Infection after total knee replacement, which is a serious and expensive complication, often represent a diagnostic and therapeutic problem. The current incidence of infection after the primary procedure is 1 to 3%, depending on the published series. A correct and timely diagnosis, classification between early and delayed infection, and which microorganisms are involved, are crucial steps in defining prevention and treatment strategies.

Determination of the annual and three years incidence of infection after primary total knee replacement; evaluation of the microorganisms involved and its resistance patterns; assessment of treatment – surgical approach and selection of antibiotics.

Collection of clinical and laboratorial data of all patients who underwent primary total knee arthroplasty between 2011 and 2013 in our hospital; definition of periprosthesic infection cases following the Musculoskeletal Infection Society (MSIS) criteria.

During the study period, 526 primary knee replacements were performed in 521 patients; with 41 patients having bilateral replacements. The mean follow-up period was 30 months; 5 patients had no follow up and 1 died in the post operatory.

We reported 9 prosthetic infections, of which 2 did not reached the MSIS criteria, but were also considered based on high clinical suspicion. The majority of the cases (6) were delayed infections. The calculated 3 year incidence of infection after primary knee replacement was 1,6%, with annual rates of 3,0% (2011), 1,7% (2012) and 0,9% (2013). The microorganisms isolated were as follows: Staphylococcus aureus and coagulase-negative staphylococci, resistant to penicillin; Streptococcus agalactiae and one isolate of Serratia marcescens, both showing multiple antibiotic resistances.

Only one case was treated with surgical debridement and conservation of prosthesis, in the other 8 cases a two-stage implant revision procedure was performed. The antibiotics selected were vancomycin, fluoroquinolones and association of gentamicin and clindamycin.

Our local infection rates are in line with the published series from reference surgical centers. The annual incidence is decreasing, probably because the majority of our infection cases are delayed (recent years, shorter follow up period) and our preventive measures are improving. The microorganisms identified are also in agreement with published data, and our antibiotic resistance pattern is a valuable information to consider in a first empirical approach.

Treatment options suitable to each case, and antibiotic protocols need to be improved in our local practice. Preventive measures in delayed infections are still under debate, and represent another future challenge.

Corynebacterium Jeikeium is a pathogen rarely involved in orthopaedic infections. Till date only 14 cases of osteomyelitis are described in the literature, envolving the tibia, foot and prosthethic (hip and joint) infection. To our knowledge, Corynebacterium Jeikeium as not been reported as an infectious agent of the spine. Our goal is to describe a case of scoliosis surgical site infection by a Corynebacterium Jeikeium specimen.

This is a retrospective and descriptive case report based on data from clinical records, patient observation and analysis of complementary exams.

We present a 24 year old female with a history of premature birth, West syndrome, spastic cerebral palsy and spina bifida. She was sent to our consult for evaluation of dorsolombar scoliosis. In October of 2014, she was submitted to surgery – posterior spine arthrodesis and instrumentation (D10 to L5) with bilateral pedicle screws and two chromium-cobalt bars. The early post-operative period was without complications. She was discharge at the seventh day of internment and was seen, fifteen days postoperative, at the consultation office, where the dressings were changed, with no signs of surgical site infection. One month post-operative, she recurs to the office because of an apparent seroma at the surgical site wound. There was no reference to fever or other signs of local/systemic infection. A swabbing of the wound was done and the patient was medicated with Ciprofloxacine, 500mg 12/12 hours – the culture came back negative. Seven days later she was seen again, maintaining the seroma with purge of a serous-aspect fluid. Antibiotic therapy was maintained and another swabbing was collected – culture came back negative. Because of suspected surgical site infection, she was re-operated at December of 2014. Surgical wound debridement was performed; three tissue samples and one exudate were sent to the microbiological department. In all samples but one was identified a Corynebacterium Jeikeium. No sensitivity test was performed. Intravenous Vancomicine, 1 gram 12/12 hours was started and maintained during 8 days. Eleven days post-operative she was discharged with oral Vibramicin, 100 milligrams 12/12 hours for two weeks. She is currently being followed at the doctor's office, with no sign of reinfection of the surgical site.

This is the first reported case describing an infection of the spine by a Corynebactereium Jeikeium. Isolation of the causative agent of infection and literature-based directed antibiotherapy are important for a successful outcome.