Failure analysis of PCA revision total knee replacement tibial component. A preliminary study using the finite...

Area of Science:

• Orthopedic biomechanics
• Biomaterials engineering
• Finite element analysis

Background:

• Tibial revision components are used to replace failed or loosened primary implants.
• Design modifications, such as removal slots, aim to improve revision surgery outcomes.
• Understanding the biomechanical performance of novel designs is crucial for patient safety.

Purpose of the Study:

• To perform a worst-case failure analysis of a stemmed, porous-coated tibial revision component with removal slots.
• To evaluate the stress distribution and potential failure modes under simulated physiological loads.

Main Methods:

• A three-dimensional finite element method (FEM) model of the tibial component was created.
• The model was subjected to simulated peak physiological loads.
• Boundary conditions included stem restraint and unsupported plateaus to represent a worst-case scenario.

Main Results:

• Stresses in the prosthesis plateau adjacent to the stem exceeded the material's yield stress in multiple regions.
• Extensive areas of the plateau experienced stresses surpassing the expected endurance limit.
• The design's inherent stress concentrations suggest a propensity for fatigue failure.

Conclusions:

• The stemmed tibial revision prosthesis with removal slots exhibits a flawed design.
• Implantation without adequate support for the prosthesis plateau is likely to lead to component failure.
• Bone remodeling around the implant may further compromise its long-term integrity.
• The current prosthesis design is not recommended for clinical use.