Reproducibility of cervical range of motion in patients with neck pain

Background: Reproducibility measurements of the range of motion are an important prerequisite for the interpretation of study results. The aim of the study is to assess the intra-rater and interrater reproducibility of the measurement of active Range of Motion ( ROM) in patients with neck pain using the Cybex Electronic Digital Inclinometer-320 (EDI-320).Methods: In an outpatient clinic in a primary care setting 32 patients with at least 2 weeks of pain and/or stiffness in the neck were randomly assessed, in a test-retest design with blinded raters using a standardized measurement protocol. Cervical flexion-extension, lateral flexion and rotation were assessed.Results: Reliability expressed by the Intraclass Correlation Coefficient (ICC) was 0.93 ( lateral flexion) or higher for intra-rater reliability and 0.89 ( lateral flexion) or higher for inter-rater reliability. The 95% limits of agreement for intra-rater agreement, expressing the range of the differences between two ratings were - 2.5 +/- 11.1 degrees for flexion-extension, - 0.1 +/- 10.4 degrees for lateral flexion and - 5.9 +/- 13.5 degrees for rotation. For inter-rater agreement the limits of agreement were 3.3 +/- 17.0 degrees for flexion-extension, 0.5 +/- 17.0 degrees for lateral flexion and - 1.3 +/- 24.6 degrees for rotation.Conclusion: In general, the intra-rater reproducibility and the inter-rater reproducibility were good. We recommend to compare the reproducibility and clinical applicability of the EDI-320 inclinometer with other cervical ROM measures in symptomatic patients.