Modular Knee Prosthesis Segmentation for Minimally Invasive Assembly

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Solution Overview

Problem

Conventional knee prostheses require large incisions for implantation, causing significant tissue damage and prolonged recovery, as they are typically single-piece metal components that cannot be accommodated through smaller openings.

Innovation Solution

A modular knee prosthesis system comprising multiple pieces for the femoral and tibial components, which can be assembled post-insertion using locking mechanisms, allowing for minimally invasive surgery through small incisions, with optional single-piece or monoblock constructions for the tibial component and a standard dome configuration patellar component for insertion without eversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a single-piece metal prosthesis is used, then the structural strength and integrity are improved, but the incision size required for implantation increases

Engineering Contradiction:

Improvestructural strengthVSAvoidincision size

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The femoral component is divided into multiple separate pieces (distal femoral component and condylar components) that can be inserted through small incisions and then assembled together inside the knee joint using locking mechanisms, resolving the contradiction between needing structural strength and minimizing incision size

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If a single-piece metal prosthesis is used, then the manufacturing simplicity is improved, but the tissue damage from large incisions increases

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidtissue damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The prosthesis is segmented into multiple components that can be manufactured separately and assembled post-insertion, allowing minimally invasive surgery with small incisions thereby reducing tissue damage while maintaining manufacturing feasibility

Inventive Principle:

Principle #1Segmentation

3Length of moving object

If modular components are used, then the incision size is reduced, but the device complexity increases

Engineering Contradiction:

Improveincision sizeVSAvoiddevice complexity

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The femoral component is divided into multiple pieces with locking joints that assemble after insertion, enabling small incisions but increasing device complexity through multiple components and assembly mechanisms

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple separate components (distal femoral component, condylar components) are designed to lock together and function as a unified prosthesis, merging their functions while maintaining the benefits of modular insertion through small incisions

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8092546B2Knee arthroplasty prosthesis

Publication Date: 2012.01.10 ZIMMER INC

AI summary

A knee arthroplasty prosthesis includes a femoral component having multiple pieces with engagement means provided for engaging various pieces of the femoral component to one another following their insertion in the incised area of the femur. A tibial component includes multiple pieces designed for assembly following positioning in the incision. The tibial component includes a Morse taper cavity on one piece of the tibial component and a Morse taper extension on another member of the component for receipt therein.