Sonographic detection, evaluation and aspiration of infected acromioclavicular joints

Objective. To describe the sonographic findings of septic arthritis of the acromioclavicular joint. Design and patients. A retrospective study of five male patients was carrie d out. Four of the patients were referred because of signs and symptoms sug gestive of glenohumeral joint septic arthritis, one for signs and symptoms suggestive of septic arthritis of the acromioclavicular joint. All the acro mioclavicular joints were evaluated with ultrasound, aspirated and the aspi rate cultured. Results. All patients had normal ultrasound findings of their glenohumeral joints and distended acromioclavicular joints as determined by ultrasound. Ultrasound examination elicited focal tenderness over the acromioclavicular joint. Aspirates of each acromioclavicular joint grew pyogenic organisms. Conclusion. Infection in the acromioclavicular joint is uncommon, but is se en in increased frequency in immune-compromised patients and intravenous dr ug users. A normal glenohumeral joint on ultrasound in a patient suspected of having a septic shoulder should prompt careful review of the acromioclav icular joint. Aspiration of the acromioclavicular joint is easily performed under ultrasound guidance.