Clinical Validity and Stability of Active and Passive Cervical Range of Motion With Regard to Total and Unilateral Uniplanar Motion

STUDY DESIGN: A study of inter- and intra-examiner reliability and clinical validity using two instruments for assessment of spinal range of motion in healthy individuals. OBJECTIVE: To assess the clinical validity, stability, and normative values for active and passive cervical range of motion as measured by the CA-6000 (Orthopedic Systems Inc., Union City, CA), an electrogoniometer. SUMMARY OF BACKGROUND DATA: The authors' early trials with the electrogoniometer yielded values that differed substantially from those in other reports. The authors sought to resolve those discrepancies and understand their sources. METHODS: Axial rotations along the transverse, coronal, and frontal planes were measured as half-cycles (i.e., left-right or flexion-extension) that were repeated seven times per trial. Test-retest data were collected on the same healthy individuals for active and passive motion using men and women aged 20-39 years. For validity, simultaneous digital dual inclinometry and electrogoniometry were performed twice over a 1-week interval. In addition, a bench test was performed for validation of axial rotation. RESULTS: Clinical reliability of the CA-6000 was high for inter- and intra-examiner studies of total active motion, and validity was high when compared with that obtained with dual inclinometry. Total range of motion had less between-trial variability than half-cycles, axial rotation and lateral bending measurements had greater reliability than did flexion-extension measurements, and active motion was more reliable than passive motion. CONCLUSION: The CA-6000 provides valid and reliable measures of cervical range of motion. Discrepancies reported elsewhere appear to have arisen from several sources, as discussed in this article.