Prediction of Hamstring Graft Diameter Based on Anthropometric Variables in Anterior Cruciate Ligament Reconstruction

Background: The diameter of the graft is an important determinant of successful anterior cruciate ligament (ACL) reconstruction. If the diameter of hamstring graft can be predicted accurately, we can determine whether this graft is suitable or we need to harvest a different one. There is no published literature in the Nepali population on the ability to accurately predict the diameter of hamstring grafts using anthropometric variables in ACL reconstruction. Hypothesis: We can accurately predict the hamstring autograft diameter using some anthropometric variables. Study Design: Cross-sectional, Descriptive Methods: An analytical cross-sectional study was conducted among seventy-four patients from January 2021 to December 2022 who underwent ACL reconstruction using a hamstring autograft in Department of Orthopaedics of Bharatpur Hospital. Several anthropometric variables recorded were; (1) Age (2) Gender (3) BMI (4) Height (5) Weight and (6) Thigh length. The hamstring grafts (semitendinosus and gracilis) were either quadrupled or pentapled and the diameter was measured with a cylindrical sizer. Pearson correlation coefficients (r) and bivariate analysis were used to identify the relationship between the predictor variables (age, gender, BMI, height, weight and thigh length) and outcome variable (hamstring graft diameter). Results: There were 19 females and 55 males. There was statistically significant association between diameter with gender (p-value=0.004), BMI(p-value=0.048), height (p-value=0.005), weight(p-value=0.005), thigh length (p-value=0.037). Age was found to have a negative correlation with graft diameter (p-value =0.401). An equation has been formulated to predict the graft diameter in relation to the height of an individual. Conclusion: Out of all the variables, height was the strongest predictor of hamstring graft diameter. Patients taller than 160 cm, weighing more than 65 kg, with BMI more than 25 kg/m2 and thigh length more than 37 cm had graft diameter 8mm or more. The graft diameter was found to be inversely related to age, with individuals older than 40 years having graft sizes less than 8 mm.