Comparison of Anteromedial and Transtibial ACL Reconstruction Using Expandable Fixation

Abstract

The influence of anatomical or nonanatomical femoral tunnel position on tunnel widening and clinical outcomes in patients undergoing anterior cruciate ligament (ACL) reconstruction is not fully understood. This retrospective study examined the influence of tunnel width and placement on anterior knee stability and clinical outcomes after ACL reconstruction using the AperFix System (Cayenne Medical Inc, Scottsdale, Arizona), a direct expandable fixation technique with autologous hamstring grafts. The records of 80 patients (79 men and 1 woman) who underwent ACL reconstruction were evaluated. In 38 patients, anatomical femoral tunnel placement was performed via an accessory medial portal (anteromedial group); in the remaining 42 patients, the femoral tunnel was positioned nonanatomically using a transtibial technique (transtibial group). Mean follow-up was 40.7 months (range, 27-60 months). Postoperative knee kinetics were measured, and clinical outcomes were assessed using International Knee Documentation Committee, Lysholm, and Tegner scores. Femoral tunnel widening was measured by comparing postoperative radiographs with final follow-up radiographs. Femoral tunnel width was significantly greater (P<.001) and anterior knee translation was significantly higher (P=.01) in the transtibial group. Lysholm and Tegner scores were not significantly different (P>.05) between the 2 groups. These findings suggest that femoral tunnel widening is associated with increased anterior joint laxity when a direct fixation technique is used for ACL reconstruction, particularly in nonanatomically positioned femoral tunnels. Anatomical femoral tunnel placement provides better anterior stability and less tunnel widening than transtibial tunnel placement; however, these benefits did not produce a detectable advantage in clinical outcomes measures.