Interrater Reliability of a Novel Goniometric Technique to Measure Scapular Protraction and Retraction

Importance: Scapular protraction and retraction are often essential for occupational performance; however, clinical assessment of these movements is uniquely challenging. Objective: To analyze the interrater reliability of a novel goniometric method to measure scapular protraction and retraction. Design: An observational, descriptive design was implemented to evaluate interrater reliability between two experienced occupational therapists who were also certified hand therapists. Setting: Academic institution. Participants: Convenience sample of graduate students (N = 80). Outcomes and Measures: The hypothesis, developed before study implementation, was that the technique would demonstrate clinically acceptable interrater reliability, defined as a standard error of measurement (SEM) <8°. Goniometric measurements of the scapula at rest, in maximal protraction, and in maximal retraction were independently obtained from each participant by each evaluator. The goniometer was aligned on the scapula using the superior angle as the axis of motion to measure the movement of the acromion relative to the frontal plane. The SEM was calculated in each position using the intraclass correlation coefficient values and the average of the standard deviations from the two raters. Results: The SEM values between the two evaluators for the resting, protracted, and retracted positions were 3.46°, 2.93°, and 2.74°, respectively. Conclusions and Relevance: The SEM between the two evaluators for each scapular position was <4°, suggesting that the technique may be clinically reliable. However, additional research regarding the reliability and validity of the technique is recommended. What This Article Adds: The findings of this study support the use of goniometry to measure scapular protraction and retraction in relation to occupational performance. The technique provides a way to quantify baseline scapular mobility and track progress.