Patellar Implant Two-Part Design Bone Ingrowth
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Solution Overview
Problem
Current patellar implants do not effectively provide a smooth friction surface for articulation with the femoral component, and there is a need for a design that allows for natural bone ingrowth and minimizes stress concentrations while maintaining structural integrity and ease of revision.
Innovation Solution
A two-part patellar implant design featuring a strong metal base with a molded polymeric portion that provides a smooth friction surface and allows for bone ingrowth, with features like porous coatings, snap-fit mechanisms, and customizable shapes to accommodate full range of motion and reduce stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal base is used for structural strength, then strength is improved, but surface smoothness for articulation deteriorates
Solution Approach 1:
The implant combines a metal base (providing structural strength) with a polymeric material (providing smooth articulation surface). This composite structure resolves the contradiction by allowing each material to fulfill its optimal function: the metal ensures mechanical integrity while the polymer provides the required surface smoothness for low-friction articulation with the femoral component.
Solution Approach 2:
Different regions of the implant have different material properties: the base portion uses metal for strength and stability, while the articulating surface uses polymeric material for smoothness. This local differentiation of material quality allows the implant to simultaneously achieve both structural strength and surface smoothness in different locations.
2Ease of operation
If a smooth friction surface is provided for articulation, then ease of operation is improved, but bone ingrowth capability deteriorates
Solution Approach 1:
The implant features localized surface treatments: the articulating surface is smoothed for low-friction movement, while the base portion incorporates porous coatings that promote bone ingrowth. This spatial differentiation of surface properties allows the implant to simultaneously achieve smooth articulation and reliable bone integration in different regions.
Solution Approach 2:
The combination of polymeric material with porous coating technology allows the implant to provide both smooth articulation (through the polymer) and bone ingrowth (through the porous structure). The composite approach enables dual functionality that neither material could achieve alone.
3Device complexity
If a single-piece implant is used, then device complexity is reduced, but adaptability for revision deteriorates
Solution Approach 1:
The implant is divided into separate components: a metal base and a polymeric articulating portion. This segmentation allows independent replacement of the polymeric surface if wear occurs, while the metal base remains in place. This modular design provides revision capability without significantly increasing overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design ensures smooth articulation with the femoral component, promotes bone integration, reduces the risk of implant failure, and facilitates easier revision surgeries by providing a stable and adaptable interface.
Implementation Method 1
provide a smooth friction surface to contact the femoral portion of a patient's knee
Implementation Method 2
features like porous coatings
Data Source
AI summary
A patellar implant is provided being of a two part construction having a strong base portion 32, 54, 72 and 92 (manufactured from a metal material or other medical grade strong material) with a molder outer material 34, 62, 80 and 100 (manufactured from a polymeric material or other softer, smoother material) at least on one side to provide a smooth friction surface to contact the femoral portion of a patient's knee.