The posterior cruciate ligament is an anatomically and biomechanically complex structure. PCL injuries are reported to occur in 1-40% of acute knee injuries, with isolated PCL tear, less common than PCL tears combined with other Iigament injuries. Controversy exists concerning the geatment of the PCL injures. Recently, arthroscopic techniques of PCL reconstruction are becoming nore refined and reproducible. Between July 1993 and May 1995, 25 operations for PCL rupture were performed in our hospital. At the follow-up examinations we noted mild to moderate posterior instablilty which was not noted at the time of operation and during the immediate postoperative period. We reviewed type (if injuries, amplitude of initial posterior tibia1 translation, surgical techniques, which seemcd to be in relation ivith the postoperative instabilities. At final follow-up, the mean Lysholm knee score was 86 points, and the posterior tibial translation 6.5mm on posterior stress radiographs. The ligament augmentation device provided no benefit. The ideal positioning and fixation of the graft and protection of the graft from abrasion seemed to be important to get a good results.