The discovertebral joints in the cervical spine may be affected in patients with rheumatoid arthritis (RA) with resulting osteochondral destruction [1,2]. A review of the clinical manifestations and treatment of atlantoaxial (C1 to C2) and subaxial subluxation in RA is presented here. The clinical features and general medical management of RA, as well as the differential diagnosis and general evaluation of the patient with neck pain and of cervical spine disorders, are discussed separately. (See "Clinical features of rheumatoid arthritis" and "General principles of management of rheumatoid arthritis in adults" and "Evaluation of the patient with neck pain and cervical spine disorders".)
Cervical joint destruction in patients with RA may lead to vertebral malalignment (eg, subluxation), causing pain, neurological deficit, and deformity. Risk factors for development of cervical subluxation include older age at onset of RA, more active synovitis, higher levels of C-reactive protein, rapidly progressive erosive peripheral joint disease, and early peripheral joint subluxations [3,4]. Both atlantoaxial and subaxial (below C2) joints may be involved.
Atlantoaxial disease — Among the joints of the cervical spine, the atlantoaxial joint is prone to subluxation in multiple directions, potentially leading to cervical myelopathy . The atlas (C1) can move anteriorly, posteriorly, vertically, laterally, or rotationally relative to the axis (odontoid and body of C2):
- Abnormal anterior movement on the axis is the most common type of subluxation. It often results from laxity of the transverse ligament induced by proliferative C1 to C2 synovial tissue but may also occur as a result of erosion or fracture of the odontoid process .
- Posterior movement on the axis can occur only if the odontoid peg has been fractured from the axis or has been destroyed.
- Vertical movement in relation to the axis is least common; it results from destruction of the lateral atlantoaxial joints or of bone around the foramen magnum .
- Vertical atlantoaxial subluxation may occur in those with initial anterior-posterior subluxation. Vertical subluxations are believed to have a worse prognosis than the other varieties .
Pathogenesis — There are two possible mechanisms for involvement of the intervertebral joints in the cervical spine in RA: