Relationship between acromial morphological variation and subacromial impingement: A three-dimensional analysis.

Area of Science:

• Orthopedic surgery
• Radiology
• Anatomy

Background:

• Subacromial impingement syndrome is a common cause of shoulder pain.
• Acromial morphology is suspected to play a role in its development.
• Accurate measurement of acromial features is crucial for understanding this relationship.

Purpose of the Study:

• To evaluate the association between various acromial morphological parameters and subacromial impingement.
• To determine if specific CT-measured features correlate with the presence of impingement.

Main Methods:

• Bilateral shoulder CT scans were performed on 138 patients undergoing arthroscopy.
• Key parameters including acromial tilt, acromial index, and critical shoulder angle were measured.
• Morphological characteristics were compared between impinged and non-impinged groups and between affected and unaffected shoulders.

Main Results:

• Patients with impingement showed significantly smaller acromial tilt, modified acromial tilt, and acromiohumeral interval.
• The impingement group exhibited larger acromial index, critical shoulder angle, acromial anterior protrusion, and acromial inferior protrusion.
• Affected shoulders in impinged patients displayed significantly different morphology compared to their unaffected counterparts.

Conclusions:

• Three-dimensional CT reconstruction is a reliable method for assessing shoulder morphology.
• Acromial morphological variations are associated with subacromial impingement.
• Further research is needed to clarify the causal relationship between acromial morphology and impingement.