Stress-shielding resistant design of custom pelvic prostheses using lattice-based topology optimization

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Materials Science

Background:

• 3D-printed custom pelvic endoprostheses offer short-term benefits for pelvic sarcoma patients.
• However, stress-shielding and peri-prosthetic bone resorption threaten long-term implant stability.

Purpose of the Study:

• To evaluate stress-shielding in pelvic prostheses.
• To introduce a novel topology optimization approach for stress-shielding resistant (SSR) implant design.

Main Methods:

• Developed subject-specific finite element and neuromusculoskeletal models for pre- and post-surgery gait analysis.
• Introduced a new topology optimization method using 3D-printable porous lattice structures for SSR design.
• Applied SSR optimization to a typical pelvic prosthesis for type II+III bone resection.

Main Results:

• The SSR-optimized implant significantly reduced predicted peri-prosthetic bone resorption volume from 44% to 18%.
• This improvement in stress-shielding was achieved without compromising the prosthesis's structural integrity.
• Compared SSR optimization against conventional optimization methods.

Conclusions:

• The stress-shielding resistant (SSR) design approach shows significant potential for improving long-term stability of custom pelvic prostheses.
• This method addresses a critical limitation in current endoprosthetic reconstruction for pelvic sarcoma.
• SSR optimization offers a promising strategy for enhanced bone integration and implant longevity.