The most important factors to consider with a firearm injury to the extremities are the possibility of vascular and nerve injuries, compartment syndrome, fractures and knowledge of the type of weapon used. Artery and nerve injuries are the major causes of mortality and long-term morbidity in extremity gunshot wounds.108
Although low-velocity injuries from handguns account for the majority of extremity injures in the civilian population, high-velocity wounds and shotgun wounds have the greatest potential for devastating injury, largely because they have a higher percentage of kinetic energy transference, have a higher degree of wound contamination, have a higher risk for compartment syndrome, and more often have associated comminuted fractures with devitalized bony fragments.109,119 Shotgun injuries, overall, have been found to have twice the mortality rate of rifle or handgun wounds.
Wounds to the shoulder have been found to represent 9% of upper extremity gunshot wounds. Approximately 15% of these wounds are associated with a vascular injury and up to 25% involve injuries to the subclavian and axillary arteries.111 Forearm gunshot wounds have been found to account for up to 20% of gunshot wounds overall, of which pulse deficits of the radial and ulnar arteries have been reported to be as high as 86% and 83%, respectively.111,112 Furthermore, penetrating forearm injuries are the most common cause of upper-extremity compartment syndrome, with a rate of 10%.30,113
Lower-extremity ballistic injuries have the highest rate of fractures. The majority involve the femur (22%-49%); the tibia accounts for 11% to 14%.5 Injuries to the hip and bony pelvis carry significantly higher morbidity and mortality due to related injuries to the abdominal and pelvic organs.114 Thigh wounds carry significant potential for vascular injury with high risk of massive hemorrhage, especially when the injury involves the medial aspect of the thigh or when a severe femur fracture occurs.
Injuries to the leg, especially the tibia, can be especially devastating. Overall, the majority of compartment syndromes are found in tibial trauma from both blunt and penetrating injuries. Gonzalez showed that 60% of patients who developed compartment syndrome in penetrating lower extremity trauma had associated tibial fractures.115