Effects of different femoral tunnel positions on tension changes in anterolateral ligament reconstruction.

PURPOSE: Several kinds of anterolateral ligament (ALL) reconstructions to augment intra-articular anterior cruciate ligament reconstruction to better control anterolateral rotational instability (ALRI) have been reported. However, the optimal femoral attachment site for ALL reconstruction is still unclear. The purpose of this study was to investigate the effects of different femoral attachment sites on the tension changes through knee motions in different situations in order to determine a recommended femoral attachment site for ALL reconstruction.

METHODS: Six fresh-frozen cadaveric knees were included. ALL reconstructions were performed with three different femoral attachment sites (F1: 2 mm anterior and 2 mm distal to the lateral epicondyle, F2: 4 mm posterior and 8 mm proximal to the lateral epicondyle and F3: position for the lateral extra-articular tenodesis). The graft tension changes were measured by a graft tensioning system during knee flexion-extension and manual maximum internal/external tibial rotation in the following situations: (1) intact, (2) ALL cut, (3) ALL and ACL cut and (4) ALL cut and ACL reconstructed. Effects of the different femoral attachment sites, the route superficial or deep to the LCL, and the situations of (1) to (4) were calculated via repeated-measures analysis of variance.

RESULTS: The tension of F1 was higher in flexion and lower in extension, whereas the tension of F2 and F3 was higher in extension and lower in flexion. F2 showed the smallest tension change. Situations of (1) to (4) did not affect tension changes. The graft tension became higher with internal rotation and lower with external rotation regardless of femoral attachment sites or situations.

CONCLUSION: With F2-4 mm posterior and 8 mm proximal to the lateral epicondyle-the reconstructed ALL had the least tension change with only a slight increase in tension as the knee extended. This result indicates that F2 is recommended for ALL reconstruction to better control ALRI, which will help determine the optimal femoral tunnel position for ALL reconstruction.