Determining 3D scapular orientation with scapula models and biplane 2D images

Area of Science:

• Biomechanics
• Medical Imaging
• Orthopedics

Background:

• Accurate 3D scapulothoracic orientation is crucial for understanding shoulder function and diagnosing pathologies.
• Existing methods for assessing scapulothoracic motion can be invasive or limited in scope.

Purpose of the Study:

• To evaluate a novel strategy for identifying 3D scapulothoracic orientation using bilateral X-ray scans and 3D scapula models.
• To compare the accuracy of this strategy against gold-standard motion capture data.

Main Methods:

• Utilized subject-specific and scaled general 3D scapula models.
• Placed retroreflective markers on scapulae and trunk, recorded with an 8-camera motion capture system.
• Acquired biplane X-ray images using an EOS Imaging system for 3D to 2D matching.

Main Results:

• The proposed strategy achieved favorable comparisons with motion capture orientations.
• Root-mean-square errors (RMSE) ranged from 3.1° to 5.5°, with a mean error of 3.9°.
• The method demonstrated accuracy for both subject-specific and scaled general scapula models.

Conclusions:

• The evaluated strategy provides an accurate method for determining 3D scapulothoracic orientation.
• This technique holds potential for clinical applications in shoulder assessment and treatment planning.