Heterotopic ossification in high-grade open fractures sustained in combat: risk factors and prevalence.

OBJECTIVES: To determine the prevalence and identify the risk factors for heterotopic ossification (HO) formation in high-grade open fractures sustained during combat and to report on the results of HO excision. DESIGN: Retrospective. SETTING: United States Army level-1 trauma center. PATIENTS/PARTICIPANTS: Seventy-six consecutive patients with 91 combat-related open Gustilo and Anderson type II and higher fractures were identified from March 1, 2003, through January 30, 2005. Fifty-nine patients with 71 fractures met criteria for study inclusion. MAIN OUTCOME MEASUREMENTS: Fractures were categorized into HO-present and HO-absent groups based on radiographic imaging. Risk factors such as injury mechanism, injury severity score (ISS), Gustilo and Anderson type, injury location, closed head injury, burn, and infection were compared between the groups. RESULTS: HO was present in 27 of 71 open fractures (38.1%). Variables associated with HO formation included ISS (p = 0.02) and injury location although infection and use of negative pressure therapy were not. Ten of 27 fractures with HO underwent excision. HO did not occur or was mild in 25 tibiae. CONCLUSIONS: HO is a common sequela of high-grade open fractures sustained in combat. High ISS and injury location to the shoulder, hip, and femur are risk factors for HO formation. The most common regions for HO excision were the elbow, forearm, and hip with mixed results. Importantly, HO did not seem to be a complication of open high-grade tibia fractures. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.