Among the various surgical procedures for correcting knee instability after ACL injury, the standard method of treatment is intra-articular ACL reconstruction with autogenous tissues. The bone-patellar tendon-bone autograft had been traditionally considered as the gold-standard surgical option. However, in an effort to minimize the donor-site morbidity associated to its harvest, semitendinosus tendon (ST) and gracilis tendon (GT) are increasingly used for ACL reconstruction. The doubled ST and GT grafts have greater mechanical strength than a bone-patellar tendonbone complex [ 22 ], and the donor-site morbidity