Flexible Hinge Prosthesis for Metacarpophalangeal Joint Assembly
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Solution Overview
Problem
Existing joint prostheses for metacarpophalangeal and proximal interphalangeal joints are complex and difficult to assemble, with implantation methods limited to specific surgical routes, making them challenging for practitioners to use effectively.
Innovation Solution
A prosthesis design featuring a flexible hinge with cylindrical bulges and a flat flexible lamella, allowing for easy assembly and multiple implantation routes, combined with an ancillary device for guiding and positioning the components, facilitates simpler assembly and broader surgical flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex structure is used in joint prosthesis, then functionality and durability are improved, but assembly difficulty and surgical complexity increase
Solution Approach 1:
The prosthesis is divided into separate modular components: first plate, second plate, and flexible hinge assembly. Each component can be independently manufactured and assembled, reducing overall complexity while maintaining functional integrity. The hinge is separated from the plates, allowing independent optimization of each part.
Solution Approach 2:
The flexible hinge is nested within the breakthrough openings in the plates, with the hinge components fitting into recesses and channels within the plate structures. This nesting arrangement simplifies assembly by pre-positioning components within the plates, reducing the number of separate assembly steps required.
2Manufacturing precision
If specific implantation route is followed, then surgical precision is improved, but adaptability to different surgical approaches is reduced
Solution Approach 1:
The prosthesis design incorporates universal features that allow it to be implanted through multiple surgical routes (dorsal, lateral, palmar) without requiring route-specific modifications. The breakthrough openings and hinge mounting structures are designed to accommodate different implantation approaches while maintaining precise alignment and functionality.
Solution Approach 2:
The flexible hinge provides dynamic adaptability, allowing the prosthesis to accommodate varying surgical approaches and patient anatomies. The flexibility enables the hinge to be positioned and secured in different orientations depending on the surgical route used, while still achieving the required precision for joint restoration.
3Strength
If traditional assembly method is used, then structural integrity is maintained, but assembly time and surgical duration increase
Solution Approach 1:
The hinge components are pre-assembled and pre-positioned within the breakthrough openings before final implantation. The flexible hinge is pre-configured with its bulges and lamella in the correct orientation, allowing for rapid insertion and securing during surgery without requiring time-consuming assembly steps in the operating room.
Solution Approach 2:
The prosthesis components are designed with self-aligning features and self-securing mechanisms that automatically position and secure the hinge to the plates during assembly. The breakthrough openings and hinge mounting structures are designed to guide the hinge into place automatically, reducing the need for complex alignment procedures and extending tools.
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a prosthesis characterised in that it comprises: a first plate (11); a second plate (21); means (30) for mounting the plates (11, 21) rotatably about a shaft (31), said means consisting of a flexible hinge (40) comprising a cylindrical, planar, flexible lamella (41) and two cylindrical bulges (42, 43) respectively associated with two edges of the lamella (41), the dimension of the cross-section of the two bulges (42, 43), measured along a direction perpendicular to the plane containing the rotating shaft (31) and crossing the two bulges, being larger than the thickness of the lamella (41) in the same direction, with a hole (44, 45) made in each of the two plates (11, 21) having a complementary shape to that of the two bulges (42, 43) and opening onto a first face of the plate; and a slit (46, 47) provided in each of the two plates (11, 21) and opening onto the hole made in said plate on a second of the faces thereof and onto the first face. The flexible hinge (40) and the two plates (11, 21) are mounted to engage with one another in such a way that the two bulges (42, 43) and the flexible lamella (41) are respectively arranged in the two holes (44, 45) and in the two slits (46, 47).