AB1197-HPR Validity and reliability of a smartphone goniometer application for measuring hip range of motion in patients with hip osteoarthritis: a pilot study

Abstract

Background Osteoarthritis (OA) of the hip affects the entire joint structure and function and leads joint capsular changes which result limitation in range of motion (ROM). Therefore, measuring ROM is an essential part of the hip assessment. Various measurement tools are available for determining the ROM such as universal goniometers (UG), digital inclinometers, motion analysis systems. Recently, smartphones equipped with suitable applications are able to measure ROM. Objectives The aim of this study was to determine the inter-rater and intra-rater reliability of a smartphone application “PT Goniometer© 2015 Mark Busman” (PTG) and investigate the agreement within PTG versus UG for active hip ROMs in patients with hip OA. Methods This study included eight people who were diagnosed with hip OA. Two physiotherapists performed the ROM measurements on affected hips by using PTG and UG. UG was employed as the reference standard. Hip ROM tests were performed in the following order; flexion, abduction, internal and external rotation. Intraclass correlation coefficient (ICC) models were used to determine the intra-rater and inter-rater reliability. The Spearman correlation coefficients were used to establish validity of PTG. Results The PTG smartphone application demonstrated good to excellent inter-rater and intra-rater reliability (ICCs >0.75) for all measured hip movements in patients with hip OA. ICC scores, minimum detectable change (MDC95) and standart error of measurement (SEM) values were indicated in Table 1 and Table 2. Additionally,UG and PTG application methods demonstrated positive correlations for all hip movements (p<0.05).Table 1. Inter-rater Reliability of the PT Goniometer Application Movement PT 1, PTG PT 2, PTG ICC (%95 CI) SEM MDC95 (Mean ± SD) (Mean ± SD) Flexion 66.18°±28.87° 63.66°±30.74° 0.99 (0.94–1.00) 0.91 2.52 Abduction 27.98°±12.93° 29.58°±13.03° 0.99 (0.90–0.99) 0.4 1.1 IR 10.86°±10.66° 11°±10.67° 0.99 (0.99–1.00) 0.33 0.91 ER 20.12°±11.74° 21.06°±12.5° 0.99 (0.96–1.00) 0.33 0.91 PT1: Physiotherapist1, PTG: PT Goniometer application, PT2: Physiotherapist 2, ICC: Intraclass correlation coefficient, CI: Confidence Interval, SEM: Standard Error of Measurement, MDC95: Minimum Detectable change at the %95 confidence level, SD: Standard deviation, IR: Internal rotation, ER: External rotation.Table 2. Intra-rater Reliability of PT Goniometer Application Movement PT 1, PTG PT1, RT PTG ICC (%95 CI) SEM MDC95 (Mean ± SD) (Mean ± SD) Flexion 66.18°±28.87° 65.64°±28.58° 0.99 (0.97–0.99) 0.91 2.52 Abduction 27.98°±12.93° 28.58°±13.61° 0.99 (0.98–1.00) 0.4 1.1 IR 10.86°±10.66° 10.96°±10.73° 0.99 (0.99–1.00) 0.33 0.83 ER 20.12°±11.74° 20.46°±11.96° 0.99 (0.98–1.00) 0.37 1.02 PT 1: Physiotherapist 1, PTG: PT Goniometer Application, RT PTG: Retest PT goniometer application, ICC: Intraclass correlation coefficient, CI: Confidence Interval, SEM: Standard Error of Measurement, MDC95: Minimum Detectable Change at the %95 confidence level, SD: Standard deviation, IR: Internal rotation, ER: External rotation. Conclusions High correlations obtained in this pilot study suggest that using a smartphone application might be a valid and a reliable method for measuring hip ROM in patients with hip OA and smartphone applications can be used in clinical settings. Studies with larger population are required for further investigation of smartphones' psychometric properties on measuring hip ROM. Disclosure of Interest None declared