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 inter-rater 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.