Shoulder pyarthrosis: a concomitant process.

Thirty cases of glenohumeral pyarthrosis are reported. Systemic immune compromise and local tissue abnormalities were each present in 74% of the adult patients. Both were present in 52%. Most adult patients were debilitated by chronic diseases. Diagnosis was frequently delayed due to mild symptoms and minimal, nonspecific laboratory findings. Poor results correlated with treatment delay. Shoulder pyarthrosis occurred ipsilateral to forearm arteriovenous dialysis fistulas in four patients. Postoperative shoulder pyarthroses were eradicated only in patients with clinically intact immune systems. Three patients (10%) with intact rotator cuffs had unsuspected associated subacromial bursa abscesses. Evaluation of suspected glenohumeral pyarthrosis should include evaluation of the subacromial bursa.