Repeated Measurements of Arm Joint Passive Range of Motion After Stroke: Interobserver Reliability and Sources of Variation

Abstract

Background Goniometric measurements of hemiplegic arm joints must be reliable to draw proper clinical and scientific conclusions. Previous reliability studies were cross-sectional and based on small samples. Knowledge about the contributions of sources of variation to these measurement results is lacking. Objective The aims of this study were to determine the interobserver reliability of measurements of passive range of motion (PROM) over time, explore sources of variation associated with these measurement results, and generate smallest detectable differences for clinical decision making. Design This investigation was a measurement-focused study with a longitudinal design, nested within a 2-arm randomized controlled trial. Methods Two trained physical therapists assessed 7 arm movements at baseline and after 4, 8, and 20 weeks in 48 people with subacute stroke using a standardized protocol. One physical therapist performed the passive movement, and the other read the hydrogoniometer. The therapists then switched roles. The relative contributions of several sources of variation to error variance were explored with analysis of variance. Results Interobserver reliability coefficients ranged from .89 to .97. The PROM measurements were influenced by error variance ranging from 31% to 50%. The participant × time interaction made the largest contribution to error variance, ranging from 59% to 81%. Smallest detectable differences were 6 to 22 degrees and were largest for shoulder movements. Limitations Verification of shoulder pain and hypertonia as sources of error variance led to a substantial number of unstable variance components, necessitating a simpler analysis. Conclusions The assessment of PROM with a standardized protocol, a hydrogoniometer, and 2 trained physical therapists yielded high interobserver reliability indexes for all arm movements. Error variance made a large contribution to the variation in measurement results. The resulting smallest detectable differences can be used to interpret future hemiplegic arm PROM measurements with more confidence.

Passive range of motion in patients with adhesive shoulder capsulitis, an intertester reliability study over eight weeks

“…This large cohort study demonstrated very good to excellent intertester reliability when examining PROM in patients with shoulder adhesive capsulitis stage II. The results in our study are comparable or better than other reliability studies measuring shoulder ROM in normal individuals or in other shoulder populations (Table 1 ) [ 8 , 13 , 16 , 17 , 20 , 22 , 24 ]. To our knowledge this is the first reliability study that has measured passive ROM in patients with adhesive shoulder capsulitis using a plurimeter, whereas most former studies have used a variety of measuring instruments and techniques.…”

Validity and reliability of smartphone magnetometer-based goniometer evaluation of shoulder abduction – A pilot study

“…There have been many studies evaluating the validity and reliability of the UG in the clinical setting, showing good inter-rater and intra-rater reliability as well as clinical validity [2,6,9,10,11,4].…”

Making Sense of the Clinical Picture

“…• Potential sources of measurement error include pain, oedema, dressings, joint injury, scarring, position of the person being tested, anxiety and environmental factors [61,[64][65][66][67][68]. This information suggests that, to be reliable, goniometric measurement and retesting of PROM should be performed for a particular client by the same clinician, or by clinicians trained in the same measurement protocol, with the person in the same body position each time.…”

“…For a change in measurement to be considered a true change in ROM (a clinically important change), the amount of change must exceed measurement error, that is, approximately 5 ∘ in the upper limb [69,70]. When recording ROM, it is essential that a consistent method be used across different clinicians in each clinical setting and where possible, across different clinical settings within which a client may receive services, to ensure reliability of measurements and allow change to be detected over time [65]. When recording ROM, it is essential that a consistent method be used across different clinicians in each clinical setting and where possible, across different clinical settings within which a client may receive services, to ensure reliability of measurements and allow change to be detected over time [65].…”