Reliability of a smartphone goniometric application in the measurement of hip range of motion among experienced and novice clinicians

Abstract

Context: Deficits in the hip range of motion are associated with hip and groin injuries. Accurate and reliable goniometric measurements are important in identifying those at risk of injury and determining the efficacy of treatment interventions. Smartphone goniometric applications are regularly used to assess joint ranges of motion; however, there is limited knowledge on the reliability of this method in relation to the hip, particularly between clinicians with different levels of experience. Objective: To determine the intratester and intertester reliability of a smartphone clinometer application for the assessment of hip goniometric measurements in healthy volunteers by an experienced and novice clinician. Design: Reliability study. Setting: University Athletic Therapy facility. Participants: Physically active, university students. Main Outcome Measures: The study determined the intra- and intertester (experienced vs novice clinician) reliability of goniometric measurements of the hip joint (modified Thomas test and seated hip internal and external rotation) using a smartphone goniometric application. Intraclass correlation coefficients (ICCs), standard error of measurement, and minimal detectable change at a 95% confidence interval were used to assess reliability. Results: Goniometric measurements demonstrated good to excellent relative intratester reliability for the modified Thomas test (ICC = .94), external rotation (ICC = .93–.95), and internal rotation (ICC = .80–.81). Intertester reliability for expert and novice clinicians was also excellent for the modified Thomas test (ICC = .98), external rotation (ICC = .95), and internal rotation (ICC = .92). Intratester and intertester standard error of measurement and minimal detectable change at 95% confidence interval values were similar for both testers and ranged from 1.9° to 3.6° and 5° to 10.1° and from 1.1° to 2.3° and 2.9° to 6.5°, respectively. Conclusion: Smartphone-based goniometric measurements of hip range of motion have high intratester and intertester reliability for novice and expert clinicians. It may be a useful, simple, and inexpensive resource for clinicians.