Anteromedial Portal Versus Outside-In Technique for Creating Femoral Tunnels in Anatomic Anterior Cruciate Ligament Reconstructions

Purpose: To determine whether the anteromedial (AM) portal and outside-in techniques in anterior cruciate ligament reconstruction differ (1) in the coronal femoral tunnel position, (2) in the femoral tunnel length, and (3) in the incidence of femoral tunnel-related complications, such as femoral socket blowout. Methods: We examined 63 knees undergone primary anterior cruciate ligament reconstructions using the AM portal technique (AM portal group) and 54 knees using the outside-in technique (outside-in group). Coronal femoral tunnel positions between the 2 groups were assessed on postoperative tunnel-view radiographs and compared. Comparisons of femoral tunnel lengths, proportions of knees with a femoral tunnel length of less than 30 mm, and incidences of femoral tunnel-related complications were performed between the 2 groups. Results: There were no significant differences in coronal femoral tunnel positions between the AM portal and outside-in groups (56.6 degrees v 56.4 degrees, P > .99). Differences in femoral tunnel lengths between the AM portal and outside-in groups did not reach statistical significance (37.6 mm and 39.0 mm, respectively; P = .097), but the tunnel length of the outside-in group showed smaller variation than that of the AM portal group in terms of standard deviation (2.7 v 6.0). In addition, the AM portal group had a significantly greater proportion of knees with a femoral tunnel length of less than 30 mm than the outside-in group (14% v 0%, P = .004). There were 2 tunnel-related complications (3%) (highly suspicious cortical blowouts) in the AM portal group and none in the outside-in group (P = .499). Conclusions: This study shows that compared with the AM portal technique, the outside-in technique can achieve a similar femoral tunnel position in the coronal plane with a reduced chance of a femoral tunnel length of less than 30 mm. Level of Evidence: Level IV, therapeutic case series.