Reliability and normative database of the zebris cervical range-of-motion system in healthy controls with preliminary validation in a group of patients with neck pain

Objective: The first aim of this study was to determine the reliability of the Zebris (Achen, Germany) ultrasound-based testing of cervical range of motion (ROM). The second aim was to develop a normative database in a healthy sample of 96 volunteers. The third aim was to evaluate, with the Zebris system, the ROM in a sample of patients with chronic neck pain compared to healthy controls to determine if cervical ROM could discriminate between these groups and between subgroups of pain patients (with or without whiplash injury). Methods: The study participants were 96 healthy volunteers, 14 patients with idiopathic neck pain, and 16 patients with chronic whiplash. Cervical ROM was measured in the 3 planes with the Zebris CMS 70P ultrasound-based motion analysis system. The intra- and interrater reliability of the protocol was tested in 12 volunteers. Results: Full-cycle measurements showed high reliability (intraclass correlation coefficient, 0.80-0.94) with the SE of measurement ranging from 4.25 degrees to 7.88 degrees. The distribution of ROM measures showed a great individual variation, with a significant age-related decrease in ROM in all directions. Range of motion was reduced in patients with chronic whiplash in all primary movements, compared to healthy subjects, whereas in patients with idiopathic neck pain, only rotation showed reduced ROM. Conclusion: Results demonstrate a high degree of test-retest reliability in measuring cervical ROM. The use of normative data for ROM when evaluating patients with neck disorders needs to take age into account. The current study has demonstrated that patients with chronic neck pain demonstrate reduced ROM, which differs between patients with idiopathic neck pain and those with chronic whiplash.