Clinical manifestations, treatment outcomes, and risk factors for sternoclavicular septic arthritis.

Septic arthritis of the sternoclavicular joint (SCJ) is an atypical and rarely seen clinical condition. The prognosis for patients with SCJ septic arthritis is often poor. The objective of this study was to compare clinical characteristics between SCJ and non-sternoclavicular joint (NSCJ) septic arthritis and to identify independent risk factors for SCJ septic arthritis. A total of 450 adult patients diagnosed with septic arthritis during the January 2002 to December 2013 study period were included in this retrospective cohort study. Patient characteristics, clinical manifestations, and treatment outcomes were examined. Univariate and multivariate analysis was performed to identify potential risk factors for SCJ septic arthritis. Thirty-three (7.3%) of 450 patients had SCJ septic arthritis and the remaining 417 patients had NSCJ. Oligoarthritis or polyarthritis were seen more often in SCJ patients than in NSCJ patients (55 vs. 19%; p < 0.05). Abscess formation and bacteremia were more commonly found at presentation in the SCJ group than in the NSCJ group (18 vs. 8%; p < 0.05 for abscess formation; and, 53.1 vs. 26.6%; p < 0.05 for bacteremia). In multivariate analysis, extra-articular infection (OR 2.7, 95% CI 1.2-6.4; p = 0.02), cirrhosis (OR 1.9, 95% CI 1.1-3.3; p = 0.02), and malignancy (OR 3, 95% CI 1.1-7.8; p = 0.03) were independent risk factors for SCJ septic arthritis. SCJ septic arthritis is an uncommon septic arthritis that frequently presents with local and systemic complications. Factors found to be significantly associated with SCJ septic arthritis were extra-articular infection and immunocompromised host. A high index of suspicion in high-risk patients is the key to achieving improved outcomes.