SAN DIEGO – Patients with osteoarthritis of the knee who wore a patellofemoral brace for 6 weeks experienced a significant reduction in pain and in bone marrow lesion volumes in the patellofemoral region, compared with those who did not wear the brace, a multicenter trial showed.
"There’s a pressing need for nonsurgical intervention for knee osteoarthritis," Dr. David T. Felson said in a press briefing at the annual meeting of the American College of Rheumatology.
"There are no currently approved structure-modifying treatments. This has been a focus of studies that have been testing modifying treatments on hyaline cartilage, which changes slowly, necessitating expensive, long-term, large trials. Even so, mechanopathology such as that caused by malalignment or meniscal tears may make it impossible to protect cartilage in existing OA," he noted.
Dr. David Felson
Dr. Felson, director of the Research in Osteoarthritis in Manchester group at the University of Manchester (England) and professor of medicine at Boston University, went on to note that bone marrow lesions (BMLs) "have been well shown to predict later cartilage loss in that location and correlate with pain and its severity. Recently, we showed that BMLs fluctuate in volume in as little as 6 weeks. Further, one small trial has suggested that zoledronic acid may shrink BMLs and reduce knee pain. That leads us to suggest that BMLs may be a viable treatment target in OA."
The patellofemoral joint "is a major source of knee pain in OA, and there has been little study of the efficacy of PF braces," he continued. "In a body mechanics study, PF bracing has been shown to increase the contact area of the PF joint. It may thereby lower the contact stress and shrink BMLs."
He and his associates set out to determine whether bracing would improve pain and lessen the volume of BMLs in patients with knee OA. They enrolled 126 patients with a mean age of 55 years whose knee pain had been present daily for the previous 3 months. Half of the patients wore a soft neoprene PF brace for a mean of 7.3 hours per day, while the other half did not.
All study participants "had to have at least a score of 40 on a 0-100 mm visual analogue scale (VAS) for nominated aggravating activity likely to originate in the PF joint," Dr. Felson said. "They had to have pain with activities such as stair climbing, kneeling, prolonged sitting or squatting, [and] they also had to have a radiographic KL [Kellgren-Lawrence] score of grade 2 or 3 in the PF joint. That score had to be greater than the KL score for the tibiofemoral compartments. They also had to undergo a clinical exam by a trained physiotherapist to confirm PF joint tenderness."
The researchers performed contrast-enhanced knee MRIs at baseline and at 6 weeks. The primary symptom outcome measure was VAS pain during the patients’ nominated aggravating activity, while the primary structural outcome measure was BML volume in the PF joint as assessed on sagittal precontrast view.
At 6 weeks, Dr. Felson reported that patients in the no-brace group had a mean reduction in their VAS pain of 1.3, compared with a reduction of 18.2 in the braced group, a mean between-group difference of 16.9 that reached statistical significance (P less than .001).
As for PF BML volume, patients in the no-brace group showed a slight increase in volume (mean, 102.7 mm3), while the braced group showed a significant decrease in PF BML volume (mean, –554.9 mm3), for a mean between-group difference of 657.6 mm3 that reached statistical significance (P = .02). "That represents about a 25% decrease in volume," Dr. Felson said.
No differences were observed between the two groups in terms of tibiofemoral BML volume or in synovitis volume.
Dr. Felson acknowledged certain limitations of the study, including its 6-week design. "OA is a long-term chronic disease," he said. "We don’t know what relevance our findings have for longer-term structure changes of the knee."
The researchers stated that they had no relevant financial conflicts to disclose.