Divergence in Femoral Tunnel during Arthroscopic Single Incision Anterior Cruciate Ligament Reconstruction Using by Bone - Patellar Tendon - Bone

Kang, Chung Nam; Kim, Dong Wook; Yoo, Jae Doo

Abstract

Divergent placement of the femoral interference screw has been described as a major pitfall in single incision endoscopic reconstruction of the anterior cruciate ligament. This study reviews the radiographic results in 30 consecutive endoscopic single-incision ACL reconstructions using interference screw fixation to find a method to reduce the divergent femoral screw fixation. We measured the angles which were determined by a line through axis of femoral bone block and axis of interference screw in anteroposterior and lateral view of knee(APD/LD),through axis of femoral tunnel and axis of tibial tunnel in the full extension-anteroposterior view(AFT),through the longitudinal axis of distal femoral shaft and axis of femoral tunnel in the anteroposterior and lateral view(APFT/LFT). Average LD(4.96+/-62degrees) was significantly larger than average APD(1.303+/-13degrees) (P=0.008). Significant correlation was present between APD and APFT(g=-0.3882, P=0.034), between LD and LFT(gamma=0.6933, P=0.000) and other variables had no significant correlation. The femoral divergence in the anteroposterior plane occurred in the case with small angle between longitudinal axis of femoral shaft and that of femoral tunnel, and vice versa in lateral plane. During drilling of femoral tunnel, more than 90 flexion causes LFT to increase and the risk of femoral divergence increases. Therefore, in the anteroposterior plane, angle between femoral tunnel and longitudinal axis of femoral shaft shoud be made as large as possible and flexion of knee should not be more than 90 during drilling of femoral tunnel.