Nonreducible rotational head tilt and lateral mass collapse. A prospective study of frequency, radiographic findings, and clinical features in patients with rheumatoid arthritis.

Of 126 hospitalized, but otherwise unselected, patients with rheumatoid arthritis, 12 (10%) had a persisting nonreducible rotational head tilt deformity (NRRHT). These 12 were grouped with an additional 12 similar subjects, previously found to have the same condition, and all 24 were compared with the remaining 114 who did not have head tilt. Patients with NRRHT differed significantly from the others in that the former were more likely to have a destructive peripheral arthritis, headache, limited neck motion, and various cervical subluxations. All 24 subjects with NRRHT had predominately unilateral collapse of the lateral masses of the atlas and/or axis, compared with only 2 of the 114 with normal head position. The head always tilted to the side of the lateral mass collapse, which appeared to be the sole or major cause of the abnormal head position.