Diagnostic Imaging for Traumatic Shoulder Dislocation

Initial Assessment

Radiography is the preferred initial diagnostic modality to confirm dislocation and identify associated fractures before attempting reduction, according to the American College of Radiology 1, 2
A standard set of shoulder radiographs should include anteroposterior (AP) views in internal and external rotation, plus an axillary or scapula-Y view, as recommended by the American College of Radiology 1, 3
Axillary or scapula-Y views are vital as acromioclavicular and glenohumeral dislocations can be misclassified on AP views alone, highlighting the importance of comprehensive imaging in diagnosis 2, 3

Post-reduction radiographs are necessary to confirm successful reduction and evaluate for any fractures that may have been obscured by the dislocation, as suggested by the American College of Radiology 4
Assessment for neurovascular compromise following reduction is critical, with the American College of Radiology emphasizing the need for thorough evaluation 5

Vascular assessment is critical in traumatic dislocations, especially with associated proximal humeral fractures, as axillary artery injury can occur, underscoring the importance of careful patient evaluation 5
CT angiography (CTA) is the preferred examination if vascular compromise is suspected following shoulder trauma, according to the American College of Radiology 5
Failure to obtain proper radiographic views, such as axillary or scapula-Y views, may lead to missed diagnosis of dislocation, highlighting the need for meticulous imaging protocols 2, 3
Attempting reduction without radiographic confirmation could worsen fracture-dislocations, emphasizing the importance of imaging in guiding treatment decisions 1
Delaying reduction increases the risk of complications, including neurovascular compromise, as noted by the American College of Radiology 5
Overlooking associated injuries, such as rotator cuff tears, which are more common in older patients with shoulder dislocation, can impact patient outcomes, as highlighted by the American College of Radiology 6

A standard trauma radiograph series including anteroposterior (AP) views in internal and external rotation PLUS an axillary or scapula-Y view is essential, as AP views alone frequently miss posterior dislocations, which are misdiagnosed in over 60% of cases initially, according to the American College of Radiology 7
Glenohumeral dislocations can be misclassified on AP views alone, and posterior dislocations are frequently missed without proper orthogonal views, as stated by the American College of Radiology 7
Anterior dislocation findings include humeral head displaced anteriorly and inferiorly to the glenoid on axillary/Y views, with associated Hill-Sachs deformity (posterolateral humeral head compression fracture) and bony Bankart lesion (anterior glenoid rim fracture), as reported by the American College of Radiology 7, 8
Posterior dislocation findings include humeral head displaced posteriorly relative to glenoid on axillary/Y views, as noted by the American College of Radiology 7
A CT scan should be performed if symptoms persist or radiographs are equivocal, as CT better characterizes fracture patterns and can definitively identify posterior dislocations, according to the American College of Radiology 7

Standard shoulder radiographs should include anteroposterior (AP) views in internal and external rotation PLUS an axillary or scapular Y view to properly evaluate for dislocation and associated fractures, as recommended by the American College of Radiology 9

MRI without contrast is indicated if radiographs show dislocation and you need to assess soft tissue injuries (rotator cuff tears, labral injuries, capsular tears) in the acute setting, as suggested by the American College of Radiology 10, 11
CT without contrast is reserved for better characterizing complex fracture patterns (especially scapular or proximal humerus fractures) when surgical planning is needed, according to the American College of Radiology 10, 11

Plain radiographs are sufficient to diagnose proximal humerus fracture and guide immediate treatment, as stated by the American College of Radiology 10
Plain radiographs are sufficient to diagnose clavicle fracture and guide immediate treatment, as stated by the American College of Radiology 10

Axillary or scapula-Y views are absolutely vital as glenohumeral dislocations are routinely misclassified on AP views, according to the American College of Radiology 12
Radiographs are the preferred initial diagnostic modality and must include three views minimum: AP in internal rotation, AP in external rotation, and axillary or scapula-Y view, as recommended by the American College of Radiology 12
CT is superior to radiography for identifying the reverse Hill-Sachs defect (anteromedial humeral head compression fracture) that occurs with posterior dislocations, according to the American College of Radiology 12

Older patients commonly have associated rotator cuff tears that must be evaluated, as noted by the American College of Radiology 13