Tensioning of the anterior cruciate ligament graft.

A great deal in variability exists in the protocols for graft tensioning. Biologic studies have not been conclusive about the optimum tension for revascularization while minimizing stress relaxation. Clinically, the risk of undertensioning the graft, and thereby not correcting the laxity, must be balanced with the risk of overconstraining the knee, which may lead to pathologic stresses on the joint cartilage, graft failure, or infrapatellar contracture syndrome . Amis and Jakob reported at the European Society of Sports Traumatology Knee Surgery and Arthroscopy scientific workshop in 1998 that most surgeons chose to impose a graft tension of 20 N to 80 N at an average of 11 degrees flexion. Preloading in full or nearly full extension limits the risk of pathologic stresses that can occur at full extension when the graft is tensioned at 30 degrees, but increases the risk of laxity at that angle. For our flexion parameters, we recommend tensioning the graft at 20 degrees to 30 degrees unless the graft tightens or shortens 5 mm or more with knee extension. If shortening occurs, tensioning should be performed in extension. The magnitude of graft tensioning should be tissue specific. For bone-patellar tendon-bone autograft or allograft, 5 pounds of tension should be applied. For hamstring graft, we apply 15 pounds of tension with each bundle tensioned individually.