Review Question - QID 214063

This patient sustained a low-velocity gunshot wound to the femur with an associated vascular injury. The presence of a vascular injury has been shown to increase the risk of infection.

A low-velocity GSW is defined as a muzzle velocity <350 meters per second or <2,000 feet per second. Recent studies have demonstrated an increased risk of local infection when vascular injury and fracture occurred together. Therefore, these patients should receive antibiotics. Conversely, retained bullet fragments have not been shown to increase the risk of infection.

Berg et al. examined the epidemiology, incidence, and distribution of firearm-related extremity trauma and the relationship between injury pattern and local or systemic complications. They report that an isolated fracture increased the risk of compartment syndrome, whereas vascular injury alone increased the risk of compartment syndrome and deep venous thrombosis. Fracture and vascular injury together also increased the risk of wound infection. They conclude that gunshot-related fracture increases the risk of vascular and nerve injury and that vascular injury, with or without fracture, is the biggest predictor of local complications.

Nguyen et al. retrospectively reviewed the rates of infection in low-energy gunshot wounds (GSWs) to the extremity. They report that the overall infection rate was 15.7% (22 patients), and the deep infection rate was 3.6% (5 patients). They concluded that infections after low-energy extremity GSWs are infrequent, but soft tissue injuries without fracture treated with a single dose of intravenous antibiotics in the emergency department had a lower rate of infection.

In a separate study, Nguyen et al. retrospectively reviewed infection rates and other complications after intra-articular (IA) gunshot wounds. They report that 3.6% of patients developed deep infections, all had associated vascular injuries. They concluded that the incidence of infection after IA gunshot injuries is low with the routine use of antibiotic prophylaxis and patients with vascular injury deserve special attention, as they are at higher risk of infection.

Watters et al. retrospectively reviewed the use of surgical débridement in the management of low-velocity gunshot injuries (GSIs) resulting in pelvis fractures. They found a deep infection related to their pelvis GSIs occurred in 7% and 6% among patients who underwent surgical débridement and those who did not, respectively. They concluded that there was no increased incidence of infection in the absence of aggressive surgical débridement of pelvis GSI wounds. The study also demonstrated that retained bullets and bullet fragments did not increase the risk of infection, even after penetrating the GI tract organs.

Figure A is a CT angiogram demonstrating a right femur fracture with a vascular injury. Figure B is a CT angiogram demonstrating a right femur fracture without a vascular injury.

Incorrect Answers:
Answer 1: Due to the location of the injury, Patient A may be at increased risk for amputation, but is not at increased risk for hip disarticulation
Answer 3: The presence of a vascular injury has not been shown to increase the risk of malunion
Answer 4: The presence of vascular injury has not been shown to increase the risk of hardware failure
Answer 5: Nerve damage, not vascular injury, would increase the risk of neuropraxia