PHILADELPHIA – A lightweight brace on the patellofemoral joint significantly improves the pain and symptoms of knee osteoarthritis, according to BRACE, the largest patellofemoral bracing trial to date.
After 6 weeks of brace wearing, pain fell an average of 16.87 points on a visual analog scale (VAS) during an activity patients reported as aggravating, compared with no brace (–18.16 vs. –1.29, P less than .001).
A 12-point reduction is considered clinically relevant on the 100-mm VAS pain scale, where 0 is no pain and 100 is worst pain, Michael Callaghan, Ph.D., said at the World Congress on Osteoarthritis.
Patrice Wendling/IMNG Medical Media
Dr. Michael Callaghan
"The feedback we got from patients each time is that the brace made their knee feel more supported, they felt more comfortable, they felt more confident," he said. "One of the things we’re thinking is that perhaps the brace gave patients the ability to use their knee a little bit more comfortably, functionally better than they could previously, and that was enough to start improving muscle strength."
Data are available to show that muscle strength did improve with brace wearing, and a recently completed biomechanical analysis should determine whether biomechanical changes were actually occurring.
Although nonpharmacologic interventions are urgently needed for knee osteoarthritis (OA), little attention has been paid to treatments specifically for the patellofemoral (PF) joint, said Dr. Callaghan, a research physiotherapist at the University of Manchester (England). About 24% of patients with knee OA have symptomatic patellofemoral (PF) OA in the absence of tibiofemoral arthritis, but more importantly, 41% have a combination of tibiofemoral and PF knee OA. Despite this, a recent editorial (Osteoarthritis Cartilage 2011;19:765-7) called the patellofemoral joint "the forgotten joint" in knee OA, he observed.
Nonsurgical treatments include anti-inflammatory medications, physical therapy, and cortisone shots. Arthroscopic debridement, lateral retinacular release, and partial or full knee replacement are reserved for more severe cases.
The one prior study of PF braces showed no effect on pain, but it compared the same brace with and without a patellar strap (Osteoarthritis Cartilage 2011;19:792-800). In clinical practice, the more relevant question is the benefit of PF bracing versus no bracing, Dr. Callaghan observed.
The 126 patients in the trial had a radiographic Kellgren-Lawrence score of 2 or 3 in the PF joint; daily knee pain for the previous 3 months with stair climbing, kneeling, prolonged sitting, or squatting; and tenderness over the lateral or medial patellar facet on palpation or a positive patellar compression test. In the trial, the mean VAS pain score was 64.6 mm, 57% of the participants were women, and the patients’ mean body mass index was 30.8 kg/m2. Their average age was 55.5 years.
Patients were randomly assigned to immediate brace treatment with the Bioskin Patellar Tracking Q Brace (Ossur, Manchester, England) or delayed treatment at 6 weeks. All patients ultimately received 12 weeks of brace, and wore their brace for an average of 7.35 hours per day.
At 6 weeks, Knee Osteoarthritis Outcome Score subscale scores for pain and activities of daily living improved significantly with the brace vs. no brace by an average of –6.70 and –5.64, respectively (8.78 vs. 2.08 and 6.67 vs. 1.03; both P = .02), Dr. Callaghan reported at the meeting, sponsored by the Osteoarthritis Research Society International.
There was a trend toward improved aggregated locomotor function with the PT brace (–2.5 vs. –1.21; P = .065) in the study, which was led by colleague Dr. David Felson, professor of medicine at the University of Manchester and Boston University.
During a discussion of the study, an attendee said that in her practice she avoids using the type of brace used in the study with a cutout over the knee in younger patients with PF pain, because of data suggesting that bracing compresses the patella and increases the contact area between the patella and the trochlear notch, thereby increasing stress rather than changing the patella position or movement. Dr. Callaghan acknowledged that compression could be an issue and said MRI data available on 30 patients are being evaluated for evidence of compression and joint space narrowing.
Arthritis Research UK funded the trial. The authors reported no relevant disclosures.