Abstract
We report a classification system based on the changes in shape of the glenoid fossa and on an evaluation of the upward migration of the humeral head, because a simple classification based on X-ray evaluation would be of great assistance to physicians dealing with the diagnosis and treatment of RA. We evaluated 150 shoulders of 118 RA patients who showed changes in the glenoid fossa after radiological examinations. The morphology of the glenoid fossa of the RA shoulder was classified into 3 types and we were able to classify a total of six types of deformities by adding the problem of upward migration of the humeral head. An additional investigation on the difference in the type of deformity between the right and left shoulder, the changes in type during the course of the study, and the relationship between this particular classification and certain patient characteristics was also included.