Reliability of navicular displacement measurement as a clinical indicator of foot posture

This study evaluated two methods for quantifying foot posture: navicular dr op and navicular drift. Five clinicians measured 20 nonpathological partici pants on two occasions. Intraclass correlation coefficients ranged from 0.3 3 to 0.76 for navicular drop and from 0.31 to 0.62 for navicular drift. The standard error of measurement, as a 95% confidence interval, ranged from /-1.5 mm to +/-3.5 mm for navicular drop and +/-3 mm to +/-5 mm for navicul ar drift. Intratester reliability was slightly better than intertester reli ability for both measurements. These results indicate that both techniques are only moderately reliable, and physicians using these measurements in cl inical practice should interpret the values in light of the magnitude of er ror associated with them.