Preoperative Prediction for Length of Patellar Tendon in Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Autograft

Abstract

Preoperative prediction of patellar tendon length is important during anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) autograft. Three methods of imaging analysis to predict patellar tendon length were compared in this study. One hundred and twenty-three patients who underwent ACL reconstruction using BPTB autograft by single surgeon during October 2002 through April 2011 were included. We measured the patellar tendon length from true and oblique lateral simple radiographs (classified according to degree of rotation) and magnetic resonance image (MRI). These values were compared with actual length measured during operation and assessed accuracy by calculating the coefficient of determination. The mean length of patellar tendon measured during operation and by true lateral and oblique lateral radiographs and MRI were 42.4±0.45 mm (range, 32.0–54.0 mm), 41.7±0.61 mm (range, 24.2–55.3 mm), 40.7±0.57 mm (range, 24.8–51.5 mm), and 41.7±0.52 mm (range, 28.7– 56.0 mm), respectively. The correlation of patellar tendon length was the most strong between actual length and value from true lateral radiograph (coefficient of determination, r=0.660) according to simple linear regression analysis. R values were 0.361 and 0.332 for oblique lateral radiograph and MRI compared to actual value, respectively. In conclusion, Patellar tendon length measured on true lateral radiograph was the best method to coincide with actual patellar tendon length among various preoperative prediction methods.