Abstract: Objective To observe the therapeutic effect of platelet-rich plasma combined with isokinetic muscle strength training on knee osteoarthritis and the changes in cartilage thickness. Methods Sixty eligible knee osteoarthritis patients admitted to the Gansu Provincial Hospital of Traditional Chinese Medicine from October 2021 to September 2023 were randomly divided into a control group of 32 cases and a observation group of 28 cases. The control group was treated with sodium hyaluronate injection combined with conventional muscle strength training, while the observation group was treated with autologous platelet-rich plasma injection combined with isokinetic muscle strength training. Western Ontarioand McMaster University Osteoarthritis Index (WOMAC) evaluation was performed on patients before treatment and 4 weeks and 6 months after treatment. The peak torque (PT) of the 60°/s and 90°/s extensor muscles on the affected knee joint was evaluated using an isokinetic muscle strength testing system, and the average thickness of the patient's articular cartilage was evaluated using an ultrasound diagnostic instrument. Results After 4 weeks and 6 months of treatment, the WOMAC score and isokinetic measurements of knee extensor muscles at 60°/s and 90°/s in both groups were better than before treatment (P<0.05). Compared between the two groups, the observation group showed better results than the control group (P<0.05). After 6 months of treatment, the average knee cartilage thickness in the observation group was better than before treatment and the control group (P<0.05). Conclusion The combination of platelet-rich plasma and isokinetic muscle strength training can effectively improve knee joint function, extensor muscle strength, and protect joint cartilage in patients with knee osteoarthritis.

Key words: knee osteoarthritis, platelet-rich plasma, isokinetic muscle strength