Apophysial joint degeneration, disc degeneration, and sagittal curve of the cervical spine - Can they be measured reliably on radiographs?

Study Design. Interexaminer reliability study. Objectives. To determine the reliability of grading apophysial joint and disc degenerative changes and the reliability of measuring sagittal curves on lateral cervical spine radiographs. Summary of Background Data. Several authors have proposed that the presence of degenerative changes and the absence of lordosis in the cervical spine are indicators of poor recovery from neck injuries caused by motor vehicle collisions. The validity of those conclusions is questionable because the reliability of the methods used in their studies to measure the presence of degenerative changes and the absence of lordosis has not been determined. Methods. Kellgren's classification system for apophysial joint and disc degeneration, as well as the pattern and magnitude of the sagittal curve on 30 lateral cervical spine radiographs were assessed independently by three examiners. Results. Moderate reliability was demonstrated for classifying apophysial joint degeneration with a intraclass correlation coefficient of 0.45 (95% confidence interval, 0.09-0.71). Classifying degenerative disc disease had substantial reliability, with an intraclass correlation coefficient of 0.71 (95% confidence interval, 0.23-0.88). Measuring the magnitude of the sagittal curve from C2 to C7 had excellent interexaminer agreement, with an intraclass correlation coefficient of 0.96 (95% confidence interval, 0.88-0.98) and an interexaminer error of 8.3 degrees. Conclusions. The classification system for degenerative disc disease proposed by Kellgren et al and the method of measurement of sagittal curves from C2 to C7 demonstrated an acceptable level of reliability and can be used in outcomes research.