Elbow dislocations in adults and children

Applied anatomy of the elbow

The elbow comprises three articulations: the ulnotrochlear articulation (a hinge joint) and the radiocapitellar and proximal radioulnar articulations (gliding joints), all of which are synovial joints [2]. The close congruent conformity of the articular surfaces along with the joint capsule, ligaments, and surrounding musculotendinous complexes bestow the elbow with inherent stability [3]. The ulnotrochlear articular contour and congruity enhance stability of the joint in the sagittal, coronal,

Pathomechanics of the injury

The Mayo Clinic has proposed that in an elbow dislocation, the lateral ligamentous complex is usually torn first, followed by the anterior and posterior capsule; the medial collateral ligament is the last structure to be injured and is usually intact with posterolateral rotatory instability [5], [9]. The dislocation is the culmination of the progress of the injuring force through three stages [10]. Stage 1 is characterized by partial or complete disruption of the lateral collateral ligament

Classification

Acute elbow dislocations per se are also referred to as simple elbow dislocations. When these dislocations are associated with fractures, they are referred to as complex elbow dislocations [13]. Further subclassification is based on the direction of the displacement of the radius and ulna in relation to the distal humerus. The dislocation may therefore be posterior, lateral, anterior, or divergent. Posterior elbow dislocation is most common [1]. There seems to be little value in distinguishing

Epidemiology

The elbow is the second most common major joint to be dislocated [1], with a reported annual incidence of 13 dislocations per 100,000 people [17]. Posterior elbow dislocations predominate. Linscheid and Wheeler [18] reported 108 posterior elbow dislocations in a series of 110 elbow dislocations. Associated fractures are more common in elbow dislocations in children and the elderly. Elbow dislocations are common in the young population and are predominantly associated with sporting injuries [17].

Clinical presentation

The history should include determination of the mechanism and severity of the injury. Dominance of the upper limb must be noted, as should the vocation and specific demands of the patient. On inspection the deformity is obvious and can be confirmed by disruption in the equilateral triangle from the tip of the olecranon to the distal humeral epicondyles when compared with the unaffected side. The distal radioulnar joint and interosseous membrane should be examined for tenderness. Careful

Investigations

Plain radiographs with an anteroposterior and a lateral projection are most valuable in determining the nature and scope of the dislocation [13]. Three-dimensional CT scanning is of value in complex cases to assess fractures and intra-articular fragments. MRI may help to identify ligamentous and cartilaginous injuries.

Treatment of adult dislocation

Treatment should begin with analgesia, followed by definitive reduction.

Treatment of children's dislocations

The majority of children's dislocations can be simply managed with a closed reduction. General anesthetic is preferred in the child.

Following reduction, it is important to confirm that there is a stable congruent reduction with a full range of motion as described in the adult.

As in the adult, fracture dislocations are an important subgroup. Those patients with an intra-articular lateral condyle fracture will require an open reduction of the lateral condyle to ensure that an anatomic reduction

Rehabilitation

Prolonged immobilization following reduction of the dislocated elbow increases the possibility of a poor outcome [19], [20], [21]. It is the postreduction stability of the injured elbow that determines the nature and pace of rehabilitation. Therefore, after a simple posterior dislocation, if the elbow is stable through the full range of motion, a broad arm sling is used for comfort and the patient is encouraged to mobilize the joint as comfort allows.

Elbows that have postreduction instability

Complications

Acute complications associated with elbow dislocations include vascular injury, compartment syndrome, and injuries to the median and ulnar nerves [13], [14], [19]. The medial humeral epicondyle, if fractured, may sometimes get entrapped in the elbow joint at the time of reduction [14]. Osteochondral fragments may also be entrapped in the joint leading to an incongruent reduction [28].

Long-term complications include flexion or extension contractures, heterotopic ossification, myositis

Prognosis

The prognosis for simple dislocations is better than for complex dislocations [5], [19], [23]. Prolonged immobilization is associated with an unsatisfactory result [19], [20]. Any elbow that is immobilized for at least 3 weeks will end up with a fixed flexion deformity. Patients with the terrible triad of injuries of the elbow have an increased risk of developing arthrosis [23]. Patients should be warned about residual flexion contractures. Expedient surgical intervention in the face of

Acknowledgements

Thanks to Ronald Heptinstall for his assistance with the preparation of the manuscript.