Shoulder Prosthesis Coupling Adapter for Independent Geometry Adjustment
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Solution Overview
Problem
Existing modular shoulder prostheses lack complete adjustability for radial offset, inclination angle, and anteversion/retroversion, requiring multiple components and inventory management, which limits flexibility and increases costs.
Innovation Solution
A humeral prosthetic system comprising a stem, a spherical head, and a coupling adapter that allows independent adjustment and fixing of radial offset, inclination angle, and version, enabling universal adjustment and reducing the need for multiple component sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If modular prostheses are used to allow adjustment of tilt angle or radial offset, then flexibility is improved, but substantial inventories of stems or heads are required
Solution Approach 1:
The coupling adapter is designed with a universal interface that can accommodate multiple stem sizes and head sizes through a single standardized connection mechanism. The adapter plate with Morse taper and ball joint configuration allows any head to be mounted on any stem by simply changing the coupling adapter, eliminating the need for size-specific modular components.
Solution Approach 2:
The prosthesis is divided into three separable components: stem, coupling adapter, and spherical head. The coupling adapter acts as an intermediary component that segments the connection between stem and head, allowing independent selection of stem and head sizes while maintaining compatibility through the standardized adapter interface.
2Adaptability or versatility
If multiple sizes of heads or stems are maintained to provide complete tilt angle and radial offset flexibility, then adaptability is improved, but device complexity and inventory management are worsened
Solution Approach 1:
The coupling adapter serves multiple functions: it provides the Morse taper connection for radial offset adjustment, the ball joint for tilt angle adjustment, and the standardized interface for version adjustment. This multi-functionality in a single component eliminates the need for multiple specialized modular components.
Solution Approach 2:
The coupling adapter merges the functions of radial offset adjustment, tilt angle adjustment, and version adjustment into a single integrated component. By combining these adjustment mechanisms that were previously distributed across multiple modular components, the system simplifies inventory while maintaining complete geometric flexibility.
3Quantity of substance
If prior art modular systems use standard heads or stems, then inventory is reduced, but complete tilt angle and radial offset flexibility is lost
Solution Approach 1:
The coupling adapter allows independent variation of multiple geometric parameters (radial offset, tilt angle, version) through its mechanical design. The Morse taper angle, ball joint radius, and adapter plate geometry are specifically designed to enable continuous adjustment of these parameters while maintaining a single standardized component design.
Data Source
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AI summary
A humeral prosthesis includes a stem component and a head component joined by an inclination component (43). The inclination component (43) is provided with an opening (44) that is designed to accommodate a pair of expandable tabs extending from a side of a plate (57). The plate (57) is also provided with a taper (59) extending opposite to the pair of expandable tabs. Inclination angle, radial offset, and version are adjustable and are separately and independently set and fixed.