The anterior cruciate ligament(ACL) is one of the main structures which have a stabilizing function of the knee. If a knee with a complete tear of ACL is not treated operatively, progressive instability develops, and the knee has a high risk of incurring meniscal is required. From March, 1989 to December 1992, we reconstructed ACL using patellar tendon with Kennedy-ligament augmentation device(LAD) in 26 patients. Nine patients had acute injuries and 17 patients had chronic rupture. In eleven patients operation was done arthroscopically, and in fifteen patients operation was done by arthrotomy. We used quadriceps tendon-patellar periosteum-patellar tendon in 16 cases and bone-patellar tendon-bone in ten cases. The length of follow-up ranged from 6 month to 33 months (mean; 10 months). We obtained satisfactory results in 22 cases.