Accuracy of femoral tunnel placement using three different techniques in performing arthroscopic all-inside anterior Cruciate Ligament reconstruction; A randomized study

Background

One of the key steps in arthroscopic Anterior Cruciate Ligament Reconstruction (ACLR) is getting the femoral tunnel at the right position to attach the graft. While the correct position has been described as a low and posterior position behind the bifurcate ridge on the medial surface of lateral femoral condyle, to reproducibly achieve it more than one technique is being used by surgeons. There are no randomized studies in literature which have evaluated the efficacy of these in a surgeon's hand. This study attempts to do that.

Methods

This randomized study was performed at a military sports injury centre by a single surgical team led by two sports fellowship-trained surgeons. One hundred fifty patients undergoing ACLR surgery were randomized to Anteromedial Portal technique e (AMP)group, Far Anteromedial portal technique (FAMP) group and Outside in drilling (OI) group. We used postoperative three-dimensional Computed Tomogram (3D CT) to study tunnel position (Magnussen method), length and orientation (Basdekis method).

Results

80 % of femoral entry points were in satisfactory position using all three techniques. The ideal position was achieved more often using FAMP & OI technique which was better than AMP, however it was not below level of significance set at P < 0.025 (18, 13 & 5 respectively using FAMP, OI and AMP techniques, p-value 0.08 OI vs AMP & 0.07 AMP vs FAMP). The average femoral tunnel length was longest in OI group 34.72 ± 2.41 mm. The mean FAMP tunnel lengths were significantly smaller than the mean tunnel length of AMP and OI groups. (p-value <0.01 FAMP vs OI and p-value <0.01 FAMP vs AMP)

Conclusion

Our study showed that all three techniques achieved acceptable femoral tunnel placement in 80 % cases. However, FAMP and OI technique further improved accuracy of achieving ideal tunnel location and OI technique predictably achieved longer tunnel length preventing risk of lateral blow out while using suspensory fixation.