PEEK Knee Implant Rib Structure for Bone Anchoring
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Solution Overview
Problem
Existing femoral and tibial implant parts for orthopedic knee joint prostheses face significant wear due to high mechanical environmental conditions and requirements, leading to instability and potential failure.
Innovation Solution
The use of a plastics material, specifically polyaryl ether ketone (PAEK), polyether ether ketone (PEEK), or PEEK composite material, for the femoral and tibial implant parts, with a three-dimensional surface structure featuring a rib structure that projects macroscopically from the surface, enhancing stability and anchoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal or ceramic materials are used for knee joint implants, then strength and stability are improved, but wear and mechanical failure increase due to high pressure loads
Solution Approach 1:
The patent changes the material parameter from metal/ceramic to plastics material (specifically PEEK or PAEK), which has different mechanical properties including lower density and different wear characteristics. This material substitution resolves the contradiction by providing adequate strength while significantly reducing wear under high pressure conditions (10-20 MPa) in the knee joint environment.
Solution Approach 2:
The patent employs composite material structures, particularly combining plastics material with reinforced elements or surface treatments. The implant may include composite constructions that integrate the benefits of polymers (wear resistance) with other materials (strength), creating a hybrid solution that overcomes the limitations of single-material approaches.
2Reliability
If plastics material is used for knee joint implants, then wear resistance is improved, but strength and stability deteriorate due to lower material strength values
Solution Approach 1:
The patent transitions from considering only material properties (2D/3D) to incorporating surface topology (adding dimensional complexity). By creating three-dimensional surface structures with ribs, protrusions, or textured patterns on the implant surface, the design enhances mechanical interlocking with bone tissue, thereby compensating for the inherently lower strength of plastics materials through geometric reinforcement.
Solution Approach 2:
The patent applies different surface qualities to different regions of the implant. Specific surface areas feature enhanced three-dimensional structures (ribs, protrusions, textured zones) that provide localized mechanical interlocking and stress distribution, while other regions maintain smooth surfaces for articulation. This localized differentiation optimizes both strength and wear resistance where needed.
3Ease of manufacture
If smooth surface is used for implant, then manufacturing is simplified, but anchoring stability deteriorates due to insufficient bone integration
Solution Approach 1:
The patent adds vertical dimensionality to the implant surface by incorporating ribs, protrusions, or three-dimensional textured patterns that project from the base surface. These features create mechanical interlocking with the surrounding bone tissue, significantly enhancing anchoring stability while remaining compatible with standard manufacturing processes like injection molding or CNC machining.
Solution Approach 2:
The patent divides the implant surface into distinct functional zones: smooth articulation surfaces for low-friction movement, and segmented three-dimensional structures (ribs, protrusions, or modular textured areas) for bone anchoring. This segmentation allows each surface region to perform its specialized function optimally without compromising the other.
Data Source
AI summary
An implant part for an orthopedic knee joint prosthesis has a surface region which faces and contacts bone in an implanted state. A least part of the implant part is made from a plastics material, in particular polyether ether ketone or polyether ether ketone composite material. The implant part has a three-dimensional surface structure in the surface region facing the bone. The three-dimensional surface structure includes a rib structure, a first rib portion extending in a plane on a surface of the surface region, or a first rib of the rib structure extending in the plane on the surface of the surface region, and a second rib portion extending in the plane on the surface of the surface region, or a second rib of the rib structure extending in the plane on the surface of the surface region extending in the plane in different directions, at least in portions.