Ultrasound evaluation of the ulnar collateral ligament of the elbow: Which method is most reproducible?

INTRODUCTION: The ulnar collateral ligament (UCL) is an important medial stabilizer of the elbow, particularly in overhead-throwing athletes. However, there is no universally accepted method for evaluating UCL thickness with ultrasound (US). OBJECTIVE: To assess reproducibility of previously published methods, as well as a modified technique, for evaluating the UCL via US. We hypothesize that a modified technique would show greater reproducibility. MATERIAL AND METHODS: Using US, the thickness of the UCL in 50 volunteers was measured by two musculoskeletal trained radiologists using two different measurement techniques. The techniques utilized were as described by Nazarian and Jacobson/Ward (JW). Technique measurements were evaluated using interclass correlation coefficients (ICC) to determine the reproducibility of each method. Twenty-eight of the subjects also underwent measurement via a modified JW technique, measured perpendicular to the ligament rather than the frame of imaging. This technique was also evaluated with ICC values. RESULTS: The ICC value for the Nazarian technique was 0.82 (very good) and 0.51 (moderate) for the JW technique. When using the modified JW technique, we found an ICC value of 0.84 (very good). Mean ligament thickness was greatest with the Nazarian technique, 6.41 mm, with the JW technique measuring 1.86 mm and the modified technique measuring 1.38 mm. CONCLUSION: US assessment of UCL thickness by all three measurement techniques are reproducible. The JW technique had less interobserver agreement when compared to the Nazarian method, whereas the modified JW technique had greater reproducibility compared to the JW technique and similar to the Nazarian technique.

Ultrasound of the elbow with emphasis on detailed assessment of ligaments, tendons, and nerves.

The high resolution and dynamic capability of ultrasound make it an excellent tool for assessment of superficial structures. The ligaments, tendons, and nerves about the elbow can be fully evaluated with ultrasound. The medial collateral ligament consists of an anterior and posterior band that can easily be identified. The lateral ligament complex consists of the radial collateral ligament, ulnar insertion of the annular ligament, and lateral ulnar collateral ligament, easily identified with specialized probe positioning. The lateral ulnar collateral ligament can best be seen in the cobra position. On ultrasound medial elbow tendons can be followed nearly up to their common insertion. The pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis can be identified. The laterally located brachioradialis and extensor carpi radialis longus insert on the supracondylar ridge. The other lateral tendons can be followed up to their common insertion on the lateral epicondyle. The extensor digitorum, extensor carpi radialis brevis, extensor digiti minimi, and extensor carpi ulnaris can be differentiated. The distal biceps tendon is commonly bifid. For a complete assessment of the distal biceps tendon specialized views are necessary. These include an anterior axial approach, medial and lateral approach, and cobra position. In the cubital tunnel the ulnar nerve is covered by the ligament of Osborne. Slightly more distally the ulnar nerve courses between the two heads of the flexor carpi ulnaris. An accessory muscle, the anconeus epitrochlearis can cover the ulnar nerve at the cubital tunnel, and is easily identified on ultrasound. The radial nerve divides in a superficial sensory branch and a deep motor branch. The motor branch, the posterior interosseous nerve, courses under the arcade of Frohse where it enters the supinator muscle. At the level of the dorsal wrist the posterior interosseous nerve is located at the deep aspect of the extensor tendons. The median nerve may be compressed at various sites, including the lacertus fibrosis, between the pronator teres heads, and the sublimis bridge. These compression sites can be identified with ultrasound.

Ultrasound of the elbow: Examination techniques and US appearance of the normal and pathologic joint.

Ultrasound studies are frequently requested for the work-up of patients with local elbow pain, which is generally caused by overuse syndromes, trauma, inflammatory diseases, or neuropathies. The technique used to examine this joint will vary to some extent depending on the precise location of the pain and other clinical findings. The aim of this article is to describe the standard technique used for elbow ultrasound, the normal anatomy of the joint, and the appearance on ultrasound of normal elbow anatomy and the alterations associated with some of the more common disorders affecting this joint.