An Unusual Case of Elbow Dislocation

The frequency of elbow dislocation is second to that of shoulder dislocation in adults.¹ Adult elbow dislocations are classified by the direction of displacement and associated fractures. They can be anterior, posterior, lateral, or divergent, with the most common type being posterior displacement of both the radius and ulna in relation to the distal humerus.^1,2 Associated injuries to the shoulder, distal radius/ulna, and carpal bones occur in 10% to 15% of cases.³ Most dislocations occur after a fall on an outstretched hand. Elbow dislocations and fractures can also occur with a high-energy direct impact.¹

This article presents a case of a nonclassified type of elbow dislocation named twisting dislocation of the elbow.

Case Report

A 55-year-old woman presented with a swollen and painful right elbow joint and a pronated forearm after falling on her outstretched right arm. There was no neurological or vascular deficit. Only 1 lateral radiograph was performed, as the patient’s painful state did not allow for an anteroposterior view. The radiograph revealed an unusual twisting dislocation, with both the humerus and the ulna being rotated by 90° and 180° respectively (Figure 1).

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Figure 1: Lateral radiographic view of a twisting elbow dislocation. Figure 2: AP (A) and lateral (B) views of a twisting elbow dislocation post-reduction.

After infiltrating 7 mL of regional anesthetic (Xylocaine 2%) into the dislocated elbow, closed reduction was performed by applying gentle external rotation to the distal humerus while an assistant was simultaneously supinating the forearm. The elbow joint was immobilized at 90° of flexion. Anteroposterior and lateral radiographs confirmed the reduction (Figure 2).

The elbow was put in a cast in 90° of flexion with the forearm slightly pronated for 3 days. On the third day the cast was replaced by a functional brace, which remained for 3 weeks. The brace allowed free range of flexion and extension but blocked pronation and supination of the forearm. The patient was encouraged to move the elbow with the brace, and no additional physiotherapy was initiated. Weight lifting was prohibited. At 3-week follow-up, the patient had regained a flexion-extension range of motion (ROM) from 40° to 110° (Figure 3). Pronation and supination were limited to a –40° to +40° range. At that point the brace was removed and specific self-executed exercises were taught. At 5-week follow-up, the elbow joint was painless with full range of motion (Figure 3), and the patient was advised to resume her normal activities. At final follow-up 1 year later, the elbow was pain-free even when stretched. The varus-valgus stress of the joint revealed no signs of instability. No periarticular calcification was noted.

Figure 3: 110° extension of the elbow 3 weeks post-reduction (A), 40° flexion of the elbow 3 weeks post-reduction (B), full extension of the elbow 5 weeks post-reduction (C), and full flexion of the elbow 5 weeks post-reduction (D).

Discussion

The annual incidence of elbow dislocation is 6 to 8 cases per 100,000 in the United States; these dislocations represent 11% to 28% of all elbow injuries. The frequency of elbow dislocation is second to that of shoulder dislocation.³

The stabilizing structures of the elbow can be thought of as a ring.⁴ The trochlear notch surrounds almost 180° of the trochlea, accounting for a large part of the stability of the elbow joint. The ulnohumeral articulation has been shown to be the most important stabilizer of the elbow joint. The posterior column, the disruption of which would be a prerequisite for anterior dislocation, is formed by the olecranon, the triceps, and the posterior aspect of the capsule, whereas the anterior column is formed by the coronoid process.⁴

The medial collateral ligament and lateral collateral ligament comprise the ligamentous stability of the elbow and act as a backup system to the elbow’s natural bony stability. The medial collateral ligament consists of 3 bands: the anterior oblique, the posterior oblique, and the transverse. The anterior band provides most of the resistance to valgus stress. The lateral collateral ligament has 2 bands: the ulnar collateral and the radial collateral.¹

Adult elbow dislocations are classified by the direction of displacement and associated fractures. Simple elbow dislocations are solely soft tissue injuries. The direction can be anterior, posterior, lateral, or divergent. Usually elbow dislocations involve posterior displacement of both the radius and ulna in relation to the distal humerus.¹

The most common accompanying bony injury of an elbow dislocation is a fracture of the olecranon process (20%), while coronoid process fracture occurs in 10% to 15% of the cases.¹ The supracondylar humerus, capitellum, and trochlea are fractured less frequently.

Simple elbow dislocations are reduced under local anesthesia in the emergency room. General anesthesia is reserved for difficult irreducible dislocations.^5-7

The rehabilitation of elbow dislocation ranges from aggressive immediate active motion to traditional plaster of Paris immobilization for several days. Forceful passive mobilization in the rehabilitation period must be avoided, since the elbow joint has a natural tendency to develop myositis ossificans following passive manipulation.⁸ Twenty years ago, authors were suggesting a period of immobilization for up to 2 weeks.^9-11 Mehlhoff et al¹² proposed that gentle, active flexion should begin as soon as pain allows, and unprotected flexion-extension should be initiated sooner than 2 weeks post-injury. The natural stability of the elbow joint against dislocation recurrence results primarily from its bony architecture, reinforced by the medial and lateral thickening of the capsule.¹³ The success of nonoperative management is thus explained by the stabilizing effect of joint surfaces, particularly during ligamentous healing.¹⁴

Surgical repair of the elbow collateral ligaments has been advocated, but there is little evidence that the results of such a repair are any better than those of nonsurgical treatment.¹⁴ The disadvantages of immobilization have been widely recognized (eg, pain, persistent stiffness, late degenerative changes, etc).^15-17 Mehlhoff et al,¹² Josefsson et al,¹⁴ and Coonrad et al¹⁸ agree that elbow stiffness has been the most common complication following dislocation. Now most authors recommend immediate accelerated functional treatment for simple elbow dislocations,^10,18-20 as long periods of immobilization may be harmful.²¹ Ross et al²⁰ used a specific protocol after closed reduction without any immobilization and achieved 95% success. Protzman¹¹ suggested immediate reduction followed by 1 to 5 days of immobilization for uncomplicated dislocations. In our case, the elbow was in a cast for 3 days for the swelling to subside, allowing the patient to become familiar with the rehabilitation program that would follow.

It seems there will always be unusual or unclassifiable types of injuries that will confirm the unwritten rule of the unlimited variation of mechanisms that produce an equally endless number of injury modalities. The elbow dislocation presented in this case report is another example of a unique type of injury that, to our knowledge, has not been previously described in the literature. Regardless of the custom-made manipulation required for its reduction, the immediate active mobilization of the joint resulted in an excellent outcome.

References

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Authors

Drs Lasanianos and Garnavos are from the Orthopedic Department, Evangelismos General Hospital, Athens, Greece.

Drs Lasanianos and Garnavos have no relevant financial relationships to disclose.

Correspondence should be addressed to: Nikolaos Lasanianos, MD, 12 Lontou St, Palea Penteli, 15236, Athens, Greece.