Heterotopic ossification in the forearm

Heterotopic ossification (HO) resulting in radioulnar cross-union occurs in approximately 2% of all forearm injuries and causes significant functional impairment. Risk factors for cross-union are incompletely understood, however, injuries to the proximal forearm account for the majority of cases. Concomitant central nervous system injury greatly increases the risk for HO after forearm fracture. Although surgical excision of forearm cross-union has produced mixed results in the past, and recurrence of synostosis has been common, more recent treatment attempts have resulted in nearly full recovery of forearm rotation. Questions remain regarding the appropriate timing for excision and the advisability of adjuvant low-dose radiotherapy to prevent recurrence. It would seem that HO resulting from local trauma in the absence of other risk factors can be safely excised 6 to 12 months after injury. Adjuvant radiotherapy may be warranted in more aggressive cases of HO with a greater risk for recurrence, such as those cases involving the proximal forearm or associated with closed head injury.