Knee Joint Rotation Point Determination for Custom Orthosis Fit

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Solution Overview

Problem

Conventional knee joint endoprostheses and orthoses are standardized and not sufficiently tailored to individual patient parameters, such as ligament tensions and rotation points, which can lead to suboptimal fit and functionality.

Innovation Solution

A method to determine the ligament tension of the inner and outer ligaments, cruciate ligaments, and rotation point of the knee joint through controlled forced movements, allowing for the collection of data that can be used to produce customized or standardized prostheses and orthoses that better match the anatomy of a patient's healthy knee joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If standardized knee joint endoprostheses and orthoses are used, then manufacturing cost and ease of manufacture are improved, but individual anatomical fit and functionality deteriorate

Engineering Contradiction:
Improvestandardized manufacturingVSAvoidindividual anatomical fit
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by measuring and determining the rotation point and ligament tensions of the healthy contralateral knee joint before the implantation surgery. These pre-obtained anatomical parameters are then used to customize the implantation procedure and prosthesis positioning, allowing standardized prostheses to be fitted with individualized precision based on pre-collected data.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating a digital or physical model of the healthy knee joint's anatomical parameters (rotation point position, ligament tension characteristics) and applying this copied information to guide the implantation on the affected side, thereby transferring individualized anatomical data to achieve precise fitting without custom manufacturing.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If individualized parameter measurement and customization are implemented, then anatomical fit and functionality are improved, but measurement complexity and device complexity increase

Engineering Contradiction:
Improveindividual anatomical fitVSAvoidmeasurement and determination system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by utilizing the patient's own healthy knee joint as the measurement source. The healthy knee's anatomical parameters are measured and then applied to the affected knee's treatment, eliminating the need for complex external measurement devices and reducing system complexity while maintaining high individualization accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses universality by developing a measurement device and method that can determine multiple anatomical parameters (rotation point position, ligament tension in multiple directions, joint stability) using a single integrated system. This multi-functional approach reduces the need for separate specialized devices for each measurement type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional standardized implantation procedures are used, then surgical time and productivity are improved, but postoperative functionality and wear resistance deteriorate

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidprosthesis functionality and wear resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by determining the rotation point and ligament tension parameters before surgery, allowing the surgical team to plan the implantation procedure in advance. This pre-planning enables standardized surgical execution with individualized precision, maintaining surgical efficiency while improving postoperative functionality and prosthesis durability through accurate positioning.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3912555B1Method for determining the point of rotation of a knee joint, method for manufacturing a knee joint endoprosthesis or overlapping knee joint orthesis and a device for the execution of a method for determining the point of rotation of a knee joint
Publication Date: 2024.05.01 POHLIG KURT
  • EP3912555B1 patent drawingFigure 1(a)~1(c)
  • EP3912555B1 patent drawingFigure 2(a)~2(c)
  • EP3912555B1 patent drawingFigure 3(a)~3(d)

AI summary

The present invention relates to a method for determining parameters of a person's knee joint, a method for manufacturing and/or implanting a knee joint endoprosthesis or a knee-spanning orthosis, a method for individually adjusting the ligament tension of a knee joint, and a device for this purpose. Such methods are used for various purposes.