Nineteen patients who had a posterior cruciate ligament injury on the 20 knee that are treated by surgical operation, between 1986 and 1991 at St. Pauls Hospital were analyzed. The results are as follows; 1. There are eighteen males and one female. The mean age of operation was 31.9 years, range between 22 to 58 years old. 2. The average follow up periods was 18 months, range of 12 to 76 months of follow-up periods. 3. Eight cases of knee had isolated posterior cruciate ligament injuries, and twelve had combined injuries. 4. In posterior cruciate ligament avulsion injuries show better results. 5. The objective and functional results were good within 62% and 87%, respectively in isolated posterior cruciate ligament injuries and 58% and 75%, respectively in combined injuries. In this study, shown better after surgery in cases of isolated posterior cruciate ligament injuries than those of combined injuries.