Subacromial space in the rheumatoid shoulder: a radiographic 15-year follow-up study of 148 shoulders

A cohort of 74 patients with rheumatoid arthritis was monitored prospectively for 15 years. At the end of the study 148 shoulders were radiographed with a standard method. The subacromial space was examined from the radiographs with a method where the acromiohumeral interval was measured from the dense cortical bone marking the inferior aspect of the acromion to a point directly above the head of the humerus. The smallest distance was recorded, and negative values were used when the original articular surface of the humerus exceeded the inferior surface of the acromion. Destruction of the glenohumeral (GH) joints was assessed by the Larsen method on a scale of 0 to 5. The relation of subacromial space measurement to the grade of destruction of GH joints was examined. The mean subacromial space was 6.7 (SD 4.4), range from -13 to 12 mm: 6.1 mm (SD 5.6) in men and 6.9 mm (SD 4.0) in women. The mean of nonaffected (Larsen grade 0 or 1) shoulders (n = 77) was 8.6 mm (SD 1.5), and the corresponding mean of the affected (Larsen grade > or =2) shoulders (n = 71) was 4.6 mm (SD 5.5). Previously reported pathologic criterion (