Microbiología de las infecciones periprotésicas de rodilla en Hospital Regional de Talca / Microbiology of periprosthetic knee infections in Regional Hospital

Introduction: Periprosthetic infection (PPI) is one of the most devastating complications of total knee arthroplasty (TKA). The incidence described in the literature is 2.4% and the most frequently isolated bacteria are Staphylococcus Aureus and Staphylococcus Coagulase-Negative (Gram positive). Polymicrobial infections represent between 10 to 37% and negative cultures between 7 to 15%. Methodology: Descriptive and retrospective study that consisted of reviewing the TKA database of the Regional Hospital of Talca during the 2018-2020 period, where knee PPIs were identified according to the diagnostic criteria validated in 2018. The cultures of patients diagnosed with PPI were reviewed, analyzing the antibiogram and resistance profile. Results: During 2018-2020, 459 TKAs were performed in our center, diagnosing 30 PPIs of the knee. 47% of PPIs were acute and 53% chronic. The results of the cultures were negative in 26.6%, 23.3% Methicillin Sensitive Staphylococcus Aureus; 13.3% Methicillin Resistant Staphylococcus Epidermidis and 13.3% of the cultures were polymicrobial. Discussion: Highlights the high resistance to methicillin, especially of Staphylococcus Epidermidis. This opportunistic pathogen has the ability to form a biofilm and, thanks to its genomic flexibility, rapidly acquires resistance to antibiotics. Polymicrobial infections have a synergistic effect that favors the persistence of the infection, which is why they will require a greater number of surgeries and prolonged antibiotic therapy. Pruebas especiales como la sonicación podrían aumentar las posibilidad de identificar al microorganismo. Conclusion: In these three years of follow-up, the PPI rate has been higher than reported annually in the literature. Gram-positive microorganisms continue to predominate, but with an increase in the rate of resistant to methicillin. Also, highlight the number of negative cultures. There would be a possible benefit theoretical in optimizing antibiotic prophylaxis in view of the large percentage of methicillin resistance and in seeking new ways to reduce negative cultures.

Ventana cortical anterior para extracción de vástago en revisión de artroplastia total de cadera: una alternativa a la osteotomía trocantérica extendida / Anterior cortical window for stem extraction in total hip arthroplasty revision: an alternative to extended trochanteric osteotomy

Total hip arthroplasty (THA) is a safe and effective procedure in patients with end-stage ostheoarthritis. In the last years the indication for THA is increasingly in younger patients, associated with rising of life expectancy, this imply an increase in revision surgeries for various causes such as: aseptic loosening, fractures and infections. In this context and in view of the need to replace the femoral component, alternatives to the classic extended trochanteric osteotomy (ETO) arise, such as the anterior cortical window (ACW), which allows the rate of complications to be reduced with excellent results. We present the case of a 51-year-old patient who sustained one episode of dislocation, who required revision surgery due to aseptic loosenig, where the ACW was used for the extraction of the stem. In addition, a review of the literature was made to show advantages and complications regarding ETO.