Sonography of the lateral ulnar collateral ligament of the elbow: study of cadavers and healthy volunteers.

OBJECTIVE: The purpose of this study was to assess the utility of high-resolution sonography in identification and characterization of the size and echogenicity of the lateral ulnar collateral ligament of the elbow in cadavers and healthy volunteers. SUBJECTS AND METHODS: The lateral ulnar collateral ligaments of four cadaveric elbows were imaged with a high-resolution linear-array ultrasound transducer. On localization, the ligaments were injected with 0.1% methylene blue under sonographic guidance. For confirmation of identification of the ligaments, the elbows were immediately dissected to reveal the exact location of the stain. The ligaments of both elbows of 35 healthy adult volunteers were imaged. RESULTS: Surgical dissection confirmed injection of methylene blue into all four cadaveric ligaments. The lateral ulnar collateral ligament was identified bilaterally over the radial head in all 35 volunteers. The mean thickness of the ligament at this point was 1.2 mm in women and men. The proximal attachment of the ligament to the humerus was well visualized bilaterally in 94.3% of volunteers. The mean thickness at this point was 1.7 mm in women and 1.6 mm in men. The distal attachment on the ulna was well visualized in 90% of elbows. The ligament was hyperechoic in relation to muscle in all volunteers. Differences in ligament measurements with regard to sex and hand dominance were not significant. Ligament thickness correlated weakly with volunteer weight, height, body mass index, and age. CONCLUSION: High-resolution ultrasound imaging is accurate for identification and measurement of normal lateral ulnar collateral ligaments. Therefore, ultrasound may prove valuable in assessment of abnormal lateral ulnar collateral ligaments.