Introduction

Monteggia fracture, characterized by proximal one third of ulna shaft fracture combined with radial head dislocation, was first described by Monteggia et al. in 1814, while recent studies included fracture of the olecranon (1). With an incidence of less than 2% of forearm injuries in children and adults, this rare combination injury could eventually lead to forearm deformities and dysfunction, if not diagnosed at an early stage, resulting in neglected Monteggia fracture (NMF) (1).

Though Monteggia fracture is well defined as radial head dislocation combined with proximal ulna fracture, the exact time point to consider a chronic phase Monteggia fracture is controversial. Recent studies recommended over 4 weeks after injury as the dividing line for Neglected Monteggia Fracture, as malunion of the ulna had already formed. If not diagnosed at an early stage, these lesions can gradually lead to forearm deformities and dysfunction, finally resulting in neglected Monteggia fracture. When the radial head is not reduced, several deformities develop at the humeroradial joint, including cubitus valgus and osteoarthritis. Adequate radiographs are crucial when the surgeons deal with forearm injuries. Opening-wedge osteotomy of the ulna restores normal ulnar length and corrects the angulation of the ulna in patients with chronic Monteggia fracture-dislocations. In addition, this eases the reduction of the radial head. Morbidity caused by annular ligament reconstruction surgery can be prevented by preserving the intact annular ligament. After dilatation and mobilization of the annular ligament, reduction of the radial head can be accomplished. Patients who receive repair of the native annular ligament were more likely to achieve lasting radiocapitellar joint stability when compared with patients who received annular ligament reconstruction or if the annular ligament was not addressed. (2) This study evaluated the effectiveness of corrective opening-wedge ulnar osteotomy and radial head relocation into the intact annular ligament in the treatment of pediatric chronic Monteggia fracture-dislocation. (4)

Our patients functionally benefited from the procedure with significant improvement in elbow pain and stability, as well as improved flexion of the elbow with stable radial head reduction. Fracture dislocations are classified according to the Bado radiological classifications. (5)

Figure 1: Bado classification of Monteggia fractures and characteristics.

Material and method

We prospectively studied the clinical and radiographic outcomes for five children with a missed Monteggia fracture. The study group included three boys and two girls who had a mean age of ten years (range, four years to sixteen years) at the time of open reduction.

Figure 8 and 9: Follow up clinical pictures

Case 2:

Figure 10: Pre op X-ray

Figure 11: Post op xray

Figure 12: Follow up of patient with nonunion and deformity

Locking compression plate could guarantee adequate stability in younger patients with mild deformities, while the gap between two osteotomy sites often requires bone graft (11)

Bor et al. (12) reported four patients who were treated with closed reduction, proximal ulnar osteotomy, and Ilizarov external fixator received good clinical outcomes. Similar results were then reported by Take et al. (13) and Yuan et al. (14). Minimally invasive operation with external fixation allows gradual and spatial correction of the ulnar deformity to reduce the displaced radial head without invading the humeroradial joint, but long duration of wearing the frame could bring certain inconvenience to daily activities and needs higher compliance of the patients (12).

Open reduction of the radial head was employed by most studies. Gallone et al. (15) found no significant difference in the rate of recurrence of dislocation between close and open reduction of the radial head.

The repositioning and reconstruction of annular ligament should be taken into consideration in NMF patients because it stabilizes the radial head during forearm rotation and prevents redislocation (16).

In NMF cases with intact annular ligament, different studies reported improved elbow mobility and stability with or without reconstruction of the annular ligament (17, 18). Other studies suggested that the reconstruction of annular ligament could be avoided unless there was detectable rotational instability of the radial head after reduction intraoperatively (19).

Excessive angulation after osteotomy of the ulna could lead to re-dislocation of the radial head and requires a second surgery to enhance stability of the radiocapitellar joint. Besides, Bado III NMF was reported with higher rate of recurrence of radial head luxation, indicating that annular ligament repair is unavoidable (20).

Conclusion

Monteggia fractures become challenging if not noticed within 4 weeks after injury. Patients then require surgery to reduce the radial head and correct forearm deformities. Classification system should take dislocation of PRUJ in to consideration, which would direct management and prognosis. Also, detailed examinations, especially radiographs, should be taken when the surgeon deals with forearm trauma. Surgical intervention, including osteotomy and angulation of the ulna, reduction of the radial head, internal or external fixation and reconstruction of the stability of the PRUJ and radiocapitellar joint, could bring satisfactory outcomes to NMF patients, while site for osteotomy of the ulna, fixation method, and whether the annular ligament needs reconstruction varies from studies.

References