Meniscal Bearing Knee Replacement with Standardized Entrapment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current unicondylar meniscal bearing knee replacement technologies face challenges with varying entrapment ranges that do not adequately prevent dislocation in smaller patients while potentially leading to overstuffing and pain in larger patients, as the existing range of bearing sizes does not sufficiently account for individual patient anatomy, resulting in suboptimal implantation and post-operative pain.
Innovation Solution
A kit of meniscal bearings with a standardized entrapment range of 3.2mm to 3.8mm, allowing for increased entrapment in smaller bearings and decreased entrapment in larger bearings, along with optional protrusions and symmetrical designs to facilitate easier implantation and reduce the risk of dislocation and overstuffing, while maintaining a consistent articulating contact surface area throughout knee movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standardized entrapment range of 3.2mm to 3.8mm is used across all bearing sizes, then dislocation prevention is improved for smaller patients, but implantation difficulty increases for larger patients
Solution Approach 1:
The patent applies parameter changes by standardizing the entrapment dimension to a specific range of 3.2mm to 3.8mm across all bearing sizes. This parameter standardization ensures adequate dislocation prevention for smaller patients while maintaining consistency in the bearing design. The entrapment is achieved through specific geometric relationships between the bearing's anterior and posterior surfaces, creating a reliable mechanical constraint that prevents dislocation regardless of patient size.
2Reliability
If larger entrapment is used to prevent dislocation, then reliability improves, but post-operative pain increases due to overstuffing
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the entrapment parameter within the range of 3.2mm to 3.8mm. This optimized parameter range provides sufficient mechanical constraint to prevent dislocation while avoiding excessive entrapment that would cause overstuffing and post-operative pain. The bearing geometry is specifically designed with anterior and posterior surfaces that create this precise entrapment dimension, balancing reliability and patient comfort.
Solution Approach 2:
The patent applies partial action by providing just enough entrapment (3.2mm to 3.8mm) to prevent dislocation without exceeding the optimal amount that would cause overstuffing. This controlled partial entrapment is sufficient for its protective function while avoiding the harmful effects of excessive constraint, thereby preventing post-operative pain associated with overstuffing.
3Ease of operation
If bearing thickness is reduced for smaller patients, then implantation ease improves, but dislocation risk increases
Solution Approach 1:
The patent resolves this contradiction by maintaining a standardized entrapment parameter of 3.2mm to 3.8mm that is independent of bearing size. This ensures that even smaller bearings provide adequate dislocation prevention through the consistent entrapment geometry, while still being thin enough for easy implantation. The anterior and posterior surface design creates this reliable entrapment dimension that scales appropriately with bearing size.
4Ease of operation
If varying entrapment ranges are used for different bearing sizes, then implantation ease improves for larger patients, but dislocation prevention becomes inadequate for smaller patients
Solution Approach 1:
The patent applies universality by implementing a standardized entrapment range of 3.2mm to 3.8mm that applies universally across all bearing sizes. This universal parameter ensures consistent dislocation prevention performance for all patients regardless of size, while the bearing design accommodates different patient anatomies. The consistent entrapment geometry provides reliable protection against dislocation across the full range of bearing sizes.
Data Source
Figure 1~2a
Figure 2b~2c
Figure 2d~3a
AI summary
A kit of parts for use in unicondylar meniscal bearing knee replacement comprises a plurality of meniscal bearings, each meniscal bearing comprising a body defining a dished first bearing surface on one side thereof and a second surface on an opposing side of the body. Each meniscal bearing has an entrapment between 3.2mm and 3.8mm. Meniscal bearings and methods of performing unicondylar meniscal bearing replacements are also described.