Septic Arthritis of the Acromioclavicular Joint: A Single-Center, 11-Year Retrospective Review

Septic arthritis of the smaller acromioclavicular joint is uncommon, with only a few reports and case series available in the literature. The aim of this outcomes analysis was to determine the prevalence of shoulder girdle septic arthritis within the authors' institution, with a particular focus on describing the authors' experience with acromioclavicular joint septic arthritis. A retrospective outcomes analysis was conducted of patients admitted to a single tertiary referral center from 2008 to 2018 with acromioclavicular joint septic arthritis. Demographic and clinical data were recorded for each patient; the modified Frailty Index score was calculated for each patient. Nine patients were identified as having acromioclavicular joint septic arthritis, making up 12% of shoulder girdle septic arthritis. Diabetes mellitus was the most prevalent comorbidity, present in 4 (44.4%) patients. Staphylococcus aureus was responsible in 55.6% and Streptococcus species in 44.4%. Seven patients were treated surgically. Mean (SD) length of antibiotic therapy was 6.2 (2.7) weeks. Mean (SD) length of stay was 6 (2.83) days (range, 4-8 days) for patients who received antibiotic therapy only and 12.7 (7.52) days for those who proceeded for operative management. Mean modified Frailty Index score was 1.1. Septic arthritis of the acromioclavicular joint is an uncommon infection that occurs both in patients with impaired immunity and in those with intact immune systems. Tailored antimicrobial therapy in conjunction with surgical intervention, when indicated, appears to result in successful suppression or eradication of infection in the majority of cases. [Orthopedics. 2021;44(4):e493-e497.].