Background: As anterior cruciate ligament (ACL) injuries became more common, ACL reconstruction using hamstring tendons autograft (i.e. semitendinosus and gracilis) has become increasingly popular. One of the problems encountered during operation is insufficient size of the graft.
Objective: In order to determine the size of hamstring graft preoperatively, the authors collect anthropometric data from the patients and compare them with the actual hamstring tendon length harvested from the patient during ACL reconstruction.
Study Design: Cross sectional diagnostic study
Material and Method: Seventy-five consecutive patients with torn ACL scheduled for reconstruction using hamstring autograft were prospectively evaluated. Preoperatively the authors recorded height, weight, body mass index, age, leg length, thigh length, thigh circumference, length and width of the femur. Intraoperative measurements of both the gracilis and semitendinosus tendons length were made after trimming the useless thin border of the graft and final diameter of the quadrupled graft. Bivariate correlation coefficients (Pearson r) were calculated to identify relationships among clinical data and hamstring graft length and diameter measured intraoperatively.
Results: Strongest correlations for graft lengths were height and leg length measurements from both physical examination and x-rays. In contrast, graft diameter was not correlated with any physical parameters.
Conclusion: Simple parameter such as height 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. Thai male who is taller than 170 cm have a good potential to have semitendinosus tendon longer than 250 mm and maybe candidates to have ACL reconstruction with semitendinosus alone. X-ray of the whole leg did not provide any better prediction of graft length.

Keywords: Hamstring, Gracilis, Semitendinosus, Anterior cruciate ligament, Preoperative planning, Hamstring length prediction