Post-arthroscopic septic arthritis of the knee. Analysis of the outcome after treatment in a case series and systematic literature review

OBJECTIVE: The aim of this study was to review the characteristics of patients with septic arthritis after ACL reconstruction comparing our results with those deriving from the literature review. PATIENTS AND METHODS: Patients with suspected post arthroscopic septic arthritis of the knee occurring within 6 months after surgery were evaluated to be included in the investigation. Septic arthritis was defined by i) clinical evidence; ii) laboratory investigations; iii) synovial fluid leukocyte count of more than 2,5 × 104/ìL or positive cultures obtained by synovial fluid aspirate. RESULTS: Thirty-nine patients (median age 25 years, range 17-42) with septic arthritis following ACL reconstruction were enrolled. Staphylococci were the main bacteria identified. Resolution within 4 weeks of local signs was observed more frequently in those receiving arthroscopic debridement and synovectomy coupled with antibiotic therapy (18/21 vs. 9/18, p<0.05). Fever was present in 33 (85%) cases. Fever disappearance and CRP normalization within 4 weeks were reported more frequently in patients receiving intravenous antibiotics (17/20 vs. 9/19, p<0.05). Similar findings were retrieved by literature analysis. CONCLUSIONS: An intravenous antibiotic therapy with surgical debridement is the firstline treatment for septic arthritis. Staphylococci are the main causative agents, justifying an empiric therapeutic approach with an anti-MRSA agent and cephalosporin.