Causes / typical injury mechanism: Elbow dislocations are the second most frequent upper extremity dislocation after shoulder dislocations.

Posterior elbow dislocations are the most common, accounting for more than 90% of all elbow dislocations. Anterior, medial, lateral, and divergent dislocations make up the rest of the cases. In all complete elbow dislocations, both the medial and lateral collateral ligaments will be torn, and unfortunately, they are the major stabilizing forces across the joint. During recovery, the biceps, brachialis, and triceps take over stabilization forces while the ligaments heal.

Classic history and presentation: Patients will likely present to the emergency department (ED) after an acute trauma and will require urgent reduction of the dislocation (see Therapy section for details on reduction).

Elbow dislocations generally occur following a traumatic injury, and more than half of all cases are the result of a fall. Other common causes include sports injuries, assaults, and motor vehicle collisions. Among the sports injuries, gymnastics, wrestling, and football have been reported to have the most occurrences of elbow dislocations. It tends to affect the patient's nondominant side.

The vast majority of cases are simple elbow dislocations, but if there is an associated fracture, it becomes a complex elbow dislocation. In approximately 10%-15% of cases, the patient will present with another upper extremity injury in addition to the elbow dislocation.

Young children with an elbow dislocation will most likely present with radial head subluxation or nursemaid's elbow. The mechanism of injury is due to an axial pulling force resulting in a tear of the annular ligament. Traumatic dislocations are rare in the pediatric population, but when they do occur, they tend to have an associated fracture.

Most often, a patient will present after an acute injury with an elbow deformity, swelling, and bruising to the area. If the patient lacks an obvious deformity but clinical suspicion is high, the joint may have spontaneously reduced prior to presentation.

Prevalence:

• Age – Elbow dislocation seems to predominantly affect younger patients (ages 10-20 years).
• Sex / gender – Elbow dislocation in adults is seen more often in male patients.

Risk factors: Direct trauma to the elbow such as a fall or assault.

Potential complications:

• Associated fracture – Most fractures will either occur at the coronoid process or radial head.
• Injury to the median, radial, or ulnar nerves, with ulnar nerve injury being the most common. However, it is possible for the median nerve to become entrapped following joint reduction.
• Injury to the brachial artery and other vasculature can occur but is rare. Note: 10%-25% of vascular injuries related to elbow dislocation will still have a radial pulse.
• Compartment syndrome
• Redislocation
• Residual instability with subluxation

Pathophysiology: This is most commonly caused by a fall onto an outstretched elbow with supination and external rotation of the forearm with valgus posterior lateral force and axial loading. Other force mechanisms could also lead to elbow dislocation but are less common. Typically, ligamentous stabilizers of the elbow tear from lateral to medial during the trauma in a circular progression.

Grade / classification system: Typically classified as simple or complex elbow dislocation. Simple dislocation is capsular ligamentous disruption only without fracture. Complex dislocation is an associated fracture. The dislocation is described anatomically based on the location of the ulna / olecranon in relation to the distal humerus.