Preoperative sonographic measurement can accurately predict quadrupled hamstring tendon graft diameter for ACL reconstruction.

Abstract

Previous studies reported sonography was inferior to MRI to predict hamstring tendon graft diameter for ACL reconstruction. This study aimed to investigate the correlation between intraoperative hamstring tendon graft diameter and its preoperative measurement using different sonographic scanning protocol from previous studies. Two cadaveric knees were utilized for validation. Sonographically guided gracilis tendon (G) and semitendinosus tendon (ST) injections were performed at myotendinous junction of sartorius using colored latex and then dissection was performed. In the clinical studies, 28 patients underwent primary ACL reconstruction were enrolled. Cross-sectional area (CSA) of G and ST were measured at myotendinous junction of Sartorius. The diameter of doubled G (2G), doubled ST (2ST) and quadrupled ST + G (4STG) were intraoperatively measured using graft sizing devices with 0.5-mm increments. Cadaveric dissection showed the presence of latex on the surface of G and ST at myotendinous junction of Sartorius in all specimens. In the clinical studies, CSA of G, ST, and ST + G significantly correlated with diameter of 2G (r = 0.464, p = 0.039), 2ST (r = 0.712, p < 0.001), and 4STG (r = 0.792, p < 0.001), respectively. As a result of the simple linear regression analysis, 4STG diameter could be predicted by the following formula: 4.345 + 0.210 × CSA. The differences between calculated diameter by this formula and intraoperative 4STG diameter were within ± 0.5mm in 89.3% (25/28) of subjects. The diameter of 2ST and 4STG can be reliably predicted based on sonographic CSA measurement preoperatively. Sonography is a cost-effective alternate to repeat MRI to predict hamstring graft diameter preoperatively. Diagnostic study; Level II.