The evaluation, classification, and management of septic arthritis of the shoulder: the comprehensive shoulder sepsis system.

BACKGROUND: Septic arthritis of the shoulder is distinctly challenging to diagnose and treat. Guidelines for appropriate workup and management are limited and do not account for the variations in clinical presentation. The purpose of this study was to present a comprehensive and anatomically based classification system and treatment algorithm for septic arthritis of the native shoulder joint. METHODS: A multicenter, retrospective analysis of all patients treated surgically for septic arthritis of the native shoulder joint was performed at 2 tertiary care academic institutions. Preoperative magnetic resonance imaging and operative reports were used to classify patients as having 1 of 3 infection subtypes: type I, confined to the glenohumeral joint; type II, extra-articular extension; or type III, concomitant osteomyelitis. On the basis of these clinical groupings of patients, the comorbidities, types of surgical management, and outcomes were analyzed. RESULTS: Sixty-five shoulders in 64 patients met the inclusion criteria for the study. Of these infected shoulders, 9.2% had type I infections, 47.7% had type II, and 43.1% had type III. Age and the time between symptom onset and diagnosis were the only significant risk factors for the development of a more severe infection. Fifty-seven percent of shoulder aspirates revealed cell counts below the standard surgical cutoff of 50,000 cells/mL. On average, each patient required 2.2 surgical débridements to eradicate the infection. Infections recurred in 8 shoulders (12.3%). Body mass index was the only risk factor for recurrence of infection. Of the 64 patients, 1 (1.6%) died acutely of sepsis and multiorgan system failure. CONCLUSION: We propose a comprehensive system for the classification and management of spontaneous shoulder sepsis based on stage and anatomy. Preoperative magnetic resonance imaging can help determine the severity of disease and aid in surgical decision making. A systematic approach to septic arthritis of the shoulder as a unique entity from septic arthritis of other large peripheral joints may lead to more timely diagnosis and treatment and improve the overall prognosis.