Abstract: Objective To evaluate the clinical effects of suture anchors on third-degree acute injury of medial collateral ligament（MCL） of knee joint. Methods Twenty-three patients（14 males,9 females） with third degree acute injury of MCL of knee joint were treated with suture anchors from January 2005 to March 2006.The time of injury to operation was 6-15 days,averaged 8 days. Results The patients were followed up for 14-19 months,averaged 15.7 months.The stability of knee joints was good in all patients.Abduction stress test was negative when the knee joint was straightened to 0 degree and flexed at 30 degree.The average Lysholm score was 89.Of the 23 patients,16 had an excellent score,4 had a good score,and 3 had a poor score. Conclusion Acute injury of MCL of knee joint can be repaired with suture anchors,which has the following advantages: small in tissue dissection,simple in procedure,and good in fixation.