Background: Although infrequently reported in amputees previously, heterotopic ossification has proven to be a common and problematic clinical entity in our recent experience in the treatment of traumatic and combat-related amputations related to Operation Enduring Freedom and Operation Iraqi Freedom. The purpose of the present study was to report the prevalence of and risk factors for heterotopic ossification following trauma-related amputation as well as the preliminary results of operative excision.

Methods: We identified 330 patients with a total of 373 traumatic and combat-related amputations who had been managed at our centers between September 11, 2001 and November 30, 2005. We reviewed the medical records and radiographs of 187 patients with 213 amputations who had adequate radiographic follow-up. Additional analysis was performed for twenty-four patients with twenty-five limbs that required excision of symptomatic lesions. The mechanism and zone of injury, amputation level, timing of excision, use of prophylaxis against recurrence, and other confounding variables were examined. Outcomes were assessed by determining clinical and radiographic recurrence rates, perioperative complications, preoperative and follow-up pain medication requirements, and the ability to be fit with a functional prosthesis.

Results: Heterotopic ossification was present in 134 (63%) of 213 residual limbs, with twenty-five lesions requiring excision. A final amputation level within the zone of injury was a risk factor for both the development and the grade of heterotopic ossification (p < 0.05). A blast mechanism was predictive of occurrence (p < 0.05) but did not correlate with grade. All patients who had been managed with excision were tolerating the prosthetic limb at an average of twelve months of follow-up. Twenty-three limbs demonstrated no evidence of recurrence, and two limbs had development of clinically asymptomatic, radiographically minimal recurrences. Six patients experienced wound-related complications that required reoperation, and two patients required subsequent minor revision surgery. There was a significant decrease in the use of pain medication following surgery (p < 0.05).

Conclusions: Heterotopic ossification following trauma-related amputation is more common than the literature would suggest, particularly following amputations that are performed within the initial zone of injury and those that are due to blast injuries. Many patients are asymptomatic or can be successfully managed with modification of the prosthesis. For patients with refractory symptoms, surgical excision is associated with low recurrence rates and decreased medication requirements, with acceptable complication rates.

Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Heterotopic ossification following traumatic and combat-related amputations. Prevalence, risk factors, and preliminary results of excision.

OBJECTIVE--To describe and quantify patterns of injury from antipersonnel mines in terms of distribution of injury, drain on surgical resources, and residual disability. DESIGN--Retrospective analysis. SETTING--Two hospitals for patients injured in war. SUBJECTS--757 patients with injuries from antipersonnel mines. MAIN OUTCOME MEASURES--Distribution and number of injuries; number of blood transfusions; number of operations; disability. RESULTS--Pattern 1 injury results from standing on a buried mine. These patients usually sustain traumatic amputation of the foot or leg; they use most surgical time and blood and invariably require surgical amputation of one or both lower limbs. Pattern 2 injury is a more random collection of penetrating injuries caused by multiple fragments from a mine triggered near the victim. The lower limb is injured but there is less chance of traumatic amputation or subsequent surgical amputation. Injuries to the head, neck, chest, or abdomen are common. Pattern 3 injury results from handling a mine: the victim sustains severe upper limb injuries with associated face injuries. Eye injuries are common in all groups. CONCLUSIONS--Patients who survive standing on a buried mine have greatest disability. Non-combatants are at risk from these weapons; in developing countries their social and economic prospects after recovery from amputation are poor.

https://www.bmj.com/content/bmj/303/6816/1509.full.pdf

Injuries from antipersonnel mines: the experience of the International Committee of the Red Cross.

Injuries to the musculoskeletal system are the most common type seen on the battlefield today. Most of these injuries are due to explosive munitions or improvised explosive devices (IED. However, due to terrorist attacks, blast-related injuries are those that both civilian and military medical personnel should be prepared to treat.1 Explosive devices are often preferred by today’s terrorists, because they are not only relatively inexpensive, but readily designed, assembled, transported, and detonated. As of 2012, bomb blasts accounted for the vast majority of all of terrorist attacks worldwide, and the trend continues upward.2 In addition, devastating explosions can occur outside the military and political environment.3

Blast and Fragment Injuries of the Musculoskeletal System

The term heterotopic ossification refers to the aberrant forma­ tion of mature, lamellar bone 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

Heterotopic Ossification Following Combat-Related Trauma

Explosive blast causes a pattern of injury including primary blast lung, secondary fragment injury and traumatic amputation of limbs. Major traumatic amputation is rare in survivors of bomb blast but common in those who die. The mechanism of such injury has not been previously determined, but must be established if protective measures are to be developed for members of the armed forces. The nature of 41 traumatic amputations in 29 servicemen who survived to reach medical care after blast injury was investigated to determine the anatomical level of amputation and the pattern of soft tissue damage. Joints were an infrequent site of amputation and the tibial tuberosity was a particularly frequent site of lower-limb severance. Comparison of the pattern of injury was made with that seen in ejecting fast-jet pilots, who frequently suffer major flailing injury; there appears to be a substantially different injury distribution. The accepted mechanism of traumatic amputation, avulsion by the dynamic overpressure, is challenged; it is suggested that the shockwave resulting from an explosion is capable of causing at least bone disruption in a limb.

B. Wongrukmitr

Papers

Combat casualties in Northern Thailand: emphasis on land mine injuries and levels of amputation.