Heterotopic Ossification Following Combat-Related Trauma

Abstract

The term heterotopic ossification refers to the aberrant forma­ tion of mature, lamellar in nonosseous tissue. Trans­ lated from its Greek (heteros and topos) and Latin (ossificatio) etymologic origins, heterotopic ossification can be literally de­ fined as bone formation in other location. The first written account of heterotopic ossification describes the treatment of symptomatic lesions. Al-Zahrawi (more commonly known in Western cultures as Albucasis ), widely considered the father of surgery, wrote in the year 1000 C. E., This callus often occurs after the healing of a fracture ... and sometimes there is limitation of the natural function of the limb ... if the callus is stony hard and its removal is urgent, incise the place and cut away the superfluous prominence, or pare it away with a scraper until it is gone; and dress the wound until it heals.' Currently, orthopaedic surgeons faced with treating mature, refractory, symptomatic heterotopic ossification are left with few options other than operative excision. Although it is remarkable that the treatment of heterotopic os­ sification has scarcely changed in the last millennium, it is gen­ erally accepted that prophylaxis against heterotopic ossification is far preferable than the later treatment of symptomatic lesions. As such, the focus of scientific effort in recent years has been directed toward prophylaxis, not treatment. The formation of heterotopic ossification has been ob­ served following total hip arthroplasty, acetabular and elbow fracture surgery, electrocution and burn injuries, and traumatic brain injury or spinal cord injury'. Following most traumatic injuries in the civilian population, the formation of heterotopic ossification is relatively rare in the absence of head injury. Even following traumatic brain injury or spinal cord injury, hetero­ topic ossification develops in only 20% and 11 o/o of patients, respectivelf. Rates of heterotopic ossification formation exceed 50% only in the setting of femoral shaft fractures with concomitant head injury', although reported rates following ace­ tabular and elbow fractures vary substantially. Numerous combat-related injury and amputation studies from the latter half of the twentieth century make no specific mention of heterotopic ossification, suggesting that it was not a common occurrence in prior conflicts 5 ·•. However, military medical texts