The Stress-Strain State in the Pelvis During Sit-to-Stand Transfer

Area of Science:

• Biomechanics
• Orthopedic Surgery
• Computational Modeling

Background:

• Early mobilization of pelvic fracture patients requires osteosynthesis methods that withstand daily movement loads.
• Currently, no predictive tools exist to evaluate the suitability of these methods.
• Understanding joint and muscle loads on pelvic structures during movement is essential for tool development.

Purpose of the Study:

• To analyze the stress-strain state of the pelvis during a sit-to-stand transfer.
• To provide insights into pelvic structural behavior under dynamic loading conditions.
• To inform the development of predictive tools for osteosynthesis method suitability.

Main Methods:

• A rigid-body musculoskeletal model predicted muscle and joint reaction forces during sit-to-stand transfer.
• Finite element analysis (FEA) was used for the first dynamic structural analysis of the pelvis during this motion.
• FEA results were compared with existing literature on pelvic stress during gait and standing.

Main Results:

• Identified similarities in stress distributions between sit-to-stand transfer, gait, and standing.
• Common high-stress areas include the acetabular notch, superior obturator foramen edge, gluteus maximus iliac attachments, and lesser sciatic notch.
• The study offers insights into the global behavior of the pelvic ring and pinpointed stress concentration sites.

Conclusions:

• The dynamic structural analysis of the pelvis during sit-to-stand transfer provides critical data for understanding pelvic biomechanics.
• Findings highlight specific anatomical regions experiencing significant stress, informing surgical implant design and patient rehabilitation.
• This research lays the groundwork for developing predictive tools to optimize treatment for unstable pelvic fractures.