Atlanto-odontoid Osteoarthritis. Appearance and Prevalence at Computed Tomography

Study Design: In this prospective study, the authors evaluated the atlanto-odontoid (AO) joint in 500 consecutive patients who underwent computed tomographies (CTs) of the brain or paranasal sinuses.

Objectives: The objective of the study was to determine age specificity of various morphologic abnormalities related to osteoarthritis at the AO joint in patients referred for CT primarily to exclude brain or sinus abnormalities.

Summary Of Background Data: In all patients, at least two axial slices through the AO joint were evaluated by two authors, and agreement was reached by consensus.

Methods: Abnormal morphology was categorized into three groups: (1) osteophytosis; (2) obliteration of the joint space; and (3) transverse ligament calcification.

Results: In a significant percentage of older individuals, some form of degenerative disease is present. These changes show a roughly linear progression with advancing age.

Conclusion: Morphologic changes related to AO osteoarthritis are frequent coincidental findings in patients referred for CT examination of the brain or paranasal sinuses. Awareness of the appearance and prevalence of degenerative changes in the AO joint on CT is important because reports in the literature and earlier findings of the authors indicate that these changes can be a source of suboccipital headache.