Heterotopic ossification after surgery for fractures and fracture-dislocations involving the proximal aspect of the radius or ulna.

BACKGROUND: The objectives of this study were to (1) determine the prevalence of heterotopic ossification after surgery for fractures and fracture-dislocations involving the proximal aspect of the radius or ulna, (2) identify risk factors associated with the development of heterotopic ossification in these injuries, and (3) characterize the severity and location of the heterotopic ossification and the associated range of elbow motion.
METHODS: From 2004 to 2008, 142 elbow fractures and fracture-dislocations involving the proximal aspect of the radius or ulna were treated surgically at our institution. Records and radiographs of 130 elbows with adequate follow-up were retrospectively reviewed to identify cases of heterotopic ossification, characterize the ectopic bone, and analyze associated risk factors. The most frequent injuries included olecranon fractures, Monteggia fracture-dislocations, and various combinations of fractures of the radial head and coronoid with or without dislocation or subluxation.
RESULTS: Heterotopic bone was identified on the radiographs of forty-eight elbows (37%). Heterotopic ossification interfered with motion in twenty-six elbows (20%), and thirteen elbows (10%) underwent additional surgery to remove heterotopic bone with the goal of improving motion. Risk factors associated with the development of heterotopic ossification included elbow subluxation or dislocation at the time of presentation, an open fracture, a severe chest injury, and a delay in definitive surgical treatment. Ectopic bone was preferentially located at the origin of torn soft-tissue structures or around fracture sites, and it was particularly common around the posterior aspect of the ulna and the neck of the radius. Heterotopic ossification was classified on radiographs as hazy immature in twenty-two elbows, limited mature in eighteen, extensive mature in five, and a complete bone bridge in three. Heterotopic ossification was more common in patients with an associated distal humeral fracture, radial head and coronoid fractures with an associated elbow dislocation (terrible triad injury), and a transolecranon fracture-dislocation.
CONCLUSIONS: Thirty-seven percent of elbows treated surgically for fractures involving the proximal aspect of the radius and/or ulna developed heterotopic ossification. In twenty percent of elbows, heterotopic ossification was associated with clinically relevant motion deficits. More severe heterotopic ossification was encountered in patients presenting with an associated distal humeral fracture, terrible triad injury, transolecranon fracture-dislocation, or Monteggia fracture-dislocation. Patients with an open injury, instability, severe chest trauma, or delay in definitive surgical treatment had a higher prevalence of heterotopic ossification.