Non-Symmetrical Knee Inserts With Sensors for Prosthetic Alignment

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Solution Overview

Problem

Existing orthopedic joint replacement procedures lack the ability to accurately account for individual patient variations, relying heavily on surgeon skill and resulting in inconsistent outcomes.

Innovation Solution

A knee measurement system with non-symmetrical shims and sensors that provide real-time quantitative measurement data for alignment, load, and motion, allowing for precise adjustment of prosthetic components during surgery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If standardized orthopedic joint replacement procedures are used, then general needs of the population are met, but individual patient variations cannot be accurately addressed

Engineering Contradiction:
Improveadaptability to individual patient variationsVSAvoidcomplexity of measurement and adjustment system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides the measurement function into multiple independent sensors placed at different locations on the prosthetic joint components. Each sensor measures specific parameters (alignment, load, motion) independently, allowing the system to capture complex individual patient variations through aggregated data from simpler individual sensing elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical measurement tools and surgeon skill-based assessment with electronic sensors and digital data processing. Sensors embedded in the prosthetic components automatically capture alignment, load distribution, and motion parameters, converting physical mechanical states into digital signals for precise analysis and adjustment.

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

2Reliability

If surgeon skill-based adaptation is used, then some individual variations are corrected, but outcomes are inconsistent

Engineering Contradiction:
Improveconsistency of surgical outcomesVSAvoidprecision of alignment and load measurement
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system implements real-time feedback by continuously monitoring alignment, load distribution, and motion parameters through embedded sensors. This data is processed to provide immediate feedback to the surgeon during surgery, enabling precise adjustments to achieve optimal fitting. The feedback loop ensures consistent, measurable outcomes rather than relying on variable surgeon skill.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Traditional mechanical measurement methods and subjective surgeon assessment are replaced with electronic sensors that objectively measure alignment angles, load forces, and motion ranges. This substitution provides precise, quantifiable data that eliminates variability in measurement precision and enables reliable, repeatable surgical outcomes.

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

3Manufacturing precision

If real-time measurement data is collected, then precise fitting is achieved, but device complexity increases

Engineering Contradiction:
Improveprecision of prosthetic joint fittingVSAvoidcomplexity of sensor system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple sensing functions (alignment measurement, load sensing, motion detection) into a single integrated prosthetic joint component. Rather than adding separate external measurement devices, the sensors are embedded within the prosthetic structure itself, combining the structural and measurement functions into one unified system that achieves precise fitting without proportionally increasing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3681381B1Non-symmetrical insert sensing system and method therefor
Publication Date: 2025.08.13 HOWMEDICA OSTEONICS CORP
  • EP3681381B1 patent drawingFigure 1
  • EP3681381B1 patent drawingFigure 2~4
  • EP3681381B1 patent drawingFigure 5~7

AI summary

An orthopedic system to monitor a parameter related to the muscular-skeletal system is disclosed. The orthopedic system includes electronic circuitry, at least one sensor, and a computer to receive measurement data in real-time. The orthopedic system comprises a first plurality of shims of a first type, a second plurality of a second type, a measurement module, and the computer. The measurement module houses the electronic circuitry and at least one sensor. The measurement module is adapted to be used with the first plurality of shims and the second plurality of shims. The measurement module has a medial surface that differs from a lateral surface by shape, size, or contour.