Decreased pain and improved dynamic knee instability mediate the beneficial effect of wearing a soft knee brace on activity limitations in persons with knee osteoarthritis

OBJECTIVE: To evaluate whether improvement of proprioception, pain or dynamic knee instability mediate the effect of wearing a soft knee brace on activity limitations in persons with knee osteoarthritis (OA). METHODS: Exploratory analysis from 44 participants with knee OA and self-reported knee instability in a laboratory trial evaluating the effect of wearing a commercially available soft knee brace. Activity limitations were assessed with the 10-meter walk test and the Get up and Go test. Knee joint proprioception was assessed by an active joint position sense test; pain was assessed with the Numeric Rating Scale (NRS); pressure pain threshold (PPT) was assessed with a hand-held pressure algometer; dynamic knee instability was expressed by the Perturbation Response, i.e. a measure reflecting a deviation in mean knee varus-valgus angle after a controlled mechanical perturbation on a treadmill, with respect to level walking. Mediation analysis was conducted with the product of coefficients approach. Confidence intervals were calculated with a bootstrap procedure. RESULTS: A decrease of pain (NRS) and a decrease of dynamic knee instability mediated the effect of wearing a soft knee brace on reduction of activity limitations (p 0.05). CONCLUSION: This study shows that decreased pain and reduced dynamic knee instability are pathways via which wearing a soft knee brace decreased activity limitations in persons with knee OA. This article is protected by copyright. All rights reserved.