Shoulder Prosthesis Glenoid Component Lateralization via Bone Graft

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Solution Overview

Problem

Inverted or anatomical shoulder prostheses often experience interference between the humeral and scapular components during adduction movements, leading to pain and potential dislocation due to the medialized position of the glenoid component, which limits the range of motion and causes osteolysis.

Innovation Solution

A surgical method involving the use of a bone graft to lateralize the glenoid component relative to the scapula, where the graft is placed between the glenoid component and the scapula, anchoring the glenoid component securely and altering its position to reduce interference and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the glenoid component is implanted in a medialized position (directly on the glenoid surface), then the surgical procedure is simple and the prosthesis structure is straightforward, but interference occurs between the humeral and scapular components during adduction movements, limiting range of motion and causing pain

Engineering Contradiction:

Improvesimplicity of surgical procedureVSAvoidinterference between humeral and scapular components

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A bone graft acts as an intermediary element positioned between the glenoid component and the native glenoid surface. This graft serves as a mediator that laterally offsets the glenoid component, creating necessary clearance to prevent interference with the humeral component during adduction movements while maintaining a relatively simple surgical procedure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution introduces a lateral dimension offset by positioning the bone graft and glenoid component laterally relative to the native glenoid surface. This dimensional change in the mediolateral plane creates the necessary clearance zone without complicating the anterior-posterior or superior-inferior positioning

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the glenoid component is positioned medially (on the native glenoid surface), then the prosthesis configuration is simple and uses existing inverted prosthesis designs, but the lower portion of the humeral prosthetic part strikes the scapula pillar, limiting adduction range of motion

Engineering Contradiction:

Improveprosthetic configuration complexityVSAvoidrange of adduction movement

Core Design Contradiction:

Device complexityVSLength of moving object

Solution Approach 1:

The bone graft functions as a mediator that laterally displaces the glenoid component, creating clearance between the humeral component and scapula pillar. This intermediary structure enables greater adduction range of motion while maintaining the simplicity of using existing inverted prosthesis designs without requiring complex custom configurations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bone graft is prepared and positioned in advance during the surgical procedure, creating the lateral offset structure before the glenoid component is implanted. This preliminary action of graft placement establishes the necessary geometric relationship to prevent impingement and maximize range of motion

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If the glenoid component is implanted directly on the glenoid surface, then the implantation procedure is straightforward, but osteolysis of the scapula may occur and the prosthesis may become dislodged

Engineering Contradiction:

Improveease of implantation procedureVSAvoidprosthesis stability and prevention of osteolysis

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The bone graft serves as an intermediary layer between the glenoid component and the native glenoid surface, distributing mechanical loads and reducing stress concentration on the scapular bone. This intermediary structure enhances prosthesis stability and prevents osteolysis while maintaining a straightforward implantation procedure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bone graft alters the mechanical parameters of the interface between the prosthesis and scapula, changing the stress distribution pattern and reducing peak stresses that would otherwise lead to osteolysis. This parameter change improves reliability without complicating the implantation procedure

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11185417B2Method and apparatus for fitting a shoulder prosthesis

Publication Date: 2021.11.30 TORNIER SA SAINT ISMIER

AI summary

Method and set of surgical instruments for fitting a shoulder prosthesis, and the shoulder prosthesis. The proposed method seeks to interpose a bone graft between the previously prepared glenoid surface (G) of a scapula (S) of a patient's shoulder and the face of a glenoid prosthetic component opposite the articular surface. The set of instruments permit the bone graft to be taken from the upper epiphysis of the humerus (H), either in situ or ex vivo.