Tunnel widening after anterior cruciate ligament reconstruction: a prospective randomized computed tomography--based study comparing 2 different femoral fixation methods for hamstring graft

Abstract

Purpose: We prospectively sought to compare the incidence and properties of tunnel widening in patients undergoing anterior cruciate ligament reconstruction with quadrupled hamstring graft by use of either EndoButton CL (Smith & Nephew Endoscopy, Andover, MA) or Transfix (Arthrex, Naples, FL) on the femoral side with a bioabsorbable interference screw in the tibial tunnel by computed tomography scan.

Methods: We included 34 patients in the study and randomized them into 2 groups--EndoButton and Transfix groups. An anteromedial portal technique was used to create the femoral tunnels in the EndoButton group, whereas a transtibial technique was used in the Transfix group. A bioabsorbable screw was used on the tibial side in both groups. Thirty patients completed the study protocol, and assessment was done at regular intervals until 12 months of follow-up was reached. The patients underwent computed tomography scans at 2 weeks, 3 months, and 6 months postoperatively. The diameters of the tunnels were measured perpendicular to the long axis of the tunnels on oblique coronal and oblique sagittal planes at 3 levels: aperture, midway, and suspension point. We performed functional scoring with the International Knee Documentation Committee 2000 Subjective Knee Evaluation score and Lysholm score.

Results: Femoral tunnel widening at the aperture and at midway was significantly greater in the EndoButton group compared with the Transfix group. A decrease in the loop length in the EndoButton group was associated with lesser tunnel widening, although this was not found to be statistically significant with the numbers available. A trend toward decreased tunnel widening at the aperture on the tibial side was observed when the tip of the screw was 10 to 15 mm away from the aperture.

Conclusions: Femoral tunnel widening was significantly less in the Transfix group compared with the EndoButton group.

Level of evidence: Level II, prospective comparative study.