Sensor-Based Knee Alignment Device for Real-Time Axis Verification

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Solution Overview

Problem

Conventional knee replacement surgery instruments lack the ability to accurately check alignment of the femur and tibia after bone cuts have been made, leading to potential instability, imbalance, and early failure of the prosthesis due to variations in mechanical axis alignment.

Innovation Solution

An alignment device comprising a femoral part and a tibial part, with optional freehand sensors, including intramedullary and extramedullary sensors, that communicate to ensure accurate alignment of the femur and tibia, providing varus-valgus, sagittal, and rotational alignment information, displayed on a screen or remote computer, allowing for real-time adjustment and verification during knee replacement surgery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional knee replacement surgery instruments are used, then the surgery can be performed, but accurate alignment of the femur and tibia cannot be checked after bone cuts, leading to potential instability and early prosthesis failure

Engineering Contradiction:
Improvealignment measurement precisionVSAvoidprosthesis reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces conventional mechanical alignment instruments with sensor-based detection systems. Sensors are attached to the femur and tibia to detect alignment parameters electronically, providing precise measurement of mechanical axis alignment, varus-valgus angles, and rotational alignment without relying on traditional mechanical gauges or visual estimation.

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

Solution Approach 2:

The alignment device provides real-time feedback during surgery through sensor readings displayed on a screen. The system continuously monitors alignment parameters and allows for immediate adjustment of bone cuts or component positioning to achieve optimal alignment, enabling closed-loop control of the alignment process.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If no alignment checking capability is provided, then the surgical procedure is simpler, but the mechanical axis alignment varies, causing instability and imbalance

Engineering Contradiction:
Improvesurgical procedure simplicityVSAvoidknee joint stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The alignment device enables surgeons to perform self-verification of alignment during the procedure. The sensor system automatically measures and displays alignment parameters, allowing surgeons to check and adjust their work independently without requiring additional specialized equipment or complex measurement procedures.

Inventive Principle:
Principle #25Self-service

3Productivity

If alignment is not accurately controlled, then the surgery can proceed quickly, but the prosthesis may fail early due to improper alignment

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidprosthesis service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The alignment device allows surgeons to check and verify alignment parameters before finalizing bone cuts or securing components. By performing alignment verification in advance of final implantation, surgeons can make necessary adjustments to prevent early prosthesis failure without delaying the overall surgical timeline.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3383284B1Alignment device
Publication Date: 2020.10.28 AGARWAL SANJEEV
  • EP3383284B1 patent drawingFigure 1
  • EP3383284B1 patent drawingFigure 2
  • EP3383284B1 patent drawingFigure 3

AI summary

The present invention discloses an alignment device, system, and method of using the alignment device. The alignment device includes a femoral portion coupled to the femoral bone and a tibial portion mounted on the bone. A method for measuring alignment characteristics of a prosthetic knee joint arranged between a femur and tibia are disclosed. The method may include obtaining an alignment device. The alignment device may include a femoral portion, a tibial portion, and wherein at least one of the femoral portion and the tibial portion include at least one sensor. The method may also include coupling the alignment device to the femur and tibia and determining a first range of motion. The method may further include performing a knee replacement operation and determining a second range of motion.