Hamstring Graft Diameter and Clinical Outcomes in Anterior Cruciate Ligament Reconstruction: A Retrospective Cohort Study

Purpose: The outcomes of anterior cruciate ligament (ACL) reconstruction can be influenced by multiple factors, including surgical technique, graft type, and fixation methods. While existing literature has extensively examined these variables, less attention has been given to the impact of graft diameter. This study aims to evaluate the effect of hamstring graft diameter on clinical outcomes and recurrence rates following ACL reconstruction, addressing a significant gap in the current research. Methods: We conducted a retrospective analysis of prospectively collected data from 107 patients who underwent ACL reconstruction with a quadrupled hamstring tendon autograft between 2007 and 2019 at Via Grumo 16, Gravesano, Switzerland. Patients were divided into two groups based on graft diameter: 5-7 mm and ≥8 mm. The primary outcome was knee stability, assessed using the KT-1000 arthrometer at six, 12, and 24 months post-surgery. Re-rupture rates and other clinical outcomes were also evaluated. Statistical analysis was performed using Kaplan-Meier survival curves, Cox regression, and non-parametric tests, with a power analysis conducted to assess the adequacy of the sample size. Results: No significant differences in knee stability, as measured by KT-1000 scores, were observed between the two groups at any follow-up interval (p > 0.05). Re-rupture rates were also comparable, with no significant association between graft diameter and the risk of re-rupture identified (p > 0.05). The study’s power analysis revealed that our sample size did not reach the 80% threshold, representing a notable limitation. Conclusion: Our findings suggest that graft diameter may not significantly influence clinical outcomes in ACL reconstruction with hamstring tendons, challenging prior assertions of its critical role. Given the study’s limitations, including its underpowered sample size, further research with larger cohorts is needed to validate these results and guide graft selection strategies.