Total Talar Prosthesis With Removable Fusion Attachments

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Solution Overview

Problem

Current total talar implants do not allow for fusion with either the navicular and/or calcaneus, leaving limited options for patients with talar necrosis or subsidence, with amputation being undesirable and fusion being a preferred alternative.

Innovation Solution

A total talar replacement prosthesis with a metallic body shell and core, featuring removable attachments for the calcaneus and navicular bones, allowing direct bonding and fusion through a metallic cancellous matrix core, enhancing bone ingrowth or on-growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a total talar implant is used to replace the talus bone, then the patient avoids amputation, but the implant cannot fuse with the calcaneus and/or navicular bones

Engineering Contradiction:
Improvefusion capabilityVSAvoidattachment options
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The prosthesis is divided into separate functional components: a body shell, a removable calcaneus attachment, and a removable navicular attachment. This segmentation allows the implant to be customized for different fusion scenarios (calcaneus fusion, navicular fusion, or both) while maintaining structural integrity, thereby resolving the contradiction between fusion capability and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The calcaneus attachment and navicular attachment are designed as removable components rather than fixed structures. This dynamic design enables the implant to adapt to different surgical requirements and patient needs, allowing for flexible configuration of fusion options while maintaining reliable bone bonding through the metallic cancellous matrix core.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If fusion with calcaneus and/or navicular is enabled, then treatment options expand beyond amputation, but the implant structure becomes more complex

Engineering Contradiction:
Improvefusion optionsVSAvoidattachment structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis design incorporates universal attachment features that can be configured for multiple fusion scenarios (calcaneus fusion, navicular fusion, or both). The removable attachments with corresponding body shell features provide a multi-functional system that handles various surgical requirements through a single implant platform, reducing overall complexity compared to multiple specialized implants.

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

Solution Approach 2:

The metallic cancellous matrix core uses porous/porous-like structure to promote bone ingrowth and on-growth, enabling reliable fusion. This material approach simplifies the attachment structure by allowing direct bone bonding without complex mechanical fastening systems, thereby achieving fusion capability while maintaining structural simplicity.

Inventive Principle:
Principle #31Porous materials

3Reliability

If a metallic body shell with removable attachments is used, then fusion capability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvebone bondingVSAvoidprosthesis fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The prosthesis merges the body shell and attachments into an integrated design where the attachments are formed as continuous portions of the body shell. This merging approach simplifies manufacturing by reducing the number of separate components that need to be assembled, while maintaining the removable attachment functionality for fusion with calcaneus and/or navicular bones through the metallic cancellous matrix core.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables secure fusion of the prosthesis to both the calcaneus and navicular bones, providing a stable and effective alternative to amputation or incomplete fusion.

Implementation Method 1

the cancellous matrix structure can enhance bone ingrowth or on-growth to fuse the prosthesis to the calcaneus bone

Methodology Applied
Scientific EffectBone ingrowth:

Implementation Method 2

the cancellous matrix structure can enhance bone ingrowth or on-growth to fuse the prosthesis to the calcaneus bone

Methodology Applied
Scientific EffectBone on-growth:

Data Source

PatentEP4236879B1Talar implant
Publication Date: 2026.03.18 WRIGHT MEDICAL TECHNOLOGY INC
  • EP4236879B1 patent drawingFigure 1A~1B
  • EP4236879B1 patent drawingFigure 2A~2B
  • EP4236879B1 patent drawingFigure 3

AI summary

Provided is a total talar replacement prosthesis that has a metallic body shell and a metallic or biologic core, where the metallic body shell includes one or both of a removable calcaneus attachment and a removable navicular attachment. The attachments, when removed, exposes a respective calcaneus-facing surface or a navicular-facing surface that can enhance fusion to the respective bones, calcaneus and/or navicular.