Tibial tunnel widening after hamstring tendon anterior cruciate ligament reconstruction: The effect of supplemental aperture fixation with autogenous bone cores

Background: Tibial tunnel widening is a common phenomenon seen with hamstring anterior cruciate ligament reconstruction. Concern exists that increased tunnel widening can lead to delayed graft incorporation, graft laxity, or difficulties in revision surgery. Hypothesis: Supplemental aperture fixation with autogenous bone cores or bioabsorbable interference screws will decrease tibial tunnel widening in hamstring anterior cruciate ligament reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: One hundred twenty-nine patients were divided into 3 groups based on type of aperture fixation: none, bioabsorbable interference screws, and autogenous bone cores. Tibial tunnel diameters were measured on plain radiographs at a minimum of 3 months postoperatively based on the timeline of tibial tunnel widening suggested by Simonian et al, and tunnel widening was quantified by the increase in tunnel diameters relative to initial reamer size. Results: Means for tunnel widening based on both anteroposterior and lateral maximum tunnel width measures were significantly different between the 3 groups (P <.05, 1-way analysis of variances); however, compared with the means for the group receiving no aperture supplementation, the means for the group receiving bioabsorbable interference screws were more than 0.8 mm wider, representing a significant increase (P <.05, Bonferroni-adjusted t tests), while the means for the group receiving autogenous bone cores were less than 0.6 mm wider than the group without aperture supplementation and not significantly different (P >.25, Bonferroni-adjusted t tests). Conclusion: Tibial tunnel aperture supplementation does not appear to decrease tunnel widening in hamstring anterior cruciate ligament reconstruction and may actually increase the amount of tibial tunnel widening.