Bone Fixation Fastener Assembly With Resilient Clip Retention
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Solution Overview
Problem
Micromotion between orthopedic screws and bone can cause loosening, leading to backout and diminished stability in bone fracture fixation systems.
Innovation Solution
A bone fixation system with clips that flex outward to secure fasteners, minimizing backout through wedging forces and resilient retention, combined with a rotation tool for easy insertion and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid orthopedic screws are used to stabilize bone fractures, then bone stability is improved, but micromotion between the screw and bone causes loosening and backout
Solution Approach 1:
The patent introduces a resilient clip that can dynamically adapt to micromotion between the screw and bone. The clip flexes outward under compression forces and returns to its original position, providing continuous retention without rigid constraint. This dynamic mechanism allows the system to maintain screw stability while accommodating physiological bone movement, preventing backout without compromising bone healing.
2Reliability
If clips are added to prevent screw backout, then screw retention is improved, but device complexity increases
Solution Approach 1:
The patent combines the retention function and the compression function into a single integrated clip component. The clip simultaneously prevents screw backout and maintains compression at the screw-bone interface through its resilient design. This merging eliminates the need for separate retention devices and compression mechanisms, reducing overall system complexity while achieving multiple functions.
Solution Approach 2:
The resilient clip is designed to automatically adjust and maintain its retention function without external intervention. When compression forces change during bone healing, the clip self-adjusts its flexion and recovery, maintaining optimal screw retention throughout the healing process. This self-regulating mechanism eliminates the need for complex active control systems.
3Ease of manufacture
If traditional fastening methods are used, then manufacturing simplicity is maintained, but removal difficulty increases
Solution Approach 1:
The patent incorporates a preliminary action feature in the form of a removal tool interface integrated into the clip design. The clip includes a feature that engages with a specialized removal tool, allowing for easy extraction during surgery. This preliminary design consideration enables simple manufacturing of the clip itself while providing a straightforward removal mechanism, eliminating the need for complex removal procedures.
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
Prevents unwanted backout of fasteners due to micromotion, maintaining stability and facilitating secure fixation and removal of bone screws.
Implementation Method 1
A resilient clip may be positioned within a cavity of the bone fixation plate... The resilient clip may flex outward in response to compression forces
Implementation Method 2
A tapered portion of the fastener head may contact the tabs of the resilient clip and apply a wedging force that causes the tabs to flex outward
Data Source
AI summary
A bone fixation assembly is disclosed. The bone fixation assembly includes a bone fixation plate with a fastener hole adjacent to a cavity. The bone fixation assembly also includes a clip including a body positioned at least partially in the cavity and a plurality of tabs extending inward from the body. The bone fixation assembly also includes a fastener with a fastener body having screw threads and a head extending from the fastener body to a first end of the fastener. The head includes a recess extending into the head from a first surface at the first end of the fastener, and further includes a backout groove that spirals around a tapered portion of the head in a direction from the first end of the fastener toward the fastener body of the fastener.