Glenoid Component Pegs with Varying Diameters for Bone Fixation
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Solution Overview
Problem
Current glenoid prosthetic implants face challenges in providing a stable and secure articulating surface for the shoulder joint, particularly in resisting various forces and minimizing bone perforation risks during implantation.
Innovation Solution
The design features a glenoid component with three or four pegs of varying diameters and lengths, including a central peg with a unique length and diameter configuration, and the use of circumferential and longitudinal grooves for enhanced fixation with bone cement or interference fit, ensuring secure anchoring and resistance to shear forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pegs are used to secure the glenoid component, then the stability and securement are improved, but the complexity of the device increases
Solution Approach 1:
The glenoid component is divided into multiple functional pegs (first peg, second peg, third peg) with different configurations. Each peg serves as an independent fixation element that can be positioned at optimal locations within the scapula, providing distributed stability while maintaining modular simplicity in the overall design
Solution Approach 2:
The pegs are designed with asymmetric characteristics - the first and second pegs have a first diameter while the third peg has a second diameter that is smaller than the first diameter. This asymmetric design allows each peg to be optimized for its specific position and load requirements, improving overall fixation reliability without requiring all pegs to be identical complex structures
2Force
If pegs with larger diameter are used, then the resistance to separation forces is improved, but the risk of bone perforation increases
Solution Approach 1:
Different pegs are assigned different diameters based on their specific functional requirements and anatomical positions. The first and second pegs have a larger first diameter for primary load-bearing positions, while the third peg has a smaller second diameter for positions where bone preservation is critical. This local differentiation optimizes force resistance while minimizing bone perforation risk at each specific location
Solution Approach 2:
The peg diameter parameter is varied across different pegs rather than using a uniform diameter. The first diameter of the first and second pegs is larger than the second diameter of the third peg, creating a parameter gradient that balances fixation strength with bone preservation based on the specific mechanical demands and anatomical constraints of each peg position
3Reliability
If circumferential and longitudinal grooves are added to pegs, then the fixation with bone cement is enhanced, but the manufacturing complexity increases
Solution Approach 1:
Circumferential grooves are added to the peg surfaces, creating curved geometric features that enhance bone cement interlocking. These grooves follow the cylindrical geometry of the pegs, allowing standard rotational molding or machining processes to create the features with minimal additional complexity while significantly improving fixation reliability through increased surface area and mechanical interlocking
Data Source
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AI summary
A prosthetic glenoid component has a body having a concave bearing surface and a convex glenoid contacting surface. First and second pegs extend outwardly from adjacent respective first and second ends of the bone contacting surface of the body, the first and second pegs have portions with a first diameter at the bone contacting surface extending for a first length and a second diameter extending from the first diameter for a second length, the first diameter larger than the second diameter. A third peg extends outwardly from the bone contacting surface intermediate the first and second pegs. The third peg has a third diameter greater than the second diameter portion of the first and second pegs and a third length greater than the first length of the first diameter portion of the first and second pegs. The third length is less than the sum of the first and second lengths.