Lattice implants that generate homeostatic and remodeling strains in bone.

Area of Science:

• Orthopedic Bioengineering
• Biomechanical Engineering
• Materials Science

Background:

• Bone remodeling is influenced by mechanical strain.
• A 1-10% increase in bone strain can stimulate bone formation.
• Current orthopedic implants do not precisely control strain environments.

Purpose of the Study:

• To develop an orthopedic implant capable of controlled strain induction in human bone.
• To utilize clinically established imaging and manufacturing techniques.
• To tailor implant mechanical properties to match bone's anisotropic and heterogeneous nature.

Main Methods:

• Manufactured titanium scaffolds with precisely controlled multiaxial apparent modulus.
• Used computed tomography (CT) scans to define mechanical properties of human tibiae.
• Tested bone-scaffold constructs under compressive loading.
• Varied scaffold modulus to achieve controlled bone strain increases (0-15%).

Main Results:

• Scaffold axial modulus closely matched bone (48-728 MPa vs. 81-800 MPa).
• Scaffold transverse modulus effectively matched bone (42-648 MPa vs. 47-585 MPa).
• Achieved precise control over bone strain, within the range known to induce positive remodeling.

Conclusions:

• Developed titanium scaffolds that can precisely control bone strain.
• Manufacturing methods and materials are clinically established for orthopedic applications.
• Implants can be designed to leverage bone's natural mechanoresponse for improved outcomes.