Effects of Blood-Flow Restricted Resistance Exercise Versus Neuromuscular Exercise on Self-Perceived Knee Pain, Function, Quality of Life, and Objective Measures of Functional Performance and Pain Sensitization in Adults With Knee Osteoarthritis-A Randomized Controlled Trial

Standard rehabilitation for knee osteoarthritis (knee-OA) combines patient education and neuromuscular exercises (NEMEX). Heavy-load resistance training (HLRT) has shown positive effects on pain, functionality, and muscle mass, but can be painful with knee-OA. Low-load blood-flow restricted resistance exercise (BFR-RE) has shown comparable effects to HLRT without promoting exercise-induced pain. Therefore, the present study examined the effect of BFR-RE vs. NEMEX on self-perceived knee pain, functional performance, and pain sensitization in knee-OA individuals. Ninety-six participants (age 56.7 ± 7.6; 49 females, 47 males) with symptomatic knee-OA were randomized to 12 weeks biweekly BFR-RE or NEMEX. BFR-RE was performed at 60%-80% of total arterial occlusion pressure. Control participants completed a 12-week NEMEX program. Both groups also attended patient education. Primary outcome: Change in the Knee injury and Osteoarthritis Outcome Score (KOOS) pain subscale from baseline to 12 weeks. Secondary outcomes: Remaining KOOS subscales, Oxford Knee Score (OKS), 30-s sit-to-stand (STS), STS power, 4 × 10 m fast-paced walking (4 × 10 m-FWT), stair climb test (SCT), spreading and local pain sensitization measured as pressure pain thresholds (PPT). No significant between-group difference in the change in KOOS-Pain was observed (+6.4 points, 95% CI = -1.0-13.7, effect size (ES) = 0.35, p = 0.07) or the remaining KOOS subscales and OKS (ES = 0.05-0.20, p > 0.05). BFR-RE demonstrated greater improvements than NEMEX for all functional outcomes (STS, STS power, 4 × 10 m FWT, SCT) (ES = 0.89-1.56, p < 0.01) and spreading sensitization (ES = 0.43-0.55, p < 0.05). BFR-RE and NEMEX were equally effective in reducing knee pain, while BFR-RE achieved greater statistical gains in functional performance and improved spreading sensitization in persons with moderate knee-OA. The enhanced improvements with BFR-RE compared to NEMEX represent novel insights that should be considered in future treatments of knee-OA.