Characteristics of High-Risk Bipolar Bone Loss Lesions Using 3-Dimensional Imaging

Area of Science:

• Orthopedic surgery
• Biomechanics
• Radiology

Background:

• The distinction between on-track and off-track bone lesions in glenohumeral instability is crucial but requires further characterization, particularly using advanced imaging techniques.
• Previous biomechanical models have provided foundational understanding, yet comprehensive evaluation of bony pathological changes, especially via 3D imaging, remains incomplete.

Purpose of the Study:

• To quantitatively compare on-track versus off-track bone lesions.
• To characterize glenoid bone loss and humeral head defects using 3D modeling software.
• To identify specific imaging features differentiating lesion types for improved clinical assessment.

Main Methods:

• A cross-sectional study involving 75 patients with recurrent anterior instability and documented Hill-Sachs lesions (HSLs) and glenoid bone loss (GBL).
• 3D models of proximal humeri and glenoids were reconstructed to quantify HSL volume, surface area, width, depth, location, and orientation (Hill-Sachs angle).
• Glenoid bone loss (GBL) percentage, width, length, and glenoid track status were calculated; groups were compared using the Mann-Whitney U test.

Main Results:

• Off-track lesions exhibited significantly greater HSL surface area, volume, and width, along with more medialized HSLs compared to on-track lesions.
• The off-track group also demonstrated significantly greater GBL percentage, width, and length.
• Further analysis indicated that larger off-track lesions had a greater Hill-Sachs angle and extended more superiorly.

Conclusions:

• Off-track bone lesions in glenohumeral instability are associated with larger glenoid bone loss, wider and more medialized Hill-Sachs lesions, and greater surface area.
• These findings highlight specific characteristics of high-risk bipolar bone loss lesions.
• This detailed characterization can simplify clinical identification and guide appropriate treatment planning for patients with recurrent anterior instability.