Objective To evaluate the surgical treatment of the acute posterolateral complex(PLC)injuries of knee joint and then observe the clinical outcome.Methods Twelve cases(12 knees)of acute PLC injuries were treated from May 2006 to October 2008.Patients' age ranged from 23 to 47 years old,average 31 years.There were 9 males and 3 females.Rebuild the anterior cruciate ligament(ACL)and posterior cruciate ligament(PCL)under arthroscope and then,locally suture the PLC injuries sites on those patients with PLC avulsion fraction.If there is PLC rupture,then locally suture the injury sites plus PLC reconstruction.Knee functions were evaluated by IKDC and Lysholm score.Results All patients were followed up for 12-18 months(mean,13.3 months).The preoperative range of motion was 118.00°±6.77°,which was 130.75°±3.05° after surgery.KT-1000 arthrometer measurement showed that the average posterior translation improved from(14.85+1.83)mm preoperatively to(4.18±1.88)mm postoperatively.Seven cases were normal(A grade),3 cases were nearly normal(B grade),1 abnormal(C grade),and 1 severely abnormal(D grade)according to IKDC standard.The preoperative Lysholm joint function score was 35-44,average 38.83 ±3.16,which was 79-91,average 84.92±3.73 after surgery.Conclusion To those acute PLC injuries with avulsion at the ligament extremities,locally suture should be taken.But for those with PLC rupture at the mid part of ligament,locally suture the injury sites plus PLC reconstruction helps get satisfactory outcome.