Decreased femur tunnel widening after augmented suspensory fixation compared to suspensory fixation for single bundle hamstring ACL reconstruction

Background:Tunnel widening after Anterior cruciate ligament (ACL) reconstruction using a hamstring graft is known to occur at follow-up. Our study aimed to investigate the effect of suspensory fixation augmentation using an interference screw on tunnel widening in single-bundle hamstring ACL reconstruction. Methods:48 patients who had single bundle ACL reconstruction with femoral fixed loop fixation technique in 15 knees, and, fixed loop with augmented aperture (bio screw) fixation in 33 knees were analyzed. The width of the tunnel was measured using radiographs immediate post-op and at follow-up within 1 year. Computerized Tomogram (CT) measurements of the tunnels and functional scores were also done with overall follow-up for the fixed loop group being 21.33 months (Standard Deviation (SD)11.14) and the Augmentation group 9.12 months (SD 3.83). Results:Midpoint femur tunnel widening was reduced in the augmentation group, with measurements of 0.74 (SD 1.05) mm Antero Posterior (AP) and 1.01 (SD 1.04) mm in the Lateral view, compared to 1.54 (SD 1.48) mm AP and 1.79 (SD1.47 mm) in the Lateral for the fixed button group. The radiological widening was considerably less in the augmentation group with a p-value of 0.07. AP aperture widening in the augmentation group was 1.25(SD 1.10 mm), and 1.09(SD0.98) mm in the lateral view. The fixed button-only group measured 1.53 (SD1.30) mm in the AP, and 1.65 (SD 1.29) mm in the lateral view, both of which were not statistically significant. The follow-up Lysholm and International Knee Documentation Committee (IKDC) scores were similar for the 2 groups. Conclusion:Femoral tunnel midpoint and aperture widening were reduced with the fixed loop with aperture (bio screw) augmentation technique for hamstring grafts in single bundle ACL fixation within 1 year with comparable functional scores. Level of evidence:4.