Segmented Keel Prosthetic Stem for Anti-Rotational Stability

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Solution Overview

Problem

Prosthetic implant devices with stemmed components face challenges such as additional torque applied to the tibial component from the femoral component, difficulty in assembling accessory components, and inefficiency in using integrated keels due to interference with tapered connections, leading to unused accessory components and complex assembly processes.

Innovation Solution

The integration of a segmented keel with wings on the tibial component stem, which allows for a sleeve to be engaged closer to the tibial tray and facilitates a longer tapered connection, reducing the need for separate keel accessories and simplifying the assembly process by accommodating machining tools to form Morse tapers without interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate keel accessory is used to provide anti-rotational engagement, then rotational stability is improved, but device complexity and assembly difficulty increase

Engineering Contradiction:

Improverotational stabilityVSAvoidnumber of accessory components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The keel structure is merged with the stem by integrating the keel wings directly into the stem body. The segmented keel wings are formed as integral portions of the stem, eliminating the need for a separate keel accessory while maintaining anti-rotational engagement functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The stem is designed to serve multiple functions: it provides structural support, enables Morse taper connection for sleeve attachment, and incorporates integrated keel wings for anti-rotational engagement. This multi-functionality eliminates the need for separate specialized accessories.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a separate keel accessory is assembled to the stem, then anti-rotational engagement is achieved, but assembly time and surgical procedure complexity increase

Engineering Contradiction:

Improveanti-rotational engagementVSAvoidassembly time during surgery

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The keel wings are combined with the stem into a single integrated component. This eliminates the assembly step of attaching a separate keel accessory to the stem, reducing surgical procedure time and complexity while maintaining anti-rotational engagement.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a full-length keel accessory is used, then anti-rotational engagement is improved, but interference with Morse taper connection and sleeve attachment occurs

Engineering Contradiction:

Improveanti-rotational engagementVSAvoidsleeve attachment capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The keel is segmented into discrete keel wings that are positioned at specific locations on the stem. This segmentation allows the Morse taper connection and sleeve attachment to occur in regions not occupied by the keel wings, eliminating interference while maintaining anti-rotational engagement functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The keel wings are positioned at specific axial and radial locations on the stem, creating localized anti-rotational engagement features. This allows other regions of the stem to remain clear for Morse taper connection and sleeve attachment, enabling both functions to coexist without interference.

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If multiple accessory components (sleeve, cone, keel) are provided for different bone conditions, then adaptability is improved, but inventory complexity and reprocessing requirements increase

Engineering Contradiction:

Improvecompatibility with different bone matterVSAvoidnumber of accessory components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The stem with integrated segmented keel wings and Morse taper connection is designed to be universally applicable for different bone conditions. The integrated design eliminates the need for separate keel, sleeve, and cone accessories, reducing inventory complexity while maintaining adaptability through the versatile stem design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20240207062A1Segmented keel for prosthetic implant having a stem

Publication Date: 2024.06.27 ZIMMER INC

AI summary

A tibial implant comprises a tibial tray component comprising a tray plate with proximal and distal surfaces, a stem and a segmented keel extending from the distal surface, the segmented keel including a first wing having a first notch proximate the stem, and a first taper extending along the stem in a first axial position axially aligned with the segmented keel. A sleeve for a stem of a prosthetic implant comprises an annular body, an inner passage extending through the annular body, the inner passage comprising a Morse taper, and a first slot extending into the annular body to intersect the inner passage and the Morse taper. A method comprises fabricating a stemmed prosthetic component from a metallic material, advancing a machining tool into a notch in a keel wing extending from the stem, and forming a Morse taper on the stem with the machining tool in the notch.