63 patients were randomized to determine the effectiveness of hyperthermia induced by microwave diathermy in treating sufferers of knee osteoarthritis. Patients were allocated to receive 30-minute sessions of either microwave diathermy at a frequency of 433.92 MHz or sham treatment three times per week for four weeks. Follow-up evaluation was conducted at the end of the therapy phase (4 weeks), and also at 16 weeks for outcomes of pain, stiffness, and function. The results indicated that patient-reported WOMAC and performance-based Timed-Up and Go test outcomes were significantly improved in those who received heat therapy compared to sham treatment patients.