A modified Marshall-Macintosh technique for anterior cruciate ligament (ACL) substitution is described. The graft is fashioned from the mid 50% to 60% of the patellar tendon extending to include prepatellar retinaculum and quadriceps tendon. A free tendon graft from the quadriceps tendon is used to reinforce the patellar tendon and retinaculum so that the graft is larger than the normal ACL. The graft is placed intraarticularly through isometric drill holes in the tibia and femur, then passed isometrically beneath the lateral collateral ligament, anchoring to Gerdy's tubercle for extraarticular reinforcement. An accelerated and aggressive knee rehabilitation program that has been employed with this surgical technique is described. Short-term results in 64 cases are encouraging.