Surgical site infection can be a devastating complication that results in significant morbidity in patients who undergo operative fixation of fractures. Reducing the rate of infection and wound complications in high-risk trauma patients by giving early effective antibiotics, improving soft tissue management, and using antiseptic techniques is a common topic of discussion. Despite heightened awareness, there has not been a significant reduction in surgical site infection over the past 40 years. Patients should be treated aggressively to eliminate or suppress the infection, heal the fracture if there is a nonunion, and maintain the function of the patient.
Rates of infection are higher in patients undergoing operative fixation of fractures compared with other orthopedic procedures.
Patients with open fractures are at the highest risk of infection, especially in cases with severe soft tissue injury.
Re-evaluation of current antibiotic infection prophylaxis in patients with open fracture is warranted.
A diagnosis of surgical site infection after fracture fixation requires a comprehensive evaluation of clinical examination, serum laboratory values, and imaging studies.
Surgical site infection can have devastating consequences for patients in orthopedic trauma surgery and innovative methods to prevent these complications must continue to be sought.
The human body is composed of 10 13 native cells and a surprising 10 14 symbiotic microbes that coexist to allow a functional, healthy lifestyle. Despite being outnumbered 10 to 1 by microbes, the body is protected by physical barriers, including skin, mucous membranes, and the immune system. Trauma and surgery disrupt these barriers and can disturb the balance, leading to surgical site infection and significant disability. This article discusses the prevention of surgical site infection in patients who undergo operative fixation of fractures and the management of this well-described complication.
Throughout history, surgical site infection has consistently been a barrier to performing operations to treat pathology. Effective anesthesia and antisepsis are justly given credit for allowing advances in surgical treatments. Anesthesia made surgery physically tolerable but especially important to surgical site infection is antisepsis. Well-known individuals in the history of medicine, including Semmelweis, Pasteur, and Lister, are credited with the development of modern asepsis. Ignaz Semmelweis in 1847, before understanding of the germ theory, deduced that unwashed hands of physicians were contaminating women during childbirth. After implementing a policy requiring physicians and medical students to wash their hands in chlorinated lime after leaving the autopsy suite to examine patients on the ward, the mortality mostly due to puerperal fever dropped from 18.3% to 2.2%.
Lister, 20 years later, applied theories developed by Pasteur identifying that microbes causing fermentation could be killed by heat and chemical solutions. He theorized that chemicals could kill microbes on the skin and surgical instruments, preventing inoculation of surgical wounds. Prior to his work, purulence was thought a normal component of the wound healing process. In the American Civil War (1861–1865), gunshot injuries to the extremities with fracture resulted in a 50% rate of amputation and a 26% mortality rate. Exsanguination and infection were the most common complications after amputation. Erysipelas (streptococcal soft tissues infection) was associated with an 87% mortality. During this time, Lister noted that more than half of patients with open fractures developed septicemia and died at the University of Glasgow. Applying theories developed by Pasteur, he treated the wounds of 11 patients who suffered open fractures with carbolic acid, intending to kill infecting microbes. Nine patients healed without infection, which was a drastic improvement from previously reported results. He published his work in 1867, 2 years after the Civil War, and although acceptance of his methods was slow, it led to significant progress in the field of surgery.
By the 1960s, advances in antiseptic technique drove down the rates of surgical site infections enough to allow for development of relatively safe operations. Stevens published a series from this time that reports rates of deep infection as low as 4.35% for all orthopedic operations. Recent published rates of return to the operating room for surgical site infection are 1.18% after primary total hip arthroplasty and 0.90% after primary total knee arthroplasty. These impressive numbers might suggest that this is a minor issue, but rates of surgical site infection have consistently been higher in patients who undergo operative fixation of acute fractures. The procedures with the highest rates of deep surgical site infection in the series published by Stevens in 1964 were “Open reduction with a plate” (13.0%) and “Débridement of open fractures” (12.1%), much higher than the overall average of 4.35%. Recent published series of operative fixation of bicondylar tibial plateau fractures with dual approaches report rates of deep infection requiring operative débridement from 17.6% to 23.6%. In patients with compartment syndrome, the rate was 36.4% and with open fracture the rate of deep infection was 43.8%. Two patients with infection in 1 series ultimately required an above-the-knee amputation. Despite advances since the 1960s in minimally invasive techniques for fracture reduction and fixation, surgical site infection rates remain a common complication in the operative treatment of fractures. The rates continue to be significant, and innovative interventions to reduce surgical site infection in this patient population would have significant impact on the field of orthopedic fracture surgery.
Type and timing of prophylactic antibiotics in fracture surgery
Published series reporting outcomes and antibiotic recommendations for infection prophylaxis in patients with open and closed fractures were developed in the 1970s and early 1980s with little recent change. Since that time, there has been significant increase in the incidence of infection with resistant organisms. In a study that established cephalosporins as the preferred antibiotic to use for prophylaxis in patients with open fracture, Patzakis and colleagues reported that 50% (11/22) patients with infection were culture positive for Staphylococcus aureus . In the entire series, infection was seen in 7.1% of all open fractures. They randomized patients with open fractures to no antibiotic prophylaxis, penicillin/streptomycin, and cephalothin. The rate of deep infection was 13.9% in the no antibiotic group, 9.7% in the penicillin and streptomycin group, and 2.3% in the cephalothin group. This study established cephalosporins as the antibiotic of choice for the next 40 years.
Around the same time, Gustilo and Anderson reported results of implementing a débridement, fixation, and intravenous antibiotic protocol for open tibia fractures. They reported that 68.4% of organisms cultured from wound infections were S aureus . None of the isolated bacteria in either series was identified as methicillin-resistant S aureus (MRSA). S aureus first became resistant to penicillins in the 1950s, and, after widespread use of methicillin, MRSA was first isolated in the United Kingdom in 1961. By the mid-1980s, MRSA became a frequently encountered hospital-acquired infecting organism. A recent published series reported a 2.5% rate of MRSA infection in patients with open fractures and 25% of patients with infections were culture positive for MRSA. Another article reporting outcomes of adding intravenous vancomycin as a prophylactic antibiotic identified MRSA as the infecting organism in 18% of cases of open fracture. This trend of increasing rates of MRSA infection over the past 20 years is mirrored in cardiothoracic surgery and hospital-acquired infections.
Re-evaluation of the current standard for appropriate prophylactic antibiotics in open and closed injuries is an interesting topic in orthopedic trauma surgery. The previously discussed study by Morris and colleagues reported that 46.5% of wound infections after fixation of bicondylar tibial plateau fractures had cultures positive for MRSA. They discussed the possibility of giving vancomycin as procedural prophylaxis as a standard protocol. Torbert and colleagues published the most comprehensive series of patients who developed infection after fixation of open and closed fractures. They found that bacteria with clinically relevant antibiotic resistance were seen in 36% of patients with deep infection. The standard established antibiotic prophylaxis (cephalosporin) established in the 1970s would not cover more than one-third of the organisms causing infection in this series. Torbert and colleagues also found that gram-negative organisms were isolated in a high number of infections in the pelvis and proximal femur, indicating that physicians should consider prophylactic coverage for these organisms in this area.
There is mounting evidence that S aureus screening and decolonization programs are effective in reducing rates of infection in cardiothoracic, orthopedic, and hospital-acquired infections. High-impact medical journals have published expert opinions recommending S aureus screening and decolonization programs in “all patients receiving an implant.” This is a broad reaching statement, but certain operations in orthopedic trauma carry a high risk of surgical site infection and any potential innovative interventions to prevent the surgical site infection would have an important impact on care delivered. Large randomized studies of medical and surgical patients have demonstrated reduced rates of hospital-acquired and deep surgical site infections with the use of screening and decolonization programs. Specifically in orthopedics, most of the literature has focused on hip and knee arthroplasty.
Appropriate timing of antibiotic administration has also been shown important in preventing infection in patients with open fractures. Most literature has suggested that appropriate antibiotics be given as soon as possible after open fractures. Patzakis and Wilkins in a later study found that infection rate was higher in patients who received prophylactic antibiotics longer than 3 hours after injury. In combat soft tissue wounds to a limb, an association with timing and rates of infection has been shown. Lack and colleagues recently examined a series of patients with Gustilo and Anderson type 3 open tibia fractures to look at timing of administration of antibiotics. In a series of 137 patients, 24 developed deep infection (17.5%). Using univariate analysis they found that receiving antibiotics less than 66 minutes after the injury resulted in lower rates of infection. Ultimately they had no infections in patients who received antibiotics within this time frame. The only other factor associated with infection was delay to soft tissue coverage, which has also been shown in other studies of open tibia fractures requiring flap coverage. This study concluded that time to operative débridement did not correlate with infection. There are smaller series that demonstrated delays greater than 8 hours are related to infection in the lower extremity. The upper extremity was not affected in this series by the time to operative débridement. The benefit of early operative débridement of open fractures to prevent infection is debatable. Large systematic reviews have not demonstrated higher rates of deep infection in patients with delayed débridement.
The length of time to administer intravenous antibiotics after definitive closure of an open fracture ranges in clinical practice recommendations from 1 to 3 days. In 1988, Dellinger and colleagues published a randomized study of patients with open fractures who received 1 day of cefonicid, 5 days of cefonicid, or 5 days of cefamandole nafate (both cephalosporins). The findings indicated that infection rates were similar between groups (12%–13%). There was no benefit to giving antibiotics longer than 24 hours after definitive closure.
The recommendations for type of prophylactic antibiotic used in patients with open and closed fractures are currently evolving and clinicians must make decisions based on the best available literature. If rates of MRSA infection are known to be high in a specific region, prophylaxis with vancomycin and a cephalosporin may be indicated for high-risk patients. Screening programs for nasal S aureus colonization may be a more focused methodology to treat high-risk patients with vancomycin, a cephalosporin, and S aureus decolonization programs. Patients with open fractures should be given antibiotics at the earliest possible time because administration less than 1 hour has shown lower infection rates, and trauma systems should consider administration in the field or in transport if this early administration cannot otherwise be accomplished. There is no proved benefit to giving antibiotic longer than 24 hours after definitive closure.
Rates of infection in common fracture fixation procedures
The risk of surgical site infection after operative fixation of fractures is variable depending on the location and severity of the injury. The Gustilo and Anderson classification categorizes open fractures based on the severity of the soft tissue injury. Multiple studies have demonstrated that increasing severity of injury in this classification correlates with higher rates of surgical site infection. In their original series, there were 8 deep infections that developed after implementation of the antibiotic and débridement protocol. Six were classified as type 3 and 2 as type 2. In a later series of open fractures by Patzakis and Wilkins, 1.4% of type 1 injuries, 3.6% of type 2 injuries, and 22.7% of type 3 injuries developed deep infections. Another recent series of patients with 106 open tibia fractures reported rates of 0% in type 1 injury, 8.7% of type 2 injuries, and 20.5% of type 3 injuries, highlighting this association.
The infection rate in closed injuries varies depending on type of injury. Rates of infection after intramedullary nailing femoral shaft fractures ranges from 0% to 2.7%. Rotational ankle fractures undergoing operative fixation also have described low rates of deep infection at 1.1%. Acetabular fractures treated with the Kocher-Langenbeck approach have an infection rate of 5.2% in large series of experienced surgeons.
The soft tissue envelope around the distal tibia is not robust in a normal state and is notorious for wound healing complications after early fixation of high-energy distal tibia fractures. Ruedi and Allgower reported their results of internal fixation for distal tibia fractures in 1969. They had a lower energy mechanism of injury in most patients and a 5% rate of deep infection in 84 patients. In high-energy fracture of the distal tibia, rates of infection were later reported from 17% to 37% after internal fixation. These alarming rates led to a trend to treat these injuries definitely with external fixation. Sirkin and colleagues reported a series of patients with intra-articular distal tibia fractures who were treated with fixation of the fibula and spanning external fixation within 24 hours of injury. They returned to the operating room an average of 12.7 days after the injury for definitive open reduction internal fixation. In closed injuries, there was 1 deep infection requiring hardware removal (3.4%), indicating that a period of soft tissue healing and reduction of swelling after the injury with the limb stabilized was a moderately safe alternative to early fixation through compromised tissues.