Intra-Articular Needle Pressure Sensing for Effused Joint Placement

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Solution Overview

Problem

Current methods for confirming intra-articular needle placement, such as those relying on atmospheric pressure detection, are inadequate for osteoarthritis patients with effusions and positively pressured joints, leading to inefficacious injections and potential pain due to undiagnosed effusions, and lack of integration with existing clinical practices.

Innovation Solution

A device that detects both sub-atmospheric and supra-atmospheric pressures using a pressure transducer and algorithm to confirm synovial cavity needle placement, indicated by LED signals, allowing for single-use, low-cost integration with current practices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pressure detection algorithms solely dependent on sub-atmospheric pressure sensing are used, then the device is simple and low-cost, but it fails to detect intra-articular cavities in effused joints with supra-atmospheric pressure

Engineering Contradiction:
Improvealgorithm complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the pressure detection parameter from solely sub-atmospheric pressure to both sub-atmospheric and supra-atmospheric pressure ranges. The algorithm now detects pressure differentials in both directions relative to atmospheric pressure, enabling reliable detection in both non-effused (sub-atmospheric) and effused (supra-atmospheric) joints.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pressure detection device is designed to universally detect intra-articular cavities across multiple joint conditions. By detecting both negative and positive pressure differentials, the single device functions reliably for both non-effused and effused joints, eliminating the need for different detection methods for different patient populations.

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

2Measurement precision

If ultrasound and fluoroscopy guidance technologies are used to confirm proper needle placement, then injection accuracy is improved, but equipment costs and staff training requirements increase

Engineering Contradiction:
Improveneedle placement accuracyVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex imaging systems (ultrasound and fluoroscopy) with a simple pressure detection device. The mechanical pressure sensing system provides adequate needle placement confirmation without requiring expensive imaging equipment or specialized operator training, while maintaining sufficient accuracy for clinical practice.

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

Solution Approach 2:

The invention employs a disposable, low-cost pressure detection device that can be discarded after single use. This eliminates the need for expensive, reusable imaging equipment and reduces the need for extensive staff training, making the technology accessible to a broader range of clinical settings.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If viscosupplement injection is administered to effused knees without proper diagnosis, then treatment cost is saved, but patient pain increases due to adding fluid to already distended joints

Engineering Contradiction:
Improvefluid volume managementVSAvoidpatient pain
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary pressure assessment before viscosupplement injection to diagnose effusion status. By detecting supra-atmospheric pressure that indicates effusion, the device enables clinicians to identify patients who require fluid removal before injection, preventing the harmful effect of adding fluid to already distended joints.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pressure detection device provides real-time feedback on intra-articular pressure status. This feedback mechanism allows clinicians to adjust their treatment plan based on the detected pressure, preventing inappropriate injection into effused joints and thereby avoiding increased patient pain.

Inventive Principle:
Principle #23Feedback

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

The device reliably confirms synovial cavity needle placement, reduces nosocomial infection risk, and supports effusion diagnosis, enhancing injection efficacy and safety across various joint conditions.

Implementation Method 1

A device that detects both sub-atmospheric and supra-atmospheric pressures using a pressure transducer

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP4076601B1Intra-articular needle placement device and method of using
Publication Date: 2026.01.07 AVANOS MEDICAL SALES LLC
  • EP4076601B1 patent drawingFigure 1
  • EP4076601B1 patent drawingFigure 2
  • EP4076601B1 patent drawingFigure 3

AI summary

The present invention relates to a device for measuring, recording, and acting in response to changes in air pressures encountered through the lumen of a connected needle. The device signals when it has been powered and signals when the device recognizes both pressures and pressure change rates indicative of intra-articular or synovial cavity joint penetration, such as knee joint penetration. Synovial cavity pressures detected and acted upon may either be supra- (positive) or sub-atmospheric (negative). Internal light emitting diodes and a laptop connected display are demonstrated as signaling and communication mechanisms. Methods for delivering medicaments into human and animal intra-articular cavities or joints such as synovial cavities are provided. Furthermore, methods for facilitating the diagnoses of joint effusion also are provided.