Fracture nonunion and delayed union

Abstract

Delayed union and nonunion of fractures exist in the pediatric population. Fracture healing requires the synergistic collaboration of mechanical support and robust biological processes to allow endochondral ossification, reestablishment of bone continuity, and subsequent remodeling to strong lamellar bone. Failure of either mechanical stability or biology may manifest as delayed fracture healing. While early recognition of potential metabolic and pharmacologic risk factors may be addressed by pre-emptive treatment using nutritional and vitamin D supplements, definitive treatment of established nonunion requires a comprehensive approach.

Key concepts: (1)Delayed unions and nonunions are more common in adult bone but can also occur in pediatric bone.(2)Fracture healing requires synergistic collaboration of mechanical support and robust biological processes; treatment of nonunions should address both the biological and mechanical factors.(3)Vitamin D is an integral component of calcium absorption and bone health.

Keywords: Bone health; Fracture nonunion; Pediatric fracture; Vitamin D.

Figure 1

KM is an 8.5-year-old gymnast who fell of the uneven bars and broke her R ulna (Fig. 1a). She suffered a refracture 4 months later and was treated with a series of casts and splints at 7 months she had persistent lucency and pain (Fig. 1b). Metabolic work revealed slightly low vitamin D level with hypercalciuria of unknown etiology. She was treated vitamin D, Calcium and underwent IM fixation of her ulna (Fig. 1c). She was subsequently seen in genetics 1 year after injury and was diagnosed with a defect in Type 2 collagen formation. Her ulna was healing at 21 months (Fig. 1d) and by 26 months was finally healed (Fig. 1e). The family and treating surgeons elected to leave the implant in. Case example courtesy of Kenneth Noonan MD MHCDS. Fig. 1a. Isolated ulna fracture in 8-year healthy gymnast. Fig. 1b. 6 months after the injury she had persistent fracture lucency after suffering a refracture Fig. 1c. IM fixation was performed at 7 months from original injury. Fig. 1d. 21 months after the fracture her ulna has periosteal bridging and a slight lucency at fracture site. Fig. 1e. 26 months after her original fracture she is fully healed.