Ballistics and gunshot wounds: effects on musculoskeletal tissues.

As a result of the increasing number of weapons in this country, as many as 500,000 missile wounds occur annually, resulting in 50,000 deaths, significant morbidity, and striking socioeconomic costs. Wounds are generally classified as low-velocity (less than 2,000 ft/sec) or high-velocity (more than 2,000 ft/sec). However, these terms can be misleading; more important than velocity is the efficiency of energy transfer, which is dependent on the physical characteristics of the projectile, as well as kinetic energy, stability, entrance profile and path traveled through the body, and the biologic characteristics of the tissues injured. Although bullets are not sterilized on discharge, most low-velocity gunshot wounds can be safely treated nonoperatively with local wound care and outpatient management. Typically, associated fractures are treated according to accepted protocols for each area of injury. Treatment of low-velocity, low-energy fractures is generally dictated by the osseous injuries, as these are similar in many regards to closed fractures. Soft tissues play a more critical role in high-velocity and shotgun fractures, which are essentially open injuries. Aside from perioperative prophylaxis, antibiotics are probably required only for grossly contaminated wounds; however, because contamination is not always apparent, most authors still recommend routine prophylaxis. High-energy injuries and grossly contaminated wounds mandate aggressive irrigation and debridement, including a thorough search for foreign material. Open fracture protocols including external fixation or intramedullary nailing and intravenous antibiotic therapy for 48 to 72 hours should be instituted. If there is vascular damage, exploration and repair are best performed after prompt fracture stabilization. Evaluation of the "four Cs"-color, consistency, contractility, and capacity to bleed-provides valuable information regarding the viability of muscle. Skin grafting is preferable when tension is required for wound closure, although other soft-tissue procedures, such as use of local rotation flaps or free tissue transfer, may be necessary, especially for shotgun wounds. Distal neurologic deficit alone is not an indication for exploration, as it often resolves without surgical intervention.