The Correlation Between Graft Size and Graft Failure in Hamstring Autograft Anterior Cruciate Ligament Reconstruction

Previous studies have investigated various factors that contribute to graft failure in hamstring anterior cruciate ligament (ACL) reconstruction. However, there is debate about the potential advantages of increasing graft diameters beyond 8 mm. In this retrospective cohort study (level of evidence III), we investigated whether increasing graft sizes beyond 8 mm diameter showed any advantages in reducing the risk of graft failure. We utilized univariate Kaplan-Meier analysis and Cox proportional hazard (PH) regression models to compare the risk of failure in the different patient groups. Mutual adjustment was performed for age, gender, body mass index (BMI), and graft strands. Graft sizes ranging between 8 and 10 mm were assessed for their association with graft failure, alongside examining the impact of graft strands, age, and BMI on graft failure. A total of 487 patients underwent hamstring autograft ACL reconstruction at our hospital between January 2016 and December 2020. Our analysis indicated that among patients undergoing hamstring autograft ACL reconstruction, the risk of graft failure was 1.64 times higher for patients with a graft size between 8.5 and 9 mm (95% CI 0.36-7.43, p=0.483) and 2.19 times higher for patients with a graft size between 9.5 and 10.5 mm (95% CI 0.42-11.31, p=0.384) compared to those with an 8 mm graft. However, there was weak evidence against the null hypothesis. Conclusion: These findings suggest that there is no benefit to increasing graft sizes past 8 mm and that other factors, like surgical technique, should be considered when assessing the risk of graft failure in patients undergoing ACL reconstruction.