Anterior cruciate ligament graft rotation. Reproduction of normal graft rotation.

The purpose of this study was to determine normal rotation of the anterior cruciate ligament and to provide a technique for reproduction of this rotation. Ten fresh-frozen knees were dissected of all soft tissue except for the anterior cruciate ligament. Specimens were secured in a vise in 60 degrees of flexion. Each tibia was allowed to spin freely on the femur, and rotation was recorded. Anterior cruciate ligament reconstructions, using bone-patellar tendon-bone grafts, were then performed on all specimens using four graft rotations. Each specimen was then tested to assess how the graft twist affected tibial rotation. The average tibial rotation of the normal anterior cruciate ligaments was 55 degrees internally. Previous descriptions of anterior cruciate ligament reconstructions have advocated medial or internal rotation of the graft to reproduce normal anatomic rotation of the anterior cruciate ligament. Our cadaveric dissections have demonstrated that the anterior cruciate ligament normally produces internal rotation of the tibia in relation to the femur. Reproduction of this anatomic rotation is accomplished with 90 degrees of lateral rotation of the tibial plug toward the fibula.