Self-Cinching Soft Anchor for Knotless Bone Fixation

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Solution Overview

Problem

Current soft suture anchors rely on friction to bunch up inside a drilled hole in the bone, which is not knotless and may not provide sufficient fixation, as they require pulling back through the hole for anchoring, limiting their ability to be inserted at a desired level without additional methods for increased fixation.

Innovation Solution

The development of soft suture-based anchors with sliding, tying flexible strands that compress the anchor body for fixation within the bone hole/socket, allowing for knotless insertion and increased final fixation, using materials like ultrahigh molecular weight polyethylene (UHMWPE) sutures and additional sutures to maintain the anchor at the desired position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the soft suture anchor is pulled back through the drilled hole/socket to achieve fixation, then the anchor bunches up and achieves fixation through friction, but the procedure is not knotless and requires additional manipulation

Engineering Contradiction:
Improvefixation reliabilityVSAvoidinsertion simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sliding strand is threaded through the anchor body and can be pulled to automatically compress and bunch up the anchor within the bone hole, eliminating the need for external manipulation or knotting. The anchor self-compresses through the simple action of pulling the sliding strand, achieving reliable fixation through friction while maintaining procedural simplicity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The anchor system is divided into the anchor body and a separate sliding strand component. This segmentation allows the sliding strand to independently compress the anchor body within the bone hole, enabling knotless fixation while maintaining ease of operation through separate functional elements working together

Inventive Principle:
Principle #1Segmentation

2Reliability

If the anchor is compressed to increase fixation within the bone hole/socket, then the anchoring reliability improves, but the anchor length decreases limiting insertion flexibility

Engineering Contradiction:
Improvefixation reliabilityVSAvoidanchor length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The anchor transitions from an uncompressed elongated state during insertion to a compressed compact state for fixation. The sliding strand mechanism enables dynamic compression of the anchor body within the bone hole, allowing the anchor to adapt its length - long during insertion for reachability, then compressed for secure fixation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sliding strand is threaded through the anchor body, creating a nested configuration where the strand passes through the anchor material. This nesting allows the sliding strand to effectively compress the anchor from within, enabling reliable fixation while maintaining insertion flexibility through the nested structural arrangement

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If friction is used to bunch up the anchor inside the drilled hole, then fixation is achieved, but the fixation strength may be insufficient without additional compression

Engineering Contradiction:
Improvefixation reliabilityVSAvoidfixation strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sliding strand is pre-threaded through the anchor body during manufacturing, preparing the anchor for compression upon deployment. This preliminary arrangement of the sliding strand through the anchor material enables immediate compression and enhanced fixation strength when the sliding strand is pulled during the surgical procedure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The anchor's physical state changes from uncompressed to compressed through the action of the sliding strand. This parameter change in compression increases the friction between the anchor and bone hole walls, transforming the fixation mechanism from relying solely on insertion friction to enhanced friction through controlled compression, thereby increasing fixation strength

Inventive Principle:
Principle #35Parameter changes

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 efficient and secure knotless fixation of soft tissue to bone by compressing the anchor within the bone hole/socket, providing a stable construct for tissue repair with reduced length and maintaining the sliding sutures for further manipulation, enhancing the anchoring process.

Implementation Method 1

The friction between the soft suture anchor and the hole/socket bunches up the anchor when pulled back through the hole/socket

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2698128B1Self-cinching soft anchors
Publication Date: 2017.07.19 ARTHREX INC
  • EP2698128B1 patent drawingFigure 1~5
  • EP2698128B1 patent drawingFigure 6~10

AI summary

A suture construct for soft tissue to bone repairs. The suture construct is a soft anchor (100) which is self-cinching and has the ability to compress from a first, extended, uncompressed position to a second, folded or compressed position. The soft anchor may have a tubular/sleeve/sheath shape and may be formed essentially of a flexible, soft material such as suture, for example, a loosely braided sheath (10) having a tubular configuration.