Assessing sensitivity of predictive shoulder simulations to uncertain soft tissue properties

Area of Science:

• Biomechanics
• Musculoskeletal modeling
• Orthopedics

Background:

• Accurate glenohumeral joint mechanics modeling relies on subject-specific passive tissue properties (ligaments, cartilage).
• In vivo data for these soft tissues remain challenging to obtain, limiting model precision.
• Understanding variability in these properties is essential for clinical applications.

Purpose of the Study:

• To evaluate how variations in glenohumeral ligament and articular cartilage properties affect shoulder joint kinematics and contact mechanics.
• To identify key soft tissue parameters influencing joint-level outcomes during scaption.
• To inform subject-specific modeling and in vivo characterization methods.

Main Methods:

• Utilized a validated musculoskeletal shoulder model.
• Employed two Monte Carlo simulation frameworks to assess parameter variability.
• Independently adjusted glenohumeral ligament (stiffness, slack length) and cartilage (elastic modulus, thickness) properties.

Main Results:

• Ligament slack length, especially of the anterior and middle glenohumeral ligaments (A-IGHL, MGHL), was the most influential parameter on secondary kinematics and joint contact.
• Articular cartilage properties significantly affected joint contact mechanics and load distribution.
• Parameter variability analysis highlighted critical soft tissue contributions to shoulder function.

Conclusions:

• Subject-specific shoulder simulations must account for soft tissue property variability.
• Ligament and cartilage properties are critical determinants of glenohumeral joint mechanics.
• Findings guide future in vivo characterization efforts and improve models for osteoarthritis and surgical interventions.