The elbow is one of the most stable joints in the body. This stability is due to the adjacent muscular attachments, collateral ligaments, and inherent stability afforded by the hingelike articulation. Because of this stability, surgical repair for acute instability is usually not required, and chronic dislocations are unusual. Despite this, however, dislocations of the elbow are commonly seen, being third in large-joint dislocations, after glenohumeral and patellofemoral dislocations.
There are five general types of elbow dislocations: (1) posterior, (2) anterior, (3) medial, (4) lateral, and (5) divergent. The vast majority of elbow dislocations are posterior, all the others being uncommon. The mechanism of injury is usually a fall on the outstretched hand.
Clinically the patient presents with the elbow in 45° of flexion. The olecranon is prominent posteriorly, and the deformity resembles a displaced supracondylar fracture. If the patient is seen immediately after the injury, the bony landmarks can be identified. Later, however, the swelling may be quite severe, with no possibility of evaluating the injury topographically. A careful assessment of the neurovascular status is performed, with specific attention to the brachial artery and the ulnar, radial, and median nerves. The examination must be performed before and after manipulation, since neurovascular complications occur in 8 to 21 percent of patients, the most frequent being injury to the ulnar nerve. Vascular complications occur in 5 to 13 percent of elbow dislocations, with brachial artery injury the most common. Endean and coworkers found absence of a radial pulse before reduction, open dislocation, and other systemic injuries (head, chest, and abdomen) to be significantly associated with an arterial injury.
Radiographically, on the lateral view, both the ulna and radius are displaced posteriorly ( Fig 2.61-1). In the anteroposterior view, there may be lateral or medial displacement, with the ulna and radius in their normal relationship to each other. A search for associated fractures should be performed. In the child, a fracture of the medial epicondyle is most commonly seen. In adults, fractures of the coronoid process, radial head, capitellum, or olecranon may occur. Initially, these fractures should only be noted, with primary attention focused on the dislocation.
After adequate sedation, reduction is accomplished by gentle traction on the wrist and forearm in the direction in which it lies ( Fig .. 261-2). An assistant applies countertraction on the arm. Any medial or lateral displacement is corrected with the other hand. Downward pressure on the proximal forearm helps to disengage the coronoid process from the olecranon fossa. Distal traction is continued, and the elbow is flexed. With reduction, a palpable "clunk" is felt as the olecranon is seated in the humeral articular surface. The elbow is then moved through its full range of motion (ROM) to assess stability. If full smooth passive ROM is not possible, the postreduction radiograph should be examined for entrapment of the medial epicondyle, especially common in children ( Fig 261-3). Instability in extension suggests associated fractures or disruption of the capsule.
FIG. 261-2. Reduction of posterior elbow dislocation. A. Operator applies gentle traction as assistant applies countertraction. Displacement is corrected with the other hand. Downward pressure on the proximal forearm disengages the coronoid process from the olecranon fossa. B. Distal traction is continued as the elbow is flexed.
FIG. 261-3. Postreduction radiograph of a posterior elbow dislocation. The medial epicondyle is fragmented in the joint space and is seen in the anteroposterior and lateral radiographs (arrow).
After reduction, the elbow is placed in a plaster splint from the axilla to the base of the fingers with the elbow in at least 90° of flexion. Because of the soft-tissue trauma and subsequent edema, cylinder casts should not be placed. A neurovascular follow-up examination should be obtained the following day.
Appropriate treatment of elbow dislocations requires adequate reduction and recognition of neurovascular complications, associated fractures, and postreduction instability. If there is any question of neurovascular compromise, the patient should be admitted for observation. Immediate orthopedic consultation should be sought if the dislocation is irreducible, if there is neurovascular compromise, for disruption of the joint capsule, if there are associated fractures, and for open dislocations.
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