Knitted Ligament Prosthesis Tissue Ingrowth

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Solution Overview

Problem

Conventional prosthetic devices for ligament reconstruction, such as ACL reconstruction, face issues with poor healing capabilities, morbidity at the autograft site, bone erosion, chronic inflammation, and device failure due to loosening and degradation, leading to instability and dysfunction in the knee joint.

Innovation Solution

A knitted prosthetic device with multiple bundles of fibers made from silk, designed to mimic the natural structure of ligament tissue, allowing for tissue ingrowth, flexibility, and even load distribution, which is compatible with conventional anchoring systems and minimizes abrasion at bone tunnel apertures, using a bioresorbable material to support the knee until new tissue growth is established.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If autograft is used for ACL reconstruction, then the ligament can be replaced with patient's own tissue, but morbidity occurs at the second surgery site and requires long rehabilitation

Engineering Contradiction:
Improvehealing capabilityVSAvoidmorbidity at autograft site
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The prosthetic device is divided into multiple sections: knitted intra-osseous sections for bone anchoring and a non-knitted intra-articular section for ligament function. This segmentation allows each part to serve its specific function optimally while avoiding the need for autograft harvesting

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The prosthetic device acts as an intermediary between the bone tunnels, providing a scaffold that mimics natural ligament structure and function without requiring living tissue from another site, thus avoiding donor site morbidity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If conventional fixation devices are used, then the graft can be anchored to bone, but bone erosion and degradation occur around the implant site leading to device loosening

Engineering Contradiction:
Improveanchoring strengthVSAvoidbone erosion
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The knitted sections of the prosthetic device have a porous, interwoven structure that allows bone tissue to grow through and around the material, creating a biological anchor that prevents bone erosion and device loosening while maintaining strong anchoring

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The device transitions from a rigid conventional fixation approach to a flexible knitted structure that can adapt to bone remodeling over time, changing its mechanical properties to maintain anchoring strength while reducing stress on surrounding bone

Inventive Principle:
Principle #35Parameter changes

3Strength

If the graft is made from strong material, then sufficient strength is provided, but the bone tunnel size must be larger affecting flexibility

Engineering Contradiction:
Improvegraft strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The knitted sections are constructed as flexible fabric structures that can be woven through bone tunnels of various sizes while maintaining adequate strength through the interwoven pattern, allowing adaptation to different anatomical configurations

Inventive Principle:
Principle #30Flexible shells and thin films

4Loss of time

If synthetic grafts are used, then surgery time is reduced and no additional trauma occurs, but poor healing capabilities and device failure due to loosening occur

Engineering Contradiction:
Improvesurgery timeVSAvoidhealing capability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The knitted structure creates a porous scaffold that facilitates bone in-growth and tissue integration, providing synthetic material that actively promotes healing rather than merely resisting it, while still allowing for reduced surgery time compared to autograft preparation

Inventive Principle:
Principle #31Porous materials

Data Source

PatentEP2139430B1Tendon prosthesis and method of manufacturing the same
Publication Date: 2019.06.05 ALLERGAN INC
  • EP2139430B1 patent drawingFigure 1~3A
  • EP2139430B1 patent drawingFigure 3B~3C
  • EP2139430B1 patent drawingFigure 4~5B

AI summary

A knitted ligament prosthesis (100) has at least two knitted sections (112, 114), where each knitted section has at least one row of fiber. The knitted prosthetic device also has at least one intra- articular section (122) disposed between the at least two knitted sections. In addition, the at least one mtra-articular section has at least one single continuous fiber traversing the at least one mtra-articular section and the at least two knitted sections, where the at least one single continuous fiber forms a plurality of traverses extending between the at least two knitted sections.