Atlantoaxial Osteoarthritis: An Overlooked Condition

Atlantoaxial osteoarthritis (AAOA) is a clinical syndrome that consists of occipitocervical pain and cervical rotation limitation. Its clinical recognition is often deficient leading to misdiagnosis and suboptimal treatment. The incidence of AAOA varies from 5% in the sixth decade to as much as 18% in the ninth decade of life. Age, female sex, and excessive occupational cervical weight-bearing are the main risk factors for AAOA. Pain originates from the degeneration of the lateral C1-C2 joints and may be referred through the greater occipital nerve. Although AAOA is not easy to see on classic cervical spine views, the open mouth odontoid view has great diagnostic value. Magnetic resonance imaging, CT scan, and/or injections may be used for confirmatory testing. Initial treatment is conservative, including physiotherapy, pain medication, and imaging-guided injections. As many as two-thirds of patients improve with conservative treatment. Indication for surgery is incapacitating pain recalcitrant to nonoperative management. Surgeons' thorough knowledge of surgical anatomy and techniques is key for the notable clinical benefits expected with the surgery. New surgical technology helps C1-C2 fusion become safer and more reliable. This review aims to synthetize available data related to AAOA and to improve the understanding of this condition and its management in the orthopaedic community.