The prevalence of osteoarthritis of the atlanto-odontoid joint in adults using multidetector computed tomography

Background: The prevalence of osteoarthritis of the atlanto-odontoid joint has been reported by radiology, autopsy, and conventional computed tomography (CT), but the prevalence has not yet been assessed by multidetector computed tomography (MDCT). Purpose: To reveal the prevalence of osteoarthritis of the atlanto-odontoid joint and to analyze the inter-relationships among gender, age, and osteoarthritis with MDCT in adults. Material and Methods: First, a series of 700 selected domestic patients aged >18 years undergoing an upper cervical MDCT scan were divided equally into seven age groups. Second, using the postprocessing technique of multiplanar reconstruction, osteoarthritis of the atlanto-odontoid joint was viewed from any direction and classified into four grades, which were normal, mild, moderate, and severe. Lastly, the incidence of the different grades of osteoarthritis was assessed, and the reproducibility was tested. Results: There was no significant difference between gender and osteoarthritis of atlanto-odontoid joint (P>0.05). The rate of osteoarthritis was 16% in the age group 18-25 years, 23% in the age group 25-30 years, 33% in the age group 30-40 years, 54% in the age group 40-50 years, 70% in the age group 50-60 years, 87% in the age group 60-70 years, and 93% in the age group >70 years. Mild osteoarthritis appeared at the earliest at age 19.6 years, moderate osteoarthritis in at earliest at age 24.2 years, and severe osteoarthritis at the earliest at age 48.5 years. The inter-observer reliability was excellent (k=0.86). Conclusion: Osteoarthritis of the atlanto-odontoid joint could be detected by MDCT in a young adult. It increased rapidly with increasing age on MDCT.