Atlantoaxial facet joint arthritis in the rheumatoid cervical spine. A panoramic zonography study.

Twenty-three patients with severe, longterm (22 years, range 8-36) rheumatoid arthritis were evaluated for rheumatoid changes in the atlantoaxial facet joints using a panoramic zonography program. Ten patients had vertical subluxation of the odontoid process. In 9 of 10 cases this mode of subluxation was associated with grade 3-4 arthritis in the facet joints. Our findings indicate atlantoaxial facet joint arthritis with bilateral collapse of the lateral facet joint masses as a cause of vertical subluxation. Furthermore, we suggest that panoramic zonography investigation is a valuable contribution to the pattern of radiographic examination of the atlantoaxial facet joint arthritis, especially for evaluation of its clinical counterparts: nonreducible lateral head tilt and vertical atlantoaxial subluxation.