The diameter of single bundle, hamstring autograft does not significantly influence revision rate or clinical outcomes after anterior cruciate ligament reconstruction.

Background: Anterior cruciate ligament (ACL) graft failure is a complication of ACL reconstruction (ALCR). Smaller autograft diameter may be a contributing factor. Our aim was to determine if hamstring autograft diameter influences graft rupture and patient-reported outcome scores.

Methods: This study included 786 consecutive patients undergoing primary, single bundle, autograft hamstring ACLR. The primary outcome was revision ACLR surgery. Secondary outcomes were patient reported International Knee Documentation Committee (IKDC) score, Knee Injury & Osteoarthritis Outcome Score (KOOS) and Tegner Activity score. Multiple logistic regression and Fischer Exact tests were employed for statistical analysis.

Results: Increasing autograft diameter did not lead to a reduction in revision ACLR surgery (odds ratio [OR], 1.093; 95% confidence interval [CI], 0.612 to 1.954; P=0.76). Revision ACLR positively correlated with male gender (OR, 3.971; 95% CI 1.109 to 14.214; P=0.03) and negatively correlated with increasing age (OR, 0.919; 95% CI 0.882-0.958, P<0.0001). There was no association between graft rupture rate and dichotomized graft size. At latest follow-up, there was no correlation between graft diameter and IKDC (Pearson's adjusted R=0.058; P=0.75), Tegner Activity score (Pearson's adjusted R=0.244; P=0.53), or any component of the KOOS (Pearson's adjusted R range: 0.008 to 0.141; P-value range: 0.21 to 0.76).

Conclusion: Increased hamstring autograft diameter did not significantly reduce revision ACLR surgery or improve clinical outcomes. Other factors such as gender and age do influence the rate of revision ACL surgery.

Study Design: Level IV, retrospective case series.