Development of a carbon-carbon hip prosthesis

Area of Science:

• Biomaterials Engineering
• Orthopedic Surgery
• Materials Science

Background:

• Hip prosthesis stems are traditionally made from metals.
• Carbon-fiber-reinforced-carbon (C-C) composites offer potential advantages due to their properties.
• Understanding bone response and biomechanical performance is crucial for C-C hip stems.

Purpose of the Study:

• To evaluate the manufacturing process and properties of C-C composites for hip prosthesis stems.
• To assess the long-term bone response (contact and ingrowth) to various C-C materials.
• To determine the biomechanical performance of C-C hip stems.

Main Methods:

• Chemical vapor infiltration for C-C composite manufacturing.
• Evaluation of chemicophysical properties based on structure.
• In vivo (2-year) assessment of cortical bone response.
• Biomechanical testing: cadaver femur implantation, fatigue testing, and finite element analysis.

Main Results:

• C-C composites infiltrated with pyrolytic carbon or silicon carbide were produced.
• Calcium phosphate-coated C-C accelerated bone formation compared to pyrolytic carbon or SiC.
• C-C stems demonstrated better stress transfer than metal prostheses.
• No fatigue damage was observed in C-C stems.
• Finite element analysis correlated stem stress distribution with mechanical testing results.

Conclusions:

• C-C materials, particularly with calcium phosphate coatings, show potential for hip prosthesis stems.
• The low modulus of elasticity of C-C may facilitate quicker bone contact.
• C-C hip stems exhibit favorable biomechanical performance and durability.