Background: International clinical guidelines offer contradictory recommendations about knee bracing as an adjunct to core recommended treatment for people with knee osteoarthritis (OA). There is a paucity of high-quality evidence on the benefits, harms, and costs of knee braces from large, publicly-funded, pragmatic, clinical trials.

Objectives: To determine the clinical- and cost-effectiveness of adding knee bracing (matched to participants’ clinical and radiographic presentation, with adherence support) to advice, written information and exercise instruction (AIE+B) compared with advice, written information and exercise instruction alone (AIE) among people with knee OA.

Methods: PROP OA (ISRCTN28555470) was a multi-centre, parallel-group, superiority, randomised, controlled trial, with embedded patient and public involvement. Adults 45 years and over with clinically diagnosed symptomatic knee OA reporting moderate-severe knee pain on weight-bearing activity (≥4 on 0-10 numerical rating scale) were recruited from general practices and community advertisements around four regions in England. Participants were randomly assigned (1:1; stratified; block; centralised web-based) to either AIE or AIE+B. The trial statistician was masked to treatment allocation; participants and intervention deliverers were unmasked. AIE was delivered within a single, in-person consultation by a trained physiotherapist. Participants randomised to AIE+B were additionally fitted with either a patellofemoral, tibiofemoral unloading, or neutral stabilising knee brace, according to their predominant compartmental distribution of knee OA. They attended a follow-up consultation with the physiotherapist at two weeks. Brief motivational interviewing and motivational text messages were used to support adherence to brace use. The primary outcome was the composite patient-reported Knee Osteoarthritis Outcomes Score (KOOS-5) (0-100) at 6 months post randomisation. Key secondary outcomes included KOOS-5 at 3 and 12 months, and KOOS subscale scores and knee pain on weight-bearing activity at 3, 6 and 12 months. Primary analysis was estimated using linear mixed models (treatment policy approach). A within-trial economic evaluation was conducted from a United Kingdom National Health Service perspective via a cost-utility analysis (cost per quality-adjusted life year (QALY) gained).

Results: Between November 2019 and September 2022, 466 participants (mean (SD) age: 64 (9) years; 213 (46%) female; 449 (97%) self-reported White ethnicity; 195 (42%) higher education; 193 (42%) employed) were randomised, with 86%, 85% and 79% returning analysable data at 3, 6, and 12 months respectively. Both groups reported improvements in KOOS-5 at 6 months, with greater improvement in AIE+B compared to AIE (AIE: adjusted between group mean difference 3·39, 95% CI 0·96 to 5·82). Key secondary outcomes generally followed a similar pattern with greatest benefits on pain and activities of daily living (Table 1). Irritation/redness of skin was more common in AIE+B vs AIE (16% vs 5%); increased swelling, and temporary increased soreness were less common in AIE+B (10% vs 27% and 18% vs 28% respectively) at 6-months. No related serious adverse events were observed. AIE+B had an incremental cost-effectiveness ratio of £10,456 per QALY with an 84% probability of being cost-effective compared to AIE at the £20,000 per QALY threshold.

Conclusion: Adding knee bracing (matched to participants’ clinical and radiographic presentation and with adherence support) to advice, written information and exercise instruction produces small additional benefits on patient-reported outcomes for people with knee OA compared to advice, written information and exercise instruction alone. This safe and cost-effective intervention provides a treatment option for managing this common condition.

REFERENCES: NIL.

Acknowledgements: This project was funded by the National Institute of Health & Care Research (NIHR) Health Technology Assessment programme (16/160/03). The braces supplied by Össur were donated and we received a discounted price on braces supplied by Bioskin, Beagle Orthopaedics, and Donjoy. NEF is funded through an Australian National Health and Medical Research Council (NHMRC) Investigator Grant (ID: 2018182). CJ is part funded by the NIHR ARC West Midlands (NIHR200165). We would like to thank those that supported the development and running of the PROP OA randomised controlled trial: participants, physiotherapists, Trial Steering Group Committee and Data Monitoring Committee members, public contributors, the Clinical Advisory Group, Keele Clinical Trials Unit and participating sites. We gratefully acknowledge contribution by representatives from the brace companies to the delivery of the physiotherapist training programme.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.