Reliability of open and closed kinetic chain subtalar joint neutral positions and navicular drop test

Subtalar joint (STJ) measurements are commonly made in the clinic to assess foot and ankle positions because of the high incidence of lower extremity dysfunctions. The purposes of this study were to investigate the intratester and intertester reliability of the open kinetic chain subtalar joint neutral (OKC STJN) and closed kinetic chain subtalar joint neutral (CKC STJN) positions and the navicular drop test (NDT). Two inexperienced testers performed repeated measurements on 15 subjects (N = 30 feet) during two testing sessions. Intratester and intertester reliability (ICC 1,1) and standard error of measurement (SEM) were determined for each dependent variable. For OKC STJN, the intratester ICC values were .06 and .27, and the intertester ICC value was .00. The intratester SEM values were 1.81 and 2.29 degrees, and the intertester was 2.51 degrees. The CKC STJN intratester ICC values were .14 and .18, with SEM values of 2.46 and 2.40 degrees. The intertester CKC ICC value was .15, with an SEM of 2.43 degrees. For the NDT, the intratester ICC values were .61 and .79, and the SEM values were 1.92 mm and 2.57 mm. The intertester ICC value was .57 and the SEM was 2.72 mm. The results reveal that both OKC and CKC STJN yield poor intratester and intertester reliability and the NDT yields poor to moderate intratester reliability and poor intertester reliability. We conclude that these foot and ankle measurements are not reliable when performed by inexperienced testers. Therefore, clinicians should practice these measurement techniques and determine their measurement error.