Nested Acetabular Cup Fastener Locking Mechanism
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Solution Overview
Problem
Existing acetabular cup fixation systems face issues with loosening and backout of fasteners during orthopedic procedures, which can lead to instability and complications in bone anchoring.
Innovation Solution
The acetabular cup system incorporates various fixation fasteners with threaded and tapered designs, self-tapping threads, and locking mechanisms, including pivotable and angled configurations, to securely engage with the acetabular cup and bone, preventing loosening and backout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fixation fasteners are used to secure acetabular cups to bone, then the procedure can be performed, but loosening and backout of fasteners occurs during use, leading to instability
Solution Approach 1:
The fixation fastener employs a nested structure where a inner fastener is contained within an outer fastener. The inner fastener features a head with a hollow cavity that receives and secures the outer fastener's head, creating a nested configuration. This nested design prevents loosening and backout by mechanically interlocking the two fastener levels, thereby resolving the stability issue while maintaining reliable bone anchoring
Solution Approach 2:
The system incorporates a locking mechanism that is预先 configured to prevent backout before it can occur. The outer fastener's head is designed with features that engage with the inner fastener's cavity in advance, creating a preliminary lock that prevents the harmful backout action before it can compromise fixation stability
2Reliability
If fixation fasteners are designed with complex locking mechanisms to prevent loosening, then reliability improves, but device complexity increases
Solution Approach 1:
Rather than adding separate locking components or complex mechanisms, the invention uses a nested fastener configuration where the inner and outer fasteners are integrated into a single cohesive unit. The heads of both fasteners are shaped to interlock naturally, providing security through their combined geometry rather than through additional locking features, thus maintaining simplicity while improving reliability
Solution Approach 2:
The invention merges the functions of multiple fasteners into a unified nested structure. The inner and outer fasteners work together as a single system, with their heads combined to provide both anchoring and locking functions simultaneously, reducing the need for separate components and simplifying the overall device structure
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 described system effectively secures acetabular cups to bone, reducing the risk of loosening and backout, thereby enhancing the stability and longevity of the fixation, allowing for optimal positioning and anchoring of the fasteners.
Implementation Method 1
The head includes a threaded portion with self-tapping threads threadably engageable with the fixation opening
Implementation Method 2
The second head portion tapered for taper lock connection with the second wall portion
Data Source
AI summary
An acetabular cup system includes an acetabular cup having a wall with an inner surface and an outer surface. The acetabular cup includes a fixation opening through the wall, the fixation opening including a first wall portion adjacent to the inner surface and a second wall portion adjacent to the outer surface. The acetabular cup system also includes a fixation fastener including a head and a shaft with a bone-anchoring portion. The fastener can be inserted though the fixation opening. The head includes a first head portion engageable with the first wall portion and a second head portion engageable with the second wall portion.