Modular Reverse Shoulder Prosthesis Stem Metaphysis Conversion

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Solution Overview

Problem

Current shoulder prostheses face challenges in accommodating varying patient anatomies, particularly in transitioning from anatomic to reverse configurations, due to fixed stem orientations and the need for multiple monoblock stems, which increases surgical complexity and inventory costs.

Innovation Solution

A modular reverse shoulder prosthesis with a stem and metaphysis that allows for rotational adjustment about a metaphyseal axis, enabling attachment at any position within 360 degrees, and a reverse insert with rotational symmetry for secure locking, facilitating conversion from anatomic to reverse configurations without removing the stem from the bone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple monoblock stems with different neck angles are provided, then adaptability to varying patient anatomies is improved, but device complexity and inventory requirements worsen

Engineering Contradiction:

Improveadaptability to varying patient anatomiesVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis is divided into separate modular components: a stem component and a metaphysis component with different neck angles. The metaphysis component can be independently selected and attached to the stem, allowing customization without requiring multiple complete stem assemblies. This segmentation enables adaptability while reducing overall device complexity and inventory requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stem component is designed as a universal base that can accommodate multiple metaphysis components with different neck angles (125, 130, 135, 140 degrees). This multi-functional design allows a single stem to serve multiple anatomical configurations, improving adaptability while reducing the need for multiple specialized stems in inventory.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple monoblock stems with different neck angles are provided, then adaptability to varying patient anatomies is improved, but inventory requirements worsen

Engineering Contradiction:

Improveadaptability to varying patient anatomiesVSAvoidinventory requirements

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

By segmenting the prosthesis into a common stem and interchangeable metaphysis components with different neck angles, the inventory requirement shifts from storing multiple complete stem assemblies to storing only the specific metaphysis components needed. This significantly reduces the quantity of materials and components that must be maintained in surgical inventory.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The universal stem component can be paired with any of the standardized metaphysis components, creating a flexible inventory system where a small set of metaphysis pieces can serve multiple surgical scenarios. This multi-functionality reduces inventory burden while maintaining adaptability to various patient anatomies.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple trial implants are performed to determine the correct neck angle, then measurement precision is improved, but loss of time increases

Engineering Contradiction:

Improvemeasurement precisionVSAvoidsurgical time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The correct metaphysis component with the appropriate neck angle can be selected and attached to the stem before final implantation. This preliminary attachment allows for accurate pre-operative planning and reduces the need for multiple trial implants during surgery, thereby maintaining measurement precision while significantly reducing surgical time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The modular design allows for dynamic adjustment and selection of the metaphysis component based on pre-operative measurements and patient anatomy. This dynamic selection process enables precise customization without requiring multiple trial implants, as the correct component can be identified and attached in advance.

Inventive Principle:

Principle #15Dynamics

4Measurement precision

If stem trialing involves insertion and removal of parts, then measurement precision is improved, but reliability of final implant fit worsens

Engineering Contradiction:

Improvemeasurement precisionVSAvoidreliability of final implant fit

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The metaphysis component can be attached to the stem in a preliminary step before final implantation, allowing for accurate measurement and verification of fit. This preliminary attachment ensures that the selected component is correct, thereby maintaining measurement precision while avoiding the need for repeated insertion and removal that could compromise the final implant fit.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20230270564A1Systems and methods for shoulder prostheses

Publication Date: 2023.08.31 STRYKER EUROPEAN OPERATIONS LIMITED

AI summary

Provided is a method for converting a modular anatomic shoulder implant to a modular reverse shoulder implant, wherein the modular anatomic shoulder implant and the modular reverse shoulder implant have novel configurations.