Sustained benefits of blood flow restriction therapy in knee osteoarthritis rehabilitation: 1-year follow-up of a randomised controlled trial

OBJECTIVE: Knee osteoarthritis (KOA) is a leading cause of global disability and remains challenging to treat. Blood flow restriction (BFR) shows promising rehabilitation outcomes, but its lasting effects in KOA are lacking. This study aimed to determine the 1-year outcomes of a BFR-enhanced exercise therapy programme in patients with KOA. METHODS: This study included 120 patients (33 male, 87 female) from a previously published randomised controlled trial comparing 12 weeks of traditional exercise therapy with and without BFR, performed twice per week. For the current analysis, patients were reassessed at 1 year. The primary outcome was the Knee Osteoarthritis Outcome Score (KOOS) questionnaire, with secondary outcomes including muscle strength and a functional test battery. Data on knee joint injections and activity levels were also reviewed at 1-year follow-up. Analyses consisted of linear mixed models with Dunn-Sidak corrections for multiple comparisons, with an intention to treat approach (NCT04996680). RESULTS: Clinically meaningful improvements at 1 year were found in favour of the BFR group for KOOS subscales 'pain' (mean difference (MD): 15.1 points ES=0.79, p=0.0039), 'symptoms' (MD: 10.5 points, ES=0.51, p=0.0074), 'activities of daily living' (ADL) (MD: 11.3 points, ES=0.54, p=0.0054) and 'quality of life' (QoL) (MD: 14.7 points, ES=0.61, p=0.0032) compared with exercise therapy without BFR. The BFR group outperformed the non-BFR group for the functional tests, and muscle strength remained significantly higher at 1 year in the BFR group (ES=0.48, p=0.0010) as opposed to no BFR. The BFR group was more active by 1.5 hours/week (p=0.036) and had 3.6 times lower odds of receiving knee injections compared with the non-BFR group. CONCLUSION: A 12-week BFR-enhanced exercise therapy programme provides benefits for pain, symptoms, ADL, QoL, muscle strength and functional capacity at 1-year follow-up while reducing the need for knee injections by 63.4% compared with traditional exercise therapy alone.