using a standard scale with scores ranging from 0 (no difficulty) to 68 (extreme difficulty).
To determine how well participants could function physically, researchers looked at range of motion, muscle strength, stair climbing ability, walking pace and balance. They also looked at other measures, including quality of life, the intensity of pain while walking and treatment side effects.
The results took them by surprise.
They found that the patients in the physical therapy group improved – but they did no better than the placebo group did; in fact, people receiving the sham treatments fared slightly better. Pain scores at the start of the study for both the active group and sham group were near the middle of the pain scale: 58.8 and 58.0, respectively. At 13 weeks, both groups had significantly lower pain scores: 40.1 for the active group and 35.2 for the sham group.
There were similar improvements in physical function. The physical function score for the active group was 32.3 at baseline and 27.5 at 13 weeks; sham group scores were 32.4 and 26.4, respectively.
After nine months, about the same number of people in both groups reported improvements in pain and function. The groups did about the same on other measures, too, although the active group had slightly better balance but more periods of increased pain and stiffness (41 percent in the active group vs. 14 percent in the sham group).
“Unfortunately, as a [physical therapist], the results were not what we had hoped for; both groups showed the opposite of what we had hypothesized,” Bennell says. “But although there were no differences between them, both groups showed benefit, and we know that people who don't receive treatment don’t improve.”
So what caused similar rates of improvement among people who received real and sham treatments?
It’s possible that the active physical therapy program was “truly ineffective,” Bennell says. But another explanation is that combining exercise and manual therapy in a single session might reduce the effectiveness of both. Alternatively, the therapy used in the study might not have targeted the right muscles to improve strength and range-of-motion in arthritic hips.
Bennell says it’s possible the benefits were due not to the therapies themselves but to participants’ expectation of improvement as well as 12 weeks of close contact with sympathetic, caring therapists, both of which are known to influence healing. “Seeing a physical therapist is likely to lead to benefits, but not in the way we thought it was,” she says.
Kathleen Mangione, PhD, a physical therapy professor at Arcadia University in Philadelphia, says she believes the study was well constructed but that it may be saying more about the type and amount of exercise studied than the effectiveness of physical therapy overall.
“I don’t think we can say physical therapy isn’t effective. I think we can say four specific manual therapy techniques and a home-based program of unsupervised and infrequent stretching were not more effective than the sham therapy,” she says. “Physical therapy is a complex biobehavioral intervention and to lump all of physical therapy together – especially when the only physical therapy in this study were four manual therapy techniques – is oversimplifying what physical therapy is and what PTs do.”
David Mayman, MD, an orthopaedic surgeon at Hospital for Special Surgery in New York who was not involved in this research, says despite the findings, there is still a role for physical therapy in hip OA management. “We treat individual patients and cannot always generalize. There will be patients with osteoarthritis of the hip who do benefit from the manipulations and exercise used in physical therapy,” he says.
If that fails, he says, “There is a broad range of options that all have varying risks and benefits, including anti-inflammatory medications, nutritional supplements, physical activity, corticosteroid injections and hip replacement surgery.”
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