Validation of single-plane fluoroscopy and 2D/3D shape-matching for quantifying shoulder complex kinematics

Area of Science:

• Biomechanics
• Medical Imaging
• Orthopedics

Background:

• Non-invasive quantification of shoulder complex kinematics is crucial in biomechanical research and clinical practice.
• Fluoroscopy with 2D/3D shape-matching is a standard technique, but its accuracy for the shoulder using single-plane fluoroscopy requires further validation.

Purpose of the Study:

• To assess the accuracy of single-plane fluoroscopy combined with 2D/3D shape-matching for quantifying the complete kinematics of the shoulder complex.

Main Methods:

• Tantalum markers were implanted into the clavicle, humerus, and scapula of four cadaveric shoulders.
• Biplane radiographs were captured at five humerothoracic elevation positions.
• Kinematic errors were calculated by comparing marker tracking with 2D/3D shape-matching results, reporting root mean square (RMS) error, bias, and precision.

Main Results:

• Glenohumeral joint RMS errors ranged from 0.7–3.3° and 1.2–4.2 mm.
• Acromioclavicular joint errors ranged from 1.7–3.4°.
• Individual bone shape-matching errors were within acceptable ranges for humerus (1.2–3.2°), scapula (0.5–1.6°), and clavicle (0.4–3.7°).

Conclusions:

• Single-plane fluoroscopy and 2D/3D shape-matching provide accurate quantification of shoulder complex kinematics.
• This method is reliable for assessing shoulder joint motion in static positions, offering valuable insights for research and clinical applications.