Two Measurement Techniques for Assessing Subtalar Joint Position: A Reliability Study

Proper assessment of the subtalar joint is critical for foot and ankle evaluation. Yet, reliability of open kinetic chain goniometric measurements of the subtalar joint has been poor. Two alternative techniques, navicular height and calcaneal position with an inclinometer, have been reported in the literature but lack reliability assessment. The purpose of this study was to determine the intertester and intratester reliability of navicular height and calcaneal position using an inclinometer. Thirty healthy, volunteer subjects (22 females, age 24 +/- 3.6 years; eight males, age 25 +/- 5.1 years) participated in this study. Two testers performed repeated measures on both feet of each subject (N = 60) during two testing sessions. Testers determined the 1) subtalar neutral position, 2) resting position, and 3) difference between these two measurements using an inclinometer for calcaneal position and navicular height. Intratester and intertester reliabilities (ICC 2, 1), standard errors of measurement, and 95% confidence intervals were determined. Intertester and intratester reliability for calcaneal position ranged from .68 to .91 for all measurements. Intertester and intratester reliability for navicular height ranged from .73 to .96 for all measurements. We conclude that these weight-bearing measurement techniques are reliable and acceptable for clinical and research purposes as measured. In addition, we hypothesize that these measurement techniques are simpler than previously described open kinetic chain methods.