What are the physical examination findings of a dislocated elbow?

Physical Examination Findings of a Dislocated Elbow

A dislocated elbow presents with visible deformity, inability to fully extend the elbow, marked swelling, and the arm held in a flexed position—typically around 80 degrees of flexion with the forearm appearing shortened and displaced posteriorly. 1

Key Physical Examination Features

Visible Deformity and Positioning

• The elbow appears grossly deformed with obvious loss of normal anatomic contour, particularly with posterior dislocations (the most common type, accounting for approximately 90% of cases). 1, 2
• The olecranon is prominent posteriorly and the forearm appears shortened relative to the upper arm. 1
• The patient holds the arm in approximately 80 degrees of flexion and resists any attempt at movement due to severe pain. 1

Inability to Extend the Elbow

• Complete inability to actively extend the elbow is the hallmark finding and is highly sensitive for significant elbow pathology including dislocation. 3
• The validated elbow extension test (performed with patient seated, shoulders flexed to 90 degrees, asking the patient to actively extend) will be markedly positive, as the patient cannot achieve full extension. 3
• This finding alone should prompt immediate radiographic evaluation. 3

Swelling and Effusion

• Marked joint swelling is universally present due to hemarthrosis and capsular disruption. 3, 4
• Visible joint effusion manifests as fullness around the elbow with loss of normal bony landmarks. 3
• The swelling typically develops rapidly within minutes to hours of injury. 4

Mechanism and Associated Findings

• The injury typically occurs from a fall on an outstretched hand with the body rotating internally on the planted elbow, creating an external rotation/valgus moment as the elbow flexes. 1
• Posterolateral rotation of 34-50 degrees and 5-23 degrees of valgus angulation characterize the displacement pattern. 1
• Soft tissue disruption progresses from lateral to medial in a predictable sequence, with the anterior medial collateral ligament often remaining intact in simple posterior dislocations. 1

Critical Neurovascular Assessment

• Always assess for neurovascular compromise, particularly ulnar nerve function, as nerve injury occurs in up to 20% of elbow dislocations. 4
• Check radial, ulnar, and median nerve function including sensation and motor strength in their respective distributions. 4
• Palpate the brachial and radial pulses and assess capillary refill, as vascular injury is rare but catastrophic if missed. 4

Instability Patterns After Reduction

• After closed reduction, test for residual instability under fluoroscopy or clinical examination. 5
• Joint widening under 10 degrees indicates slight instability, greater than 10 degrees indicates moderate instability, and frank redislocation represents severe instability. 5
• The lateral pivot-shift apprehension test is the most sensitive examination for posterolateral rotatory instability, the most common pattern of recurrent instability. 2

Common Pitfalls to Avoid

• Do not assume stability based on appearance alone—always perform systematic neurovascular examination before and after any reduction attempt. 4
• Do not miss associated fractures, particularly radial head, coronoid process, or medial epicondyle fractures, which convert a simple dislocation into a complex injury requiring different management. 5, 3
• Do not overlook wrist examination—always assess the distal radioulnar joint for occult Essex-Lopresti injury. 4
• Persistent inability to extend after reduction mandates advanced imaging (CT or MRI) to identify occult fractures or soft tissue injuries. 3