Self-Centring Elbow Fixation Device Without Guide Wire

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Solution Overview

Problem

Current external fixation devices for elbow treatment require invasive procedures, such as the insertion of a supracondylar guide wire, causing trauma, radiation exposure, and risk of nerve lesion, with potential misalignment issues affecting the efficacy of the fixation.

Innovation Solution

A self-aligning elbow fixation device that eliminates the need for a supracondylar guide wire, utilizing arched and linear slots with locking mechanisms and a hinge to define the articulation axis, ensuring stable alignment with the elbow's center of rotation, and incorporating protective elements to prevent contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a supracondylar guide wire is used for positioning the fixation device, then the alignment with the centre of rotation can be achieved, but the procedure causes trauma to the articulation, exposes to radiation, and risks ulnar nerve lesion

Engineering Contradiction:
Improvealignment precisionVSAvoidtrauma and nerve risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the supracondylar guide wire from the system entirely. Instead of using an invasive wire for positioning, the invention employs a self-aligning mechanism where the fixation device automatically positions itself relative to the centre of rotation through geometric constraints and self-centring features, eliminating the harmful extraction of a guide wire through bone

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixation device incorporates self-aligning features that allow it to automatically position itself correctly without requiring external guidance tools. The device uses self-centring mechanisms and geometric relationships between its components to achieve proper alignment with the centre of rotation autonomously, eliminating the need for invasive positioning procedures

Inventive Principle:
Principle #25Self-service

2Measurement precision

If a supracondylar guide wire is used for positioning, then alignment can be obtained, but the operation duration is prolonged and device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidoperation duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The fixation device is pre-designed with self-aligning geometric features and self-centring mechanisms built into its structure before the surgical procedure. This preliminary design allows the device to automatically assume the correct position once applied, eliminating the time-consuming steps of inserting and positioning guide wires during the operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By removing the guide wire positioning system entirely, the patent eliminates the time required for wire insertion, radioscopic control, and wire removal. The self-aligning mechanism performs the alignment function more quickly and directly through mechanical means rather than requiring iterative positioning under radiation guidance

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If a supracondylar guide wire is used, then positioning is possible, but the procedure requires radioscopic control increasing radiation exposure

Engineering Contradiction:
Improvepositioning accuracyVSAvoidradiation exposure
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the radioscopic control system (optical/electromagnetic) with a purely mechanical self-aligning system. The fixation device uses geometric constraints, self-centring features, and mechanical relationships between components to achieve accurate positioning without requiring external radiation-based guidance, thereby eliminating radiation exposure entirely

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If the fixation device uses movable cursor to accommodate flexion and extension, then the device adaptability is improved, but the device complexity increases

Engineering Contradiction:
Improvemovement accommodationVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fixation device incorporates a cursor that can move along an arched slot to dynamically accommodate the changing position of the centre of rotation during elbow flexion and extension. This dynamic adjustment allows the hinge to maintain proper alignment throughout the range of motion, transforming a static structure into an adaptive one that responds to physiological movement

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2170188B1A self-centrin elbow fixation device without guide wire
Publication Date: 2012.09.12 BIGAZZI PROSPERO
  • EP2170188B1 patent drawingFigure 1~2
  • EP2170188B1 patent drawingFigure 3
  • EP2170188B1 patent drawingFigure 4~6

AI summary

A first arched slot or slit connection element (15) and a second linear slot or slit connection element (19, 21) are provided for cursors (13, 30) which can slide and be locked along said slots or slits; the connection element engaged with the humeral stem is self-centring and is provided with a hinge (32, 34) defining the articulation axis of the elbow, when - after repeated flexion-extension - said cursor is no longer subject to significant movements.