Femoral tunnel enlargement after anterior cruciate ligament reconstruction using RigidFix compared with extracortical fixation

Purpose The aim of this study was to compare femoral tunnel enlargement after anterior cruciate ligament (ACL) reconstruction surgery using hamstring autograft tendons fixed by bioabsorbable femoral trans-tunnel pins with that in patients in which the graft was fixed with extracortical fixation. Methods Forty-three patients were randomly selected from our database and included in the study. Femoral tunnel diameter was measured by computed tomography in 20 patients who underwent ACL reconstruction via anteromedial portal technique using autologous quadruple hamstrings, fixed with two bioabsorbable trans-tunnel pins, RigidFix, on the femoral side and compared with 23 patients in whom extracortical fixation, EndoButton CL, was used. The diameter of the femoral tunnel was measured at a distance of 5 mm from the tunnel entrance and at the largest diameter along the tunnel axis. Data were compared with the diameter of the drill used during surgery. Clinical evaluation was performed using the Lysholm score, IKDC subjective score and anterior knee laxity measurements. Results Femoral tunnel enlargement 5 mm from the entrance and at the largest diameter was greater in the RigidFix group than the EndoButton group. There were no significant differences between the two groups regarding age, gender, post-operative Lysholm score, IKDC subjective score or knee laxity measurements. Conclusion The present study showed greater enlargement of the femoral bone tunnel when a bioabsorbable trans-tunnel pin system was used with the medial portal technique when compared to extracortical fixation. These findings confirm that femoral tunnel widening should be considered when RigidFix was used in ACL reconstruction by anteromedial portal technique. Level of evidence III.