Performance of the tibial component in total knee replacement

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Biomaterials science

Background:

• Conventional total knee replacements may lack adequate mechanical support in patients with proximal tibial bone deficiency.
• Extensive deficiency in tibial cancellous bone presents challenges for prosthetic component stability and longevity.

Purpose of the Study:

• To develop and analyze a custom prosthetic tibial component design for patients with significant tibial cancellous bone deficiency.
• To evaluate the biomechanical performance of conventional versus custom designs under various loading conditions.

Main Methods:

• Finite-element analysis was used to examine conventional and custom prosthetic tibial components.
• Simulations were performed under several loading configurations, focusing on worst-case eccentric loading scenarios.
• The efficacy of a salvage-design concept involving direct load transfer to the tibial cortical shell was analytically tested.

Main Results:

• Employing a metal tray and metal peg with conventional designs can reduce stress on the underlying cancellous bone.
• A custom salvage-design concept successfully transferred load directly to the tibial cortical shell.
• Stresses in the remaining cancellous bone were significantly reduced by using a thickened metal tray and a metal support buttress.

Conclusions:

• Metal trays for the tibial plateau are advantageous and recommended when supporting tibial bone is insufficient.
• Custom prosthetic designs enabling direct load transfer to the cortical shell are necessary for knees with large bone defects.