Tibial Component With Segmented Medial-Lateral Inserts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current total knee prostheses face challenges in recreating the physiological stability and mobility of healthy knee joints due to the exclusive use of either fixed or movable inserts, which fail to accurately replicate the anatomical and kinematic disparities between the medial and lateral compartments, leading to inferior kinematic and proprioceptive performance.
Innovation Solution
A tibial component with a base element featuring a medial and lateral portion, where the medial portion is fixed and the lateral portion is movable, allowing for complementary inserts that mimic the natural anatomy and kinematics of the knee joint, reducing the risk of dislocation and wear while enhancing stability and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed insert is used to ensure joint stability, then the risk of dislocation is eliminated, but the insert experiences greater wear due to the flat lateral joint surface interfacing with the convex femoral surface
Solution Approach 1:
The tibial component is divided into two separate inserts: a fixed medial insert and a movable lateral insert. This segmentation allows each insert to have optimized surface geometry for its specific compartment, with the lateral insert having a concave surface to reduce wear while the medial insert provides stability.
Solution Approach 2:
Different surface geometries are applied to different compartments: the medial insert has a flat surface for stability, while the lateral insert has a concave surface to maximize contact area and reduce wear. This local differentiation resolves the contradiction between stability and wear resistance.
2Object-generated harmful factors
If a movable insert is used to maximize contact area and reduce wear, then the risk of wear is reduced, but the risk of insert dislocation increases due to the absence of a locking mechanism
Solution Approach 1:
The lateral compartment uses a movable insert with concave surface for reduced wear, while the medial compartment uses a fixed insert for stability. This segmentation allows the movable insert to function without dislocation risk from the fixed medial side.
Solution Approach 2:
The prosthesis combines both fixed and movable insert approaches in a single device, with the fixed medial insert providing stability and the movable lateral insert providing wear resistance, thus merging the advantages of both approaches.
3Device complexity
If a single fixed or movable insert design is used for both medial and lateral compartments, then the device complexity is reduced, but the kinematic and proprioceptive performance becomes inferior to healthy knee joints due to inability to recreate compartmental disparity
Solution Approach 1:
The single insert is divided into two separate inserts with different fixation methods and surface geometries, allowing each compartment to be optimized for its specific kinematic requirements while maintaining a relatively simple overall structure.
Solution Approach 2:
Each compartment receives a customized insert design: the medial compartment gets a fixed insert for stability, while the lateral compartment gets a movable insert for mobility, thereby recreating the natural compartmental disparity without excessive complexity.
Data Source
AI summary
A tibial component of a total knee prosthesis which includes a base element provided with a medial portion and a lateral portion, which can be fixed on the proximal surface of the tibia-; The base element has shape and dimensions that are complementary to those of at least one protective insert (one single insert or two separate inserts: one medial and one lateral).—— In particular, the medial portion is provided with coupling elements for coupling by pressure to the insert (a configuration generally termed “fixed insert”).——— By contrast, the at least one insert is resting on the lateral portion.