Immediate effects of valgus bracing on knee joint moments during walking in knee-healthy individuals: Potential modifying effects of body height

• Published in: Gait & posture 2020-07, Vol.80, p.383-390
• Main Authors: Pua, Yong-Hao, Tan, Hong-Han, Mentiplay, Benjamin F, Lim, Leon Zhi-Xia, Tham, Asher Chi-Weng, Quek, Joshua Jia-En, Woon, Ee-Lin, Yeh, Ting-Ting, Tan, Celia Ia-Choo, Hunt, Michael A, Clark, Ross Allan
• Format: Article
• Language: English
• Subjects: Adult; Biomechanical Phenomena; Body Height; Braces; Cross-Over Studies; Female; Gait Analysis; Healthy Volunteers; Heel; Humans; Knee; Knee adduction moment; Knee Joint - physiology; Male; Motion capture; Range of Motion, Articular; Valgus bracing; Walking; Young Adult
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2020.06.025

•Valgus bracing did not significantly reduce various KAM measures during walking.•Body height may play a moderating role in reduction of KAM in valgus bracing.•Reduction in KAM with brace use was more pronounced with lower body height.•Consideration of body height could be critical to design of effective knee braces. The goal of valgus knee brace treatment is to reduce medial knee joint loading during walking, often indicated by external knee adduction moment (KAM) measures. However, existing healthy-subjects studies have been equivocal in demonstrating KAM reduction with valgus knee bracing. What are the immediate effects of valgus bracing at different tension levels on KAM during walking at a controlled speed and does body height modify the brace-KAM associations? Data from 32 knee-healthy participants were analysed in this randomized crossover trial. Participants performed walking trials at controlled speed (1.3 ± 0.065 m/s) both with and without an Ossür Unloader One® brace. During the bracing condition, valgus tension was incrementally increased, from zero tension to normal tension and to maximum tolerable tension. Valgus bracing minimally increased knee flexion at heel-strike (P < 0.001) in a dose-dependent manner and minimally reduced gait velocity (∼0.015m/s) across all tension levels. Valgus bracing, overall, did not significantly reduce the various KAM measures. However, brace use at maximal tension was associated with a 0.04Nm/kg (9.2 %) increase in first peak KAM amongst participants with a body height of 1.75 m and a 0.03Nm/kg (7.6 %) decrease in first peak KAM amongst participants with a body height of 1.55 m. Valgus bracing did not reduce the various KAM measures during walking; however, body height may play a moderating role. Given knee brace sizes vary more in circumference than length, this result may be due to the ratio between effective moment arm length relative to limb length. A deeper understanding of the potential neuro-biomechanical effects of valgus knee bracing and how these effects are potentially modified by body height may be critical to the design of effective knee braces.