Therapeutic Strategies for Post-Osteosynthesis Osteomyelitis

Abstract

Objectives: The main objective in post-osteosynthesis surgical site infection (SSI) is to consolidate the fracture and prevent chronic osteomyelitis. The purpose of this study is to evaluate the risk factors for SSI recurrence in patients treated for osteo-articular infection at the Federal University of São Paulo. Methods:After retrospectively evaluating all SSI episodes occurring from December 2004 to December 2008 in patients undergoing osteosynthesis at the orthopedics department, 110 of them were included. SSIs were treated with at least 4-6 week antibiotic therapy cycles and followed up for one year with the results being analyzed using univariate and multivariate analysis models.Results: Most patients were 18-89 years old, with a mean age of 39.8, the majority being male (84.5%). In 37 patients, the causative agent was isolated with Staphylococcus being the most frequently observed (38.8%). In 83 (75.4%) patients, the antimicrobial treatment mostly with ciprofloxacin and clindamycin was started within less than five days from the onset of symptoms. SSI recurrence occurred in 34/110 (30.9%) patients. After one-year follow-up, 19 (17.3%) patients persisted with infection and only 10 (9.1%) did not have their fractures consolidated. The univariate analysis showed the performance of more than one surgery to stabilize the affected limb (OR 3.7 IC95=1.1-12.7 p=0.045), presence of converting osteosynthesis (OR 3.6 IC95=1.1-11.3 p=0.023), internal synthesis (OR 3.0 IC95=0.99-9.2 p=0.043) and longer duration of surgery (OR 0.4 IC95=0.1-1.6 p=0.029) as risk factors for SSI recurrence. In the multivariate analysis, the only variable independently associated with SSI relapse was duration of surgery (OR 1.3 IC95=1.1-1.7 p=0.015). Conclusions:After one year follow-up, using a specific protocol, most patients showed resolution of infection and only 9.1% had their fractures unconsolidated. The only independent risk factor associated with SSI recurrence was prolonged surgery. It is possible to treat a patient with post-osteosynthesis SSI with a course of 4 to 6 weeks of antibiotic therapy.