Side-Mounted Augments for Modular Knee Prosthesis Revision

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Solution Overview

Problem

Current prosthetic knee joint systems face challenges in revision surgeries due to the inability to disconnect distal femoral articulation components from augments without removing the entire assembly, making it difficult to address bone deficiencies and maintain joint alignment.

Innovation Solution

A modular knee prosthesis system that allows for the separation of distal femoral articulation components and augments before removal, utilizing a unique connector system with angled bores and recessed cement pockets for secure attachment and easy disassembly, enabling surgeons to revise the implant without disassembling the entire assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional screw or pin connection mechanisms are used to attach augments to distal femoral articulation components, then the augments can be securely attached to compensate for bone deficiencies, but the entire assembly cannot be disassembled without removing it from the bone during revision surgery

Engineering Contradiction:
Improveattachment strengthVSAvoidease of disassembly
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The connection mechanism is divided into separate segments: a connector component with external threading and a receptacle component with internal threading. This segmentation allows the connector to be detached from the receptacle independently, enabling disassembly of the augment from the distal femoral articulation component without removing the entire assembly from the bone during revision surgery.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector is designed to be extractable from the receptacle. The connector can be removed from the receptacle that is embedded in the distal femoral articulation component, allowing the augment to be disconnected and removed separately during revision procedures while leaving the distal femoral articulation component in place.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If augments are permanently fixed to distal femoral articulation components, then stable support is provided for bone deficiencies, but revision surgery becomes complex requiring removal of the entire assembly

Engineering Contradiction:
ImprovestabilityVSAvoidrevision surgery complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection system transitions from a static permanent fixation to a dynamic reversible connection. The threaded connector can be inserted to provide stable fixation when needed, and subsequently removed when revision is required, allowing the system to adapt between stable support and easy revision states without requiring complex revision procedures.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If conventional connection methods are used, then simple attachment is achieved, but the ability to selectively disconnect components for revision is lost

Engineering Contradiction:
Improveattachment simplicityVSAvoiddisconnection capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The connector-receptacle system serves multiple functions: it provides secure attachment during initial implantation, enables selective disconnection for revision surgery, and allows for potential reattachment or replacement of components. This multi-functionality maintains attachment simplicity while adding the versatility of selective disconnection that conventional methods lack.

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

Data Source

PatentEP2682073B1Knee prosthesis system with side-mounted augments
Publication Date: 2015.04.08 DEPUY (IRELAND) LTD
  • EP2682073B1 patent drawingFigure 1~2
  • EP2682073B1 patent drawingFigure 3~4
  • EP2682073B1 patent drawingFigure 5~7

AI summary

A modular knee prosthesis system comprises a distal femoral articulation component (10), a distal augment (60), a posterior augment (62) and a first connector (78) for securing at least one of the augments to the distal femoral articulation component through a bore (74) in the augment and an opening (57, 58, 59) in the distal femoral articulation component. The distal femoral articulation component has a distal bone-facing surface (26, 28), a posterior bone-facing surface (30, 32) and an opening. The openings into the bores of the augments are in the medial or lateral side surface of the augment. Both augments can be mounted and removed from the distal femoral articulation component from either the medial or lateral side.