Evaluating the effect of equipping an unloading knee orthosis with local muscle vibrators on clinical parameters, muscular activation level, and medial contact force in patients with medial knee osteoarthritis: A randomized trial

Background: Unloading knee orthosis is prescribed for people with unicompartmental knee osteoarthritis (OA) to unload the damaged compartment. However, despite its benefits, wearing unloading knee orthoses in the long term may decrease knee muscle activity and have a side effect on knee OA progression rate. Objectives: Therefore, this study aimed to determine whether equipping an unloading knee orthosis with local muscle vibrators improves its effectiveness in improving clinical parameters, medial contact force (MCF), and muscular activation levels. Methods: The authors performed a clinical evaluation on 14 participants (7 participants wearing vibratory unloading knee orthoses and 7 participants wearing conventional unloading knee orthoses) with medial knee OA. Results: Wearing both orthoses (vibratory and conventional) for 6 weeks significantly improved ( p < 0.05) the MCF, pain, symptoms, function, and quality of life compared with the baseline assessment. Compared with the baseline assessment, the vastus lateralis muscle activation level significantly increased ( p = 0.043) in the vibratory unloading knee orthoses group. The vibratory unloading knee orthoses significantly improved the second peak MCF, vastus medialis activation level, pain, and function compared with conventional unloading knee orthoses ( p < 0.05). Conclusions: Given the potential role of medial compartment loading in the medial knee OA progression rate, both types of unloading knee orthoses (vibratory and conventional) have a potential role in the conservative management of medial knee OA. However, equipping the unloading knee orthoses with local muscle vibrators can improve its effectiveness for clinical and biomechanical parameters and prevent the side effects of its long-term use.