INTRAOPERATIVE CULTURES OBTAINED DURING TOTAL PRIMARY HIP ARTHROPLASTY TO PREDICT PROSTHETIC JOINT INFECTION.

Abstract

Introduction: The most important cause of prosthetic joint infection (PJI) is the contamination of the wound during the surgery. Nowadays, it doesn’t exist any image or laboratory test for early detection of prosthesis with a higher risk of developing a PJI.

Aim: The primary aim was to evaluate the usefulness of different intraoperative samples during the surgery of implantation of a primary hip arthroplasty (PHA) as a predicting factor of PJI.

Methods: A prospective cohort study was performed. All patients (n= 278) who underwent a PHA from January ’06 to November ’08 were included. Three samples: a piece of articular capsule (TS), a swab (S) and synovial fluid (SF) inoculated into blood flask were taken in each patient during the first 45 minutes of surgery. Other possible risk factors of PJI like age, sex, ASA, comorbidity and surgical time were registered.

Results: A total of 278 patients were included. 30 cultures (8 SF, 13 TS and 9 S) were positive in 29 patients. The most frequent microorganism isolated was Coagulase-negative staphylococci (CNS) (66.6%). The rate of PJI (early and late) in the subgroup of patients with positive intraoperative cultures for CNS was 25% while in the subgroup with all negative cultures was 5.2% (RR=4.8; p=0.007). Other factors significantly associated with a higher rate of PJI in the univariate analysis were: ASA III (RR=9.12; p=0.02), cardiopathy (RR= 2.82; p=0.04), obstructive pulmonary chronic disease (RR=5; p=0.02) and rheumatoid arthritis (RR=4.16; p=0.04). Multivariate analysis found ASA III (Odds ratio 10.9; CI 95% 1.27–94.6; p=0.02) and a positive intraoperative culture for CNS (Odds ratio 5.92; CI 95%=1.8–19.85; p=0.03) as independent risk factors for PJI.

Conclusion: Positive intraoperative culture for CNS during PHA was independently associated with the development of PJI.