Osteoarthritis of the alanto-axial joint.

Thirty-one patients suffering from osteoarthritis of the atlanto-axial joint are described, suggesting that this disease is not particularly uncommon. The most characteristic radiological signs are narrowing of the joint space from loss of articular cartilage, marginal cortical thickening and osteophyte formation. Histological examination in the cadaver has shown thinning and fibrillation of articular cartilage and intra-cartilaginous ossification. The radiological appearances of the atlanto-axial joint are classified in three types, lateral atlanto-axial, atlanto-odontoid and mixed. Peak age distribution occurs between 50 and 69 years of age. Patients complain of occipital pain, a stiff shoulder and paraesthesia of the fingers. Treatment was conservative in all cases except one, a 63-year-old woman with severe occipital pain. A transoral atlanto-axial fusion was performed in this case with marked improvement. The transoral approach allows fixation and curettage of the degenerative lesions.