## Abstract

Surgical site infection (SSI) is disastrous in orthopedic practice as it is difficult to rid the bone and joint of the infection. This study was aimed to assess the prevalence of SSI in orthopedic practice and to identify risk factors associated with surgical site infections. All patients admitted to the orthopedic male and female wards between January 2006 and December 2011 were included in the study group. The data, which were collected from the medical charts and from the QuadraMed patient filing system, included age, sex, date of admission, type of admission (elective versus emergency), and classification of fractures. Analyses were made to find out the association between infection and risk factors, the χ2  test was used. The strength of association of the single event with the variables was estimated using Relative Risk, with a 95% confidence interval and P < 0.05. A total of 79 of 3096 patients (2.55%) were included: 60 males and 19 females with the average age of 38.13 ± 19.1 years. Fifty-three patients were admitted directly to the orthopedic wards, 14 were transferred from the surgical intensive care unit, and 12 from other surgical wards. The most common infective organism was Staphylococcus species including Methicillin Resistant Staphylococcus aureus (MRSA), 23 patients (29.11%); Acinetobacter species, 17 patients (21.5%); Pseudomonas species, 15 patients (18.9%); and Enterococcus species, 14 patients (17.7%). Fifty-two (65.8%) had emergency procedures, and in 57 patients trauma surgery was performed. Three (3.78%) patients died as a result of uncontrolled septicemia. SSI was found to be common in our practice. Emergency surgical procedures carried the greatest risk with Staphylococcus species and Acinetobacter species being the most common infecting organisms. Proper measures need to be undertaken to control infection rates by every available method; antibiotics alone may not be sufficient to win this war.

Surgical site infection (SSI) is defined as microbial contamination of the surgical wound within 30 days of an operation or within 1 year after surgery if an implant is placed in a patient.1  It is estimated that annual incidence of SSI in the United States is 1.07%; with 8000 deaths directly related to SSI2  and a financial cost of treatment to $10 billion. The problem of SSI is universal; in the United Kingdom, the extra cost for each SSI is approximately €2500 (US$3394),3  and the length of the hospital stay increases between 5.8 and 17 extra days.4  Surgical-site infections cause increased morbidity, mortality, extended hospital in-patient stays, and economic burden to the hospital resources.58

Many preventable causes of SSI have been identified, and if proper measures are implemented, the incidence could be reduced. Patients, surgeons, and nurses, as well as operative room atmosphere and instrumentation are prime areas of concern. Various methods have been established to reduce infections in implant surgery, but infection does occur.

The washing of hands and maintaining basic hygiene,9  prophylactic antibiotics given at the proper time and at the correct strength,10  surgical clothing,11  and reducing the flow of staff in the operating room1214  all contribute to lowering the incidence of infection.

This study was aimed to assess the prevalence of SSI in orthopedic practice at King Fahd Hospital of the University, Al Khobar, and also to identify risk factors associated with surgical site infections.

## Patients and Methods

The data gathered arose from a retrospective chart review of 3096 patients who underwent orthopedic surgical procedure during January 2007 and December 2011 at King Fahd Hospital of the University, a 500-bed tertiary care center in Al Khobar, Saudi Arabia. Our main aim was to detect the occurrence of SSI within 30 days of the surgical procedure. The data, which were collected from the medical charts and from the QuadraMed patient filing system (QuadraMed Corporation, Reston, Virginia, USA), included age, sex, date of admission, type of admission (elective versus emergency) and classification of fractures. The components of the National Nosocomial Infections Surveillance (NNIS) system surgical-patient risk index used in this study were as follows:

1. 1.

A preoperative anesthesia risk scoring system as per Anesthesia Society of America (ASA);

2. 2.

Gustillo wound classification (GWC); and

3. 3.

“T time,” defined as the 75th percentile of the duration for each operative procedure.

As a standard practice prophylactic, intravenous antibiotics were given on call to the operating room. The infection was assessed by the infective organism, sensitivity of the antibiotics, and recovery. Any additional days the patient stayed in the hospital were calculated on the basis of standard discharge after each such procedure. The incidence rate of SSI, according to the different categories of the individual components of the index (ASA, GWC, and T time), was calculated. The strength of the association between each of these factors and the incidence rate of SSI were estimated using the Goodman-Kruskal G coefficient. A measure of association between 2 variables established on an ordinal level. Analyses were made to find out the association between infection and risk factors, the χ2  test was used. The strength of association of the single event with the variables was estimated using Relative Risk, with a 95% confidence interval and P < 0.05.

## Results

A total of 79 of 3096 patients who had orthopedic or trauma operations contracted an SSI. The incidence of SSI was 2.55%. There were 60 males and 19 females with an average age of 38.13 ± 19.1 years. The demographic data are given in Table 1. Fifty-three patients were admitted directly to the orthopedic wards, 14 were transferred from the surgical intensive care unit and 12 from the surgical wards. Infection was significantly higher in patients who underwent an emergency procedure P < 0.001.

Table 2 lists the procedures carried out, showing that the majority were trauma. The average operating time was 151.7 ± 44.5 minutes (range, 40–370 minutes). Patients overstayed in the hospital owing to infection for an average of 24.75 days (range, 3–150 days). Sixty-two patients (78.4%) had various complications, and 3 patients (3.79%) died directly as a result of uncontrolled septicemia. Table 3 gives the different organisms and the percentages.

The most common infective organism was Staphylococcus species including Methicillin Resistant Staphylococcus aureus (MRSA) in 23 patients (29.11%), Acinetobacter species in 17 (21.5%), Pseudomonas species in 15 (18.9%), and Enterococcus species in 14 (17.7%).

Sixty-one patients (77.21%) cultured a single organism, 15 had 2 infecting organisms, and 3 patients cultured more than 2 organisms. In all patients who had 2 or more organisms, Acinetobacter species was the common organism.

## Discussion

The incidence of SSI in the present study was 2.55%, which is below the reported worldwide incidence of 2.6% to 41.9%.15  Second, our study differs from the literature in that SSI was more common in younger patients, whereas studies reported SSI to be high in patients of over 55 years of age. This could be because the majority of our patients were operated on due to trauma, and it has been reported that preoperative soft-tissue damage is a major risk factor for developing SSI.16  The other independent risk factors for patients developing SSI were having an emergency operation and having prolonged surgery. The majority of patients with infection had an ASA score of 1, but other studies have suggested that the higher the ASA score, the higher the risk of infection.1618

The movement and number of staff in the operating room is long known to influence the incidence of SSI. In our patients, we have practiced to reduce the staff in the operating room to essential staff only, and this has shown that there was no serious deep-seated infection post arthroplasty, whereas during other types of surgery the entry and exit of the staff was not controlled. The incidence of SSI was significantly higher in trauma surgery versus total joint arthroplasty (P < 0.001). There are apparent unintended differences in the quality of care that exist between patients undergoing joint arthroplasty or spinal surgery and those undergoing trauma surgery. There could be a couple of reasons for these differences. During total joint replacement, scoliosis and other spine surgery senior staff are available, while routine trauma surgery is performed by junior staff. Last, because of the gravity of infection in a patient with arthroplasty, surgeons tend to extend extra care while operating, and arthroplasty surgeons go the extra mile to limit SSI on the basis of research,1920  and monitoring the quality of care.21  Barring the level of the surgeon, the other preventable differences cannot be justified.

There are limited data available to review with regard to SSI in Saudi Arabian patients. Abdel-Fattah22  reported after a 12-month study of nosocomial infection from a military hospital, the incidence of SSI was 12.9%, whereas Khairy et al23 reported an incidence of 6.8% after a prospective study. In both studies, the incidence appears higher than in our study. Even though the authors did not specify the different specialties these patients were taken. In the recent past, the outbreaks of Acinetobacter infections, which occur in intensive care units, have caused much concern to health care providers, hospital administrators, and patients at large. Trauma patients who are admitted to the ICU initially always carry a risk of infection, which they carry from the ICU to the wards. In this series, the majority of the patients who contracted an SSI and cultured Acinetobacter species apparently had been admitted to the ICU, which is the primary breeding ground for such organisms. Our study shows that Acinetobacter organisms are increasing their presence in the orthopedic wards, and this needs to be controlled. At present it appears that the morbidity and mortality that they cause are enormous and sometimes beyond the control of the treating physicians.

## Results

This study has some limitations as well as strengths. It is limited in that we studied only the patients who developed infection postoperatively. The study would have had more strength if we gathered the data of all 3096 patients who were operated on and compared them with the infected group.

In conclusion, this study shows that the incidence of SSI in orthopedics and trauma patients is comparable with the reported incidence in the literature. We believe that development of SSI is a complex process, which is dependent on several different factors related to the patient, the surgical environment (such as the ICU), staff involvement, and finally the surgical technique. We were able to identify the areas that need to be addressed to further reduce the incidence of SSI in our patients.

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