Is screw divergence in femoral bone-tendon-bone graft fixation avoidable in anterior cruciate ligament reconstruction using a single-incision technique? A radiographically controlled cadaver study.

Interference screw fixation of patellar tendon bone-tendon-bone grafts for anterior cruciate ligament reconstruction has proven to be a method with high pullout strength if screw divergence is avoided. Twenty-four fresh-frozen cadaveric human knees were used to identify the ideal position for a portal and an optimal knee flexion angle to obtain parallel placement of screw and bone block. On all specimens, anterior cruciate ligament reconstruction was performed using a single-incision technique. In the first part of this study, screw placement was analyzed in the frontal plane. In the second part, screw placement was investigated in the sagittal plane, measuring the additional flexion required between femoral tunnel drilling (at 60 degrees of knee flexion) and screw insertion to obtain parallel screw placement. For both part I and II, image intensification was used. In the third part, femoral screw placement was carried out through a paraligamentous approach and with additional flexion of 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, and 60 degrees. This study shows that screw placement with minimal divergence in the frontal and sagittal planes can be achieved by inserting the screw through a nearly central portal and flexing the knee an additional 35 degrees to 40 degrees.