Hamstring Graft Size Prediction

Background Recently we retrospectively collected clinical data to predict hamstring graft diameter. Prospective data collection will improve and further define prediction of hamstring graft size. Hypothesis Clinical anthropometric data can be used to predict hamstring graft size. Study Design Cohort study (prevalence); Level of evidence, 1. Methods Fifty consecutive patients with anterior cruciate ligament deficiency scheduled for reconstruction using hamstring autograft were prospectively evaluated. Preoperatively we recorded height, weight, body mass index, age, gender, leg length, thigh length, shank length, bilateral thigh circumference, and Tegner score. Intraoperative measurements of both the gracilis and semitendinosus tendons were made, including absolute length before fashioning the graft and final diameter of the quadrupled graft using sizing tubes calibrated to 0.5 mm. Bivariate correlation coefficients (Pearson r) were calculated to identify relationships among clinical data and intraoperatively measured hamstring graft length and diameter. Results Strongest correlations for graft lengths were height and leg length measurements. Shorter persons with shorter leg, thigh, and shank lengths tended to have shorter gracilis and semitendinosus grafts. Likewise, the strongest correlations for graft diameter were weight and thigh circumference. Self-reported activity level and age did not correlate. Gender comparison revealed that women who were shorter, lighter, and had smaller body mass indices were more likely to have smaller graft diameters and shorter graft lengths. Conclusion Patients weighing less than 50 kg, less than 140 cm in height, with less than 37 cm thigh circumference, and with body mass index less than 18 should be considered at high risk for having a quadrupled hamstring graft diameter less than 7 mm. When separated by gender, small graft diameters are most likely in older, short, female subjects with small thigh circumferences or young, skinny, male subjects with small thigh circumferences and low body mass index. Common clinical measurements can be used for preoperative identification of patients at risk for insufficient graft tissue and would be useful for patient counseling and alternative graft source planning.