Effects of Massage on Pain, Muscle Co-Contraction, and Knee Loading in Medial Knee Osteoarthritis: A Randomized Controlled Trial Protocol

Background: Increased joint loading and muscle co-contraction during gait contribute to the progression of knee osteoarthritis (OA). Although massage benefits for knee OA are documented, evidence based on objective biomechanical outcomes remains limited. This study aims to investigate the effects of massage on pain, muscle co-contraction and joint loading after a 12-week intervention in patients with medial knee OA. Methods/Design: This parallel, two-arm randomized controlled trial will enroll 56 participants with medial knee OA. Participants will be randomly assigned to either a Massage group or a Healthcare Education group for a 12-week intervention delivered twice weekly. The massage protocol will use standardized Shi’s manual therapy techniques targeting periarticular knee soft tissues, including the quadriceps, hamstrings, and surrounding structures. The primary outcome is the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes include WOMAC stiffness and function, antagonist muscle co-contraction, knee kinetics and kinematics (including the external knee adduction moment [EKAM]), and temporospatial gait parameters. Outcomes will be assessed at baseline and after the 12-week intervention. Discussion: This is the first randomized controlled trial to simultaneously evaluate the midterm (12-week) effects of massage on pain, muscle co-contraction and EKAM. The findings may provide novel evidence on the biomechanical mechanisms of massage beyond traditional subjective assessments and have important implications for developing individualized, mechanism-oriented rehabilitation strategies. Trial Registration: International Traditional Medicine Clinical Trial Registry: ITMCTR2025001524. Keywords: knee osteoarthritis, muscle co-contraction, knee loading, massage, randomized controlled trial