Cement Restrictor Inserter with Depth Guide

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Solution Overview

Problem

Current surgical instruments lack a reliable method to accurately position cement restrictors during orthopaedic procedures, as the correct placement is obscured and existing depth guides are difficult to visualize and interpret, especially for complex implant systems with varying sizes.

Innovation Solution

A cement restrictor inserter instrument with a handle, shaft, and body shaped to match orthopaedic implants, featuring a visible depth guide and releasable attachment mechanism, allowing precise alignment with bone features to ensure correct cement restrictor placement, using spacers to position the depth guide feature at a fixed position relative to the inserter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If markings are provided on the inserter to guide cement restrictor depth, then depth guidance is provided, but the markings are difficult to see and read during surgery

Engineering Contradiction:
Improvedepth guidanceVSAvoidvisibility of markings
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent applies high-contrast color markings (such as black markings on a white background or fluorescent colors) on the inserter shaft to enhance visibility during surgery. The color contrast principle makes the depth markings easily visible under surgical lighting conditions, directly resolving the visibility problem while maintaining measurement precision.

Inventive Principle:
Principle #32Color changes

2Adaptability or versatility

If multiple markings are provided for different implant sizes, then guidance for various implants is available, but it becomes difficult for the surgeon to recall which marking to use

Engineering Contradiction:
Improveguidance for different implant sizesVSAvoidease of selecting correct marking
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies different visual characteristics (such as different colors, patterns, or spacing) to markings corresponding to different implant sizes. Each marking is locally differentiated with unique visual properties that make it easily distinguishable, allowing surgeons to quickly identify and select the correct marking for their specific implant without confusion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The markings on the inserter are designed to correspond to and copy the sizing system used by the prosthetic implant manufacturer. This creates a direct visual link between the implant size designations and the inserter markings, making it intuitive for surgeons to select the correct marking based on their implant size selection.

Inventive Principle:
Principle #26Copying

3Reliability

If the cement restrictor is inserted to ensure proper cement distribution, then good implant fixation is achieved, but excess cement may complicate revision surgery

Engineering Contradiction:
Improveimplant fixationVSAvoidexcess cement
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces reliance on surgeon memory and estimation with a mechanical depth stopping system. The inserter includes a depth stop or limiting feature that mechanically prevents insertion beyond the target depth, ensuring consistent and accurate cement restrictor positioning that achieves proper implant fixation while preventing excess cement placement.

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

4Manufacturing precision

If the correct cement restrictor position is achieved, then proper cement amount is ensured, but the position is hard to visualise during insertion

Engineering Contradiction:
Improvecement restrictor positioningVSAvoidvisualisation of position
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent incorporates high-visibility visual indicators such as colored bands, fluorescent markings, or contrasting color patterns on the inserter shaft that make the cement restrictor position easily detectable during insertion. These visual cues allow surgeons to accurately determine insertion depth without difficulty, achieving precise positioning while maintaining ease of detection.

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP4081143B1Surgical instruments
Publication Date: 2024.10.09 DEPUY (IRELAND) LTD
  • EP4081143B1 patent drawingFigure 1
  • EP4081143B1 patent drawingFigure 2
  • EP4081143B1 patent drawingFigure 3

AI summary

A cement restrictor inserter instrument (130) comprises an inserter (131) having a handle (132) at a proximal end, a cement restrictor attachment formation (137) at a distal end for releasably attaching a cement restrictor (150), a shaft (136) extending from the proximal end to the distal end and a stop (138) on the shaft and between the proximal end and the distal end; and a body (140) having a shape corresponding to the shape of an orthopaedic prosthetic implant, a spacer (142), a visible depth guide feature (190) and a releasable attachment mechanism by which the body is releasably attachable to the shaft, and wherein the spacer is configured to position the visible depth guide feature at a fixed position relative to the inserter when the spacer abuts the stop corresponding to a target cement restrictor position when the visible depth guide feature is aligned with a feature of a bone of a patient in which the cement restrictor is to be inserted.