Tiltable Pin Instrument for Joint Implant Fixation

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Solution Overview

Problem

Current instruments for inserting joint implants, such as the RM Pressfit socket, require multiple handles for different sizes, lack efficient hand-twist functionality, and are difficult to disassemble for cleaning and sterilization due to numerous small parts.

Innovation Solution

An instrument with a tiltable movable pin that can exert force on the joint implant's inner surface for secure fixation, featuring a support surface and connection to a handle via a shaft, allowing for optimal alignment and fixation without the need for multiple handles or complex disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple handles with grip heads are used for different implant sizes, then each implant size can be precisely accommodated, but the device complexity and number of parts increase

Engineering Contradiction:
Improveadaptability to different implant sizesVSAvoidnumber of handles and grip heads
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a single handle design that can accommodate multiple implant sizes through a universal gripping mechanism. The grip head is designed with adjustable or interchangeable elements that can secure different sized implants without requiring separate handles for each size, thus achieving multi-functionality while reducing the total number of components.

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

Solution Approach 2:

The patent employs nested or telescopic components within the handle structure that allow the grip head to adjust its dimensions to match different implant sizes. This nesting principle enables one handle to effectively become multiple handles by containing adjustable sub-components that can be configured for various implant diameters and lengths.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If the striking plate is turned by fingers, then the structure can be simple, but the operation reliability decreases due to possible slipping

Engineering Contradiction:
Improvesimplicity of turning mechanismVSAvoidreliability of hand twist operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the direct manual finger-turning mechanism with an improved gripping interface that provides better mechanical advantage. This substitution maintains structural simplicity while enhancing operational reliability by preventing slippage through optimized friction surfaces, gear mechanisms, or cam-based locking features that convert rotational motion more effectively.

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

3Manufacturing precision

If many small parts are used in the instrument, then the fixation mechanism can be precise, but the ease of cleaning and sterilization decreases

Engineering Contradiction:
Improveprecision of implant fixationVSAvoidease of disassembly for cleaning
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent combines multiple small parts into fewer integrated components without sacrificing fixation precision. By merging the gripping elements, centering mechanisms, and fixation components into unified structures, the design maintains the necessary precision for secure implant fixation while reducing the total number of parts that require disassembly for sterilization.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the instrument into modular components that can be easily separated for cleaning and sterilization. This segmentation allows the handle, grip head, and insertion mechanism to be detached as fewer larger units rather than many small parts, making the sterilization process more efficient while maintaining precise fixation capability through the modular interfaces.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If the movable pin is rotated radially, then the pin can be aligned parallel to the longitudinal axis, but the force generation in the direction of the bearing surface is insufficient

Engineering Contradiction:
Improvealignment precision of pinVSAvoidforce on bearing surface
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The patent employs an asymmetric pin design where the pin's cross-section or orientation is not radially symmetric. This asymmetry allows the pin to generate both alignment precision and sufficient force on the bearing surface simultaneously, as the asymmetric geometry creates mechanical advantage in the force generation direction while maintaining precise angular positioning capability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent transitions from purely radial pin movement to a mechanism that incorporates axial or longitudinal dimension changes. By adding movement or forcing capability in another dimension (not just radial rotation), the pin can simultaneously achieve precise alignment through radial positioning while generating adequate force through axial compression or lever arm mechanisms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3622921B1Instrument for inserting and a method for fixing an articulated implant to the instrument head
Publication Date: 2021.08.04 MATHYS AG BETTLACH
  • EP3622921B1 patent drawingFigure 1
  • EP3622921B1 patent drawingFigure 2
  • EP3622921B1 patent drawingFigure 3A~3B

AI summary

An instrument for inserting a joint implant (310) with an instrument head (300A) has at least one movable pin (330), wherein the movable pin (330) is tiltable.