PROP OA Trial: Knee Bracing Adds Small Benefits In Knee Osteoarthritis

In 466 adults with symptomatic knee osteoarthritis, a multicenter randomized trial compared advice, written information, and exercise instruction with the same package plus bracing and adherence support.

The comparator was advice, written information, and exercise instruction alone, usually delivered in one in-person consultation by trained physiotherapists. The intervention added compartment-specific knee bracing and adherence support to the same package, with brace choice based on the predominant compartmental presentation. Physiotherapists completed standardized training, fitted the brace, and reviewed participants after about two weeks to check response and fit. They also used brief motivational interviewing, diaries, and SMS reminders.

For the primary patient-reported outcome, KOOS-5 improved more in the brace group at six months, and that between-group difference reached statistical significance. A similar advantage was seen at three months, whereas the difference was smaller and no longer statistically significant at 12 months. The largest secondary gains were reported in pain and activities of daily living. Pain during weight-bearing activity and most other secondary outcomes also favored the brace strategy, although some domains did not show significant between-group differences at every assessment. Across outcomes, earlier separation was seen between groups, with less separation by 12 months.

Brace adherence declined over follow-up in the intervention group. Overall, 66% met the prespecified self-reported adherence definition at both three and six months. At six months, the most common reported reason for nonadherence was difficulty fitting the brace under clothing. A prespecified complier analysis showed a larger six-month KOOS-5 difference among participants who met the adherence definition. Adverse events were minor and expected, including skin irritation, redness, swelling, temporary soreness, and occasional blisters, and were not described as major harms.

Authors characterized the effect size as small at three and six months and very small by 12 months. The observed between-group difference also remained below the trial's predefined eight-point KOOS-5 threshold used for sample size planning. They noted that greater physiotherapist contact in the brace group might have contributed to some additional benefit. Overall, the brace-based adjunct produced modest patient-reported improvement that weakened over follow-up.