Method

We applied the JS-BACH classification to the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort. This prospective study of newly diagnosed PJI collected 2-year outcome data from 653 participants enrolled in 27 hospitals. The definition of PJI treatment failure at 24 months was any of the following: death, clinical or microbiological signs of infection, destination prosthesis removed, or ongoing antibiotic use.

Method

This was a population-based, nationwide, cohort study. We included 74,771 from the Danish Multidisciplinary Hip Fractures Register (1) consisting of patients 65 years of age or older, who underwent surgery between January 1^st 2005 and December 31^st 2016 for all types of hip fracture. Cross-linkage with the Danish National Patient Register and The Danish Civil Registration system was made.

Demographic data extracted included vital status, civil status, gender, age, Body Mass Index (BMI), fracture classification (AO/OTA 31A-C) and surgical procedures binary registered as joint replacement or internal fixation, Charlson comorbidity index (CCI) and secondary diseases not included in CCI. Outcome was reoperations due to deep SSI in accordance with the definition from Centre for Disease Control (2). We computed cumulative incidence rates and risk ratios (RR) by calendar year periods and by different risk factors, considering death as competing risk and adjusting for age, gender, CCI, fracture type and surgery type.