Rheumatoid arthritis of the shoulder. Description and standard radiographs.

The course of rheumatoid arthritis in the shoulder is evaluated in 143 patients. In a period of 29 years, 630 x-rays were taken of 286 shoulders. In this series 2 or more x-rays per shoulder were taken of 89 patients (29 male, 60 female). The various changes in the glenohumeral and acromioclavicular joints are described. Gross destruction appears to be rare, compared to the more frequently seen minor cystic changes. The progress of the disease is often slow or halting. One or both of the shoulders in some of the patients (15 male and 29 female) did not have any detectable x-ray changes, although some of them were followed up for more than 20 years. During our follow-up it became apparent that the acromioclavicular and glenohumeral joints do not follow the same course neither in time nor in severity of joint destruction. Therefore, we divided the shoulder joint into the acromioclavicular and glenohumeral joint. One normal stage and 5 stages of pathology are recognised to fit into previously published schemes of the other joints. Stage 5 appears to be a new phenomenon of neojoint formation, under the previous humeral head with the inferior glenoid rim. Joint disease in the acromioclavicular joint could be divided only into 3 stages.