The radiograph shows his injury. What is the injury, and how would you treat it?
Diagnosis: Posterior Elbow Dislocation
The elbow is formed by the articulation of the semilunar proximal aspect of the ulna between the humeral condoyles and the radius, and is stabilized by the ulnar collateral, radial collateral, and annular ligaments. It is protected posteriorly by the olecranon bursa. The elbow is the second most commonly dislocated major joint in adults after the shoulder, and is the most commonly dislocated joint in children. (Hand Clin 2008;24:139.)
Dislocation of the elbow is typically closed and posterior as the result of falling onto an extended elbow. Elbow dislocations that occur with an associated fracture are named “complex” (versus simple with an isolated dislocation). The main ligamentous stabilizer of the elbow is the medial collateral ligament. (Wheeless' Textbook of Orthopedics; http://bit.ly/NNf6qt.) Closed injuries are rarely associated with vascular injury in isolated elbow dislocations while anterior or open elbow injuries commonly have an associated neurovascular (e.g., brachial artery and median nerve) disruption. Neuropraxias, on the other hand, are not uncommon: approximately 20 percent of cases have an associated median or ulnar nerve injury. (Hand Clin 2008;24:9.) Dislocation of the elbow associated with radial head and coronoid fractures is known as the “terrible triad” because it can result in post-traumatic arthritis, pain, and stiffness if not treated properly. (Clin Orthop Relat Res 2014 Jan 29 [ePub Ahead of Print].)
Patients typically present with a flexed and shortened upper extremity with a tender posterior enlargement. The differential diagnosis of elbow injury includes evaluation for evolving compartment syndrome. Given the risk for neurovascular injury, a prompt evaluation should be performed to determine if the ulnar nerve, median nerve, or brachial artery is compromised.
Radiographs are the initial modality to evaluate and confirm a suspected elbow dislocation. (See photo.) Care should be taken to identify any secondary fractures depending on the mechanism.
Patients with posterior dislocations require reduction of the joint. Prompt reduction should be performed if neurovascular injury is present. Standard trauma resuscitation and evaluation procedures should be taken to identify any other associated injuries. Reduction of the joint should be performed with procedural sedation. Patients with simple posterior dislocations should be encouraged to prevent prolonged (greater than two weeks) immobilization from a sling because this has been shown to increase the risk of flexion contracture. (Injury 2007;38:1254.)
Operative repair is typically reserved for significant injury (including rupture of the flexor forearm muscles and instability after repositioning), recurrent dislocations with significant instability on passive ranging, fracture dislocations, or prolonged dislocations (more than two or three weeks). (Adv Orthop 2013;2013:951397.) A Cochrane review found, despite these recommendations, that “there is insufficient evidence from randomized controlled trials to determine which method of treatment is the most appropriate for simple dislocations of the elbow in adults.” (Cochrane Database Syst Rev 2012 18;4:CD007908.) It also concluded that surgery has not been shown to be superior to conservative management for simple dislocations of the elbow in adults.
Unfortunately, as many as 60 percent of patients with elbow dislocation will have chronic stiffness and pain even with optimal care. (J Bone Joint Surg Am 2011;93:1220.) Complications of simple posterior elbow dislocations include long-term valgus laxity depending on the amount of medial collateral damage. Heterotopic ossification can also occur in as many as 20 percent of patients. (Clin Orthop Relat Res 1967;50:129.)
Patients should be counseled about the signs of delayed neurovascular compromise, and close orthopedic evaluation should be arranged. This patient was successfully reduced in the ED, splinted, and sent for follow-up with orthopedic surgery.
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