Radial Head Implant with Arc-Segment Head for Ulnar Contact
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Solution Overview
Problem
Existing radial head implants face challenges in achieving precise surface contact with the ulnar component due to their cylindrical shape and straight sides, making it difficult to insert them into the intramedullary canal at the correct angle, which can result in suboptimal joint articulation and stability.
Innovation Solution
A radial head implant with a non-cylindrical, symmetric head having sides formed of multiple arc segments and a straight stem with a bullet-shaped tip, allowing for easier insertion and accommodating non-parallel canal axes, ensuring surface contact with the ulna and facilitating better joint articulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cylindrical radial head implant with straight sides is used, then the implant structure is simple and easy to manufacture, but it provides only point contact with the ulnar component and makes it difficult to achieve precise surface contact
Solution Approach 1:
The radial head implant replaces the traditional cylindrical shape with a non-cylindrical shape where the head portion is formed of multiple arc segments with no straight sections. This curved geometry enables surface contact between the radial head and the ulnar component, improving contact precision while maintaining manufacturability through standardized forming processes.
2Device complexity
If a traditional cylindrical radial head implant is used, then the implant design is simple, but it is difficult to insert at a precise angle to achieve proper articulation with the ulnar component
Solution Approach 1:
The non-cylindrical head portion formed of multiple arc segments provides a streamlined profile that facilitates insertion at precise angles relative to the ulnar component. The curved geometry allows the implant to be inserted with the radial implant axis at a precise angle, achieving proper surface contact and articulation.
Solution Approach 2:
The implant introduces a concave portion near the distal end of the head, adding geometric complexity in the radial dimension. This concave feature permits a smaller angle of approach to the radial medullary canal when passing near the distal humerus, easing the implantation process.
3Ease of manufacture
If a radial head implant with a non-optimized head shape is used, then the implant is easier to manufacture, but it does not accommodate a radius whose proximal canal axis is not parallel with the articulation surface of the ulnar component
Solution Approach 1:
The non-cylindrical head portion formed of multiple arc segments creates a geometry that accommodates varying anatomical configurations. This curved design allows the radial head implant to work with a radius whose proximal canal axis is not parallel with the articulation surface of the ulnar component, providing adaptability to different patient anatomies.
Solution Approach 2:
The concave portion near the distal end of the head adds dimensional complexity that enables the implant to accommodate non-parallel canal axes. This geometric feature allows the implant to be inserted successfully even when the proximal canal axis is not parallel with the ulnar articulation surface.
Data Source
AI summary
A radial head prosthesis for implantation in a distal radius. The implant includes a head portion and a stem portion. The stem portion has a cylindrical shaft and tapered tip. The head portion includes a recess for engagement with the stem portion. The head portion includes a first bearing surface for articulation with a humerus, and a second bearing surface for articulation with an ulna. The second bearing surface includes at least one concave and one convex portion immediately adjacent one another.