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

Area of Science:

• Biomechanics
• Rehabilitation Science
• Orthopedics

Background:

• Clinical assessment of scapular movement is complex due to intricate scapulothoracic joint biomechanics.
• Accurate measurement of scapular protraction and retraction is crucial for evaluating upper extremity function.
• Existing measurement techniques may present challenges in terms of reliability and validity.

Purpose of the Study:

• To evaluate the concurrent validity, reliability, and precision of goniometry for measuring scapular protraction and retraction.
• To establish goniometry as a dependable clinical tool for scapular assessment.
• To compare goniometric measurements with a motion analysis system.

Main Methods:

• Observational, descriptive study design involving 50 healthy adults.
• Two experienced raters performed goniometric measurements of scapular positions using specific anatomical landmarks.
• Dartfish motion analysis system was used for digital measurement, with blinded researchers analyzing data.
• Statistical analysis included interrater reliability (ICC, SEM) and concurrent validity (Pearson's r, Bland-Altman plots).

Main Results:

• Goniometric measurements demonstrated excellent interrater reliability (ICCs = .89–.99) and acceptable SEM values.
• Minimum detectable changes ranged from 1.7° to 5.3°.
• Concurrent validity was strong, with a mean variance of less than 1° compared to Dartfish analysis (r = .84–.92).

Conclusions:

• Goniometric measurement of scapular protraction and retraction is a reliable and valid technique.
• The precision and accuracy meet or exceed those of goniometric methods used for other joints.
• This method can be efficiently implemented by occupational therapists and other rehabilitation practitioners for clinical assessment.