A prospective, randomized study comparing arthroscopic and open anterior cruciate ligament (ACL) reconstructions was undertaken. Neither the patients nor the physical therapists were made aware of which technique was used. The central one third of the patellar tendon with proximal and distal bone plugs was utilized as the graft material to reconstruct the ACL in all cases. Rehabilitation was identical for each group. The following variables were compared: postoperative pain score, operating time, estimated blood loss (EBL), quantity of analgesics used, complications, range of motion at 1, 3, and 6 months, a 6-month evaluation consisting of Lachman's, anterior drawer, and pivot shift tests, amount of thigh atrophy, and Cybex II tests. Statistical significance was achieved (P < .05) in only three parameters. The 1-month postoperative range of motion, the 6-month postoperative thigh atrophy, and the Cybex II test (knee extension at 60 degrees/sec) were statistically different favoring the arthroscopic method.