Abstract

Introduction Surgical site infections (SSI) are related to a surgical procedure and affect the surgical wound or deeper tissues. With continuing emphasis on clinical governance and quality control, there is increasing demand from both patients and government for methods of assessing surgical results. Rates of morbidity and mortality may play important roles in these assessments. When crude comparisons between hospitals in the incidence of SSI are made, these should at least be stratified by the type of procedure. The aim of this study is to fix SSI incidence in relation to surgical procedure.

Methods This report contains data of 19.948 procedures collected from 1996 to 2008 at a Specialist Orthopaedic Hospital and analyzed by a specific software designed for the study of infection in orthopaedic and trauma surgery.

The SSI surveillance is focused on categories of surgical procedure (Hip Arthroplasty, Knee Arthroplasty, Spine Surgery and Hip Fracture Surgery) with each category containing a defined set of similar procedures. A basic of demographic data and details about operation itself are collected for each procedure. Patients are followed up throughout their hospital stay and after hospital discharge.

We present the incidence of SSI by risk group and surgical procedure. SSI are categorized in type, moment of diagnosis and micro-organisms reported.

Analysis of the data was performed (SPSSv15.0 ®). Statistical methods used to determine significance were the independent samples t test, Pearson X2 test, Odds ratio and Spearman correlation coefficient, with a significance level of p<0,05.

Results Rates of SSI are highest in hip hemiarthroplasty after fracture and in hip and knee revision procedures. Rates of SSI increase with the number of risk factors present in the patient, especially after fracture procedures. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. 38% of the infections arise after one year of surveillance.

Conclusions Our results confirm difference in rates of SSI depending of surgical procedure in orthopaedic and trauma surgery. We believe that our decision to monitor infection with a long term follow up it's the better way to avoid under-reporting of infection. Our study has also demonstrated the extent to which the emerging problem of infection due to MRSA has affected orthopaedic surgery. The risk of acquiring SSI caused by MRSA was particularly high in patients after hip fracture surgery. Rates of SSI increase with the number of risk factors present in the patient, especially after fracture procedures. Globally, the most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. 38% of the infections arise after one year of surveillance.