Intrarater and interrater reliability of first metatarsophalangeal joint dorsiflexion: Goniometry versus visual estimation

Background: Visual estimation (VE) and goniometric measurement (GM) are commonly used to assess first metatarsophalangeal joint dorsiflexion. The purposes of this study were to determine the intrarater and interrater reliability of VE and GM and to establish whether reliability was influenced by the experience of the examiner. Methods: Ten experienced and ten inexperienced examiners evaluated three real-size photographs of a first metatarsophalangeal joint positioned in various degrees of dorsiflexion on two separate occasions. Results: Experienced examiners demonstrated excellent intrarater and interrater reliability for GM (intraclass correlation coefficient [ICC], >0.953; standard error of measurement [SEM], 1.88°-2.58°) compared with inexperienced examiners, who showed fair-to-good intrarater and interrater reliability (ICC, 0.322-0.597; SEM, 2.0°-3.0°). For VE, inexperienced examiners demonstrated fair-to-good interrater and excellent intra-rater reliability (ICC, 0.666-0.808), which was higher compared with experienced examiners (ICC, 0.167-0.672). The SEM (2.8°-4.4°) was less varied than that of experienced examiners (SEM, 3.8°-6.4°) for VE, but neither group's SEMs were clinically acceptable. Conclusions: Although minimal differences between intrarater and interrater reliability of GM and VE are noted, this study suggests that GM is more reliable than VE is when used by experienced examiners. These findings support the continued use of GM for first metatarsophalangeal joint dorsiflexion assessment.