Outcomes Following Low-Energy Civilian Gunshot Wound Trauma to the Lower Extremities: Results of a Standard Protocol at an Urban Trauma Center

Abstract

Background

Lower extremity injuries secondary to low-energy gunshot wounds are frequently seen in the civilian populations of urban areas. Although these wounds have fewer complications than high-energy gunshot injuries, the functional and psychological damage is still significant making appropriate timely orthopaedic treatment and follow-up imperative.

Purpose

The purpose of this study is to present our outcomes in the treatment of low-energy gunshot wounds in a civilian population at an urban, level one trauma center in patients treated by a standard protocol.

Methods

One hundred and thirty three patients who sustained 148 gunshot wound injuries were treated at our level one trauma center between January 1^st, 2009 and October 1^st, 2011. Following IRB approval, we extracted information from medical records regarding hospital course, length of stay and type of operative or non-operative treatment. If available, injury and post-operative radiographs were also reviewed. Patients were contacted by telephone to obtain Short Musculoskeletal Function Assessment (SMFA) surveys, pain on a scale of 0–10 and for the determination of any adverse events related to their shooting.

Results

There were 125 men (94.0%) and 8 women (6.0%) with an average age of 27.1 years (range 15.2–56.3). Seventy-six patients (57.1%) did not have any health insurance upon admission. The average length of stay in the hospital was 4.5 days (range 0.0–88.0). Fifty-one gun shots (34.5%) resulted in fractures of the lower extremities. Patients underwent a total of 95 lower extremity-related procedures during their hospitalization. Twenty-two patients (16.5%) experienced a complication related to their gunshot wounds. 38% of the cohort was available for long-term functional assessment At a mean 23.5 months (range 8–48) of follow up, patients reported mean Functional and Bothersome SMFA scores of 19.6 (SD 15.9) and 10.9 (SD 15.6) suggesting that these patients have poorer function scores than the general population. These patients still had pain related to their gunshot injury with an average pain score of 2.16 (range 0–8).

Conclusions

Gunshot injuries to the extremities may involve bone, soft tissue, and neurovascular structures. Execution of appropriate therapeutic methods in such situations is critical for treating surgeons given the potential for complications. At our level one trauma center, gunshot victims were predominantly young, uninsured adult men. Complications included infection, compartment syndrome, and arterial injuries. Functional data collected demonstrated that patients continued to have difficulties with ADL's at long-term follow-up.

Introduction

Civilian gun violence rates have decreased since 1993, but still accounts for around 500,000 violent crimes per year¹. Civilian gun violence rates are steadily increasing in the United States with each passing decade. Lower-energy weaponry, such as handguns and shotguns, typically inflict most of these injuries².

A lower severity of tissue damage is expected as opposed to injuries inflicted by higher velocity weapons. However, depending on how missile mechanical factors interact, variations in the extent of damage may be appreciated. Damage caused by gunshots directed to the lower extremities can be especially extensive owing to the anatomical structure of lower extremities.

At our center, the orthopaedic and trauma surgeons tend to be more aggressive in treating extremity gunshot wounds than many of centers in our local area. The purpose of this paper is to present and discuss our experience in the treatment of low-energy gunshot wounds to the lower extremities.

Methods and Materials

Institutional review board (IRB) approval was obtained and we retrospectively reviewed cases of low-energy gunshot wounds to the lower extremities in a civilian setting over a 22-month span. One hundred and thirty three patients with gunshot wounds to the lower extremities were identified in the trauma database of our level one center. Medical records were obtained and information regarding hospital stay management course, and insurance methods were recorded. The appropriate operative details and radiographic imaging studies were collected and assessed. At our institution, a standard protocol was developed for the management of all gunshot wounds to the extremities as follows: Soft tissue wounds superficial to the fascia were washed out and debrided in the emergency room without antibiotic treatment. Injuries that appeared to have deep muscle or bony involvement were taken for operative I & D and given IV antibiotics for 24–48 hours depending upon the extent of injury noted in the OR. Operative irrigation and debridement was our most commonly used treatment modality. Hennessy et al regards this procedure necessary for the removal of surface contaminants and debris³. Burg et al also supports this method as standard protocol for all gunshot injuries to assist with complication prevention i.e., infection⁴.

We attempted to contact each patient by telephone to obtain long-term outcome information. Fourteen patients (10.6%) were currently incarcerated or expired and unable to be contacted. Outcomes were evaluated and scored using the Short Musculoskeletal Function Assessment (SMFA) at long-term phone follow-ups.

Results

Injury and Treatment

A total of 133 patients with 14 low-energy gunshot wounds to the lower extremities were identified as eligible for this study. Nine patients sustained bilateral injuries, which were counted as 2 wounds. The mean age of the study group population was 27.1 years (range: 15.2–56.3). There were 125 men (94.0%) and 8 women (6.0%). Patients underwent a total of 95 procedures during their hospitalization. Mean hospitalization time was 4.52 days (range: 0–88). Gunshot wounds caused 51 total fractures, with 6 patients (11.7%) receiving multiple fractures (counted as sustaining 1 gunshot injury or wound). Six fractures locations were identified, 1 fracture site was unknown due to amputation. The exact distribution is depicted in Figure 1a. The remaining 9 injuries (65.5%) consisted of soft tissue damage only. Forty-three patients underwent operative treatment. Figure 1b displays the definitive treatment modality distribution for all operative injuries. Twenty-eight percent of all patients underwent formal irrigation and debridement in the operating room as a definitive treatment, while 21% of patients had additional fracture fixation (intramedullary nailing, external fixation and open reduction internal fixation procedures utilizing plates and screws). Forty-six percent of operative patients underwent fixation with an intramedullary nail. Of the 6 (11.8%) fractures treated with external fixation devices, 3 (50.0%) of these devices were converted to intramedullary nailing, whereas the remaining 3 (50.0%) were treated definitively with the original external fixator. In addition, 6.3% of patients had an extremity angiogram procedure for questionable vascular status. Of the patients who went to the OR, foreign body removal was performed in 6.3% of the cohort.

Figure 1a. Distribution of gunshot-inflicted fractures.

Figure 1b. Distribution of definitive operative treatments.

Complications

The overall complication rate in the series was 15% (22 complications out of 148 injuries). See Table 1 for complete breakdown of complications. Of the 9 injuries associated with vascular injury to the lower extremity, 5 (55.6%) were associated with bony fractures. Two (1.4%) gunshot wounds were associated with nerve damage. One of the 2 injuries was complicated by nerve injury was associated with a fracture of the femoral shaft. Neither of these nerve injuries were concomitant with vascular injury. The patient who developed vasospasm was managed with heparin to salvage the limb. Patients who developed compartment syndrome were successfully treated with a fasciotomy One patient with a comminuted tibia fracture underwent a below the knee amputation five days after placement of an external fixator due to focal necrosis of bony and soft tissue. One patient required a revision surgery for an infected nonunion of the tibia; the patient's intramedullary nail was replaced with an antibiotic nail and subsequently healed after several subsequent procedures.

Table 1.

Number and rates of complications among 143 injuries

Gunshot wound complications
	Vascular Injury	Nerve Damage	Acute Infection	Vasospasm	Compartment Syndrome	Amputation	Revised surgery
148 injuries	9 (6.1%)	2 (1.4%)	7 (5.3%)	1 (0.8%)	3 (2.3%)	1 (0.8%)	1(0.8%)

Hospital Details

The average length of hospital stay in days varied according to the type of injury sustained by patients. Forty-three out of 97 (44.3%) patients with soft tissue injuries only were discharged on the day of admission, most of which underwent non-operative treatment. The average length of hospital stay for soft tissue injuries without vascular damage was 1.2 days (range 0–10). Patients who sustained bony injuries along with soft tissue injuries average length of hospital stay was 7.1 days (range 0–88). The average length of stay for patients who sustained vascular injuries along with other soft tissue injuries was 11.7 days (range 0–24). Those injuries that included a combination of vascular, bony and soft tissue injuries stayed for an average 17.0 days (range 0–35, 0 = died same day of admission). Patients who sustained multiple organ injuries had hospital stays at an average of 13.5 days (range 2–33). The average cost of hospital stay for the different gunshot inflicted injuries is listed in Table 1.

Outcomes

Out of the 133 patients enrolled, 14 were incarcerated or expired and 55 patients were unable to be contacted and therefore lost to follow up. Fifty patients (37.6%) successfully completed the Short Musculoskeletal Function Assessment Questionnaire. Scores were obtained at a mean of 24 months (range: 8–48) of follow up. Patients reported a mean total standardized SMFA score of 10.1 (SD: 12.7). Pain related to gunshot injuries were at an average pain score of 2.16 (range 0–8). Thirteen (9.8%) patients are currently incarcerated and one (0.8%) patient expired shortly after injury.

Discussion

The treatment of low-energy gunshot wounds is contingent on the degree of tissue damage generated by the bullet. Typically, damage is classified according to bullet speed as low-velocity gunshot injuries (<2000 ft/s) or high velocity gunshot injuries (>2000ft/s); however, the amount of harm one bullet is capable of causing is in fact related to a variety of factors. Flight, behavior, and projectile effects in combination with bullet type, velocity and mass are all significant elements. Thus, decisions pertaining to the management of gunshot wounds should not be based solely on weapon velocity⁵.

The primary survey addresses emergencies related to airway, breathing and circulation (ABC). Once issues regarding these parameters have resolved a thorough physical exam is done as part of the secondary survey. Entrance and exit wound patterns can then be appreciated. Physician recognition of characteristic wound patterns may hasten treatment implementation and heighten suspicion for probable associated injuries⁶ which will be further aided by imaging obtained.

In our study population, the infection rate was low with 7 (5.3%) patients developing primary superficial infections and 1 (0.8%) patient a deep soft tissue infection. Our infection rate was similar to most studies analyzing lower-velocity injuries treated without prophylactic antibiotic treatment⁷. Marcus et al's data demonstrated that patients who did not receive antibiotics prophylactically in the emergency department fared no worse or better in terms of early or late infections compared to those who had prophylactic treatment⁸. Dickey and Howland et al also concluded that antibiotics were not necessary in the routine management of lower-velocity injuries^2,9. Conversely, Patzakis and Woloszyn et al both felt that prophylactic antibiotic treatment was beneficial for patients with these types of injuries^7,10. Furthermore, Meleney et al stated that 3 days of intravenous antibiotic therapy is optimal for infection prevention of contaminated wounds¹¹.

In terms of treatment following establishment of infection, all seven acute infections in our cohort resolved with appropriate antibiotic treatment and surgery. However, the one case with the deep infection associated with a non-union ended up undergoing a revision surgery in which an intramedullary nail was exchanged for an antibiotic nail.

The standard of care for gunshot fractures at our institution begins with primary stabilization of the patient and ends with fracture analysis. In the emergency department, a complete physical examination is followed by neurological exam; open fractures are covered with sterile dressings to separate the wound from environmental bacteria. Once any emergencies have been addressed, radiographs of the fracture site are taken (including the joint above and below the fracture site) for delineation of the extent of bony and soft tissue injury.

In the recent literature, intramedullary nailing has been labeled as the primary treatment method for low-velocity femoral fractures^12,13. The most commonly used fixation method in our cohort was intramedullary nailing. Weil et al reported intramedullary nailing as their most common modality for gunshot inflicted fractures followed by external fixation¹⁴. Conversely, Burg et al reported external fixation (36%) as their primary fixation tool and intramedullary nailing (28%) as second⁴. Our experience with low-velocity gunshot wounds demonstrate that select bony injuries can be treated operatively with immediate internal fixation rather than extended external fixation as Burg et al reported.

Tissue swelling is to be expected in extremity fracture, thus, fasciotomies should be performed when concern for the development of compartment syndrome is present. Three patients (2.3%) developed compartment syndrome in our cohort, and all were treated with fasciotomy without long-term complication.

Arterial damage in the lower extremity can be a limb or life-threatening situation and demands immediate attention. Dor lac et al reviewed the cause of death for gunshot victims at their institution and found that over half of their patients died from excessive loss of blood secondary to arterial damage within the lower extremity¹⁵. To help expedite the treatment of such critical injuries, Smith et al proposed specific hard signs to look for when vascular injury is suspected; no palpable pulses, signs of ischemia, excessive bleeding, and pulsating or expanding hematoma¹⁶. Burg et al also reported on a sensitive test for identification of vascular damage; an ankle brachial index (ABI) of 0.9 or less⁴.

In this series, when arterial damage was suspected, an angiogram (6.3%) and/or surgical exploration (5.3%) was performed. Knudson et al found that the use of Duplex Doppler Ultrasonography as a replacement to angiography was equal in sensitivity in detecting vascular injury and yet non-invasive¹⁷. Ziperman et al supports the use of surgical exploration in these situations and recommends that it be done for all gunshot injuries². Overall, angiography and exploration have been accepted in the literature as the mainstay of investigation when vascular injury suspicion is high⁶. Nerve injury can present as numbness, tingling, paralysis or any combination of those three⁶. Two (1.4%) gunshot wounds at our institution were associated with peripheral nerve damage. These neurological injuries were treated non-operatively It has been reported that neurological deficits associated with lower-velocity gunshot injuries may resolve without surgical intervention⁸.

Outcomes of gunshot wound patients were measured using the SMFA questionnaire. Compared to valid normative SMFA data (baseline of musculoskeletal health of the general population)¹⁸, functional, daily, and mobility indexes of gunshot wound patients all proved to be worse at latest follow-up compared with the general population. Interestingly, both mean bothersome and emotional standardized scores were better in the gunshot patients compared to the general population.

In conclusion, with thorough physical examination and fracture analysis, primary stabilization, irrigation and debridement in the emergency room, appropriate fixation, and proper follow-up care, low-velocity gunshot wounds can be successfully treated with high patient satisfaction rates. With better recognition of these types of injuries, substantial improvements can be made to patient lives and the healthcare system alike.