Evaluation of a method to quantify posture and scapula position using biplanar radiography

Area of Science:

• Orthopedics
• Medical Imaging
• Biomechanical Engineering

Background:

• Quantifying scapular position and orientation in upright patients is crucial.
• Existing biplanar radiography methods struggle with consistent patient positioning for scapular and spinal imaging.

Purpose of the Study:

• To develop and validate a novel method for assessing scapular kinematics using upright biplanar radiographs.
• To establish reliable clinical parameters for scapular position and orientation.

Main Methods:

• Acquired two sets of biplanar radiographs for 3D reconstruction of the spine/ribcage and scapula.
• Performed two-stage scapular alignment (coarse and adjusted) based on anatomical landmarks.
• Computed clinical parameters: protraction, internal rotation, tilt, and upward rotation.
• Assessed reproducibility using in vivo data and accuracy using cadaveric CT scans.

Main Results:

• Mean error for clinical parameters was under 2°.
• 95% confidence intervals for reproducibility ranged from 2.5° to 5.3°.
• Confidence intervals were smaller than inter-participant variability.

Conclusions:

• The developed method offers high accuracy and reproducibility for assessing scapular kinematics.
• This technique shows potential for identifying distinct patterns in pathological populations.
• Enables precise 3D quantification of scapular position and orientation in upright individuals.