Introduction: Infection after hip or knee replacement occurs with low frequency but shares high morbidity. Aim of this study was an evaluation of incidence and risk factors related to post operative infection after joint lower limb joint replacement in an orthopaedics unit.
Material and methods: This is a monocentric, retrospective, case control study over the years 2000 to 2002. All first intention Total Hip and Knee Replacement and revision cases for mechanical reasons that became infected were identified. Demographic, surgical and medical variables, potentially associated to prosthetic infection were compared for these patients to a control group of non ifected patients over the same time, matched for sex, age and surgery type.
Results: Ten patients, all male, contracted post operative joint infection, out of 630 Total Hip or Knee Arthroplasties. This represented 1.2% after hip replacement and 3.1% after knee replacement. Bacteriological datas showed a majority of Staphylococal infection (5 aureus, 1 epidermidis), 2 among these being resistant to meticillin, but also evidence of ENT commensals (2 Streptococci milleri, 1 Actinomyces) and one epidermal commensal (Propionobacterium acnes). Univariate analysis: datas associated with increased risk of infection were diabetes melitus (OR 9.3; CI 95% 1.4–63), operating time exceeding 120 minutes (OR15.5 ; CI 95% 1,73–139,66), superficial wound infection (odds ratio 29; CI95% 2,77–303,32), coinfection outside the operation site (urinary tract , dental infection) (OR: 9,3 ; CI 95% 1,33–63,2). In our study an MNIS score higher than 1, autologous transfusion, locore-gional anaesthesia with or without the use of a catheter, antibioprophylaxis that did not comply with national recommendations could not be drawn as a risk factor.
Discussion: Incidence of infection and risk factors related to infection in our study were found similar tothe results of published datas. The small number of events (10 cases) did not allow us to realize multivariate analysis and could explain that some known risk factors such as non recommended antibioprophylaxis, could not be elicitated. However these results suggested the need to reevaluate the system of prevention of infection in our centre such as protocolization of antibioprophylaxis and screening for and treatement of perioperative coinfection.
