Prosthesis Selection via Digital Overlay Scaling

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Solution Overview

Problem

Existing methods for selecting orthopedic prostheses, such as hip or knee implants, face challenges in accurately matching the scales of radiological images and prosthesis layers, leading to potential errors and high computational costs due to imprecise image processing.

Innovation Solution

A method involving digital radiological imaging with a reference radio-opaque object, where a digital overlay with a marker is superimposed and scaled manually to match the radiological image, using geometric similarity transformations to ensure accurate sizing and positioning of the prosthesis layers without altering the image size, allowing for intuitive scale adjustment via a graphical interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If automatic digital analysis with image smoothing filter is used to determine the diameter of the reference ball, then the process is automated, but the computational cost increases and measurement precision may deteriorate due to errors in contour determination

Engineering Contradiction:
Improveautomation of diameter measurementVSAvoidprecision of ball diameter measurement
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent creates a digital copy (overlay) of the prosthesis with an integrated marker that replicates the reference object's appearance. This copy is superimposed on the radiological image and manually scaled to match the reference object, avoiding the need for complex automatic contour detection while maintaining accuracy through visual verification.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The marker on the overlay serves as an intermediary element that facilitates scale matching between the radiological image and the prosthesis representation. By manually aligning the marker with the reference object, the user creates an intermediate reference point that simplifies the scaling process without requiring complex image processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If image smoothing filter and gradient analysis are used to determine the reference ball contour, then automatic processing is achieved, but the computational resources required increase significantly

Engineering Contradiction:
Improveprocessing speed of scale determinationVSAvoidcomputational resource consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential scaling function from the complex image processing chain. Instead of applying smoothing filters and gradient analysis to the entire image, the method extracts only the reference object representation and uses a simple marker overlay for scaling, eliminating unnecessary computational steps.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than processing the radiological image to extract the reference ball contour automatically, the patent inverts the approach by placing a marker on an overlay and manually scaling it to match the reference object. This reverses the computational burden from complex image analysis to simple visual alignment.

Inventive Principle:
Principle #13The other way round (Inversion)

3Use of energy by moving object

If manual measurement of the reference ball diameter is performed, then computational resources are saved, but measurement precision may be compromised and time consumption increases

Engineering Contradiction:
Improvecomputational resource consumptionVSAvoidtime required for scale determination
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent prepares the overlay with a marker in advance, positioned and scaled relative to the prosthesis representation. This preliminary preparation allows the user to perform only the essential scaling operation during the actual selection process, reducing both time and computational effort compared to performing measurements or complex image processing during the procedure.

Inventive Principle:
Principle #10Preliminary action

4Extent of automation

If the radiological image is processed to automatically determine the scale coefficient, then automation is improved, but the user loses intuitive means to verify the scale correction

Engineering Contradiction:
Improveautomatic scale coefficient calculationVSAvoidintuitive verification of scale matching
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The marker on the overlay can be designed with distinct visual characteristics (such as color, pattern, or brightness) that make it easily distinguishable from the radiological image and reference objects. This visual distinction provides the user with an intuitive means to verify that the marker is correctly aligned with the reference object and that the scale is properly matched.

Inventive Principle:
Principle #32Color changes

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

This approach simplifies and robustly achieves scale matching, reducing errors and computational costs, enabling precise selection of prostheses by allowing manual intervention and intuitive scale verification, even with poor-quality reference object representations.

Implementation Method 1

obtaining in digital form a radiological image of the area of the patient's body intended to receive the prosthesis, the image comprising the representation of a reference radio-opaque object

Methodology Applied
Scientific EffectX-ray absorption: Absorption (EM radiation)

Data Source

PatentEP3028675B1Graphical selection of a prosthesis with bone anchor
Publication Date: 2017.07.19 X NOV IP SARL
  • EP3028675B1 patent drawingFigure 1~2
  • EP3028675B1 patent drawingFigure 3~4
  • EP3028675B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for selecting a prosthesis (16) to be fitted to a patient, comprising a step of obtaining a digital radiographic image (2) of the area of ​​the patient's body intended to receive the prosthesis, the image comprising the representation of a radiopaque reference object (12) positioned near said area, followed by a step of superimposing a digital overlay (14) representing the prosthesis or an element of said prosthesis (16) onto the image for positioning purposes. In step (b), the overlay (14) includes a marker (18) intended to be superimposed on the representation of the reference object (12) by moving the overlay, said overlay being able to be enlarged or reduced so that the size of the marker (18) corresponds to that of the representation of the reference object (12), so as to align the respective scales of the radiographic image (2) and the overlay (14).