Atlanto-axial subluxation

• In rheumatoid arthritis, atlanto‐axial subluxation can occur due to destruction of the synovial joint between the atlas and the dens and rupture of the transverse ligament
• Subluxation can result in cord compression which can be fatal

Management

• Less severe cases (seen on flexion‐extension views) may be treated with a collar to prevent flexion
• More severe cases may require surgical fusion

Lower cervical subluxations

• Lower cervical subluxations can occur due to destruction of the synovial facet joints and uncovertebral joints by RA
• There is potential for cord compression (myelopathy) with upper motor neuron signs (wide based gait, weakness, increased tone, upgoing plantar response)
• Measurements are taken from flexion‐extension x-rays

Management

• If instability does not involve/threaten neurological structures - conservative management (analgesia, physio)
• More severe cases may require stabilisation/fusion

Other causes of atraumatic cervical spine instability

• Atraumatic cervical spine instability can also occur in Down's syndrome