Related Experiment Video
Updated: Jul 3, 2026
10:10
Reverse Total Shoulder Arthroplasty
Published on: July 5, 2011
Zone-specific acromial cortical thickening after reverse shoulder arthroplasty.
Kazuhiro Ikeda1,2, Shotaro Teruya3, Hiromitsu Tsuge3,4
1Department of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan. ikdkzhr1129.med@gmail.com.
International Orthopaedics
|July 2, 2026
Summary
Acromial cortical thickening after reverse shoulder arthroplasty (RSA) progresses in specific zones, potentially indicating fracture risk. This study quantifies these changes over two years using CT scans.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Radiology
Background:
- Acromial and scapular spine fractures are complications of reverse shoulder arthroplasty (RSA).
- Quantitative assessment of pre-fracture cortical changes is challenging.
- Understanding bone remodeling post-RSA is crucial for improving outcomes.
Purpose of the Study:
- To evaluate longitudinal changes in inferior acromial cortical thickness after RSA.
- To utilize computed tomography (CT)-based acromial coronal views for quantitative assessment.
- To correlate cortical thickness changes with fracture development.
Main Methods:
- A multicentre retrospective cohort study of 44 patients undergoing RSA.
- Division of the acromion into three zones: lateral acromion (I), acromial base (II), and scapular spine (III).
- Measurement of inferior cortical thickness at the center of each zone at immediate post-op, 1 year, and 2 years.
Main Results:
- Cortical thickness increased in Zones II and III from immediate post-op to 2 years, while Zone I remained unchanged.
- Thickness changes correlated with cortical area changes (Spearman's ρ=0.55).
- Five shoulders (11.4%) developed fractures, with delayed fractures showing preceding cortical thickening in Zones II and III.
Conclusions:
- Inferior acromial cortical thickening after RSA shows selective progression in Zones II and III.
- These findings suggest region-specific post-operative acromial remodeling.
- Understanding these localized changes may clarify fracture pathomechanisms and improve patient outcomes.
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