Healing of the proximal bone clock in anterior cruciate ligament reconstruction with bone-patellar-tendon-bone graft - a CT-controlled study

Anterior cruciate ligament (ACL) reconstruction with the middle third of the patellar ligament is a widely used method to re-establish knee function after ACL-injury. However, there is still considerable debate about the operative technique and graft fixation The goal of this study was to evaluate ACL-reconstruction with bone-patellar tendon-bone (BPTB) graft and femoral fixation with endobutton clinically as well as to evaluate bone tunnel placement and tunnel morphology with CT and x-ray. 51 patients, who had undergone ACL-reconstruction with BPTB-graft and fixation with Endobutton, were evaluated clinically. In 51 cases standard x-ray films - anterior-posterior (AP) and lateral - and in 50 cases computed tomography (CT) scans were obtained. Femoral tunnel placement was measured with a three-dimensional coordinate system on both x-ray films and CT scans. Tunnel widening and bone block healing where determined with CT on both the femoral and the tibial side. 40 patients had a normal or nearly normal knee function, 6 patients scored abnormal and none of the patients was rated severely abonormal according to the International Knee Documentation Committee (IKDC) form. Tunnel placement could not be determined on plain x-rays in 46 cases on the AP-films and in 8 cases on the lateral films. Average position: AP: 89,8 %, lateral: 38,5 %. On CT-scans the position could be measured in all 50 cases. Average position CT: AP: 90,5 %, lateral: 34,1 %. Tunnel widening on the femoral side was < 10 % in 36 cases, 10-20 % in 9 cases and 20-40 % in 4 cases. On the tibial side 20 patients showed an enlargement of < 10 %, and only 2 patients with > 40 % tunnel widening where obtained. Femoral bone block healing was complete in all cases. This operative technique shows good clinical results, which are comparable to other studies on ACL-reconstruction with BPTB-grafts. Suspensory femoral fixation with Endobutton does not cause any significant tunnel widening as it was reported when using the same fixation but hamstring grafts. Average tunnel position was comparable to other studies. However, CT scans are superior to plain radiographs when determining tunnel position. (author)