A reliability study of the universal goniometer, fluid goniometer, and electrogoniometer for the measurement of ankle dorsiflexion.

This study investigated the reliability of three goniometers, the universal, fluid, and electro-goniometers, in the measurement of ankle dorsiflexion. Intra- and interobserver reliability were assessed using 10 healthy volunteers and five observers. A standardized ankle position was used to measure full range of active dorsiflexion. Intraobserver reliability was assessed using one observer over two successive occasions. Interobserver reliability was assessed among five observers over five separate occasions. A one-factor analysis of variance to examine intraobserver reliability demonstrated no significant difference between each of the devices on the two occasions. A multifactorial analysis of variance demonstrated significant differences among observers and again among devices (P < 0.001). Secondary analysis for interdevice reliability demonstrated significant differences among the three devices (p < 0.1). The study suggests that each device cannot be used reliably among observers or be used interchangeably, and clinical judgment based on angular changes of less than 10 degrees are invalid if rigid protocols are not followed.