Validation of the flexible electrogoniometer for measuring thoracic kyphosis

Area of Science:

• Biomechanics
• Spinal health
• Medical device validation

Background:

• Thoracic kyphosis assessment traditionally relies on static Cobb angle measurements from radiographs.
• Existing non-invasive tools often provide only static measurements or are limited to laboratory settings.
• The flexible electrogoniometer (FEG) offers dynamic, out-of-laboratory joint angle measurement but requires validation for thoracic spine application.

Purpose of the Study:

• To evaluate the accuracy of the flexible electrogoniometer (FEG) for measuring thoracic kyphosis.
• To determine the test-retest reliability of the FEG in assessing thoracic spine angles.
• To establish the concurrent validity of the FEG by comparing its measurements to radiographic Cobb angles.

Main Methods:

• Bench testing of the FEG against a plurimeter to assess accuracy.
• Test-retest reliability assessment involving 12 subjects performing functional activities over two separate weeks.
• Concurrent validity evaluation by comparing FEG thoracic spine measurements with radiographic Cobb angles in upright and slumped postures.

Main Results:

• Excellent accuracy was observed between the FEG and plurimeter (r > 0.99), with minor loss at extreme ranges.
• Very strong test-retest reliability was demonstrated (intraclass correlation coefficient = 0.92).
• The FEG angle showed a high correlation with the mid-Cobb angle (r = 0.81), indicating good concurrent validity.

Conclusions:

• The flexible electrogoniometer (FEG) is an accurate and reliable tool for measuring thoracic kyphosis.
• FEG measurements demonstrate strong correlation with the gold-standard Cobb angle, particularly when aligned with the mid-Cobb angle.
• The FEG presents a promising, valid method for dynamic thoracic spine assessment in various settings.