A radiographic study of the effect of a modern orthotic device in the treatment of rheumatoid atlantoaxial subluxation.
To study the ability of a new open-type collar to restrict atlantoaxial subluxation.
Atlantoaxial subluxation is common in rheumatoid arthritis, and thus, the development of conservative treatments is important. It has been shown that a custom-made stiff collar significantly restricts atlantoaxial subluxation in approximately half of patients with unstable atlantoaxial subluxation.
In 30 successive patients with rheumatoid atlantoaxial subluxation, lateral view radiographs were taken in flexion, extension, and neutral positions without a collar and in flexion with the Headmaster collar.
The mean atlantoaxial distance during flexion was 7.1 +/- 1.8 mm and during extension was 1.0 +/- 1.0 mm, and the mean instability was 6.1 +/- 2.3 mm. In the 20 cases with the greatest stabilizing effect, the mean atlantoaxial distance during flexion with a collar was 1.1 +/- 1.3 mm, whereas in 10 patients with lesser effect it was 6.7 +/- 2.5 mm (P < 0.0001). The lesser stabilizing effect was associated with the presence of atlantoaxial subluxation in the neutral position.
The Headmaster collar is an effective and useful tool in the conservative treatment of simple unstable atlantoaxial subluxation, but an ordinary custom-made stiff collar is still often needed. These two collars are complementary, and their selection and use must be determined individually.