Pediatric elbow dislocations are uncommon, accounting for 3–6% of all elbow injuries [1, 2] with an average age around 10–11 years [2,3]. They are typically classified based on the displacement of the radius and ulna. Posterior and posterolateral are the most common, but anterior, medial, lateral, convergent, and divergent dislocations also occur. Convergent dislocation involves the translocation of the proximal radius and ulna, while in divergent dislocation the ulna displaces medially and the radius displaces laterally ^[4]. The first reported case of a convergent dislocation case was documented by Harvey and Tchélébi in 1979 ^[5]. Since that time, including this report, there have been 27 cases of elbow dislocation with proximal radius-ulna translocation reported in the literature in the pediatric population [1,5-23] and multiple in the adult literature [14,24,25]. No closed reduction (CR) maneuver has been published. This injury is often missed initially or misdiagnosed. Patients will present with elbow pain, swelling, fixed pronation, and occasionally neurovascular injuries. Delayed recognition may lead to poor functional results [5,8,14,19]. The key to diagnosis is early radiographic recognition of disruption of the radiocapitellar relationship. A line through the proximal radius should intersect the capitellum in all radiographic planes. Computed tomography (CT) scan may also aid in diagnosis ^[20]. This report presents a case of early detection and CR of an elbow dislocation with proximal radioulnar translocation and reviews existing pediatric cases. It also includes a detailed description of the CR technique.

A 9-year-old female fell from a bunk bed onto an outstretched arm, initially diagnosed with a left elbow dislocation at a community hospital (Fig. 1). Despite CR attempts and improvement in flexion and extension, she remained in fixed pronation and was transferred to our hospital for further evaluation. On arrival, three view radiographs of the left elbow were obtained and demonstrated a proximal radioulnar translocation (Fig. 2). CR was again attempted in our emergency department with no change in the radiographic appearance. A CT scan was obtained due to concern for intra-articular fragment blocking reduction. Instead, it more clearly showed a radioulnar translocation. Fig. 3 is the 3D reconstruction of the elbow which shows the ulna articulating with the capitellum and the radius articulating with the trochlea, consistent with this diagnosis.

Overnight, the patient developed an ulnar nerve palsy that was not present in the initial evaluation at either hospital. The patient was acutely taken to the operating room for reduction and ulnar nerve exploration. Concentric reduction was achieved via CR using the technique described below. Intraoperative fluoroscopy confirmed reduction with the restoration of the radiocapitellar and ulna-trochlear articulation (Fig. 4). After reduction, the elbow had full passive flexion, extension, pronation, and supination compared to contralateral side. Due to her acute ulnar nerve symptoms, it was felt she then warranted exploration of her ulnar nerve. A medially based incision was made to explore the ulnar nerve which was intact but bruised (Fig. 5). The medial periosteum had been avulsed from the distal humerus and was repaired with suture. Throughout the range of motion, there was no subluxation of the ulnar nerve. The patient was placed into a long arm splint for 2 weeks and subsequently transitioned to a hinged elbow brace.

By 3 months postoperatively, her ulnar nerve palsy symptoms had resolved. Radiographs demonstrated maintenance of reduction of the radiocapitellar and ulna-trochlear joints (Fig. 6). At follow-up 2 and 1/2 years after the injury, the patient had resumed her previous level of function. On examination, she had full and symmetric flexion and extension, full supination, and lacked only 5° of pronation when compared to the unaffected side (Fig. 6). She had normal sensation and distal motor function. Radiographs from this follow-up show maintained reduction with a small amount of ossification medially, thought to be due to previous periosteal avulsion from her dislocation (Fig. 7).

CR technique

A key aspect of a successful CR of a pediatric proximal radio-ulnar translocation is the successful identification of the injury before the reduction attempt. Once identified, the following reduction maneuver (Fig. 8a, b, c) can be attempted:

1. Position the patient supine with the arm extended
2. Reduce ulnohumeral dislocation first if present
3. Palpate the head of the radius, noting that it will be medial to its typical anatomic position
4. Position one hand around the patient’s distal forearm, and one around the elbow so that the thumb is positioned directly over the radial head (Fig. 8a)
5. Using the hand around the distal forearm, apply axial traction through the elbow. At the same time, hyper pronate the patient’s forearm (Fig. 8b)
6. Using the hand positioned at the elbow, apply direct pressure over the radial head. At the same time, use the other hand to apply forced supination to the forearm (Fig. 8c).

Elbow dislocations with proximal radioulnar translocations are rate in pediatrics, with 27 cases reported in the literature (Table 1). Proposed mechanisms include axial loading to the proximal radius after a fall onto a hyperpronated and outstretched hand. Isbister proposed that it is due to axial loading with a valgus stress on an outstretched supinated hand ^[9]. Harvey described it as an iatrogenic injury as a result of traction and pronation during attempted CR without appropriate identification of the injury ^[5]. The exact mechanism is difficult to determine, however, Keny et al. recently published a cadaveric study illustrating this mechanism on a cadaveric model, showing forearm hyperpronation with a valgus strain on the elbow, causing rupture of the medial collateral ligament, followed by the radial collateral ligament and ulnar insertion of the annular ligament, leading to transposition of the radius and ulna ^[21]. Identification of the injury in a timely manner is important for restoration of elbow function.

Most cases required open reduction (n = 21, 78%) with or without internal fixation to restore a congruent elbow joint [1,5,7-19,22,23]. Six cases (22%) were successfully treated with CR [6,15,20,21]. Often, these injuries are accompanied by other fractures including the radial head, radial neck, and coronoid process. Fourteen (52%) cases involved a radial head or neck fracture [1,6,8-10,13,14,17,18,22,23]. Two cases (7%) had an associated coronoid process fracture [7,8]. Only eleven cases (41%) had no associated concurrent fractures [5,11,12,15,16,19,20,21]. The most common complication in this review was incomplete ulnar nerve palsy which occurred in 14 cases (52%), all of which recovered within 1 year [5,7,9,15,16,18-23]. Additional complications were ulnar nerve entrapment within the proximal radioulnar joint (n = 1) ^[19], median nerve palsy (n = 2) [12,23], heterotopic ossification (n = 4) [9,13,17,18], non-union or malunion of the proximal radius after fixation (n = 2) [14,18], and avascular necrosis of the radial head (n = 1) ^[5]. The injury is often missed or misdiagnosed on presentation. Thirty percent (8) of the injuries were missed, with delay in care ranging from 1 day to 3 months [1,5,8,11,12,15,17,19]. There are a variety of reasons why the injury may initially go unrecognized. First, this injury is rare, and treating providers may be unaware of it and fail to recognize the injury pattern. Second, most commonly reported, during CR a palpable clunk is often felt giving the false sense of reduction [20,22]. Third, the lateral radiograph may appear reduced. Evaluation of the anterior-posterior radiograph is necessary to appreciate the translocation. Fourth, post-reduction, there is an increase flexion-extension arc of the forearm. However, the forearm remains pronated with minimal supination, a term referred to as “pseudoreduction” [1,7,20,22]. To avoid misdiagnosis and a delay in treatment, it is essential to recognize the injury, assess the lateral and the anterior-posterior radiographs with scrutiny, perform CR when possible, and proceed to the operating room when CR is not successful. In our review, 83% of these cases required open reduction.

This report provides a CR technique consisting of axial traction, hyperpronation followed by forced supination, and direct pressure on the radial head to successfully reduce a proximal radio-ulnar translocation when identified early and appropriately.

This case underscores the importance of vigilance in diagnosing complex elbow injuries and highlights the efficacy of timely identification and CR of proximal radioulnar translocations. Despite initial challenges and acute ulnar nerve palsy that underwent exploration, our patient achieved complete functional recovery without the need for an open reduction. The CR maneuver is detailed in this paper. The patient’s ulnar nerve symptoms completely resolve within 3 months. Two years later, they have full range of motion and are actively participating in gymnastics with no limitations. Physicians must maintain a high index of suspicion for these injuries, carefully evaluating radiographs and promptly intervening when indicated.

Pediatric proximal radioulnar translocation is a rare injury that is critical to identify when present, as it is associated with a high rate of missed injury, neurovascular compromise, and need for open reduction. CR is possible and can lead to a favorable outcome without the need for open surgery. A technique is described in this article. This project was undertaken as a case report project at Shriners Hospitals for children and, as such, was not formally supervised by an Institutional Review Board.