Contact studies between total knee replacement components developed using explicit finite elements analysis

Area of Science:

• Biomechanics
• Biomaterials Engineering
• Orthopedic Surgery

Background:

• Polyethylene wear is a major cause of failure in total knee replacement (TKR) prostheses.
• Understanding the relationship between joint mechanics and wear is crucial for improving implant longevity.

Purpose of the Study:

• To develop a pneumatic knee joint simulator to investigate the correlation between knee kinematics and polyethylene wear in TKR.
• To analyze the contact stress distribution within the TKR implant during simulated walking.

Main Methods:

• A five-degree-of-freedom (DOF) pneumatic simulator was created.
• A patient-specific TKR model was fabricated using rapid prototyping based on CT scans.
• Kinematics and kinetics were recorded using video analysis and force plates during simulated walking.
• Finite element analysis (FEA) was performed to compute contact stress distribution.

Main Results:

• The simulator accurately replicated knee joint kinematics and kinetics.
• FEA revealed specific patterns of contact stress distribution within the polyethylene component.
• The study identified a correlation between simulated joint loading and predicted wear patterns.

Conclusions:

• The combination of axial loading and anterior-posterior stress significantly contributes to abrasive wear of the polyethylene component in TKR.
• This simulator provides a valuable tool for evaluating TKR prosthesis behavior and optimizing implant design for enhanced durability.