A Reliable, Valid, and Efficient Goniometric Technique to Measure Scapular Protraction and Retraction

Clinical assessment of the scapula is challenging because of the complex biomechanics of the scapulothoracic joint.

To analyze the concurrent validity, reliability, and precision of goniometry in measuring scapular protraction and retraction.

Observational, descriptive design.

Academic.

Sample of 50 healthy adults.

Two experienced raters (occupational therapists and certified hand therapists) measured the resting, protracted, and retracted positions of the scapulae using the superior angle, frontal plane, and acromion as anatomical landmarks. The Dartfish motion analysis system was then used by a blinded researcher for digital measurement of the same scapular positions. Descriptive (means and standard deviations) statistics and reliability analysis (intraclass correlation coefficient [ICC], standard error of measurement [SEM]) were used to analyze interrater reliability. Additional statistics, including Pearson's r and Bland-Altman plots, were used to assess concurrent validity.

Measures obtained by both raters demonstrated excellent interrater reliability (ICCs = .89-.99; SEM = .63-1.9: For minimum detectable changes, range = 1.7°-5.3°, and for percentage of the minimum detectable change, range = 7-20%). The mean variance between goniometric measurements and Dartfish values was less than 1°, with very strong correlation (r = .84-.92).

The reliability and validity meet or exceed similar psychometric properties of goniometric techniques for other joints of the human body. Goniometric measurement of scapular protraction and retraction is a reliable and valid technique that can be efficiently implemented by rehabilitation practitioners. Plain-Language Summary: Protraction and retraction of the scapula are important, foundational movements of upper extremity function but have proven uniquely challenging to measure. The present findings support the use of goniometry as a valid, reliable, and efficient method for the assessment of scapular protraction and retraction by occupational therapists and other rehabilitation practitioners.