Posteromedial Dislocation of the Elbow With Lateral Condyle Fracture in Children

Abstract

Posteromedial dislocation of the elbow in children is an extremely rare injury. The current study describes four boys with posteromedial dislocation of the elbow associated with a displaced fracture of the lateral humeral condyle. The patients ranged in age from 6 to 12 years (average age, 9 years 6 months). Closed reduction of the elbow dislocation and open reduction of the lateral humeral condyle fracture with fixation by Kirschner wires by a lateral approach was done in each patient. This was followed by 4 weeks immobilization wearing a long-arm cast. There were three excellent results and one good result. Healing and return of normal function occurred in all but one patient who had minor loss of full extension. Average duration of followup was 7 years 6 months (range, 3–13 years). Dislocation of the elbow associated with a displaced fracture of the lateral humeral condyle can be treated by closed reduction of the elbow dislocation and open anatomic reduction and fixation of the lateral condyle fracture with good results.

Traumatic dislocation of the elbow is a rare injury in children constituting 3% to 6% of all elbow injuries. ^1,15 Dislocations of the elbow are described by the direction of displacement of the radioulnar unit from the distal humerus. Ninety-five percent of dislocations are posterior and of these 70% are posterolateral. These dislocations may be associated with avulsion of the medial epicondyle ^1,9,15 and infrequently with fracture of the lateral humeral condyle. ^6,12,14 Medial or posteromedial dislocations of the elbow were described by Stimson ¹⁰ in 1900 and later by Tachdjian ¹¹ in 1990.

This is a retrospective study of four patients with posteromedial dislocation of the elbow associated with a displaced fracture of the lateral humeral condyle.

MATERIAL AND METHODS

Between 1986 and 1996 four boys 11, 6, 12, and 9 years of age with a posteromedial dislocation of the elbow and a fracture of the lateral condyle of the humerus were treated by the authors (Table 1). The mechanism of injury was presumably a fall with the hand and elbow in extension. According to Watson-Jones ¹³ the fractures of the lateral humeral condyle are classified as Type III (displaced and rotated fractures) and according to Rang ⁸ as Type II (unstable fractures) (Fig 1A, B).

TABLE 1: Data on the Patients

Fig 1A–F.: A radiograph shows the elbow in a 6-year-old boy (Patient 2) with (A) a posteromedial dislocation of the elbow associated with (B) a grossly displaced fracture of the lateral humeral condyle after a fall from a height (2 m). A radiograph shows (C) the same elbow 10 days after an open anatomic reduction and stabilization of the fracture with two smooth K wires. (D) The distal ends of the K wires were left protruding from the skin for easy removal without an anesthetic. Eight years postoperatively the radiograph shows (E) the elbow is normal. (F) Function of the elbow also is normal.

In all four patients the elbow dislocation was reduced under general anesthesia by a closed method. After the closed reduction the fracture of the lateral humeral condyle was reduced in all four patients by open methods by a lateral approach and was stabilized with two smooth Kirschner (K) wires (Fig 1C, D) in three patients (Patients 1, 2, and 4) and with three K wires in one patient (Patient 3). The distal ends of the K wires were left protruding from the skin for easy removal without an anesthetic. In all four patients the fractured lateral humeral condyle was grossly medially and distally rotated. Intraoperatively and immediately after the fixation of the fracture the elbow was clinically stable.

Postoperatively the limb was immobilized in a long-arm cast for 4 weeks with the elbow flexed at 90° and the forearm in neutral position. The K wires were removed once the fracture was healed, which was approximately 4 weeks in all four patients. Active mobilization of the elbow was encouraged and no physiotherapy was used.

Hardacre et al ² described the following functional and cosmetic criteria for evaluation of the results. According to them an excellent result means no loss of motion, no alteration in the carrying angle, and no symptoms. A good result is characterized by a satisfactory functional range of motion, lacking no more than 15° complete extension. Any alteration in carrying angle had to be inconspicuous, and no arthritic or neurologic symptoms could be present. A poor result included disabling loss of motion, conspicuous alteration of the carrying angle, arthritic symptoms, ulnar neuritis, radiographic findings of nonunion, or avascular necrosis. The carrying angle determination may be inaccurate when there is any loss of extension, and the cosmetic effect of alteration of the angle is subjective.

RESULTS

The patients were followed up for an average of 7 years 6 months (range, 3–13 years). At the latest followup no deformity or instability was seen. The range of elbow motion was full extension and 140° flexion in three of the patients, whereas the fourth patient healed with a small intraarticular gap because of inappropriate reduction and lacks 15° extension. Rotational movements of the forearm were supination 85° and pronation 85° in all four patients (Table 2). Neither heterotopic bone formation nor valgus or varus deformity appeared in the elbow region in any patient because of growth disturbances.

TABLE 2: Patient Treatment and Followup

According to the functional and cosmetic criteria of Hardacre et al ² the results were excellent (Fig 1E, F) in three patients and good in one patient.

DISCUSSION

Tachdjian ¹¹ is the only author, to the best of the current authors’ knowledge, who described a case of medial dislocation of the elbow associated with fracture of the lateral humeral condyle. McLearie and Merson ⁶ published a review of five patients with displaced fracture of the lateral humeral condyle associated with posterolateral dislocation of the elbow. In the current series the elbow was dislocated posteromedially in all four patients.

There was no neurovascular compromise to the injured limb. The fractured lateral condyle along with part of the distal humeral metaphysis was displaced grossly and was medially and distally rotated.

Numerous authors agree that prompt open reduction and internal stabilization of the displaced lateral humeral condyle fracture in children give the best results. ^2–5,7 Anatomic reduction of the fracture was achieved in three of four patients (Patients 1, 2, and 4), whereas a gap in the articular surface between the lateral and medial humeral condyle remained because of inappropriate reduction in the fourth patient. In the third patient a lack of 15° extension of the elbow was seen at followup probably because of this gap. In these patients, an intraoperative radiograph would have been helpful, and therefore is strongly recommended to document that the reduction and internal fixation is satisfactory.

None of the patients had any complications and all have done well after this course of treatment.

The posteromedial dislocation of the elbow associated with a displaced fracture of the lateral humeral condyle is a rare injury and is not difficult to treat. Reduction of the elbow by closed methods and stabilization of the lateral condyle fracture by open anatomic reduction are appropriate treatments.

Acknowledgment

The authors thank Margaritis J. Kyrkos, MD, for translation and formatting of the manuscript.