Elbow dislocation !

An elbow dislocation is when the forearm bones come out of the elbow joint, nearly always backward; it is the second most dislocated large joint in adults.

Updated 2026-10-29

Structures involved

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What it is

Loss of contact between the humerus and the ulna and radius at the elbow, nearly always with the forearm bones displaced backwards (posterior dislocation). It is the second most common major joint dislocation in adults after the shoulder.

Who gets it

Typical in young adults and adolescents after falls during sport, and in older people after simple falls. In children, supracondylar fractures are more common than dislocations after a similar fall.

Causes

Fall onto an outstretched hand with the elbow extended
Combined axial load, valgus and supination of the forearm
High-energy trauma such as traffic accidents

Risk factors

Contact sports, gymnastics, skating and cycling
Falls in older adults
Ligamentous laxity
Previous elbow dislocation

Pathophysiology

Injury usually progresses from lateral to medial (Horii circle): the lateral ulnar collateral ligament fails first, then the capsule, and finally the medial collateral ligament. Simple dislocations involve only soft tissues; complex ones include fractures. The brachial artery and the median and ulnar nerves cross the elbow and can be stretched or trapped.

Classification

By direction: posterior or posterolateral (most common), anterior, medial, lateral, divergent
Simple (no fracture) versus complex (with fracture)
Terrible triad: elbow dislocation with radial head fracture and coronoid process fracture, highly unstable
Other complex patterns: dislocation with medial epicondyle fracture in adolescents

Symptoms and signs

Severe pain and obvious deformity after a fall
Elbow held in partial flexion, unable to move
Prominent olecranon at the back of the elbow
Swelling and later bruising

Diagnosis

Clinical: Deformity with loss of the normal triangle between the epicondyles and the olecranon. Clinicians check radial and ulnar pulses, capillary refill, and median, ulnar and radial nerve function before and after reduction, and examine the shoulder and wrist.
Tests: Not usually needed. Pulse oximetry or Doppler of the hand if circulation is in doubt.
Imaging: X-rays before and after reduction in two views to confirm direction, look for fractures (radial head, coronoid, epicondyles) and confirm a concentric reduction. CT for complex fractures; angiography if arterial injury is suspected.

Differential diagnosis

Supracondylar humerus fracture (especially in children)
Radial head or olecranon fracture
Monteggia fracture-dislocation
Radial head subluxation in young children
Isolated radial head dislocation

Goal of treatment

Reduce the joint promptly, protect the artery and nerves, restore a stable elbow and recover motion while avoiding stiffness.

Treatment

Acute: Prompt closed reduction under analgesia or sedation, followed by checks of pulses and nerves and post-reduction X-rays.
Conservative: Simple stable dislocations: short immobilisation in a splint for comfort, then early protected movement to avoid stiffness.
Surgical: Surgery for complex dislocations (terrible triad: fixation or replacement of the radial head, coronoid fixation and lateral ligament repair), irreducible or unstable joints, and arterial injury.
Rehabilitation: Physiotherapy to regain flexion, extension and forearm rotation.

Complications

Stiffness and loss of full extension (the most common)
Recurrent instability
Heterotopic ossification
Brachial artery injury
Median or ulnar nerve injury, sometimes with nerve trapped in the joint
Compartment syndrome and post-traumatic arthritis

Prognosis

Simple dislocations usually do well with early movement, though a small loss of extension is common. Complex injuries, especially the terrible triad, carry more risk of stiffness, instability and arthritis.

Prevention

Protective technique and equipment in sport
Fall prevention in older adults

Test yourself

Think of the answer, then tap the question to see it.

What is the most common direction of elbow dislocation?

Posterior (or posterolateral): the ulna and radius move backwards relative to the humerus.

What is the terrible triad of the elbow?

Elbow dislocation with a radial head fracture and a coronoid process fracture; it is highly unstable and usually treated surgically.

Which artery and nerves must be checked before and after reducing an elbow dislocation?

The brachial artery (radial and ulnar pulses) and the median, ulnar and radial nerves.

Which ligament usually fails first in a posterolateral elbow dislocation?

The lateral ulnar collateral ligament, at the start of the lateral-to-medial injury sequence (Horii circle).

What is the most common complication after a simple elbow dislocation?

Stiffness, especially loss of full extension, which is why early movement is encouraged.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Posterior Elbow Dislocation (StatPearls (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

Elbow capsule highlighted on the Durgical 3D model