Experimental and numerical static failure analyses of total hip replacement interfaces.

Area of Science:

• Biomedical Engineering
• Materials Science
• Orthopedic Surgery

Background:

• Cemented joint replacement success hinges on implant-bone fixation.
• Aseptic loosening remains a primary cause of hip implant failure, necessitating revision surgery around 10 years post-implantation.

Purpose of the Study:

• To experimentally evaluate tensile and shear strengths of implant-cement and cement-bone interfaces.
• To investigate factors influencing interface strength, including sandblasting parameters and implant material.
• To compare experimental strength data with stresses determined through finite element analysis.

Main Methods:

• Mechanical testing to determine interface tensile and shear strengths.
• Finite element analysis (FEA) using SolidWorks and ANSYS Workbench to model total hip replacement stresses.
• Experimental investigation of sandblasting parameters and implant material effects on interface strength.

Main Results:

• Stresses on total hip replacement interfaces exceeded experimentally determined tensile and shear strength values in certain regions.
• Damage to contact surfaces was observed in areas where stress surpassed interface strength.
• Identification of specific damage sites within the implant-cement and cement-bone interfaces.

Conclusions:

• Current cemented hip implant designs experience stresses that can compromise interface integrity.
• The findings highlight critical areas prone to failure, guiding future implant design and material selection.
• Understanding interface stress and strength is essential for enhancing the longevity of cemented joint replacements.