Fractures of the medial epicondyle have been a topic of considerable debate, with evolving issues regarding evaluation and treatment of these injuries. In this paper, we aim to specifically address the current literature pertaining to radiographic evaluation and evolving operative indications for isolated fractures of the medial epicondyle. The breadth of our discussion will not include fracture dislocations or fractures associated with neurovascular injury.
The medial epicondyle of the humerus is an apophysis that serves as a point of attachment for the forearm flexor muscles, the pronator teres, and the medial collateral ligament (MCL). Fractures of the medial epicondyle make up approximately 12% of all pediatric elbow fractures1 and occur most commonly in children between the ages of 7 and 15.2 This injury is typically secondary to a valgus stress at the elbow joint, leading to an avulsion fracture from the pull of the flexor and pronator muscles. Such trauma may result from a fall or from athletic activities, especially throwing.3
Patients will typically present with the elbow held in flexion, have pain and tenderness on the medial aspect of the joint, and describe a history of the aforementioned trauma or activity. Overhead athletes may specifically report a popping sensation or sound while throwing, followed by immediate pain. About half of all pediatric medial epicondyle fractures are associated with concurrent elbow dislocation.2,4,5 Furthermore, as the ulnar nerve passes just posterior to the medial epicondyle, ulnar nerve dysfunction may be seen in 10% to 15% of patients.5–7
Typically, anteroposterior (AP) and lateral radiographs of the affected elbow are obtained, and treatment decisions are made according to these findings and those on clinical examination. Additionally, stress radiographs may help the clinician in assessing the stability of the elbow joint. On an AP plain film of a normal elbow, the medial epicondyle will typically demonstrate a smooth cortical contour. In fractures of the medial epicondyle, however, disruption of this contour with an avulsion of the apophysis may be seen. All views should also be carefully evaluated for fracture fragments within the articular space. The reliability of AP and lateral radiographs in guiding clinical decisions is the subject of recent debate and therefore will be addressed later.
The classic indications for nonoperative treatment include nondisplaced or minimally displaced fractures with a stable elbow.7–9 Such patients are typically immobilized until healing, although another option is a combination of immobilization followed by an early range-of-motion (ROM) exercises. Despite the fact that nonoperative therapy may provide fibrous union, the intermediate and long-term functional results of nonsurgical treatment are thought to be excellent.9–13
The established indications for operative intervention include open fractures, gross elbow instability, intra-articular incarceration of the fracture fragment, or ulnar nerve symptoms (Fig. 1).8,9,14 These patients are generally treated with open reduction and internal fixation with the use of screws, pins, or suture. Many authors prefer Kirschner wires in very young patients with open physes, whereas screws may be suitable in adolescents (Fig. 2).14 When a cannulated screw is used, a washer can be used to improve fixation stability and prevent fragment comminution during screw insertion. For small fragments, a guide pin may be placed into the center of the fragment to serve as a joystick and aid in reduction. When anatomic reduction is achieved, the guide pin is advanced. Care should be taken if a threaded guide pin or Kirschner wire is inserted bicortically, as the radial nerve may be at risk laterally.
Although the literature is scarce regarding combined acute medial epicondyle fractures and MCL ruptures in pediatric patients, the treating clinician should be alert to the possibility of such associated injuries. After securing the medial epicondyle intraoperatively, the surgeon should check the elbow for any persistent pathologic laxity. Direct inspection of the MCL can also be performed if there is significant discrepancy. We have anecdotally noted late instability in a throwing athlete referred to us after nonunion of a markedly displaced fracture that was initially treated nonoperatively. Late fixation of a medial epicondyle nonunion may be performed in select circumstances. However, careful bone bed preparation should be performed and fractional lengthening of the flexor pronator mass may be required to allow for anatomic reapproximation of the medial epicondyle.
Any surgical intervention should proceed with constant awareness of the location of the ulnar nerve. Additionally, misplacement of any instrumentation into the olecranon fossa could increase the risk for postoperative loss of elbow extension. An evolving trend in postoperative care, especially in adolescents with screw fixation, is early ROM therapy soon after treatment. This may lessen the risk of decreased elbow extension after stable, anatomic fixation. Overall, excellent intermediate and long-term outcomes are well documented in surgically treated patients.9,10,15,16
For several decades, a subject of considerable debate has been moderately to markedly displaced fractures that do not fall into the classical operative and nonoperative criteria. To date, there is no consensus as to what specific magnitude of displacement should serve as the standard criterion for operative intervention. Researchers have used 3, 5, 9 mm, or an undefined “significant” amount of displacement as criteria for surgery, whereas some series do not specify their operative indications.5,8–10,13,17–21
The utility of displacement as measured on plain radiographs has also recently come into question. In 1 study, both intraobserver and interobserver agreement on measurements of these fractures by 5 reviewers were found to be low.22 “Disagreement” was defined as a difference of >2 mm on repeat measurement. Reviewers disagreed with each other an average of 54%, 87%, and 64% on AP, lateral, and oblique views, respectively. The authors suggest that intraobserver reliability may improve with an increased level of training, but even experienced surgeons are likely to disagree on the degree of displacement.22
Another study retrospectively reviewed 11 cases of medial epicondyle fractures that were originally diagnosed as nondisplaced or minimally displaced, and then compared displacement on plain radiographs and 3-dimensional computed tomography scans.23 The mean anterior displacement on lateral radiographs was 0.9 mm, but was found to be an average of 8.8 mm on 3-dimensional computed tomography. In this cohort, 6 of the 11 patients who were initially diagnosed as “minimally displaced” on x-ray actually had >1 cm of displacement.23
One reason for the suboptimal reliability of plain radiographs in these fractures may be the lack of a standardized system by which to measure displacement. For example, one may measure the distance between any 2 points between the fragment and the bone from which it came, resulting in a plethora of potential values (Fig. 3). Some authors suggest using AP radiographs whenever possible, as this view was found to have the best intraobserver and interobserver reliability, and to measure the displacement at the point of maximal distance between the fragment and its origin.22 However, variations in the obliquity of AP radiographs may contribute to an appearance of medial displacement, which seems to be overestimated in the AP view.23 Furthermore, there exists the possibility that displacement alone does not necessarily predict elbow stability, and stress radiographs may help identify patients with unstable elbows.
Both nonoperative and operative interventions have been shown to yield good clinical outcomes. Several authors have achieved good results from nonoperative treatment9–11 and some have suggested no difference in the long-term function between surgical and nonsurgical intervention.9 A systematic review of the literature examined data from 14 studies (498 patients) to evaluate operative versus nonoperative treatment of pediatric medial epicondyle fractures. Although the authors found that the odds of radiographic union were 9.33 times higher with operative fixation than with nonoperative treatment, they found no difference in pain or ulnar nerve symptoms at final follow-up between the 2 groups.7 We believe that the equivalence noted in clinical studies and systematic reviews provides equipoise for further prospective studies.
The authors of the aforementioned systematic review also note that although operative intervention may not have any significant functional advantage in the long term, there seems to be a rising trend favoring surgery over nonoperative treatment in many centers.7 One may argue that if both groups of patients do well in the long term, how vital are clinical decision-making guidelines for patients who do not fall under the classic treatment indications? Those that favor surgical intervention hypothesize that open reduction and internal fixation provide greater stability of fixation, allowing for earlier ROM exercises. Furthermore, although previous studies have not clearly considered the impact of the increasing intensity of children’s athletics, there remains the possibility that operative fixation may be advantageous for athletes, especially “overhead” athletes who compete in sports with high demands on the elbow (Fig. 2). The primary goals of treatment for any fracture of the medial epicondyle are avoidance of painful nonunion and minimization of the risk of symptomatic valgus instability. Therefore, the decision to operate necessitates consideration of a number of factors, including the mechanism of injury, the degree of elbow stability, and the functional goals of the patient.
The optimal treatment of pediatric medial epicondyle fractures remains the subject of much debate. Although most authors agree that surgery is appropriate for patients with a grossly unstable elbow, ulnar nerve dysfunction, or an intra-articular incarcerated fracture fragment, there is no consensus on treatment guidelines for children who do not fall into this group. A number of studies suggest that standard AP and lateral radiographs are likely insufficient for the measurement of fracture displacement and subsequent clinical decision making. In addition, multiple authors have found no difference in the long-term functional outcome between operative and nonoperative treatment in patients with moderate displacement, although published studies have not evaluated this difference in competitive “overhead” athletes who place heavy demands on the elbow. We believe that prospective studies will help create standardized treatment guidelines. Until then, the relative indications for surgery must be weighed carefully on a case-by-case basis, and patients and their families should be counseled as to the risks and benefits of both operative and nonoperative treatment.
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