Femur finite element model instantiation from partial anatomies using statistical shape and appearance models

Area of Science:

• Orthopaedic surgery
• Biomechanical engineering
• Medical imaging

Background:

• Accurate bone models are critical for orthopaedic reconstructions.
• Contralateral side methods require intact bone and symmetry.
• Statistical shape and appearance models (SSAMs) show promise for geometric reconstruction but lack mechanical property validation.

Purpose of the Study:

• To compare the accuracy of SSAM-based reconstructions from partial bone anatomies against contralateral methods.
• To evaluate stress and strain differences under identical loading conditions for different reconstruction techniques.

Main Methods:

• SSAMs were developed using 40 female cadaveric CT scans.
• Finite element models were created for reconstructions from partial bone.
• Musculoskeletal simulations provided boundary conditions for analysis.
• Comparisons included surface deviations, anatomical measures, maximal stresses, and strains.

Main Results:

• Surface errors for SSAM reconstructions were comparable or slightly larger than contralateral methods, depending on bone availability.
• Anatomical measures were similar between the two reconstruction approaches.
• Contralateral reconstructions showed slightly smaller strain errors (up to 6% on average).

Conclusions:

• SSAMs utilizing partial bone geometry present a feasible alternative to contralateral-based reconstructions in orthopaedics.
• This approach can provide accurate geometric models for surgical planning and simulation.