Rotatable Metaglene Assembly for Bone Stock Conservation

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Solution Overview

Problem

Current treatments for rotator cuff deficient shoulders with glenoid erosion or defects often require sacrificing healthy bone stock, may involve complications with bone grafts, and necessitate a two-stage surgical approach, which is invasive and inconvenient for patients.

Innovation Solution

A shoulder prosthesis kit featuring metaglene components with adjustable fasteners and augment designs that allow for customizable fit and attachment to the glenoid, enabling conservation of healthy bone stock and potentially eliminating the need for bone grafts, while allowing for single-stage restoration of shoulder joint function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If asymmetric bone preparation is performed to create support for metaglene component, then proper support surface is created, but healthy bone stock is sacrificed

Engineering Contradiction:

Improvesupport surfaceVSAvoidbone stock

Core Design Contradiction:

Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The metaglene component is divided into modular segments including the metaglene body, augment portions, and bearing component that can be selectively assembled. This segmentation allows the surgeon to use only the necessary portions to restore the glenoid surface without removing additional healthy bone, as the modular design can adapt to various defect configurations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of removing bone to create support (traditional approach), the invention adds support through the augment portion that extends into the glenoid cavity. This inverted approach builds up the deficient area rather than cutting into healthy bone, thereby preserving bone stock while achieving proper support for the bearing component.

Inventive Principle:

Principle #13The other way round (Inversion)

2Stability of the object's composition

If bone graft is used to fill eroded areas, then adequate support is provided, but complications from graft non-union may occur

Engineering Contradiction:

Improvesupport surfaceVSAvoidgraft union

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The augment portion serves as an intermediary structure between the eroded glenoid bone and the metaglene bearing component. This intermediary provides immediate structural support and load distribution without relying on biological graft union, thereby eliminating the risk of graft non-union while still filling and supporting the deficient glenoid area.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The augment portion is designed to be self-supporting with features such as porous structure or coating that allow direct osseointegration with the host bone, eliminating the need for separate bone graft material. The structure serves its own function of providing support and integration without requiring additional biological materials that might fail to union.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If interposition shoulder arthroplasty is performed, then pain is eased and joint function is retained, but it is only a temporary solution requiring follow-up surgery

Engineering Contradiction:

Improvejoint functionVSAvoidtime to definitive treatment

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The invention merges the bone support function (augment portion) and the joint articulation function (bearing component with glenosphere) into a single integrated metaglene assembly. This combination allows simultaneous correction of glenoid defects and restoration of joint function in one procedure, eliminating the need for separate interposition arthroplasty followed by definitive reconstruction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The metaglene component is designed with multi-functionality: the augment portion provides structural support and defect reconstruction, while the bearing component with glenosphere provides joint articulation. This universal design addresses both the structural deficiency and functional requirement in a single implant, making the procedure definitive rather than temporary.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If two-stage surgical approach is used for shoulder reconstruction, then comprehensive treatment is achieved, but patient risk and inconvenience increase

Engineering Contradiction:

Improvetreatment comprehensivenessVSAvoidsurgical risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention combines multiple treatment functions into a single surgical procedure: defect assessment, augment placement for structural support, and bearing component implantation for joint function. This merging of previously separate surgical stages into one procedure maintains comprehensive treatment while reducing surgical risk and patient inconvenience associated with multiple operations.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3005987B1Rotatable reverse metaglene assembly

Publication Date: 2017.07.19 DEPUY SYNTHES PROD INC

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AI summary

A metaglene assembly for use in a shoulder prosthesis includes a metaglene body, an augment, a void, at least one fastener hole, and at least one fastener. The metaglene body has a lateral, prosthesis-facing side, and a medial, bone-facing side. The augment extends medially from the medial, bone-facing side of the metaglene body. The void is defined by a portion of the medial, bone-facing side of the metaglene body and a lateral portion of the augment. The fastener hole extends from the void through the augment. The fastener is configured to extend within the fastener hole.