The transtibial approach is widely used for femoral tunnel positioning in ACL reconstruction. Controversy exists over the superiority of this approach over others. Few studies reflected on the reproducibility rates of the femoral tunnel position in relation to the approach used. We reviewed AP and Lat X-ray radiographs post isolated ACL reconstruction for 180 patients for femoral tunnel position, tibial tunnel position and graft inclination angle. All patients had their operations performed by one surgeon in one hospital between March 2006 and Sep 2010. All operations were performed using one standard technique using transtibial approach for femoral tunnel positioning. Two orthopaedic fellows, with similar experiences, reviewed blinded radiographs. A second reading was done 8 weeks later. Pearson inter-observer, intra-observer correlation and Bland-Altman agreements plots statistical analyses were done. Mean age was 29 years (range 16–54), Pearson intra-observer correlation shows substantial to perfect agreement while Pearson's inter-observer correlation shows moderate to substantial agreement. Previous literature proved that optimal femoral tunnel position for the best clinical and biomechanical outcome is for the centre of the tunnel to be at 43% from the lateral end of the width of the femoral condyles on the AP view and at 86% from the anterior end of the Blumensaat's line on the lateral view. In our study 85% of the femoral tunnels were within +/− 5% of the optimal tunnel position on the AP views, and more than 70% of the femoral tunnels were within +/−5% of the optimal tunnel position on the Lateral view. Interobserver and intraobserver corelations show moderate to substantial agreement, Bland-Altman agreement plots show substantial agreements for interobserver and intraobserver measurements. These results were found to be statistically significant at 0.01 Based on our results we conclude that using one standardised transtibial technique for ACL reconstruction can result in high reproducibility rates of optimal femoral tunnel position. Further studies are needed to validate our results and to study the reproducibility rates for different approaches and techniques.
