3D scapular orientation on healthy and pathologic subjects using stereoradiographs during arm elevation

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• Scapular kinematics alterations are documented in various shoulder pathologies.
• Existing literature shows discrepancies in scapular movement direction and amplitude.
• Inconsistent findings may stem from varied methodologies and patient populations.

Purpose of the Study:

• To analyze scapular orientation in healthy and pathologic shoulders.
• To compare scapular movement at rest and during 90° lateral arm elevation.
• To investigate scapular kinematics in rotator cuff tear (RCT) and subacromial impingement syndrome (SIS) patients.

Main Methods:

• Sixty-five participants were clinically examined and underwent shoulder MRI.
• Subjects were categorized into healthy, RCT, and RCT + SIS groups.
• 3D scapular models were created from stereoradiographs at rest and 90° arm elevation.

Main Results:

• No significant differences in scapular orientation at rest between groups.
• Scapular orientation during lateral elevation did not differ between healthy and RCT groups.
• The RCT + SIS group showed significantly reduced upward rotation during lateral elevation.

Conclusions:

• Scapular kinematic alterations in symptomatic individuals are multifactorial.
• A correlation exists between subacromial impingement and altered scapular orientation during arm elevation.
• These findings highlight the impact of impingement on scapular mechanics.