Knee Prosthesis with Selectable Medial and Lateral Bearings
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Solution Overview
Problem
Current knee joint prostheses lack flexibility in accommodating individual patient needs, particularly in terms of articulation and ligament reconstruction, as they often rely on fixed or standard bearing components that may not fully replicate the anatomical motion and ligament functionality of the natural knee joint.
Innovation Solution
A knee joint prosthesis assembly featuring a femoral component with medial and lateral condyles connected by a patellar track, a unitary tibial component with independent medial and lateral bearings that can be selectively fixed or mobile, and a locking mechanism to secure these bearings to the tibial component, allowing for customizable articulation and accommodation of anterior and posterior cruciate ligaments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed or standard bearing components are used in knee joint prostheses, then the structure is simple and easy to manufacture, but the flexibility to accommodate individual patient needs and replicate anatomical motion is reduced
Solution Approach 1:
The bearing component is divided into separate medial and lateral bearings that can be independently selected and attached to the tibial tray. This segmentation allows customization for each patient's anatomical needs while keeping each individual bearing relatively simple in structure.
Solution Approach 2:
The prosthesis offers a choice between fixed bearings (for stability) and mobile bearings (for anatomical motion replication). This dynamic approach allows the surgeon to select the appropriate bearing type based on patient-specific requirements, enhancing adaptability without requiring all designs to be complex.
2Adaptability or versatility
If independent medial and lateral bearings are used, then the articulation and ligament reconstruction can be customized, but the device complexity and number of components increases
Solution Approach 1:
The tibial tray is designed with universal attachment features (engagement lips and grooves) that can accommodate both fixed and mobile bearings on either medial or lateral sides. This multi-functionality allows the same base component to serve multiple customization purposes, reducing the need for entirely different component sets.
Solution Approach 2:
The engagement lips and grooves are strategically positioned on the tibial tray to allow selective attachment of bearings at specific locations (medial or lateral sides). This local quality approach enables customization of articulation characteristics at specific joints while maintaining a relatively simple overall component structure.
3Ease of operation
If mobile bearings are used to replicate anatomical motion, then the natural articulation is enhanced, but the stability and risk of dislocation may be reduced
Solution Approach 1:
The system allows dynamic selection between mobile bearings (for natural articulation and motion replication) and fixed bearings (for maximum stability). This dynamic capability enables the surgeon to choose the appropriate bearing type based on the patient's activity level, ligament status, and anatomical requirements, balancing motion and stability needs.
Solution Approach 2:
Different bearing types (mobile or fixed) can be applied locally at the medial and lateral sides of the tibial tray based on specific functional requirements. For example, a mobile bearing can be placed on the lateral side to replicate natural motion while a fixed bearing is placed on the medial side to provide stability, allowing localized optimization of both articulation and stability.
Data Source
AI summary
A knee joint prosthesis assembly according to the present disclosure can include a femoral component, a unitary tibial component, a medial bearing, and a lateral bearing. The femoral component can have a medial and a lateral condyle portion connected by a patellar track portion. The femoral component can form an opening between the medial and lateral condyles. The unitary tibial component can have a medial portion that includes a first posterior engagement lip and a first outer securing lip. The tibial component can further include a lateral portion that includes a second posterior engagement lip and a second outer securing lip. The medial bearing can have a first posterior groove formed thereon that selectively engages the first posterior engagement lip and a first outer groove that selectively engages the first outer securing lip.