Intra-rater reliability of knee flexion and extension range of motion measurement through the photogrammetry method

Abstract

Although there are several methods for determining the range of motion (ROM), low reliability, low sensitivity, subjectivity or lack of information related to the typical error of measurement (TEM) may compromise interpretation of testing results. The aim of this study was to test the intra-rater reliability of the ROM measurement and the photogrammetry method for same day (internal consistency) and between days (stability) for knee active extension and passive flexion. Eighteen active male volunteers (24.5±3.7 years, 79.3±10.1 kg and 174.8±4.2 cm) were selected to participate in the study. After identification of anatomical landmarks used for reference, knee passive flexion and active extension were recorded by photography and then analyzed using an angular dimension tool from CorelDRAW®. The reliability of the measurement and the instrument was determined using intraclass correlation coefficient (ICC) and TEM. Data distribution was observed using the graphical representation of Bland e Altman. The method showed a perfect reliability (TEM=0.01 and ICC=1.0) for both extension and flexion movements. The measurement showed high reliability 0.97 and 0.93 (internal consistency) and 0.96 and 0.83 (stability) (TEM=2.9 and 4.0%, p<0.001) for knee extension and flexion, respectively. The method showed to be very reliable with a low typical error of the measurement knee extension and flexion ROM, showing to be adequate for application in both, clinical and research settings.