The reliability and validity of goniometric elbow measurements in adults: A systematic review of the literature

Background The universal goniometer is a simple measuring tool. With this review we aimed to investigate the reliability and validity of the universal goniometer in measurements of the adults' elbow. Methods Preferred Reporting Items for Systematic reviews and Meta-Analysis guidelines were followed and our study protocol was published online at PROSPERO. A literature search was conducted on relevant studies. Methodological quality was assessed using the Quality Appraisal of Diagnostic Reliability (QAREL) scoring system. Results Out of 697 studies yielded from our literature search, 12 were included. Six studies were rated as high quality. The intrarater reliability intraclass correlation coefficient ranged from 0.45 to 0.99, the interrater reliability ranged from intraclass correlation coefficient 0.53–0.97. One study providing instructions on goniometric alignment did not find a difference in expert versus non-expert examiners. Another study in which examiners were not instructed found a higher interrater reliability in expert examiners. One study investigating the validity of the goniometer in elbow measurements found a maximum standard error of the mean of 11.5° for total range of motion. Discussion Overall, the studies showed high intra- and interrater reliability of the universal goniometer. The reliability of the universal goniometer in non-expert examiners can be increased by clear instructions on goniometric alignment.