Factors influencing the reliability of different designs of goniometer : a literature review

Different designs of the goniometer are available for clinical measurements of joint range of motion (ROM), including: universal goniometers, gravity-dependent goniometers and electrical goniometers. Reliability of the goniometer is essential in clinical practice. Several factors can influence reliability, including: pathology, number of testers, type of motion, joint characteristics and procedure followed. Hence, it is important to understand how reliability can change with these factors. An electronic and manual literature search was conducted into the reliability of different goniometers. A variety of search terms were used with no limits or restrictions. Papers sourced were graded according the Scottish Intercollegiate Guideline Network guidelines. Normal subjects and patients with variety of pathologies participated in the studies reviewed. The active and passive motion of lower limb joints was studied. Both intratester and intertester reliability was examined. Several studies directly compared between the reliability of different goniometric designs. Variation in methodology and measurement procedures across different studies affected the ability to make comparison between them. The majority of studies concluded that intratester measurements were more reliable than intertester measurements. Reliability of measurements varied across joints involved, with measurements of more complex joints proving less reliable than simple joints. In addition, the reliability of the measurements altered depending on pathology. Moreover, some studies confirmed that measuring active motion was more repeatable than passive motion. Furthermore, some studies suggested that standardising the method of measurement increases reliability. Finally, reliability differed between the different goniometric designs and most studies stated that goniometers should not be used interchangeably. In Conclusion, clinicians should be cautious when: choosing the appropriate type of goniometer and interpreting or comparing measurements taken using different designs. Additional studies of appropriate design should be conducted to provide better understanding of goniometer measurements obtained.