Modular Knee Prosthesis Alignment System 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 simulating natural knee motion and managing forces across the joint line.

Innovation Solution

A system comprising a frame with attachment portions, an alignment member, a bushing, and a block, along with a posterior stabilized (PS) box guide assembly, which cooperate with an intramedullary (IM) member to position and align components accurately, allowing for modular adapters and augments to adjust the prosthesis' alignment and offset, thereby enhancing stability and accommodating bone loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a revision knee prosthesis is designed to provide adequate stability by eliminating cruciate ligament functions, then joint stability is improved, but the ability to simulate natural knee motion is reduced

Engineering Contradiction:
Improvejoint stabilityVSAvoidnatural knee motion simulation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The prosthesis design allows dynamic adaptation between different motion constraints. The system can transition between CR, PS, and hinged configurations based on the patient's specific needs and remaining ligament function, enabling the joint to adapt its degree of freedom dynamically rather than being fixed in one configuration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the constraint parameters of the prosthesis based on bone loss severity and ligament condition. By adjusting parameters such as the degree of motion restriction and the position of the joint line, the system optimizes both stability and natural motion simulation for each specific revision case

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If modular adapters and augments are added to accommodate bone loss and adjust alignment, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvealignment adjustment capabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The modular components including adapters and augments are designed with universal interfaces that can be combined in multiple configurations. A single set of modular components can address various bone loss scenarios and alignment requirements, reducing the need for multiple specialized components and thereby managing complexity while maintaining high adaptability

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

3Manufacturing precision

If precise alignment tools and multiple guides are used during preparation, then manufacturing precision is improved, but device complexity and surgical time increase

Engineering Contradiction:
Improvealignment precisionVSAvoidnumber of alignment tools
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment system merges multiple alignment functions into integrated guide structures. The guides combine alignment reference, cutting guidance, and component positioning functions in single structures, reducing the number of separate tools needed while maintaining precise alignment capability throughout the preparation process

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2222249B1Knee joint prosthesis system
Publication Date: 2012.08.29 BIOMET MFG LLC
  • EP2222249B1 patent drawingFigure 1
  • EP2222249B1 patent drawingFigure 2
  • EP2222249B1 patent drawingFigure 3A~3B

AI summary

A system for cooperating with an elongated IM member during preparation of a bone for receiving a prosthesis can include a scaffold, skeleton or frame (1362). An alignment assembly (1364) can be selectively coupled to the frame. The alignment assembly can cooperate with the IM member to position the frame relative to the bone. A cutting block (1366) can be selectively coupled to the frame. According to other features, a posterior stabilized (PS) box guide assembly (1470) can have a PS box guide attachment portion that selectively couples with the first attachment portion of the frame. A posterior foot (1470) can selectively couple with a second attachment portion on the frame. The posterior foot can be positioned to occupy space of a joint line in an installed position.