Predisposing factors for recurrence of chronic posttraumatic osteomyelitis: a retrospective observational cohort study from a tertiary referral center in Brazil

BACKGROUND The incidence of posttraumatic osteomyelitis (PTO) is increasing despite new treatment strategies. Assessment of patients' outcomes following PTO is challenging due to multiple variables. The study goals are to determine the frequency of recurrence following PTO treatment and identify factors predisposing patients to treatment failure. METHODS Between August 01, 2007 to August 30, 2012, a single-center retrospective cohort study was performed among 193 patients diagnosed with PTO following orthopedic surgery for fracture care. Bone and soft tissues were collected for cultures and PTO was defined according to CDC/NHSN criteria. Patient, injury, surgery-associated variables, and microbiological records were reviewed for risk factors associated to recurrence of PTO. Univariate and multivariable analyses using logistic regression were performed, with p <0.05 considered significant. RESULTS Thirty-eight patients (20%) of 192 diagnosed and treated for PTO failed their treatment. Factors associated with recurrence were age between 61 and 80 years [hazard ratio (HR) = 6.086, 95% confidence interval (CI) = 2.459;15.061, p = <0.001], age above 80 years [HR = 9.975 (95% CI = 3.591;27.714), p = <0.001], intraoperative blood transfusion [HR = 2.239 (95% CI = 1.138;4.406), p = 0.020], and positive culture for Pseudomonas aeruginosa [HR = 2.700 (95% CI = 1.370;5.319), p = 0.004]. CONCLUSIONS Risk factors associated with recurrence of PTO are difficult to measure. The present study revealed that elderly patients, intraoperative blood transfusions, and infection due to P. aeruginosa were independently associated with recurrence of PTO. These factors should warn clinicians of a higher failure rate following treatment of PTO. Trial registration: ISRCTN71648577. Registered 18 May 2017. Retrospectively registered.