Modular design of the tibial insert for cruciate-retaining and posterior-stabilized total knee prosthesis

Abstract

The increase in the prevalence of knee osteoarthritis has resulted in an increased demand for total knee arthroplasty surgeries. This has created challenges in the efficient manufacture of its components, particularly the tibial insert. The demand for different sizes and thicknesses of materials necessitates a complex system for managing inventory, resulting in an inefficient allocation of resources. Confronted with this challenge, the conception of a modular tibial insert configuration that is compatible with cruciate-retaining and posterior- stabilized knee prostheses was proposed. This initiative aimed to reduce the inventory of components, enhance the efficiency of the manufacturing process, and optimize the utilization of materials.To address this challenge, an iterative approach grounded in the principles of Design Thinking and Lean Startup methodology was employed to engineer the mechanical anchoring mechanism. Consequently, CAD models, finite element analysis simulations, and three-dimensional fabricated prototypes were developed, along with CNC milling production tests.Preliminary results suggest that the modular approach could reduce machining times by optimizing cutting parameters, reducing the volume of components in a company's and hospital's inventory, and reducing material waste. Despite the study's limitations, including the lack of dynamic testing and ISO standards, the functional feasibility of the assembly through a press-fit anchoring system provides a foundation for future development of definitive modular knee implants.