Bone Fixation Device with Pliable Connecting Arm

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Solution Overview

Problem

Existing bone fixation devices face issues with deformation causing aperture distortion, leading to inaccurate fitting and potential movement relative to the bone, and are often complex in design, making them difficult to twist and remove without damaging the bone.

Innovation Solution

A bone fixation device with plastically deformable connecting arms that twist and bend before screw receiving members, allowing for accurate alignment and attachment without distorting apertures, featuring cylindrical and threaded apertures with a lip for secure screw engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the plate is deformed to ensure a close fit between the plate and the bone, then the fit quality is improved, but the apertures become distorted which reduces screw fitting accuracy

Engineering Contradiction:

Improveplate fit to boneVSAvoidaperture shape accuracy

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The bone fixation device is divided into distinct functional segments: rigid screw receiving members that maintain aperture precision, and a pliable connecting arm that provides deformability for bone contouring. This segmentation allows the plate to be deformed for fit without distorting the apertures, as the deformation is isolated to the connecting arm portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the device have different mechanical properties: the screw receiving members are made rigid to preserve aperture geometry and screw fitting accuracy, while the connecting arm is made pliable to enable deformation for achieving a close fit to the bone contour. This local differentiation of material properties resolves the contradiction between deformability and precision.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a traditional rigid bone fixation device is used, then the device structure is simple, but the device cannot be twisted or bent to align with the bone

Engineering Contradiction:

Improvedevice alignment capabilityVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The connecting arm is designed with dynamic mechanical properties, being pliable rather than rigid, which allows the device to be twisted and bent during implantation to achieve proper alignment with the bone. This dynamic characteristic enables adaptability without requiring complex adjustable mechanisms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The device utilizes changes in mechanical parameters along its structure - the connecting arm has different stiffness characteristics compared to the screw receiving members. This parameter differentiation allows the device to be deformed for alignment while maintaining structural integrity and aperture precision during the deformation process.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the connecting arm is made pliable to allow deformation, then the device can be bent and twisted for alignment, but the screw receiving members may deform during the process

Engineering Contradiction:

Improvedevice deformation capabilityVSAvoidscrew receiving member accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The device is segmented into a pliable connecting arm and rigid screw receiving members, allowing deformation to be localized to the connecting arm while the screw receiving members remain undistorted and maintain their precise geometry for accurate screw engagement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The screw receiving members are designed with localized rigidity to resist deformation during the bending and twisting of the connecting arm. This local quality ensures that even when the connecting arm is deformed for alignment, the screw receiving members maintain their dimensional accuracy and aperture geometry.

Inventive Principle:

Principle #3Local quality

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 can be easily deformed to fit a bone without distorting apertures, allowing for precise alignment and secure fixation, and can be twisted and bent for optimal placement, simplifying the attachment procedure and reducing the risk of bone damage during removal.

Implementation Method 1

the arm being more pliable than the screw receiving members such that (a) on twisting the device about its long axis the arm twists before the screw receiving members deform; and (b) on bending the device along its long axis the arm bends before the screw receiving members deform

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2786719B1Bone fixation device

Publication Date: 2017.03.15 CUNLIFFE MARK RICHARD

AI summary

A bone fixation device comprising first and second screw receiving members, each member having an aperture extending therethrough for receiving a screw; and a plastically deformable connecting arm extending between the screw receiving members along a long axis defined by the first and second screw receiving members; the arm being adapted to be more pliable than the screw receiving members such that (a) on twisting the device about its long axis the arm twists before the screw receiving members deform; and (b) on bending the device along its long axis the arm bends before the screw receiving members deform.