Meniscus Prosthesis Composite Materials for Cartilage Protection
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Solution Overview
Problem
Current meniscus prostheses face challenges in providing optimal mechanical properties and ease of implantation in the knee joint, with existing solutions often requiring lengthy osseous ingrowth for fixation and potentially damaging surrounding cartilage due to material stiffness.
Innovation Solution
A meniscus prosthesis with an arc-shaped body comprising a main portion made of a first biocompatible, non-resorbable material with a low tensile modulus and reinforcing and fixation parts made of a second biocompatible material with a higher tensile modulus, allowing for strong fixation and reduced deformation, along with the use of sutures or cables for easy implantation and prevention of cartilage damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single biocompatible material is used for the entire meniscus prosthesis, then the implantation is simplified, but the mechanical properties are insufficient to withstand joint stresses while protecting cartilage
Solution Approach 1:
The meniscus prosthesis uses a composite structure with two distinct biocompatible materials: a softer first material (tensile modulus ≤100 MPa) for the main body to protect cartilage, and a stiffer second material (tensile modulus ≥101 MPa) for reinforcing and fixation parts to withstand mechanical stresses. This composite approach resolves the contradiction by combining materials with complementary mechanical properties.
Solution Approach 2:
Different regions of the meniscus prosthesis are assigned different material properties: the main body portion contacts cartilage and uses softer material to prevent damage, while the reinforcing part and fixation parts use stiffer material to provide structural support and secure anchoring. This local differentiation of material quality addresses the mechanical strength requirement without compromising cartilage protection.
2Strength
If a stiffer material is used for the meniscus prosthesis, then the structural strength is improved, but the surrounding cartilage may be damaged
Solution Approach 1:
The prosthesis combines a softer first material for the cartilage-contacting main body with a stiffer second material for the reinforcing and fixation parts, allowing structural strength to be achieved without transmitting excessive stress to the cartilage.
Solution Approach 2:
The softer first material is specifically positioned in the main body portion that directly contacts the cartilage surfaces, while the stiffer second material is confined to the reinforcing part and fixation parts that do not contact cartilage, thus protecting cartilage while maintaining overall structural strength.
3Reliability
If bone plugs are used for fixation of the meniscus prosthesis, then the fixation is achieved, but the osseous ingrowth takes a relatively long time
Solution Approach 1:
The invention changes the fixation mechanism from relying on slow biological osseous ingrowth of bone plugs to using mechanical interlocking through through-holes that accommodate sutures or cables. This parameter change in the fixation approach significantly reduces the time required for secure fixation while maintaining reliability.
Solution Approach 2:
Sutures or cables serve as intermediary elements that pass through the fixation parts and are anchored in the bone, providing immediate mechanical fixation without requiring prolonged osseous ingrowth. This intermediary mechanism bridges the prosthesis and bone rapidly and reliably.
4Ease of manufacture
If a monolithic structure is used for the meniscus prosthesis, then the manufacturing is simplified, but the mechanical properties cannot be optimized for different functional regions
Solution Approach 1:
The prosthesis is manufactured as a composite structure with two different biocompatible materials formed in a single integrated component. The first material forms the main body while the second material forms the reinforcing part and fixation parts, combining manufacturing efficiency with region-specific mechanical optimization.
Solution Approach 2:
The main body, reinforcing part, and fixation parts made of different materials are merged into a single monolithic prosthesis structure, maintaining manufacturing simplicity while achieving differentiated mechanical properties in different regions through the use of composite materials.
Data Source
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AI summary
The invention is directed to a meniscus prosthesis comprising an arc-shaped meniscus prosthesis body having a main portion (1) comprising a reinforcing part (2) and two end portions (1A, 1B) comprising fixation parts (2A, 2B), wherein the main portion (1) comprises a part made of a first biocompatible, non- resorbable material extending between the two end portions (1A, 1B), wherein the reinforcing part (2) and the fixation parts (2A, 2B) are made of a second biocompatible, non-resorbable material and wherein the reinforcing part (2) extends between the fixation parts (2A, 2B) and wherein the fixation parts (2A, 2B) have a through hole (3A, 3B), the first biocompatible, non-resorbable material has a tensile modulus of at most 100 MPa as determined by ISO 527-1 and the second biocompatible, non-resorbable material has a tensile modulus of at least 01 MPa as determined by ISO 527-1.