Modular Prosthesis Assembly Tool with Low-Friction Threaded Mechanism
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Solution Overview
Problem
Current modular prostheses face challenges in securely locking components due to insufficient mechanical advantage, suboptimal ergonomics, and the difficulty in accurately positioning and orienting components during joint arthroplasty, leading to complications such as overtightening and increased inventory needs.
Innovation Solution
A device with a handle system that applies opposing forces to lock and unlock tapered connections between modular prosthesis components, featuring a low-friction threaded connection and a mechanism to control angular orientation, allowing for precise assembly and disassembly while preventing over-tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locking mechanisms are used for modular prosthesis components, then assembly is possible, but mechanical advantage is insufficient and overtightening occurs
Solution Approach 1:
A specialized assembly tool acts as an intermediary device between the surgeon and the prosthesis components. The tool includes a first member that engages the first component and a second member that engages the second component, with a relative motion feature that translates rotational input into precise axial displacement. This intermediary mechanism provides controlled mechanical advantage, ensuring secure locking without overtightening.
Solution Approach 2:
The assembly tool incorporates a relative motion feature (such as a threaded connection or cam mechanism) that changes the displacement parameter based on rotational input. This allows precise control over the locking force applied, transforming the assembly process from a force-dependent operation to a displacement-controlled operation, thereby eliminating overtightening while ensuring reliable component locking.
2Adaptability or versatility
If modular components are used to accommodate varying anatomy, then patient-specific fit is improved, but component positioning and orientation precision is reduced
Solution Approach 1:
The assembly tool is designed as a universal device that can accommodate multiple combinations of modular prosthesis components. The tool's first and second members are configured to engage various component types, and the angular orientation feature can replicate different angles, making the single tool applicable to diverse anatomical situations while maintaining precise positioning control.
Solution Approach 2:
The invention replaces manual positioning and estimation methods with a mechanical system that includes an angular orientation feature. This feature cooperates with the first and second members to precisely control and replicate the angular orientation between components, substituting surgeon skill and estimation with a deterministic mechanical positioning system that ensures consistent precision across different modular component combinations.
3Adaptability or versatility
If multiple prosthesis variations are maintained in inventory for different anatomical needs, then patient-specific requirements are met, but inventory complexity and cost increase
Solution Approach 1:
The prosthesis system is segmented into modular components (first component and second component) that can be independently selected and combined. The assembly tool enables precise assembly of these modular segments, allowing a limited set of standardized components to be configured for various anatomical requirements, thereby reducing the need to maintain large inventories of pre-configured complete prostheses.
Solution Approach 2:
The assembly tool serves as a universal platform that can assemble different combinations of modular components. By providing a single tool that can handle various component types and configurations, the system allows hospitals to maintain smaller inventories of modular parts rather than large inventories of complete pre-assembled prostheses, reducing inventory complexity while maintaining the ability to meet diverse anatomical needs.
4Ease of manufacture
If tapered connections are used for modular components, then assembly is simplified, but mechanical advantage for secure locking is insufficient
Solution Approach 1:
The assembly tool serves as an intermediary mechanism that enhances the tapered connection's locking capability. The tool's relative motion feature translates rotational input into controlled axial displacement, applying progressive force to the tapered interface. This ensures the tapered connection achieves full engagement and secure locking without requiring excessive manual force or complex assembly procedures.
Solution Approach 2:
The assembly tool transforms the assembly process from a simple push-fit operation to a controlled displacement process. The relative motion feature (threaded connection or cam mechanism) provides mechanical advantage, converting small rotational movements into precise axial displacement that ensures the tapered connection achieves optimal engagement. This parameter control ensures reliable locking while maintaining assembly simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides sufficient mechanical advantage for secure component locking, optimizes ergonomics for easy handling, and allows for precise angular control, reducing complications and inventory requirements while simplifying the assembly process.
Implementation Method 1
The first member and the second member include relative motion features that are adapted to reduce friction between each other. The relative motion features may, for example, include a threaded connection.
Implementation Method 2
The device provides sufficient mechanical advantage for secure component locking
Implementation Method 3
The first member and the second member include relative motion features that are adapted to reduce friction between each other
Data Source
AI summary
An assembly tool for assembly of a first component of a prosthesis to a second component of the prosthesis for use in joint arthroplasty is provided. The tool includes a first member in contact with the first component and a second member connected to the second component. The first member defines a first member longitudinal axis. The first member and the second member provide for the assembly of the first component of the prosthesis to the second component of the prosthesis. The second member provides relative motion of the second member with respect to the first member when the second member is rotated relative to the first member about the first member longitudinal axis. The first member and the second member have relative motion features adapted to reduce friction that cooperate with each other to provide the relative motion of the first member with respect to the second member.