Meniscal Repair Depth Penetration Limiter With Self-Stopping Retention

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Solution Overview

Problem

Current tissue repair devices lack features to prevent the inadvertent removal of the depth penetration limiter from the device housing, requiring manual reinsertion and complicating the surgical process due to high surface friction, necessitating a secondary operation to couple the limiter to the depth tube.

Innovation Solution

A depth penetration limiter with a built-in self-stopper feature, utilizing a cantilevered flexure that engages a recess in the housing to prevent distal movement and a connection feature with increased pull-off resistance to secure the depth tube, enhancing ease of use and reducing operational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sliding limiter is used to control penetration depth, then depth control is achieved, but the limiter can be inadvertently removed from the housing

Engineering Contradiction:
Improvepenetration depth controlVSAvoidlimiter retention
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The limiter assembly is designed with a self-retaining mechanism where the depth tube's distal end features an enlarged diameter that mechanically engages with the housing's internal geometry. This self-service design automatically prevents inadvertent removal without requiring additional active retention components, thereby maintaining depth control reliability while avoiding over-complication.

Inventive Principle:
Principle #25Self-service

2Reliability

If the limiter is coupled to the depth tube, then depth control is maintained, but high surface friction makes coupling difficult

Engineering Contradiction:
Improvelimiter-depth tube couplingVSAvoidcoupling operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The depth tube's distal end is designed with an enlarged diameter creating a curved, tapered surface that interfaces with the housing. This curvature allows the tube to be easily pushed into place during assembly, with the tapered geometry guiding alignment and reducing friction during the coupling operation, while still providing secure retention once assembled.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of operation

If the inner diameter of the depth tube is increased to facilitate coupling, then ease of assembly is improved, but pull-off resistance decreases

Engineering Contradiction:
Improveassembly easeVSAvoidpull-off resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The depth tube features a localized enlargement of the inner diameter specifically at the distal coupling region, while the rest of the tube maintains its original dimensions. This local quality change facilitates easy insertion and coupling during assembly, while the enlarged section's geometric interlocking with the housing provides sufficient pull-off resistance to prevent accidental separation during use.

Inventive Principle:
Principle #3Local quality

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 self-stopper feature and connection design prevent accidental disengagement of the limiter, simplifying surgical procedures by ensuring secure attachment and reducing the need for manual reinsertion, thereby improving operational efficiency.

Implementation Method 1

a cantilevered flexure on a bottom surface of the limiter that deflects as it is moved through the housing. As the flexure passes the edge of a recess in the housing, the flexure returns to its original shape, trapping the flexure within the recess

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4120924B1Depth penetration limiter for a tissue repair device
Publication Date: 2025.07.02 SMITH & NEPHEW INC
  • EP4120924B1 patent drawingFigure 1
  • EP4120924B1 patent drawingFigure 2A~2C
  • EP4120924B1 patent drawingFigure 3A

AI summary

Depth penetration limiters for use with meniscal repair devices which have a built-in, self-stopper feature to prevent the limiter from disengaging from the device housing. The self-stopper feature is a cantilevered flexure on a bottom surface of the limiter that deflects as it is moved through the housing. As the flexure passes the edge of a recess in the housing, the flexure returns to its original shape, trapping the flexure within the recess and preventing further distal movement of the limiter/depth tube. A connection feature on the limiter provides increased pull-off resistance of the depth tube from the limiter.