Objective: To analyze the traumatic pathological characteristics of posterolateral dislocation of knee joints and its treatment.Methods: Nine cases of posterolateral dislocation of knee joint, 5 cases of fresh injuries (the fresh injury group) and 4 cases of old injuries ( the old injury group) were reviewed and analyzed. In the fresh injury group 4 cases failed in close reduction due to "buttonholing" through the medial joint, among them 3 cases underwent repair of the damaged ligaments. In the old injury group 2 cases underwent ACL and MCL repair only in acute stage, but re-dislocated. Of the rest 2 cases 1 was associated with peroneal nerve injury and the other was not treated in acute stage. One case was associated with comminuted fracture of the tibial condyle and popliteal artery injury. Open reduction was performed in 3 cases. One case was fixed with 2-crossed pin and another was fixed with one pin through the tibial and femoral condyle and second pin with olecranization fixation. Plaster immobilization for 6-8 weeks respectively was required. In the old injury group in 1 case ACL and PCL repair ( Augustine method ) and posterolateral structure were performed and olecranization fixation and plaster immobilization for 6 weeks was needed.Arthrodesis of the knee was done for the patient with comminuted fracture of the tibial condyle and popliteal artery injury.Results: All the cases were followed up for 1-23 years ( average 6 years). Knee stability in 4 cases with repair of the ligaments was improved, although PDT showed ( + ) with different degrees. The results of the patients treated with ligamentous reconstruction were much better than those of the patients without any repair. Conclusions: Well understanding of the traumatic pathological characteristics, repair of the damaged ligaments, augmentation of olecranization fixation and postoperative immobilization for 6 weeks are the key points of successful treatment.