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Emergency and Acute Medicine - Shoulder Dislocation
Shoulder dislocation is a common injury due to the highly mobile and inherently unstable nature of the glenohumeral joint. The majority are anterior dislocations (90–96%), typically caused by forces applied to an abducted and externally rotated arm. Posterior dislocations are less common and frequently missed; they occur when force is applied to an adducted, internally rotated arm, often during seizures, electrocution, or trauma. Inferior dislocations (luxatio erecta) are rare and result from hyperabduction, often associated with falls from height and frequently accompanied by neurovascular injury. In children, true dislocations are uncommon and fractures should be suspected, while in older adults, associated fractures are more frequent.
Patients typically present with severe shoulder pain and limited movement. In anterior dislocation, the shoulder appears “squared off,” with a prominent acromion and anterior fullness, and the arm is held slightly abducted and externally rotated. Posterior dislocation presents with the arm adducted and internally rotated, a prominent coracoid process, and a posterior bulge. Inferior dislocation is distinctive, with the arm fixed overhead and the humeral head sometimes palpable along the chest wall.
Evaluation must always include careful assessment of neurovascular status, especially the axillary nerve, both before and after any manipulation. Imaging is essential prior to reduction unless delay would be harmful. Standard radiographs should include anteroposterior and either axillary or scapular Y views. Associated findings may include Hill–Sachs lesions, Bankart lesions, or fractures of the greater tuberosity. Posterior dislocations may show the classic “light bulb” sign on X-ray and are often missed without appropriate imaging views.
Management requires prompt reduction to minimize complications such as post-traumatic arthritis. Adequate analgesia and muscle relaxation are critical, using procedural sedation (e.g., opioids and benzodiazepines, or agents like etomidate or propofol) or intra-articular local anesthetic. Several reduction techniques can be used for anterior dislocations, including scapular manipulation, Stimson technique, traction-countertraction, and slow external rotation. Posterior and inferior dislocations require modified reduction approaches, often involving traction and directed manipulation.
After successful reduction, confirm alignment with repeat imaging and reassess neurovascular status. Immobilize the shoulder in a sling or immobilizer. Younger patients typically require immobilization for 2–3 weeks, while shorter durations are recommended in older patients to prevent stiffness and frozen shoulder.
Admission is indicated if reduction fails, if general anesthesia is required, or if there is neurovascular compromise. Most patients with successful reduction can be discharged with immobilization and arranged orthopedic follow-up. Recurrent dislocations may require surgical intervention.
A key clinical point is to always document axillary nerve function prior to reduction. Missing posterior dislocations and failing to identify associated fractures or nerve injury are common pitfalls.
Shoulder dislocation is a common injury due to the highly mobile and inherently unstable nature of the glenohumeral joint. The majority are anterior dislocations (90–96%), typically caused by forces applied to an abducted and externally rotated arm. Posterior dislocations are less common and frequently missed; they occur when force is applied to an adducted, internally rotated arm, often during seizures, electrocution, or trauma. Inferior dislocations (luxatio erecta) are rare and result from hyperabduction, often associated with falls from height and frequently accompanied by neurovascular injury. In children, true dislocations are uncommon and fractures should be suspected, while in older adults, associated fractures are more frequent.
Patients typically present with severe shoulder pain and limited movement. In anterior dislocation, the shoulder appears “squared off,” with a prominent acromion and anterior fullness, and the arm is held slightly abducted and externally rotated. Posterior dislocation presents with the arm adducted and internally rotated, a prominent coracoid process, and a posterior bulge. Inferior dislocation is distinctive, with the arm fixed overhead and the humeral head sometimes palpable along the chest wall.
Evaluation must always include careful assessment of neurovascular status, especially the axillary nerve, both before and after any manipulation. Imaging is essential prior to reduction unless delay would be harmful. Standard radiographs should include anteroposterior and either axillary or scapular Y views. Associated findings may include Hill–Sachs lesions, Bankart lesions, or fractures of the greater tuberosity. Posterior dislocations may show the classic “light bulb” sign on X-ray and are often missed without appropriate imaging views.
Management requires prompt reduction to minimize complications such as post-traumatic arthritis. Adequate analgesia and muscle relaxation are critical, using procedural sedation (e.g., opioids and benzodiazepines, or agents like etomidate or propofol) or intra-articular local anesthetic. Several reduction techniques can be used for anterior dislocations, including scapular manipulation, Stimson technique, traction-countertraction, and slow external rotation. Posterior and inferior dislocations require modified reduction approaches, often involving traction and directed manipulation.
After successful reduction, confirm alignment with repeat imaging and reassess neurovascular status. Immobilize the shoulder in a sling or immobilizer. Younger patients typically require immobilization for 2–3 weeks, while shorter durations are recommended in older patients to prevent stiffness and frozen shoulder.
Admission is indicated if reduction fails, if general anesthesia is required, or if there is neurovascular compromise. Most patients with successful reduction can be discharged with immobilization and arranged orthopedic follow-up. Recurrent dislocations may require surgical intervention.
A key clinical point is to always document axillary nerve function prior to reduction. Missing posterior dislocations and failing to identify associated fractures or nerve injury are common pitfalls.
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