Sacroiliac joint auricular surface morphology modulates its mechanical environment

Area of Science:

• Biomechanics
• Anatomy
• Medical Imaging

Background:

• The sacroiliac joint (SIJ) is crucial for transmitting mechanical energy between the upper and lower body.
• Significant variations in SIJ auricular surface morphology exist.
• The influence of SIJ morphology on its mechanical behavior is not well understood.

Purpose of the Study:

• To investigate the relationship between SIJ auricular surface morphology and its biomechanical response.
• To understand how variations in cartilage thickness, surface area, and volume affect stress and deformation.

Main Methods:

• Computed tomography (CT) scans from 281 individuals were used to extract pelvic ring geometry.
• Finite element models were created to simulate SIJ mechanical loading.
• Measurements included auricular surface area, SIJ cartilage thickness, and SIJ cartilage volume.

Main Results:

• SIJ cartilage thickness showed strong sex sensitivity but weak dependence on age or laterality.
• Auricular surface area and cartilage volume varied non-linearly with age, peaking around menopause in females.
• Larger SIJs with greater auricular area and cartilage volume demonstrated reduced stress and deformation under load.

Conclusions:

• SIJ morphology plays a significant role in its biomechanical response.
• Morphological variations may be linked to the risk of SIJ dysfunction.
• Understanding these relationships can aid in diagnosing and treating SIJ-related conditions.