The effect of femoral tunnel widening on one-year clinical outcome after anterior cruciate ligament reconstruction using ZipLoop® technology for fixation in the cortical bone of the femur

• Computer tomography (CT) scan was used for measuring the femoral tunnel widening via OsiriX software processing.
• The correlation between the International Knee Documentation Committee (IKDC) scores and femoral tunnel widening was evaluated.
• This study revealed a significant widening of the femoral tunnel.
• A significant correlation could be established between femoral tunnel widening close to the joint and the IKDC scores.

BackgroundThe effect of femoral tunnel widening on clinical outcomes of anterior cruciate ligament (ACL) reconstruction has been rarely investigated. In this study, ACL reconstructions were performed using semitendinosus and gracilis (STG) tendon grafts and single cortical fixation on the femoral side. The aim was to analyze femoral tunnel widening at one year and to evaluate its effect on clinical and laximetric outcomes.MethodsA total of 46 patients were enrolled in this prospective continuous single-operator monocenter study. Clinical protocol included pre-operative and one-year evaluation with subjective and objective International Knee Documentation Committee (IKDC) clinical scores. Computed tomography (CT) scan was used for radiographic examination during the follow-up period. The femoral tunnel widening was measured as a three-dimensional (3D) image using OsiriX software. The cross-sectional area of each tunnel was measured at four different locations.ResultsThe subjective preoperative IKDC score was 50 and one-year postoperative score was 81.8. The side-to-side difference in knee laxity decreased from 2.94 to 0.74 mm. The objective IKDC score during the final follow-up was rated A in 27 patients and B in 17. CT scan data revealed an average of 49.32% cone-shaped widening of the femoral tunnel. Femoral tunnel widening at the level of the joint (F4) was negatively correlated with the IKDC subjective score at one year.ConclusionsThis study revealed a significant widening of the femoral tunnel by demonstrating its conical shape at one year post-surgery. A significant correlation could be established between femoral tunnel widening close to the joint and IKDC scores.