Lower-Limb Coordination Responses to Knee Bracing in Females with Anterior Knee Pain

Background: Anterior Knee Pain (AKP) during running has been partially attributed to lower-limb kinematics. Mechanical deviances from asymptomatic cohorts at the hip, knee, shank and foot have been reported for joints and segments in isolation. Appraisal of lower-limb coordination and its variability may provide important insight into the role of proximal and distal lowerlimb joint and segment couplings during running with AKP. The extent to which current knee bracing strategies (standard-fit and custom-fit) for pain moderation influence lower-limb couplings may assist in the development of empirically informed recommendations for AKP management. The aim of this study was to investigate lower-extremity kinematic couplings of AKP participants during running without bracing and when wearing standardand custom-fit knee braces. Methods: Eighteen females (nine AKP, nine asymptomatic) performed ten running trials at a fixed speed (3.2 m·s-1) in a customfit knee brace, a standard-fit knee brace and no brace. Three-dimensional unilateral lower-limb kinematics data were obtained from which, joint and segment angles were calculated. Hip-knee, knee-ankle, thigh-shank and shank-foot coordination and coordination variability were determined using a modified vector coding technique. Results: AKP participants spent less time in knee internal rotation-dominant couplings (P < 0.05) and a greater proportion of stance in ankle eversion-dominant couplings (P = 0.01; ES = 0.62). Frontal plane hip-knee couplings were found to differ for AKP participants when wearing standardand custom-fit braces (P = 0.04; ES = 0.39). Overall, bracing conditions had the greatest influence on the asymptomatic cohort. No coordination variability differences were found between groups or conditions. Discussion: Participants with AKP ran with different lower-limb coordination strategies than their asymptomatic counterparts. Localized joint bracing (standardand custom-fit) did not oppose the coupling mechanics found in the AKP cohort when running in the unconstrained condition. It is therefore suggested that pain management strategies which consider the whole limb may be more effective than knee braces alone.