Agreement between clinical measures to classify foot posture in asymptomatic adults

BACKGROUND: Various clinical measures of static foot posture have been developed and used. However, consensus among clinical measures to classify foot posture remains to be established. Therefore, this study aimed to determine the level of agreement as a reliability component between two common clinical methods in asymptomatic adults: the normalised navicular height truncated (NNHt) and the Foot Posture Index-6 (FPI-6). METHODS: The NNHt and FPI-6 were conducted on 102 asymptomatic adults. The measurement sequence was randomly arranged for each participant. Weighted Kappa (K(w)) was used to determine the agreement between the methods. RESULTS: Both the NNHt and FPI-6 achieved similar foot posture distributions: approximately 40–50% of the participants had a normal foot, approximately 40% had a pronated foot and approximately 10–20% had a supinated foot. The agreement between the methods to classify foot posture was excellent (K(w) = 0.84). CONCLUSIONS: The present study found excellent agreement between two commonly used clinical measures. This finding highlights the NNHt and FPI-6 consensus for foot posture classification in asymptomatic adults.