BACKGROUND: Both open and closed kinetic chain exercises can be applied to meniscal lesions in the knee joint, but their mechanisms are different. There is still no clinical report on the improvement of meniscus lesions by the two exercise methods. OBJECTIVE: To observe the effects of open kinetic chain exercise and closed kinetic chain exercise on meniscus lesions in young patients. METHODS: Forty-nine young patients with meniscus lesions were treated with rehabilitation and conservative treatments. They were randomly divided into two groups using a random digital table method: a biofeedback open kinetic chain group (n=25) treated with basic therapy combined with terminal knee extension biofeedback training, and a leg press closed kinetic chain group (n=24) treated with basic therapy combined with single-leg press training. The basic treatment included electro-acupuncture, manipulation therapy and unarmed exercise therapy. Biofeedback open chain training was conducted with Myotrac infinitie biofeedback instrument produced by Thought, Canada. Closed chain training with leg press was conducted using pedal accessories of GYM80 intelligent strength training system, Germany. All the trainings were conducted once a day for 3 consecutive weeks. Curative effects were assessed by joint range of motion (ROM) during knee joint flexion and extension, total ROM, visual analogue scale score, modified Lysholm knee score, and activity of daily Iiving score. The study protocol was implemented in line with the relevant requirements of Sichuan Provincial Orthopedic Hospital. All the patients were informed of the study procedures. RESULTS AND CONCLUSION: Assessment for ROM: After treatment, the ROM during joint flexion and extension and total ROM in the biofeedback open kinetic chain group were significantly better than the baseline (P < 0.05), the ROM during joint extension and total ROM in the leg press closed kinetic chain group were significantly better than the baseline (P < 0.05), and the ROM in the biofeedback open kinetic chain group was higher than that in the leg press closed kinetic chain group, but there was no significant difference between two groups (P > 0.05). Assessment for pain and function: The two groups had statistically significant improvements on visual analogue scale score, modified Lysholm knee score, and activity of daily living score after treatment (P < 0.05). Compared with the biofeedback open kinetic chain group, the activity of daily living score was higher in the leg press closed kinetic chain group (P < 0.05). The two groups had satisfactory effects on the knee joint ROM, pain and functional performance. Therefore, biofeedback open kinetic chain exercise has a better improvement on the knee joint ROM, while the leg press closed kinetic chain exercise shows better outcomes in the improvement of knee functional performance and activity of daily living based on the basis of pain control. [ABSTRACT FROM AUTHOR]