The Subtalar Joint Axis Palpation Technique: Part 2 - Results on reliability and validity using cadaver feet.

Abstract Background Clinically locating the point of no rotation to determine the subtalar joint axis (STJA) location by applying pressure on the plantar surface of the foot, was described by Kirby in 1987, but never validated. The purpose of this study is to extend a previously validated mechanical model to cadaver feet and to examine the intra-intertester reliability. Methods Four testers, with different levels of experience, determined the STJA location and moved the STJ through its range of motion capturing the movement using kinematic analysis. The comparison of the spatial STJA location determined by palpation between and within testers determined the inter- and intratester reliability. The helical axis method was performed to validate the model. Results The intrarater reliability varies from high (α = 0.96) to low (α = 0.26) for the slope and is in general high (α between α= 0.78 and α=0.95) for the intersection. The interrater reliability scores moderate to high, depending on the specific cadaver specimen. Concerning the exact location of the subtalar joint axis, no significant difference was found between the results determined by different testers and the helical axis method. Conclusion The palpation technique as part of the Subtalar Axis Location and Rotational Equilibrium Theory proposed by Kirby is a reliable and valid clinical tool. Experience in performing the palpation technique has a positive influence on the accuracy of the results. In the context of evidence based practice, this technique could be a standard tool in the examination of patients with lower limb related pathology.