3D video-based deformation measurement of the pelvis bone under dynamic cyclic loading

Area of Science:

• Biomechanics
• Orthopaedic Engineering
• Medical Imaging

Background:

• Dynamic 3D deformation of pelvic bones is critical for designing long-lasting oncological implants.
• Current implant designs often lack patient-specific dynamic deformation data.
• Accurate measurement of pelvic bone deformation is needed for improved implant design.

Purpose of the Study:

• To develop and validate a system for measuring dynamic 3D deformation of whole pelvis specimens.
• To combine a material testing machine with 3D video motion capture for realistic biomechanical analysis.
• To generate a dataset for enhanced orthopaedic implant design.

Main Methods:

• A pelvis specimen was subjected to dynamic sinusoidal loading on a material testing machine.
• Passive reflective markers were attached to the pelvis and tracked by a 3D video motion capture system.
• 3D deformation was computed, and accuracy was verified using a 3D micro-motion-stage.

Main Results:

• Measurement accuracy was dependent on the number of cameras used (±0.036 mm with 2 cameras, ±0.022 mm with 6 cameras).
• The system's noise level was the limiting factor, resulting in a measurement accuracy of ±0.036 mm.
• The detectable movement was smaller than the noise level, indicating high sensitivity.

Conclusions:

• The developed 3D test setup enables dynamic testing of anatomical specimens and biomaterials.
• The resulting 3D deformation data can improve material characterization and biomechanical modeling.
• This approach facilitates the reliable design of complex orthopaedic implants.