Static structural analysis of different stem designs used in total hip arthroplasty using finite element method

Area of Science:

• Biomaterials Engineering
• Orthopedic Implant Design
• Mechanical Analysis of Medical Devices

Background:

• Hip joint implants are crucial for restoring mobility due to age-related wear and tear.
• Common implant materials include Cobalt Chromium (CoCr), titanium, and stainless steel.
• Stringent design requirements aim to prevent aseptic loosening and revision surgeries.

Purpose of the Study:

• To evaluate various hip implant stem and acetabular cup designs and material combinations.
• To identify optimal configurations for enhanced mechanical performance and longevity.
• To inform decision-making in the selection of hip implant components.

Main Methods:

• Modeling of circular, oval, elliptical, and trapezoidal stem designs with three cross-sectional profiles using CATIA V-6.
• Static structural analysis performed using ANSYS R-19 to assess mechanical properties.
• Comparison of different design shapes, profiles, and material combinations for stems and acetabular cups.

Main Results:

• Profile 2 demonstrated the lowest deformation and von Mises stress across all designs.
• The trapezoidal stem with profile 2 exhibited superior mechanical properties.
• Cobalt Chromium (CoCr) stems paired with Ceramic on Ceramic (CoC) acetabular cups showed enhanced durability.

Conclusions:

• Cobalt Chromium (CoCr) is the preferred material for hip implant stems.
• The trapezoidal stem design with profile 2 consistently reduced deformation and stress.
• Ceramic on Ceramic (CoC) acetabular cups outperformed conventional Ceramic on Polyethylene (CoPE) materials.
• The optimal hip implant configuration identified is a CoCr trapezoidal stem (profile 2) with a CoC acetabular cup.