Patients with acute elbow dislocation tend to present with pain, soft tissue swelling and an obvious deformity of the elbow (Fig. 24.1). A thorough neurovascular examination of the upper extremity should always be performed. Closed elbow dislocations are rarely associated with vascular injury, and only a handful of brachial artery injuries associated with closed simple elbow dislocation have been reported.⁷ In open dislocations, however, the brachial artery is more often disrupted due to the forcible hyperextension of the elbow. Median and/or ulnar nerve injury is also commonly associated with such injuries. Neurapraxia has been reported to occur in approximately 20% of elbow dislocations and usually involves the anterior interosseous branch of the median nerve and/or the ulnar nerve. Ulnar nerve palsy has been reported in 14% of adult elbow dislocations, and the incidence is much higher in paediatric elbow dislocations with an associated medial epicondyle fracture. Most neurological deficits are transient, but entrapment of the median nerve within the elbow joint following reduction is relatively common in paediatric elbow dislocations and if not recognized will cause permanent disability.⁸ The wrist and shoulder joints should be carefully examined to rule out a concomitant upper extremity injury, which have been noted in 10–15% of acute elbow dislocations.⁹ Of note, the distal radio-ulnar joint (DRUJ) and forearm interosseous membrane should always be examined for tenderness and instability to rule out an associated interosseous membrane disruption.

Figure 24.1 Clinical photograph (A) and lateral radiograph (B) of a posterolateral elbow dislocation. Note the obvious deformity and prominence over the posterior elbow.

Courtesy of Glen Ross MD, New England Baptist Hospital.

Anteroposterior (AP) and lateral radiographs are normally sufficient to allow diagnosis of the dislocation. The films should be examined to determine the direction of forearm displacement so that the injury can be appropriately classified. In addition, a careful assessment must be made to identify whether there is any evidence of bony injury. Standard preoperative radiographs sometimes make it difficult to diagnose a medial coronoid fracture. If the initial radiographs show any small pieces of bone, it should not be assumed that this is bone from the radial head as the fragments may represent a medial coronoid fracture. If a medial coronoid fracture is missed and the elbow assumes a subluxed position, then an arthritic ulnohumeral articulation will result, which can be very difficult to treat if diagnosed late. If there is doubt as to whether bony fragments are present a CT scan following reduction of the dislocation is appropriate.

Simple elbow dislocations are acutely treated with reduction. Reduction requires adequate muscular relaxation and appropriate analgesia. This is usually done in the emergency department with intravenous or intramuscular medication. The acute treatment of the posterior or posterolateral dislocated elbow in the emergency department is to place the patient in the prone position and to supinate the patient’s arm. With the proximal part of the arm over a padded bolster on the edge of the examining table, pressure is applied to the olecranon tip in a distal and posterior direction as the elbow is gradually flexed, resulting in reduction. Muscular relaxation is necessary for adequate reduction, and the quality of the reduction often provides a clue to postreduction stability. A palpable reduction ‘clunk’ is a favourable sign of joint stability (Fig. 24.2).¹⁰

Figure 24.2 AP (A) and lateral (B) radiographs of a simple posterolateral elbow dislocation. The elbow was subsequently reduced under muscular relaxation and the assistance of fluoroscopy. Anteroposterior (C) and lateral (D) radiographs demonstrate a concentric reduction with the elbow flexed to 90° in a plaster splint.

Following successful reduction, the range of motion and stability of the elbow are assessed. The vast majority of simple elbow dislocations are unstable to valgus stress, and this is best tested in pronation to lock the lateral side. The elbow is generally stable in 90° or more of flexion. It is essential, however, to evaluate the elbow in a position of near or full extension to determine the tendency for redislocation. If the elbow is unstable in this position, this signifies a potentially unstable joint. If elbow instability occurs in 30° of flexion, the forearm can be placed in maximum pronation to maximize the stress on the medial collateral ligament. This results in reduction of the posterolateral subluxation. As a result, the elbow should be immobilized in pronation in this situation.

After determining that the elbow reduction is stable in 30° of flexion, post-reduction AP and lateral radiographs should be performed to document concentric reduction in two planes. In difficult cases, fluoroscopy may be of significant assistance. The radiographs should be assessed for joint widening, irregularity or malalignment. Persistent instability or joint widening may indicate posterolateral rotatory instability or the interposition of soft tissue or osteochondral fragments (Fig. 24.3).

Figure 24.3 Lateral radiograph obtained immediately following closed reduction of a simple elbow dislocation. Note the persistent joint widening which may indicate posterolateral rotatory instability or interposition of soft tissue or osteochondral fragments.

Once the elbow is reduced and radiographs confirm an adequate reduction, a decision must be made as to how long to immobilize the patient and when to allow active exercises.

Clinical Pearl 24.1

Simple posterolateral elbow dislocations are acutely treated with closed reduction. A concentric reduction should be confirmed and documented with AP and lateral radiographs. The radiographs should be assessed for joint widening, irregularity or malalignment.

Treatment and rehabilitation

A stable elbow articulation following reduction of a simple dislocation will generally allow early flexion and extension, as long as valgus stress is prevented. The vast majority of simple elbow dislocations, therefore, can be treated non-operatively. Only in situations of persistent redislocation and/or elbow instability is surgery indicated. In terms of non-operative management, recommendations concerning the type and duration of immobilization tend to vary widely. Over the last several years, multiple studies have been performed to investigate the type and duration of immobilization following closed reduction of elbow dislocations as well as the role of surgical intervention following simple elbow dislocation.¹⁰^–¹³

Clinical Pearl 24.2

Persistent elbow instability or joint widening may indicate posterolateral rotatory instability or interposition of soft tissue or osteochondral fragments.

Non-operative treatment

The vast majority of simple elbow dislocations can be definitively treated without surgical intervention. Multiple studies over the past several years have compared surgical versus non-surgical management, the duration of immobilization and the type of immobilization used.^11,^12,^14,¹⁵

In a publication from 1984, Josefsson et al re-examined 52 patients with a simple elbow dislocation treated with a period of immobilization at an average follow-up of 24 years after the injury. They noted that 50% of the patients had no residual signs or symptoms. However, approximately 35% of the patients had a slight or moderate loss of full extension, and this was found to be associated with early degenerative changes in the joint and/or periarticular calcification. At long-term follow-up, none of the 52 patients had suffered a redislocation. They concluded that dislocation of the elbow without an associated fracture, when treated by conservative methods, had a good prognosis in spite of the usually extensive damage to the periarticular structures.¹¹ In another study, by Josefsson et al, 62 patients were followed for an average of 5 years following simple elbow dislocation. Thirty-four patients were treated non-operatively with closed reduction and immobilization in a plaster cast, while 28 patients were treated surgically with primary ligament repair followed by immobilization in plaster. Ligament repair was performed medially in all cases and laterally in only 17 at an average of 2 days following the injury. The authors found no significant difference in pain or range of motion between the two groups. As a result, they found no evidence to recommend primary surgical treatment of ligamentous injuries associated with simple elbow dislocations.¹²

In 1988, Mehlhoff et al published a series of 52 simple elbow dislocations treated with traditional closed reduction, but with varied duration of immobilization before initiating active motion. The average follow-up was 34.4 months. They noted that prolonged immobilization after the injury was strongly associated with an unsatisfactory result. Those immobilized for more than 25 days had significantly larger flexion contractures and more severe symptoms compared to patients immobilized for less than 2 weeks. As a result, they concluded that early active motion is crucial in rehabilitation of the elbow following a dislocation injury.¹ Proztman et al published a series of 49 simple elbow dislocations and noted similar findings to Mehlhoff et al. Patients immobilized for less than 5 days had returned to full activity within an average of 6 weeks of the injury, with an average flexion contracture of 3°. They concluded that while the extremity is certainly more comfortable if immobilized for the first 7–10 days after injury, the price to be paid for that short-term comfort is a longer period of disability as well as an increased flexion contracture. They therefore recommended reduction followed by only 1–5 days of immobilization.¹³

In a study from the United States Naval Academy, Ross et al treated 21 simple elbow dislocations with closed reduction and immediate supervised active range of motion starting the day after injury. No splints or slings were used. The final range of motion averaged −4–139°, and all patients attained extension within 5° of the contralateral side. Each patient also obtained their final range of motion within an average of 19 days following reduction of the dislocation. One patient experienced a redislocation, and, at final follow-up there was only one case of recurrent instability that required surgical repair. The authors concluded that aggressive immediate motion rehabilitation allows nearly full elbow motion and an excellent functional outcome. It should be noted, however, that the United States Naval Academy has a select group of athletes as well as unique resources to deal with sports medicine injuries.¹⁴

Some authors have also recommended longer periods of immobilization following reduction of a simple elbow dislocation. Schippinger et al prospectively studied 45 patients with a simple elbow dislocation with an average follow-up of 61 months. All patients were treated by closed reduction and then randomized to a period of immobilization of less than 2 weeks, 2–3 weeks or more than 3 weeks. Although not statistically significant, they noted better pain and functional results in patients immobilized for less than 3 weeks. The authors suggested that immobilizing for 2 weeks enhances patient comfort by allowing rapid subsidence of swelling and providing pain relief, and does not adversely affect the eventual outcome.¹⁶

A recent review article by Cohen et al recommended splinting simple elbow dislocations in approximately 90° of flexion for 5–10 days following radiographically verified reduction. As the unstable elbow can redislocate even in a well-moulded splint or cast, repeat radiographs should be obtained at 3–5 days and again at 10–14 days to ensure maintenance of reduction. They then recommend initiating range-of-motion exercises with interval splinting for comfort and support. Extension is gradually increased over the subsequent 3–6 weeks. Vigorous passive motion is avoided as it can cause swelling and pain and may be associated with the development of ectopic ossification.¹⁰

Some studies have also evaluated the types of non-operative treatment available. In a recent report by DeHaan et al, a meta-analysis was performed to identify the best available treatment for simple elbow dislocations. Two randomized controlled trials and six observation comparative studies were included with a total enrolment of 342 patients. The authors noted a better range of motion, less pain, better functional scores, shorter disability and shorter treatment time after functional treatment with a sling and early range of motion compared to plaster immobilization. Of the 342 simple dislocations, there was only one redislocation (0.3%). The authors recommended assessing the elbow for instability after reduction of the dislocation by valgus and varus testing and by the lateral pivot shift test. When the elbow is considered stable, functional treatment rather than plaster immobilization is advocated.² Maripuri et al came to similar conclusions when retrospectively reviewing 42 simple elbow dislocations treated with either plaster immobilization or a sling with early mobilization. They noted significantly better functional outcomes in the sling and early mobilization group compared to the plaster immobilization group.¹⁵

It is important to note that patients seen within the first several weeks after reduction of an elbow dislocation will often show residual subluxation on the lateral radiograph. This has been called the ‘drop sign’ and represents residual laxity of the joint. Although often an initial cause of concern, if there are no fractures associated with the dislocation this ‘drop sign’ can be treated by active exercises. It is also important to note that when the lateral X-ray is taken at follow-up it should be taken with the elbow by the patient’s side while actively contracting the biceps. At many institutions, the lateral X-ray is taken with the arm abducted onto a plate. In this position there will be an apparent subluxation as a result of placing a varus force onto a recently dislocated elbow.

If the patient is started on active contraction of the biceps and triceps, the ‘drop sign’ will resolve over a period of several weeks in the majority of patients. In a series of 23 patients, Duckworth et al showed that residual subluxation may occur following both operative and non-operative treatment. Patients started in active elbow flexion exercises while avoiding shoulder abduction and varus stresses demonstrated resolution of the ‘drop sign’ on follow-up radiographs. At a 2-year follow-up, the arc of motion averaged 20–132° with average pronation of 78° and average supination of 64°.¹⁷

This evidence from the literature would suggest that following reduction of an acute elbow dislocation an early range-of-motion protocol will result in an extremely low recurrence of elbow instability.

Clinical Pearl 24.3

Patients seen several weeks following closed reduction will often show residual subluxation on the lateral radiograph. This represents residual joint laxity and is known as a ‘drop sign’. This usually resolves over a period of several weeks with initiation of active biceps and triceps exercises.

Operative treatment

Recurrent instability following simple elbow dislocations is extremely rare, and occurs in only 1–2% of cases.^1,^12,¹⁸ Redislocation of the elbow with passive range of motion or redislocation in plaster immobilization implies severe valgus instability with disruption of some aspect of the lateral collateral ligament complex. In these situations and when clinical examination demonstrates recurrent elbow instability in 30° of flexion surgical treatment should be considered.

Repair of the lateral ligament complex will normally restore elbow stability and it is rarely necessary to address the medial collateral ligaments. McKee et al defined the pattern of soft tissue disruption of the lateral soft tissue structures in patients requiring operative repair for a dislocation or fracture–dislocation. They concluded that repair of the lateral soft tissue structures should be an integral part of the surgical strategy for elbow dislocations requiring surgical treatment.¹⁹

The operative approach involves a Kocher skin incision, after which the deep fascia is divided along the supracondylar ridge and between the extensor carpi ulnaris and anconeus. The common extensor origin is then partially reflected to expose the torn lateral ligament complex. A running non-absorbable suture is then placed in the lateral ligament and the suture ends passed through drill holes in the lateral epicondyle and securely tied.

Acute avulsion of both the medial collateral ligament and the flexor pronator group should be suspected if after repair of the lateral collateral ligament the elbow remains unstable. In this situation these structures will also need to be repaired. Acute instability rarely requires a graft for reconstruction and it is normally possible to suture repair the medial collateral ligament and flexor/pronator origin.

When exposing the medial side of the joint, the ulnar nerve must be identified and protected. In most cases, the origin of the flexor/pronator mass will have pulled away from the medial epicondyle, and the underlying disrupted medial collateral ligament will be easily visualized. This is mobilized and repaired by placing a Bunnell-type non-absorbable stitch through the ligament and then passing the suture ends through drill holes in the medial epicondyle. The sutures are tied securely over the medial epicondyle. The flexor/pronator mass is then securely repaired with further drill holes through bone.

It should be noted that external fixation can be used if bony and ligamentous stability are not easily achieved or if an unstable elbow persistently redislocates in a well-fitting cast or splint. It is extremely rare to need external fixation if there are no fractures occurring with the acute dislocation, but if a comminuted coronoid fracture occurs then placement of an external fixator can be used if the coronoid fracture is not amenable to plate or screw fixation.

Summary Box 24.2 Treatment

The majority of simple elbow dislocations are treated conservatively by closed manipulation and a short period of immobilization.

Surgery is indicated for recurrent dislocation and normally involves repair of the lateral ligament complex.

Rarely is repair of the medial ligament required.

Outcomes and complications

Most patients who sustain a simple elbow dislocation can be treated non-operatively and regain function with an adequate arc of motion. Lansinger et al reported good to excellent results in 75–100% of patients at long-term follow-up.²⁰ However, because there is significant injury to the soft tissues, some patients continue to complain of persistent pain, loss of motion and instability. The most common complications following a simple elbow dislocation are stiffness, instability and heterotopic ossification.

Stiffness (see also Ch. 28)

Elbow stiffness is thought to occur due to thickening and fibrosis of the anterior joint capsule. It has been reported that most patients lose the terminal 10–15° of elbow extension following a dislocation.¹⁰ Josefsson et al followed 52 patients for an average of 24 years following simple elbow dislocations and noted an average loss of elbow extension of 12°. Some of these patients, however, were unaware of the reduction in their range of extension. The authors also noted that patients who sustained a lateral dislocation had a somewhat greater loss of extension, although this difference was not statistically significant.¹¹ Early active mobilization may be helpful in reducing this complication.

Many authors have recommended the use of dynamic elbow splints if motion is not steadily improving within 4–6 weeks of the injury. If the stiffness is severe, surgical intervention is indicated. It is generally considered that patients require an arc of motion from 30° short of full extension to 130° of flexion (100° of motion) for activities of daily living. Husband et al used a lateral approach to release post-traumatic elbow contractures in seven patients and achieved an average increase in the arc of motion of 46°.²¹

Instability (see also Chs 25–27)

Insufficiency of the lateral elbow ligaments can lead to subtle instability of the elbow following dislocation. This is known as valgus posterolateral rotatory instability. Without lateral stabilization there is insufficient lateral joint support to hold the ulna reduced to the humerus and the ulna sags.²² In this situation, the ulnohumeral joint does not dislocate but rather pivots, opening up laterally in supination.²³ Lateral radiographs reveal posterior translation of the radial head with widening of the ulnohumeral joint space. This can be accentuated with the elbow in supination, and the deformity reduces with forearm pronation.

It is known that all simple elbow dislocations result in rupture of the medial and lateral collateral ligament complexes. Josefsson et al evaluated 31 patients with a diagnosis of a simple elbow dislocation. The authors examined all elbows under anaesthesia, followed by surgical exploration at an average of 2 days after the injury. Valgus instability was noted in 100% of the elbows, and varus instability was apparent in 26% of the elbows. Approximately 29% of the elbows were easily redislocated under general anaesthesia. Subsequent surgical exploration of the medial collateral ligament complex was performed in all 31 patients and exploration of the lateral collateral ligament complex was performed in 18 patients. The authors noted the medial collateral ligament was totally ruptured or avulsed in all 31 cases, and all 18 laterally explored elbows also demonstrated complete rupture or avulsion of the lateral collateral ligament complex. In addition, the degree of muscular damage was correlated with the tendency to redislocate under anaesthesia.²⁴

The pivot shift test is useful for examining elbows with suspected posterolateral instability. The patient is positioned in the supine position with the arm above and behind the head. The arm is initially held in extension with supination and is then taken into flexion with a valgus axial compression force. As this manoeuvre is performed the radial head, which is initially dislocated on the capitellum, suddenly reduces. This test can also be performed in full elbow flexion with supination and a valgus force. As the arm is taken into extension, the radial head can be felt to dissociate from the capitellum. It should be noted that in the awake patient these tests are near impossible to do and may elicit apprehension.

In examining the medial side of the elbow for instability, the medial collateral ligament can be examined for laxity in a similar way with the arm abducted and overhead behind the patient. If the forearm is pronated and a valgus stress applied to the arm in full extension, the ulnohumeral articulation can be noted to open up.

Evaluation of both the medial and lateral ligaments is best done under fluoroscopic guidance.

If a patient has clinical and/or radiographic evidence of lateral elbow instability after a simple elbow dislocation, they should avoid forearm supination for a period of several weeks to allow adequate healing of the lateral collateral ligament complex. Either a hinged elbow orthosis or a cast brace that keeps the forearm in pronation can be used. Reconstruction of the lateral collateral ligament complex is indicated in patients with symptomatic instability of the elbow.²⁵

Heterotopic ossification

In a retrospective review of 62 simple elbow dislocations, Josefsson et al noted heterotopic ossification in 76% of patients at long-term follow-up. The most common sites of periarticular calcification were anterior, medial and/or lateral to the elbow joint. The authors also noted a strong correlation between the presence of the heterotopic ossification and the loss of extension of approximately 10°. However, this was only noted in patients with lesions medially and/or laterally.¹²

Heterotopic ossification is usually evident on radiographs within 4–6 weeks of injury (Fig. 24.4). It is often associated with closed head injury, delayed surgical intervention and aggressive passive joint manipulation after dislocation.¹⁰ In high risk patients, prophylaxis with a non-steroidal antiinflammatory medication, bisphosphonate or low-dose radiation should be considered. If the heterotopic ossification remains symptomatic, operative resection can be discussed. Most surgeons allow the process to mature before considering operative resection. This often occurs between 3 and 4 months following injury. Recurrence, if it occurs, is usually minor following surgical excision.