This report presents the mid-term results of 55 cases of anterior cruciate ligament (ACL) lesions surgically treated in "acute phase" using intra-articular transfer of the semitendinosus and gracilis tendons, performed at the First Orthopedic Clinic of "La Sapienza" University in Rome since 1979. The follow-up is based on clinical (point system comprising subjective and objective criteria), instrumental (KT-1000 arthrometer), and radiographic (comparative AP view radiographic exam of the knees under load) data. On the basis of the results obtained, ACL reconstruction with the semitendinosus and gracilis tendons in the treatment of acute lesions can provide the patient with a good possibility of complete functional recovery of the knee.