Using Dynamic Stereo X-ray Imaging for In Vivo Acromioclavicular Joint Kinematics Assessment: A Preliminary...

Area of Science:

• Orthopedic biomechanics
• Sports medicine
• Medical imaging

Background:

• Acromioclavicular joint (ACJ) disruptions are common in contact sports athletes.
• Understanding ACJ biomechanics and treatment effects on kinematics is limited.
• Lack of in vivo measurement tools for scapular and clavicular motion hinders research.

Purpose of the Study:

• Evaluate dynamic stereo x-ray (DSX) for in vivo ACJ kinematics assessment.
• Compare ACJ kinematics, range of motion, and strength in treated vs. uninjured shoulders.
• Hypothesize successful DSX measurement and identify kinematic abnormalities in treated shoulders.

Main Methods:

• Controlled laboratory study using dynamic stereo x-ray (DSX) and CT scans.
• Assessed 14 participants (11 surgical, 3 nonoperative ACJ disruption).
• Measured ACJ kinematics during abduction, scaption, and flexion; compared to contralateral shoulders.

Main Results:

• DSX successfully measured in vivo ACJ kinematics during functional movements.
• No significant differences found between surgically treated and uninjured shoulders.
• Nonoperative shoulders showed trends towards increased internal rotation and scapular rotation/tilting.

Conclusions:

• DSX imaging is a promising tool for evaluating in vivo ACJ kinematics.
• Provides data for future studies on treatment impacts on shoulder girdle mechanics.
• Facilitates informed clinical decisions regarding ACJ injury management.