Sonography of the Normal Anterior Cruciate Ligament: A Preliminary Report

Currently, sonography is not used routinely for the evaluation of anterior cruciate ligaments (ACLs). The purpose of this study is to show that sonography can be used to directly evaluate the ACL. A normal individual and a patient with a chronic left ACL tear that was not repaired underwent magnetic resonance imaging (MRI) and sonographic examination in a 90° knee flexion position. A 7–9 MHz linear ultrasound transducer was used to obtain sonographic images at the infra-patellar region. We subsequently compared the MRI and sonographic images to define the ACL images. We proved our hypothesis by using a Kelley to pinpoint the ACL during the arthroscopic examination of a knee with normal ACL. Thirty-three normal right knees in 33 individuals also received sonographic examination for confirmation of our study. The ACL appeared as a hypoechoic band attached 11.00 ± 1.24 mm perpendicularly inferior to the tibia plateau. Its mean diameter was 8.30 ± 1.46 mm.