Injured Marines at risk for abnormal bone growth

Marines and other military personnel who are wounded in combat as the result of a high-energy trauma, such as a bomb blast, are likely to develop an abnormality known as heterotopic ossification. In this condition, bone forms within the soft tissues, such as muscle located near a fracture or other bone injury. New research conducted at the National Naval Medical Center in Bethesda, MD, is helping to pave the way for a better understanding of the mechanisms of the condition, and better courses of prevention and treatment. A discussion of the study appears in the May 2009 issue of The Journal of Bone and Joint Surgery. "The purposes of this study were to report our experiences with high-energy wartime extremity wounds, to define the prevalence of heterotopic ossification in these patients, and to determine the factors that might lead to development of the condition," said lead author Lieutenant Commander Jonathan Agner Forsberg, MD.

Dr. Forsberg and his team compared data from 243 patients who were treated for orthopaedic injuries between March 1, 2003 and December 31, 2006 at the medical center, including patients who underwent:

• amputation
• external or internal fixation of one or more fractures
• removal of damaged, dead or infected tissue, or 'debridement'

The researchers considered variables such as:

• age and gender of the patient
• location and mechanism of injury
• location of the heterotopic ossification
• presence and severity of brain injury

The team also compared patients' Injury Severity Scores, which are values assessed to individual patients based on the number and types of injuries they have sustained.

The study determined risk factors for the development of this condition which include:

• an age of less than 30 years
• the presence and severity of traumatic brain injury
• the presence of an amputation
• multiple injuries to the extremities
• a high Injury Severity Score

Heterotopic ossification is often associated with injuries to the brain or spinal cord, which can cause the entire body to react as though it is under attack. This type of response is known as a systemic inflammatory response. Dr. Forsberg believes this unique response to massive injury is the key to understanding why the abnormal bone growth occurs more often in military wounds than in those commonly treated in the civilian population.

"Systemic inflammation is detrimental to this patient population," Dr. Forsberg noted. "We believe that this sort of response contributes significantly to the development of heterotopic ossification, and is the reason why the condition is more prevalent in the war-wounded population."

Dr. Forsberg also said further study to be conducted at the medical center will focus heavily on treatment methods geared toward prevention of the condition.

"Once we develop a better understanding of the events that cause heterotopic ossification, one of our primary recommendations will be treatments to prevent the condition from occurring," noted Dr. Forsberg.

Source: American Academy of Orthopaedic Surgeons