Objective To evaluate the clinical effect of protecting the saphenous nerve with the suture anchor on repairing the medial collateral ligament injury of the knee joint. Methods From June 2014 to June 2016, 48 cases of medial collateral ligament injuries of the knee joint were repaired with suture anchors of the saphenous nerve in the 107th Hospital of PLA. Results All patients were followed up for 12-18 months, with an average of 14.6 months. All the patients were followed up with good stability of the knee joint. The 30 degree flexion stress test of the knee joint showed that 2 cases were positive forⅠdegree, and the stress test of the extension position was negative. The X-ray examination showed that the internal and external articular space of the knee joint was symmetrical and good, and the anchors did not loose or move in the bone. The average knee flexion before operation was (43.19 ± 2.60)°, and 1 year after operation was (135.62 ± 3.68) °. And the flexion of knee 1 year after operation was higher than that before operation (t=5.37, P<0.01). The Lysholm score was (43.19 ± 2.60) points before operation, and 1 year after operation was (93.69 ± 5.39) points, and the postoperative score was higher than that before operation (t=4.85, P<0.01). The grade of efficacy was excellent in 42 cases, good in 4 cases, fair in 2 cases, and the excellent and good rate was 95.8％(46/48). Conclusions The repair of medial collateral ligament injury with suture anchors under the protection of the hidden nerve can effectively prevent the symptoms of numbness in the medial area of the knee joint. It is simple, fixed and can be repaired under direct vision. It is reliable to restore the strength of the ligament and maintain the stability of the medial knee joint. It is worthy of clinical push and wide application.