Anterior cruciate ligament graft fixation. Comparison of hamstring and patellar tendon grafts

Abstract

This study assessed the tensile properties of hamstring and patellar tendon anterior cruciate ligament reconstructions in older cadaveric knees (age range, 48 to 79 years). Mechanical testing to failure was conducted by translating the tibia anteriorly at 1 mm/sec with the knee in 20 degrees of flexion. The strongest gracilis-semitendinosus graft fixation technique (103% of intact anterior cruciate ligament) had the tendons doubled and secured with soft tissue washers (P < 0.01). However, all reconstructions using gracilis-semitendinosus grafts were significantly less stiff than the intact anterior cruciate ligament specimens regardless of fixation technique (P < 0.01). The highest strength patellar tendon graft fixation technique (84% of intact anterior cruciate ligament) was obtained with a combination interference screw and suture technique. The difference in stiffness between a patellar tendon graft and an intact anterior cruciate ligament was not significant when interference screws were placed at both ends of the graft (P > 0.05). Both types of grafts failed most often on the tibial side. With appropriate fixation, both grafts approximated the intact anterior cruciate ligament in strength, but only patellar tendon grafts secured with interference screws were comparable in stiffness.