Spontaneous healing of hypertrophic pseudoarthrosis of pediatric mid shaft ulna with elastic stable intramedullary nailing in situ: A case report

Abstract

Forearm fractures are the most common type of fractures in pediatric age. As children have excellent healing potential, fracture nonunion is a very uncommon complication. Elastic intramedullary nailing, a minimally invasive technique, is an excellent treatment modality for the unstable forearm shaft fractures in children, which can seldom lead to nonunion. Here, we present a case of hypertrophic pseudoarthrosis of mid shaft of ulna in a 13-year-old male, which healed spontaneously with elastic stable intramedullary nailing in situ.

Introduction

The most common type of fractures in children are those of the forearm (metaphyseal followed by shaft), which typically heal well without the need for surgery. For children with unstable forearm shaft fractures, elastic stable intramedullary nailing (ESIN) is currently the preferred therapy since it permits early mobilization without the need for plaster. ¹ Nonunions following ESIN in children have only been reported infrequently and are poorly documented. We report a case of spontaneous healing of hypertrophic nonunion of the ulna in a child with both bone forearm fractures managed with ESIN.

Case report

A 13-year-old male was brought to the emergency room of our hospital with a complaint of pain and swelling over right forearm after he fell from a tree while playing. He sustained a closed fracture of the left radius and ulna (American Orthopedic Pediatric Comprehensive Classification of Long Bone Fractures 21-D/4.1) ² (Figure 1(a)). He sustained no other injuries. After pre-op investigation, he was planned for closed reduction and intramedullary elastic nailing, which was successful for radius was. However, open reduction was needed for ulna and elastic nail was placed with usual technique (Figure 1(b)). The postoperative period was uneventful, and the left forearm was splinted in an arm pouch sling. Mobilization of the forearm was started after 2 weeks. Early physiotherapy included active assisted flexion and extension exercises of elbow and wrist together with active assisted forearm supination and pronation in full range. Under regular follow-up, at 6 months, the radius united but the ulna developed a hypertrophic nonunion (Figure 1(c)). As there were no clinical symptoms and the range of motion was not restricted without any relevant axial malalignment, we did not indicate surgical revision. The patient was kept in a close follow-up. Ten months after the trauma, a bony consolidation without any axial malalignment could be documented (Figure 1(d)). The ESIN was removed after 1 year. He has full supination and pronation of the affected forearm.

Figure 1.

(a) Pre-op X ray showing both bone fracture of forearm. (b) Post-operative X ray showing elastic stable intramedullary nailing in both radius and ulna. (c) X ray at 6-month follow-up showing nonunion of ulna. (d) X ray at 10 months showing spontaneous union of ulna.

Discussion

Accounting for almost 20% of all fractures, forearm fractures are the most common type of fractures in pediatric age. Out of these injuries, 50% involved both bones and were found to be significantly more common among males in a review by Caruso et al. ³

Conservative management with long-arm casting is still the preferred first line of treatment for pediatric forearm fractures. Both plate fixation and flexible nailing are acceptable treatment options if adequate reduction cannot be achieved. ⁴ ESIN, a minimally invasive technique introduced in the early 1980s, allows good stabilization and plaster free post reductive mobility and has excellent outcomes. ⁵ As children have excellent healing potential, fracture nonunion is a very uncommon complication.^6,7 In a review of 592 children, only 6 cases of pseudoarthrosis were reported and all of those were observed in ulna, using 6 months cut off for radiological appearance of bony consolidation. ⁵ Definitions of union and nonunion status are imprecise and subject to disagreement.^{8 –10} While some emphasize time duration, others contend that the radiographic appearance of no advancement toward union during an interval is sufficient to make the diagnosis of nonunion. ¹¹

Open reduction and wide bone exposure, poor fixation, an inadequate period of immobilization (<8 weeks), and early hardware removal (<3 months) are considered as the cause of nonunion. ¹² The middle third of the ulna is stated to have a relative “watershed-zone” for the intraosseous circulation. ¹³ Open surgical procedures, damaging, or at least impairing the periosteal tissue due to compromise of local vascularization and/or removal of fracture hematoma may affect the natural fracture healing even in children.^14,15 Open reduction and distraction of the fracture during nail insertion may have contributed to delayed bone healing in our case as well.

Treatment of the nonunion must be individualized, but usually requires excision of the nonunion fibrous tissue, bone grafting, and internal fixation. ¹¹ Performing a revision surgery for nonunion is tedious and associated with more surgical morbidity at bone graft donor sites. ¹⁶ It has always been a matter of dilemma regarding the time and strategy of intervention in case of pediatric nonunion. Of the six cases of nonunion of ulna in both bone forearm fractures, Fernandez et al reported surgical intervention in four cases (for axial deviation and broken nail) and no intervention in two cases, achieving spontaneous healing over long run (10–11 months). ⁵ As our patient had no clinical symptoms, restricted range of motion or misalignment, no operative intervention was performed. This report adds to the growing body of literature that open reduction and fixation with ESIN of a pediatric ulna can seldom lead to nonunion. This approach can be applied in cases where the in situ nails itself has not fractured and the patient has no clinical symptoms of nonunion.

Conclusion

In cases with hypertrophic pseudarthrosis with no clinical symptoms and no restriction or limitation of movements, a conservative approach with closed monitoring may be a satisfactory treatment option.