Modular Adjustable Knee Spacer for Joint Infection Treatment

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Solution Overview

Problem

Current knee spacer devices are inflexible, difficult to adjust, and require extensive preparation, leading to challenges in maintaining joint space and antibiotic delivery during prosthesis removal and treatment, with existing solutions often involving toxic materials and inadequate coverage of the infection area.

Innovation Solution

A modular, adjustable knee spacer device with a tibial and femoral unit comprising fixable and adjustably fixable components, allowing for self-adjustment and easy implantation, using biologically compatible materials that can be additivated with antibiotics for targeted infection treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spacer devices are made of bone cement and customized extemporaneously, then the spacer can be adapted to the infection area, but the implantation time increases and toxic substances are involved

Engineering Contradiction:
Improveadaptation to infection areaVSAvoidimplantation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The spacer device is pre-formed with modular components before the surgical procedure, eliminating the need for extemporaneous customization. The pre-packaged modular system allows surgeons to select and assemble components during surgery without requiring time-consuming on-site fabrication, thus reducing implantation time while maintaining adaptability to the infection area.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spacer is divided into modular components (tibial component, femoral component, and interchangeable inserts) that can be pre-prepared and then assembled during surgery. This segmentation allows for rapid assembly of customized spacers without requiring extemporaneous fabrication, resolving the contradiction between adaptability and implantation time.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If pre-formed spacer devices are used, then implantation is simplified, but the devices cannot be adapted from patient to patient

Engineering Contradiction:
Improveimplantation simplicityVSAvoidpatient-specific adaptation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The spacer device employs a universal modular platform with standardized interfaces that can accommodate multiple insert sizes and configurations. This allows a single pre-formed device platform to serve multiple patient anatomies and infection scenarios, achieving both implantation simplicity and patient-specific adaptability through the ability to interchange components.

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

Solution Approach 2:

The device is segmented into standardized modular components that can be mixed and matched to create patient-specific configurations. The tibial component, femoral component, and various inserts are designed as separate interchangeable elements, allowing surgeons to assemble customized spacers from pre-formed components during surgery.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If a short spacer is placed where a long prosthesis was implanted, then implantation is simpler, but part of the bone is not treated with antibiotic

Engineering Contradiction:
Improveimplantation easeVSAvoidinfection treatment coverage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The spacer device incorporates adjustable and interchangeable components that allow the effective antibiotic treatment length to be dynamically adapted to match the original prosthesis length and the extent of infection. Surgeons can select from multiple insert lengths and configurations to ensure complete coverage of the infected bone segments, preventing untreated areas while maintaining ease of assembly.

Inventive Principle:
Principle #15Dynamics

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

Enables effective adjustment and quick, easy implantation of the spacer device, ensuring comprehensive antibiotic delivery and maintaining joint space, thereby preventing tissue atrophy and bacterial proliferation, while being adaptable to individual anatomical measurements.

Implementation Method 1

studies carried out in the field have revealed that the bone tissue absorbs in a concentrated manner all the (even a few) antibiotic molecules daily released by the spacer

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the antibiotic is released by the spacer in contact with or near the bone tissue, in which case the amount of antibiotic reaches locally the effective concentration

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3215065B1Improved adjustable modular spacer device for the articulation of the knee
Publication Date: 2020.02.12 COSSINGTON LTD
  • EP3215065B1 patent drawingFigure 1~2
  • EP3215065B1 patent drawingFigure 3
  • EP3215065B1 patent drawingFigure 4~12

AI summary

The present invention concerns a knee spacer device intended to be implanted temporarily at the joint area between the tibia and femur of a patient for replacing an infected joint prosthesis and for maintaining the size or spaces of the patient's joint area before implanting a new prosthesis, the spacer device comprising a tibial unit as well as a femoral unit.