Graft Failure of Reconstructed Anterior Cruciate Ligament Using Hamstrings

We have performed 181 anterior cruciate ligament (ACL) reconstructions using hamstrings from 1997 to 2001 in our hospital. The purpose of this study was to clarify the cause of graft failure of reconstructed ACL.There were 4 patients (2.2%) with recurrent instability due to graft failure. All patients were male, and their mean age was 18.8 years at primary ACL reconstruction. We used four-strand graft of semitendinosus tendon in these patients, and isometry was less than 4mm at surgery. We measured the position of the tibial tunnel on postoperative lateral X-ray. Inadequate anterior positions were observed in 2 patients. Before re-rupture, the KT-2000 arthrometer showed the average side-to-side difference to be 2.7mm. High intensity signal on magnetic resonance imaging (MRI) was observed within the reconstructed ACL graft in 3 patients. Three patients had minor injury less than 1 year after surgery. The main causes of graft failure were considered to be graft impingement and failure of graft incorporation. Graft impingement can be avoided by properly positioning the bone tunnel and performing adequate notchplasty. The cause of failure of graft incorporation was not clarified clinically. It is necessary to carefully examine patients who suffer minor injury less than 1 year or show high intensity on MRI after reconstruction.