Anthropometric data and the cross-sectional area (CSA) of the semitendinosus and gracilis tendons measured with preoperative MRI to predict graft diameter for anterior cruciate ligament reconstruction

Introduction Anterior cruciate ligament (ACL) reconstruction with quadrupled hamstring tendon autograft is a safe and reproducible surgery with good functional outcomes. Currently there is no consensus on capability of graft diameter planning. Objectives To investigate the influence of anthropometric data and cross-sectional area of semitendinosus (ST) and gracilis (GR) tendons according to preoperative magnetic resonance imaging (MRI) on intraoperative graft diameter. Material and methods The study included 111 consecutive patients (69 men and 42 women), who underwent ACL reconstruction with quadrupled hamstring autograft between 2015 to 2018. Height, weight and BMI were recorded in all patients preoperatively. Semitendinosus and gracilis tendons cross sectional areas (CSAst and CSAgr, respectively) were evaluated on preoperative MRI axial images. We also calculated doubled and quadrupled graft diameters (CSAst+gr and CSA4p, respectively) based on obtained MRI data. Collection of intraoperative data included length of each tendon separately, length and diameter of the resulting autograft. We used linear regression and Pearson correlation coefficient were used. The cross-sectional areas were correlated to antropometric and intraoperative data. Using logistic regression, we determined the probability of obtaining a graft diameter of ≥ 7.5 mm. A critical level of statistical significance was set as 5 % (p ≤ 0.05). Results The median age accounted 37.4 ± 0.89 (13-58) years, height - 174.6 ± 0.84 (156-200) cm, weight - 78.5 ± 1.52 (45-120) kg, BMI - 25.6 ± 0.37 ( 18.49-41.5). Intraoperatively GR average length was 224.7 ± 3.06 (80-340) mm, ST - 256.3 ± 2.97 (160-340) mm, quadrupled graft - 111.3 ± 1.42 (80-140) mm. The most common graft diameter was 7 mm in females and 7.5 mm in males. We found strong positive correlation between graft diameter and CSA4p, СSAst+gr, CSAst, weight and height. Linear regression showed that graft diameter was influenced by CSA4p, СSAst+gr, CSAst and height. If CSA4p was ≥ 72 mm2, the probability of obtaining a graft of ≥ 7.5 mm at the time of surgery reached 90.6 %. Conclusion CSA4p may be used as a predictive characteristic for graft diameter preoperative planning. Our findings show that graft diameter was mainly influenced by height, СSAst+gr, CSAst and CSA4p.