What can the Radiologist do to Help the Surgeon Manage Shoulder Instability?

Abstract

Imaging of the shoulder forms an important adjunct in clinical decision making in patients with shoulder instability. The typical lesions related with classic anterior and anteroinferior shoulder dislocation are an anteroinferior labral avulsion with or without bony fragment of bone loss – a (bony) Bankart lesion – and a posterolateral humeral head impaction fracture – the Hill-Sachs lesions. These are relatively straightforward to identify on imaging, although normal variants of the inferior labrum and variants of labral damage may cause confusion. Other capsuloligamentous lesions, often associated with less typical types of instability, are much more difficult to identify correctly on imaging, as they occur in the anterosuperior part of the glenohumeral joint with its many normal variants or because they result in more subtle, and therefore easily overlooked, changes in morphology or signal intensity. This paper aims at describing the appearance of the normal and pathologic glenohumeral joint related to shoulder instability. Ample reference will be given as to why identification of abnormalities, whether normal or pathologic, is important to the surgeon facing a treatment decision.

Accuracy of Magnetic Resonance Arthrography in the Detection and Classification of Chronic Anteroinferior Labrum Lesions

“…It has been suggested to aquire images in the abduction with external rotation (ABER) position. This position stresses the anterior labrum and ligamentous complex and if a tear is present contrast fluid is seen to track into it [6,7,9,10] .…”

“…Since Bankart discribed the 'essential lesion' in shoulder instability different types of labrum injuries have been recognized in the arthroscopic and imaging literature. A more detailed classification of the labrum lesions has been reported, and several Bankart variants such as Perthes lesion and Alpsa lesion have been described [3,6,7] .…”