Hamstring Autograft in ACL Reconstruction: A 13-Year Predictive Analysis of Anthropometric Factors and Surgeon Trends Relating to Graft Size

BACKGROUND: Small-diameter autograft hamstring grafts have been linked to graft failure after anterior cruciate ligament (ACL) reconstruction. The frequency of hamstring autografts that actually meet ideal size criteria remains unknown. PURPOSE: To examine a large cohort of patients to (1) evaluate sizing variability among a large cohort of surgeons and (2) identify patient factors most predictive of hamstring autograft size. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 1681 ACL reconstructions with hamstring autograft were analyzed as completed by 11 surgeons over a 13-year period. Patient demographics (age, height, weight, body mass index, sex) and intraoperative details (including graft diameter and strands) were extracted. Univariate and multivariate regression analyses were performed to correlate patient demographics with graft size and to develop a predictive model for hamstring graft size. RESULTS: The mean height and weight of patients included in this study were 172.7 cm and 80.1 kg, respectively; 59% of patients were male. The mean diameters of hamstring autografts were 8.4 mm and 8.2 mm for the tibial and femoral ends of the graft, respectively. A total of 55.1% of grafts were ≤8 mm. Mixed-effects linear modeling revealed that height, weight, sex, and use of ≥5 strands correlated with graft size (P < .001), while age did not. The predictive multivariate model based on the statistically relevant factors demonstrated a moderate correlation (r = 0.39, R (2) = 0.150), illustrated a predictive equation, and proved height to be the greatest determinant of graft size. CONCLUSION: Marked variability in graft size distribution was found among surgeons, and more than half of all grafts did not reach the ideal size for hamstring autograft ACL reconstruction. A predictive equation including anthropometric factors may be able to provide the expected graft size. The risk of early graft failure may be mitigated with preoperative consideration of anthropometric factors—most importantly, height—in preparation for possible augmentation, additional strands, or alternative graft sources.