Elongated Pin with Threaded Conical End for Bone Fixation
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Solution Overview
Problem
Existing external fixation systems for bone fractures lack a solution that balances the simplicity and lightness of temporary systems with the stability and robustness of permanent systems, while also avoiding infection risks and facilitating straightforward surgical application.
Innovation Solution
An elongated pin with a threaded conical end is implanted into the cortical portion of the bone, allowing for a strong gripping action without damaging the medullary canal, and is used in conjunction with a plate clamp element to create a stable fixation system that can be used for both temporary and permanent applications, including bone lengthening procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a permanent external fixation system is used to provide high stiffness and stability, then the stability and robustness of fixation is improved, but the weight and complexity of the system increases
Solution Approach 1:
The fixation system is divided into separate functional components: pins with threaded conical ends for bone anchoring, clamp elements for securing pins, and bars for connecting clamps. This segmentation allows each component to be optimized independently, reducing overall system weight while maintaining stability through proper distribution of fixation points.
Solution Approach 2:
The patent transitions from traditional heavy permanent fixation systems to a lighter system by changing the anchoring mechanism dimension - using threaded conical pins that screw into cortical bone rather than relying on heavy plates and screws. This dimensional change in the anchoring approach enables weight reduction while preserving fixation stability.
2Strength
If traditional bone screws are used to secure fixation devices, then the gripping action and fixation strength is improved, but the risk of infection and surgical complexity increases
Solution Approach 1:
The invention extracts the essential gripping function from traditional bone screws and implements it through a simplified threaded conical pin design. By taking out only the necessary anchoring capability and removing unnecessary components, the system achieves strong gripping action while reducing infection risk through minimized surgical intervention and fewer bone-penetrating elements.
Solution Approach 2:
The threaded conical pins are designed as simple, lightweight anchoring elements that can be easily inserted and removed. While individual pins are simple and lightweight (analogous to disposable elements), collectively they provide robust fixation. The simplicity of each pin reduces surgical complexity and infection risk while maintaining overall system strength.
3Strength
If pins are implanted into the medullary canal to achieve strong fixation, then the fixation strength is improved, but the invasiveness and risk of complications increases
Solution Approach 1:
The threaded conical pins are designed to engage only the cortical portion of the bone, which provides sufficient anchoring strength for external fixation. By localizing the anchoring action to the cortical layer rather than penetrating the medullary canal, the system achieves adequate fixation strength while significantly reducing surgical complexity and associated risks.
4Weight of moving object
If a lightweight fixation system is used to reduce infection risk, then the simplicity and lightness is improved, but the stability and robustness deteriorates
Solution Approach 1:
The fixation system employs composite construction with pins made of lightweight materials (such as titanium or aluminum alloys) that provide high strength-to-weight ratio. The combination of these lightweight pin materials with the cortical bone engagement mechanism creates a composite system that is both lightweight and stable, resolving the contradiction between weight reduction and stability maintenance.
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 solution provides stable and robust fixation while minimizing invasiveness, reducing the risk of infection, and allowing for easy insertion and axial load distribution, with pull-out forces comparable to screws implanted in the medullary canal, thus offering a lightweight yet effective fixation system.
Implementation Method 1
The end portion 4 with tip has a conical shape with an external thread, forming a conical threaded end portion for insertion into the cortical portion of a bone
Data Source
AI summary
The invention relates to an elongated pin (2) for an external modular fixation system for temporary and/or permanent fixation applications to treat bone fractures and to connect two or more bone fragments to each other, comprising an elongated stem (3) extending along a longitudinal axis with a first end portion (4) and an opposite second end portion (5), said first end portion (4) having a tip for the insertion of the first end portion (4) into a bone, wherein said first end portion (4) has a conical shape with an external thread, forming a conical threaded end portion, the extension of said conical threaded end portion along the longitudinal axis being determined by the depth of penetration of the conical end portion limited to only the cortical portion of the bone.