• In patients with unilateral knee osteoarthritis, the affected medial and lateral thigh muscles show significantly reduced activation and efficiency, with higher fatigue risk and unbalanced activation.
• The affected tibialis anterior and gastrocnemius muscles exhibit compensatory activation and abnormal co-activation, with the tibialis anterior showing the most pronounced compensation and increased fatigue risk.
• Surface electromyography reveals that the affected side has lower muscle activation ratios, indicating impaired neuromuscular control and potential for muscle atrophy.
• These findings highlight the need for targeted rehabilitation to address muscle imbalances and fatigue in knee osteoarthritis patients.