patient-specific acetabular implants Mojtaba Barzegari Fernando - - PowerPoint PPT Presentation

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patient specific acetabular implants
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patient-specific acetabular implants Mojtaba Barzegari Fernando - - PowerPoint PPT Presentation

Dec 11, 2022 27 likes •168 views

Computational optimization and biodegradation of 3D-printed patient-specific acetabular implants Mojtaba Barzegari Fernando Perez Boerema Liesbet Geris Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium

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Computational optimization and biodegradation of 3D-printed patient-specific acetabular implants

Mojtaba Barzegari Fernando Perez Boerema Liesbet Geris

Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium

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SLIDE 2

Authors declare to have no conflict of interest.

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Disclosure

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SLIDE 3
  • Gaining popularity in recent years
  • Acetabular implants
  • Design optimization
  • Optimizing mechanical stability
  • Considering biodegradation behavior

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Patient-specific 3D Printed Implants

(Source: 3D Systems Inc.)

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SLIDE 4

Bone Resorption in Current Implants

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Normal Bone Osteoporotic Bone

(Algaecal, 2017, Encyclopedia Britannica Inc, 2013; adike, Shutterstock)

Reversal Bone Resorption Bone Formation Resting Bone Mineralization

  • Underloading of the bone leads to

bone resorption

  • Mismatch between the bone and the

implant stiffness causes implant failure

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  • Implants should be removed at the end of their lifetime
  • Some extra bone is also removed along with the implant
  • Making at least part of the implant from biodegradable materials

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Bone Removal in Revision Surgeries

(Source: 3D Systems Inc.)

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SLIDE 6
  • Challenges:
  • Optimization of material properties of the implant
  • Tuning the biodegradation behavior
  • Can be solved by:
  • Topology optimization of the implant
  • Mathematical modeling of biodegradation

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Problem Definition

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SLIDE 7

Collect patient’s data

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Model Workflow

Digitally reconstruct bone defect Derive 3D bone geometry Print optimized implant Create computer model

  • f the joint

Patient Optimize implant design Create 3D model of the biodegradable part of the implant Simulate the biodegradation behavior of the implant Construct the computational model

Optimization Biodegradation

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SLIDE 8

Topology Optimization

  • Two patient-specific models
  • Maximize the long-term implant stability
  • The difference of Strain Energy Density is

used to evaluate the performance of the designs during the optimization

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The model captures:

  • 1. The chemistry of dissolution of metallic implant
  • 2. Formation of a protective film
  • 3. Effect of ions in the medium

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Mathematical Model of Biodegradation

Mg

Mg2+ 𝑓− OH− H2 Cl− H2O

Mg Mg OH 2

Mg2+

Mg Mg OH 2

(1) (2) (3)

OH− Mg2+

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SLIDE 10

Optimization Results

ρ

<<1 >50%

|Δσ|

  • 0.2
  • 1

0.2 1 Δσ

Stress shielding Stress increase

Bone volume

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SLIDE 11

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Biodegradation Results

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SLIDE 12

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Experimental Data and Model Calibration

(Abidin et al., Corrosion Science, 2013)

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  • We have developed in-silico models to investigate
  • Reduction of implant-induced stress shielding
  • Partially replacement of the implant over time
  • Once validated and coupled, the models will serve as an important tool to find

the appropriate biodegradable implant designs

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Conclusion

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SLIDE 14

Thank you for your attention

This research is financially supported by the PROSPEROS project, funded by the Interreg VA Flanders - The Netherlands program