Sacroiliac joint involvement in classical or definite rheumatoid arthritis.

In 188 patients with rheumatoid arthritis 564 radiologic examinations of the sacroiliac joints were performed. Severe blurring of the joint space or ankylosis were uncommon. The involvement was related to an age > 40 years at the onset, high values of the ESR and involvement of most joint groups in the limbs and cervical spine. Sex, presence or high titres of the rheumatoid factor and antinuclear antibodies were unrelated to lesions of the sacroiliac joints. A relation to the severity of rheumatoid arthritis rather than to the immunologic condition is suggested.