Study design: A radiographic study of the effect of a modern orthotic device in the treatment of rheumatoid atlantoaxial subluxation.
Objective: To study the ability of a new open-type collar to restrict atlantoaxial subluxation.
Summary of background data: 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.
Methods: 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.
Results: 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.
Conclusion: 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.