Flexible Prosthetic Bearing with Encased Modulus Portions
Solution Overview
Problem
Existing prosthetic joint bearings fail to maintain congruent contact throughout the range of joint movement while mimicking natural flexibility, leading to issues like increased wear, reduced longevity, and the need for non-anatomical shapes.
Innovation Solution
A bearing design that combines anatomical components with a flexible, modular structure using a lower modulus portion encased within a higher modulus portion, allowing for full congruent contact and shock absorption, and featuring a reinforcing element that extends to form an attachment member for secure placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If anatomically shaped prosthetic bearings are used, then patient fit and natural tissue retention are improved, but the ability to maintain congruent contact throughout the range of joint movement deteriorates
Solution Approach 1:
The bearing uses a flexible polymer material with specific elastomeric properties that allow it to deform and adapt to anatomical shapes while maintaining congruent contact. The material's elasticity and flexibility parameters enable it to conform to the natural joint geometry during movement, resolving the contradiction between anatomical shape compatibility and congruent contact maintenance.
Solution Approach 2:
The bearing is constructed from composite or reinforced polymer materials that combine flexibility with structural integrity. This allows the bearing to maintain its anatomical shape while providing the necessary rigidity to support joint loads and maintain congruent contact throughout the range of motion.
2Strength
If rigid bearing materials are used, then joint support adequacy is improved, but the ability to mimic natural cartilage flexibility deteriorates
Solution Approach 1:
The bearing material's mechanical parameters (elastic modulus, hardness, flexibility) are specifically selected to match natural cartilage properties. The elastomeric polymer provides a balance between strength for joint support and flexibility for mimicking natural cartilage behavior during movement and loading.
Solution Approach 2:
The bearing uses a flexible polymer structure that can deform under load similar to natural cartilage, while still providing adequate joint support. The flexible nature allows it to conform to anatomical surfaces and maintain congruent contact throughout the range of motion.
3Reliability
If non-anatomical bearing shapes are used, then congruent contact is improved, but patient fit and natural tissue retention deteriorate
Solution Approach 1:
The flexible polymer material enables the bearing to maintain congruent contact while adopting anatomical shapes. The material's elasticity allows it to conform to the natural joint geometry and adapt to anatomical variations between patients, providing both congruent contact and patient-specific fit.
4Duration of action of stationary object
If thicker bearing components are used, then durability and shock absorbance are improved, but bone conservation and ease of insertion deteriorate
Solution Approach 1:
The elastomeric polymer material provides high shock absorbance and durability even in thinner configurations. The material's viscoelastic properties allow it to absorb impact loads effectively, enabling the use of thinner bearings that conserve bone while maintaining adequate longevity and shock protection.
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
This design achieves low wear, increased longevity, improved kinematics, and ease of insertion/replacement, enabling use in younger patients with more natural tissue retention and reduced trauma, while allowing for thinner components and better bone conservation.
Implementation Method 1
due to the material properties of the bearing, this design offers: shock absorbance
Implementation Method 2
previous anatomically shaped prosthetic bearings have not been suitable for maintaining congruent contact throughout the range of joint movement, as they are not able to mimic the natural flexibility of cartilage
Data Source
Figure 1A~2A
Figure 2B~5
AI summary
A bearing for a total or partial joint replacement prosthesis: the bearing having a body and a reinforcing element which strengthens the bearing and which forms an attachment member, and/or the bearing being formed at least partially from polymeric or composite material the bearing comprising a lower modulus portion and a higher modulus portion, one portion of the bearing being at least partially encased by the other portion of the bearing. Also provided is a method for of forming the bearing, and a total or partial joint replacement prosthesis comprising the hearing.