THE RELIABILITY OF A SMARTPHONE GONIOMETER APPLICATION COMPARED WITH A TRADITIONAL GONIOMETER FOR MEASURING ANKLE JOINT ROM

Abstract BACKGROUND: Evaluation of range of motion (ROM) is integral to assessment of the musculoskeletal system, is required in health fitness and pathologic conditions, and is used as an objective outcome measure. Several methods are described to check ROM, each with advantages and disadvantages. Hence, this study introduces a new device using a smartphone goniometer to measure ankle joint ROM. OBJECTIVE: To test the reliability of smartphone goniometry in the ankle joint by comparing it with the universal goniometer (UG) and to assess interrater and intrarater reliability for the smartphone goniometer record (SGR) application. METHODS: Fifty-eight healthy volunteers (29 men and 29 women aged 18-30 years) underwent SGR and UG measurement of ankle joint dorsiflexion and plantarflexion. Two examiners measured ankle joint ROM. Descriptive statistics were calculated for descriptive and anthropometric variables, as were intraclass correlation coefficients (ICCs). RESULTS: There were 58 usable data sets. For measuring ankle dorsiflexion ROM, both instruments showed excellent interrater reliability: UG (ICC = 0.87) and SGR (ICC = 0.89). Intrarater reliability was excellent in both instruments in ankle dorsiflexion: UG and SGR (mean ICC = 0.91). For measuring ankle plantarflexion, both instruments showed excellent interrater reliability: UG (ICC = 0.76) and SGR (ICC = 0.82). Intrarater reliability was excellent in both instruments in ankle plantarflexion: UG (mean ICC = 0.85) and SGR (mean ICC = 0.82). CONCLUSIONS: Smartphone-based goniometers can be used to assess active ROM of the ankle joint because they can achieve a high degree of intrarater and interrater reliability.