The elbow is one of the more highly constrained and stable joints in the body, yet dislocation is not uncommon.^1,2 Because of its intrinsic stability, redislocation is rare in the elbow in contrast to the shoulder. Most acute elbow dislocations are posterior. There are no previous reports in the literature of a recurrent elbow dislocation presenting as a normal elbow and subsequently dislocating. We describe the management of this patient, highlight the lessons learnt, and describe best practice for similar cases.

CASE REPORT

A 58 year old female presented to the accident and emergency (A&E) department with extensive bruising and swelling of the right arm and the elbow following a fall in the garden. The elbow movements were restricted with no distal neurovascular deficit. Anteroposterior and lateral radiograph of the elbow was interpreted as normal and the patient was discharged with analgesics and limb elevation advice (figs 1 and 2). The patient returned to the A&E 2 days later with increasing pain and deformity. She was advised that the management plan was correct as the initial radiograph showed no dislocation.

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Figure 1

 Anteroposterior radiograph of elbow at initial presentation. Reproduced with permission.

Figure 2

 Lateral radiograph of elbow at initial presentation. Reproduced with permission.

Three weeks later the general practitioner referred the patient to the on call orthopaedic doctor because of continued pain and swelling. On examination the elbow was still swollen with a restricted range of movement. Radiographs of the elbow were repeated, which showed a posterolateral dislocation of the elbow (figs 3 and 4). The elbow was reduced in the A&E department and referred to the fracture clinic. At two weeks review in the clinic, the elbow had dislocated again. Subsequent treatment involved examination under anaesthesia (EUA) in the theatre where the elbow was found to be grossly unstable; after application of external fixator and transolecranon pin (fig 5), which was removed at 4 weeks, the elbow was found to be stable. There had been no further dislocation and the patient was referred to the physiotherapy department for mobilisation of the elbow. At four months review the elbow was stable with an extension loss of about 30°.

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Figure 3

 Anteroposterior radiograph of the dislocated elbow. Reproduced with permission.

Figure 4

 Lateral radiograph of the dislocated elbow. Reproduced with permission.

Figure 5

 Radigraph of the elbow treated with external fixator and transolecranon pin. Reproduced with permission.

DISCUSSION

Recurrent instability of the elbow joint is uncommon but it is a debilitating disorder when present. The elbow is the second most commonly dislocated large joint after the shoulder in adults and the most common in children.² Recurrent dislocation is an uncommon sequelae. It usually occurs in association with intra-articular fracture or generalised ligament laxity, but can occur following simple dislocation.^2,3 We can find no mention in the literature of an elbow dislocating two days after the index injury, when at initial presentation the elbow was found to be in joint.

The elbow is a highly constrained joint and the stability depends on the bony architecture and the integrity of the ligaments, capsule, and muscles around the joint. The articular surface of the elbow is congruent and the bony surfaces minimise the risk of dislocation. The medial and lateral collateral ligaments are strong and play an important role in the stability of the joint. Theories on the most important factors in the stability of the joint have changed over 20 years.⁴ The medial collateral ligament was believed to be the important stabiliser and posterolateral dislocation was not possible if the medial collateral ligament remained intact.⁵ Recently attention has focussed on the lateral ulnar collateral ligament as the primary constraint to posterolateral instability⁶ and the secondary constraints of the extensor muscle origin, fascial bands, and lateral intermuscular septum.⁷

Elbow instability may be classified by time (acute, chronic, or recurrent), by direction (medial, lateral, posterolateral, or anterior), by associated injuries (fracture of the coronoid, radial head, capitellum, medial and lateral epicondyle, disrupted proximal radio-ulnar joint), or by mechanism of injury (hyperextension, axial compression, valgus and supination, or valgus stress).

Clinical evaluation includes careful history of the injury and the events causing instability and examination, including the valgus stress test and the posterolateral instability test.⁶ Routine anteroposterior and lateral radiographs may reveal associated bony injuries, degenerative changes, and heterotrophic bone around the elbow. In posterolateral rotatory instability, the lateral view with the forearm supinated may show widening of the humero-ulanr joint with inferior subluxation of the radial head.

Magnetic resonance imaging and computed tomography arthrogram may be used to identify ligamentous injuries.⁸ EUA may be indicated when the history is convincing or the clinical examination unhelpful.

LESSONS LEARNT AND BEST PRACTICE

Our patient had clearly suffered a significant ligamentous injury, which allowed the elbow to dislocate, reduce spontaneously, and then subsequently redislocate. This case highlights that recurrent elbow dislocations can present in joint. Although the initial radiographs showed that the elbow was not dislocated, careful scrutiny of the radiographs retrospectively showed tiny bony avulsions from the medial and lateral epicondyles. This suggested that the elbow had sustained significant ligament injury, which may predispose to recurrent instability. This needs to be specifically noted on the initial x rays. The subsequent attendance two days later was documented as showing deformity of the elbow. The mistake was in assuming that the patient’s condition remained the same and that there was no need to re-evaluate the situation and take more x rays. The elbow was almost certainly dislocated at this stage. It emphasises the need to assess the patient on his or her own merits despite previously normal investigations.

Once the elbow was found to be dislocated at three weeks, a reduction in theatre would have been more appropriate as an EUA at this stage would have revealed the gross instability and a stabilising procedure could have been performed forthwith. Finally, the patient was referred to the fracture clinic with a two week appointment. All dislocated joints should be seen at the next available clinic, no more than a few days from the injury, to ensure that the relocated joint remains in place.