Insights into posttraumatic heterotopic ossification in extremity war injuries

Heterotopic ossification (HO) denotes the formation of mature lamellar bone in nonosseous or soft tissue. HO is a well-known complication of trauma; however, in the war-wounded population the incidence is much higher than that in the civilian population. While the pathophysiology and molecular biology of HO are subjects of continued investigation, the current model stipulates that high-energy trauma causes a chronic inflammatory state facilitating a fibrous osteoinductive environment leading to endochondral ossification. There is no standard prophylaxis regimen for combat-related HO since conventional therapies such as radiation and nonsteroidal antiinflammatory drugs carry a higher risk of complications compared with that in the civilian population. Treatment of symptomatic HO begins with conservative management and eventually surgical excision in the appropriately selected patient. Through improved understanding of the pathophysiology and basic science of the disorder, recent investigative efforts have focused on development of an appropriate prophylactic agent, as well as treatment therapy, for this condition in the war-wounded. This article reviews the current literature on combat-related HO and describes the experience with this disease process at our institution.