Modular Knee Prosthesis Augments for Bone Loss

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Solution Overview

Problem

Current knee joint prostheses face challenges in providing adequate stability and accommodating bone loss during revision procedures, particularly in cases where existing prostheses need to be replaced due to damage or deterioration, and require customization to match individual patient needs.

Innovation Solution

The development of a modular knee joint prosthesis system that includes interchangeable tibial and femoral components, stems, adapters, and augments, allowing for various configurations such as crutiate retaining, posterior stabilized, fully constrained, and hinged knee prostheses, with adjustable offsets and Morse-type taper fits for secure attachment, enabling intra-operative selection to suit specific patient requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a modular prosthesis system with multiple components is used, then adaptability and versatility are improved, but device complexity increases

Engineering Contradiction:
ImproveadaptabilityVSAvoidcomplexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis system is divided into multiple modular components including femoral components, tibial components, stems, adapters, and augments. Each component can be independently selected and combined to match specific patient needs, allowing customization while managing complexity through standardized interfaces and modular architecture.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If customized configurations are selected intra-operatively, then adaptability is improved, but loss of time occurs

Engineering Contradiction:
ImproveadaptabilityVSAvoidtime
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

Multiple pre-designed component variants with different geometries, offsets, and configurations are prepared in advance as part of the modular system. Surgeons can select from pre-engineered options during surgery rather than customizing components intra-operatively, reducing decision time while maintaining adaptability to patient-specific requirements.

Inventive Principle:
Principle #10Preliminary action

3Strength

If Morse-type taper fits are used for attachment, then strength is improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovestrengthVSAvoidprecision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The Morse-type taper interface utilizes specific geometric parameters including taper angle, diameter ratios, and surface finish specifications to achieve both high connection strength and manufacturing feasibility. The standardized taper dimensions balance the need for strong mechanical attachment with practical manufacturing tolerances.

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

This modular system provides enhanced stability and adaptability, allowing surgeons to customize knee joint prostheses during procedures to address bone loss and individual patient needs, ensuring optimal fit and function while minimizing bone removal.

Implementation Method 1

Morse-type taper fits for secure attachment

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The female tapered receiving portion can cooperatively engage the male tapered insertion portion by way of a Morse-type taper fit

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2104474B1Knee joint prosthesis system
Publication Date: 2012.08.29 BIOMET MFG LLC
  • EP2104474B1 patent drawingFigure 1
  • EP2104474B1 patent drawingFigure 2
  • EP2104474B1 patent drawingFigure 3A~3B

AI summary

A modular knee prosthesis can include a femoral component (112) haying a superiorly extending portion (130), a first femoral bearing surface (114) and a second femoral bearing surface (116). The superiorly extending portion can define a first tapered augment receiving surface (132). A tibial component (12) can have an interiorly extending portion (28) and a tibial bearing surface. The interiorly extending portion can define a second tapered augment receiving surface (30). A first augment (400) can define a first receiving bore and a first stepped surface. A second augment (402) can define a second receiving bore and a second stepped surface. The first and second augments are adapted to mate at the first and second stepped surfaces in a first portion at the first tapered augment receiving surface of the femoral component and in a second position at the second tapered augment receiving surface of the tibial component.