Risk Factors Associated with Diagnoses of Heterotopic Ossification in Recent Combat Amputees

Abstract : A significant complication impairing the rehabilitation of recent combat amputees is heterotopic ossification (HO), excess bone growth in residual limbs. Few studies have analyzed risk factors for HO among amputees injured in Operation Enduring Freedom and Operation Iraqi Freedom. The present research investigated injury factors and complications associated with HO diagnoses during routine clinical encounters by retrospective review of medical records of combat amputees injured between 2001 and 2005 (n = 382). The results showed 18% of patients had HO diagnoses, which were significantly associated with increased injury severity, amputations at higher levels (e.g., above elbow and above knee versus below elbow and below knee) and in lower limbs, and increased rates of several complications: osteomyelitis, infections, deep vessel thrombosis, and pulmonary embolism. The present study extended previous research by showing significant associations between early complications and HO diagnoses. Medical record diagnoses were valid predictors of HO risk factors in a large sample. A diagnosis of HO occurred in approximately 1 in 5 patients, although this rate appeared low due to under reporting early in Operation Enduring Freedom and Operation Iraqi Freedom.