Implant Component Assembly Screw Retention Mechanism
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Solution Overview
Problem
Modular joint replacements face difficulties in disassembly due to self-locking tapered connections, which are challenging to separate and require significant force, especially in limited surgical access spaces.
Innovation Solution
An implant component assembly with a screw retention unit that allows the assembly screw to rotate within a channel, facilitating easy assembly and disassembly by preventing the screw from falling out and providing controlled movement, thus enabling secure attachment and detachment without damaging surrounding tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tapered connection is used to provide self-locking properties and lasting connection, then the connection strength and stability are improved, but the ease of disassembly deteriorates
Solution Approach 1:
The connection system is segmented into two functional parts: the tapered connection interface that provides self-locking strength, and the separate assembly screw that provides controlled disassembly capability. The assembly screw acts as an independent segment that can be selectively engaged or disengaged without affecting the tapered connection's structural integrity.
Solution Approach 2:
The assembly screw serves as an intermediary mechanism between the two implant components. It provides a controlled force application point that mediates the disassembly process, allowing the components to be separated without directly applying force to the self-locking tapered interface, thus preserving tissue structures.
2Ease of operation
If significant force is applied to separate self-locking tapered connections, then the disassembly capability is improved, but the risk of tissue damage increases
Solution Approach 1:
The assembly screw acts as an intermediary that distributes and controls the separation force. Instead of applying significant force directly to the tapered connection and surrounding tissue, the screw provides a controlled mechanical advantage that gradually separates the components, minimizing harmful forces transmitted to the soft tissue structures.
Solution Approach 2:
The assembly screw is pre-positioned within the assembly channel during implantation. This preliminary placement allows the screw to be readily available for future disassembly procedures without requiring additional surgical access or tissue disruption, enabling controlled force application when needed.
3Ease of operation
If the assembly screw is made movable within the assembly channel, then the ease of assembly and disassembly is improved, but the risk of screw displacement deteriorates
Solution Approach 1:
The assembly screw is designed with dynamic characteristics that allow it to move freely within the assembly channel during assembly and disassembly operations. The screw can be inserted, rotated, and removed without restriction. However, the system maintains reliability because the screw's movement is functionally controlled - it only moves when intentionally operated, and its position is naturally constrained by the channel geometry during normal implant function.
Data Source
AI summary
The present disclosure provides an implant component assembly for a joint replacement. The assembly comprises an implant component, the implant component including an interface part for attaching another implant component and an assembly channel. The assembly further comprises an assembly screw for securing the other implant component to the implant component, the assembly screw having a longitudinal axis, a screw head, and a screw shank and being insertable into the assembly channel. A screw retention unit of the assembly is configured for keeping the assembly screw within the assembly channel and allowing rotation of the assembly screw about the longitudinal axis.