Talar Dome Implant Geometry for Navicular and Calcaneus Fusion

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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 ankle fusion or amputation being the primary choices, and amputation being undesirable.

Innovation Solution

A talar dome prosthesis with a mounting surface featuring at least three non-co-planar flat bone-contacting surfaces and a guide instrument for precise reaming and cutting to simplify the preparation of the talus for implantation, reducing the number of required cuts from four to three.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If current total talar implants are used, then the implant can be attached to the talus bone, but fusion with the navicular and/or calcaneus is not allowed

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

Solution Approach 1:

The mounting surface is segmented into multiple non-co-planar flat bone-contacting surfaces, each capable of contacting different bone structures. This segmentation allows the single implant to interface with multiple bones (talus, navicular, calcaneus) simultaneously, enabling fusion capabilities without requiring multiple separate implants.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mounting surface is designed with at least three non-co-planar flat bone-contacting surfaces that can universally interface with different bone structures. This multi-functional design allows the same implant to serve multiple purposes: attaching to the talus bone and simultaneously enabling fusion with the navicular and/or calcaneus, thereby increasing adaptability without proportionally increasing complexity.

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

2Productivity

If traditional talus preparation methods are used, then the talus can be prepared for implantation, but the number of required cuts is high (four cuts)

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidnumber of cuts
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The guide instrument merges multiple cutting functions into a single integrated device. It simultaneously guides multiple cutting tools to create the necessary non-co-planar flat surfaces on the talus bone in one surgical step, reducing the number of separate cutting operations from four to three, thereby improving surgical efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide instrument is designed to pre-establish the precise geometry and orientation of the mounting surface before implant insertion. By incorporating guide pins, reamer guides, and cutting guides into a single pre-configured instrument, the necessary bone preparation is accomplished in advance with fewer steps, reducing the number of required cuts while ensuring proper alignment.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4104777B1Talar implant
Publication Date: 2026.04.08 WRIGHT MEDICAL TECHNOLOGY INC
  • EP4104777B1 patent drawingFigure 1A
  • EP4104777B1 patent drawingFigure 1B~1C
  • EP4104777B1 patent drawingFigure 2A

AI summary

Provided is a prosthesis for ankle arthroplasty including a talar dome component configured to be attached to a talus bone. Also provided is a guide instrument for guiding a reamer to prepare a talus to receive the talar dome component.