Tunnel Widening After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Computed Tomography–Based Study Comparing 2 Different Femoral Fixation Methods for Hamstring Graft

Abstract

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. 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. 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. Femoral tunnel widening was significantly less in the Transfix group compared with the EndoButton group. Level II, prospective comparative study.