By Alice Goodman
SAN DEIGO — For the first time, a scientific study has shown that a simple slip-on knee brace reduces bone marrow lesions and pain associated with osteoarthritis.
“There is a pressing need for nonsurgical interventions for knee osteoarthritis, but there are no currently approved structure-modifying treatments,” said lead investigator David Felson, MD, from Boston University.
“Bone marrow lesion change offers a tremendous opportunity for drug development in osteoarthritis. Unlike cartilage loss, bone marrow lesions are associated with pain. They could be a structural treatment target if we can demonstrate repeatedly that treatments are effective,” he explained.
It is thought that bone marrow lesions represent areas of bone trauma caused by increased focal stress across the knee. They fluctuate in volume in as little as 6 weeks, Dr. Felson explained. One of the goals of this study was to demonstrate that bone marrow lesions can be a viable treatment target; the other was to determine whether a knee brace can reduce pain.
Dr. Felson presented the results here at the American College of Rheumatology 2013 Annual Meeting.
The 126 patients with painful knee osteoarthritis were randomized to wear a knee brace for a median of 7.35 hours per day for 6 weeks, or to not wear a brace. None of the patients participated in any exercise program over the course of the study.
Mean age was about 55 years, slightly more than half of the cohort was female, and median body mass index was above 30 kg/m². All patients reported pain when performing daily activities, such as climbing stairs, kneeling, and prolonged sitting or squatting. All had radiographic evidence of knee joint damage and tender knee joints on physical examination.
The primary outcome measure was change in pain score on a visual analog scale (with 0 indicating no pain and 100 indicating severe pain). Pain score during activity declined about 18 points in patients wearing the brace, but there was almost no change in patients not wearing the brace (P < .001).
There was substantial improvement in the brace group on the pain subscale of the Knee Injury and Osteoarthritis Outcome Score, but no improvement in the no-brace group.
At baseline, contrast MRI showed that bone marrow lesion volumes in the patellofemoral joint, which was affected by the brace, were almost identical in the 2 groups. At 6 weeks, contrast MRI showed a significant 25% decrease in volumes at the patellofemoral joint in patients in the brace group (P = .02). In the joint on the leg not involved in the intervention, there was no difference in bone marrow lesion volume change between the 2 groups.
The major limitation of this study was that it was only 6 weeks; knee osteoarthritis is a chronic long-term disease. However, Dr. Felson noted that the research team “followed a lot of the patients for 3 months or longer, and 75% were still wearing the brace, so it appears to be feasible as a longer-term strategy.”
“You could call this a ground-breaking study,” said session moderator Eric Matteson, MD, from the Mayo Clinic in Rochester, New York. “The researchers used a simple technology and assessed it in a scientific way. No one has done that before. The biological effects of the brace and pain reduction were significant,” he said.
Dr. Matteson said that it would have been informative if the researchers had measured the effect of the brace on activity during the study, perhaps with a pedometer.
Session comoderator Mary Cronin, MD, said that when patients feel better, they are more mobile and more likely to exercise. “There is not much helpful treatment out there for knee osteoarthritis patients,” she added.