How to read a shoulder X-ray (X-ray) for dislocation?

From the Guidelines

To read a shoulder X-ray for dislocation, anteroposterior (AP) views in internal and external rotation and an axillary or scapula-Y view are essential, as they provide vital information in evaluating traumatic shoulder injuries, including acromioclavicular and glenohumeral dislocations. When evaluating a shoulder X-ray for dislocation, it is crucial to examine the glenohumeral joint, looking for abnormal positioning of the humeral head relative to the glenoid. The humeral head should be centered in the glenoid fossa, and any displacement, such as anterior, posterior, or inferior, can indicate a dislocation 1.

Key features to assess include:

• The "light bulb sign", which suggests rotation from dislocation, making the humeral head appear circular rather than oval
• Associated fractures, particularly Hill-Sachs lesions and Bankart lesions
• The relationship between the humeral head and glenoid, which can be clearly seen on the axillary view
• Comparison with the uninjured shoulder, if possible, to identify subtle abnormalities

It is also important to note that radiography should be performed upright, as malalignment of the shoulder can be underrepresented on supine radiography 1. Additional views, such as the Bernageau view, can be effective in demonstrating the degree of bone loss of the glenoid or humeral head, but the standard shoulder series, including AP, lateral/Y view, and axillary views, is typically sufficient for initial evaluation. Radiographic findings should always be correlated with clinical examination findings, including pain, limited range of motion, and visible deformity.

From the Research

Reading Shoulder X-Rays for Dislocation

To read shoulder X-rays for dislocation, several key points should be considered:

• The role of post-reduction radiographs in determining the success of shoulder dislocation reduction and identifying potential fractures 2
• The comparison of different sedation methods, such as intraarticular lidocaine, intravenous procedural sedation, and peripheral nerve blocks, for reducing anterior shoulder dislocations 3, 4, 5
• The evaluation of procedural sedation and analgesia versus nerve blocks for reduction of fractures and dislocations in the emergency department 5

Key Findings

• Post-reduction radiographs can provide important information about the success of reduction and the presence of fractures, with one study finding that 37.5% of fractures may be visible only on post-reduction X-rays 2
• Intraarticular lidocaine and peripheral nerve blocks may be effective alternatives to intravenous procedural sedation for reducing anterior shoulder dislocations, with potential benefits including reduced time spent in the emergency department and lower complication rates 3, 4, 5
• Procedural sedation and analgesia versus nerve blocks for reduction of fractures and dislocations in the emergency department may have similar efficacy, but nerve blocks may be associated with fewer adverse events and shorter lengths of stay 5

Sedation Methods

• Intraarticular lidocaine:
  • May be as effective as intravenous procedural sedation for reducing anterior shoulder dislocations 3
  • May have a shorter emergency department length of stay compared to intravenous procedural sedation 4
• Intravenous procedural sedation:
  • May have a higher complication rate compared to intraarticular lidocaine and peripheral nerve blocks 3, 4, 5
  • May require longer recovery times compared to propofol 6
• Peripheral nerve blocks:
  • May be as effective as intravenous procedural sedation for reducing anterior shoulder dislocations 4, 5
  • May have fewer adverse events and shorter lengths of stay compared to intravenous procedural sedation 5