Tibial Insert Post and Recess for Mobile Bearing Conversion

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Solution Overview

Problem

Current orthopedic procedures for knee arthroplasty require complex surgical interventions to convert between fixed and mobile bearing knee prostheses, and existing systems necessitate removal of tibial baseplates and inserts for bearing replacement or design changes, increasing surgical complexity and procedural time.

Innovation Solution

A system comprising a tibial baseplate and an insert with a rotation post that allows the bearing to pivot, enabling conversion between fixed and mobile bearing configurations without removing the tibial baseplate, and allowing multiple bearings with different designs to be substituted without removing the insert or baseplate, using connection mechanisms such as dovetail bosses and peripheral rails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed bearing knee prosthesis is converted to a mobile bearing prosthesis using existing systems, then the bearing configuration can be changed, but the tibial baseplate and insert must be removed, increasing surgical complexity and procedural time

Engineering Contradiction:
Improvebearing configuration conversionVSAvoidsurgical procedure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The prosthesis is divided into separable components: the tibial baseplate remains implanted while the insert and bearing can be independently removed and replaced. The insert includes a specific connection mechanism with a recess that receives a post from the bearing, allowing modular assembly and disassembly without removing the baseplate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tibial baseplate with its connection mechanism serves multiple functions: it provides structural support, anchors the insert, and enables both fixed and mobile bearing configurations through the same interface. The connection mechanism with recess and post design allows universal compatibility across different bearing types.

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

2Ease of repair

If bearings are replaced in existing knee prostheses, then wear damage can be addressed, but the insert and tibial baseplate must be removed, increasing surgical time and complexity

Engineering Contradiction:
Improvebearing replacementVSAvoidsurgical procedural time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The bearing and insert are designed as separable modular components. The bearing can be independently removed from the insert by disengaging the connection mechanism, allowing bearing replacement without disturbing the implanted tibial baseplate or requiring removal of the insert.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection mechanism with recess and post is pre-configured to enable tool-free or minimal-tool bearing removal. The design anticipates future bearing replacement needs by providing an inherently removable interface rather than a permanent fixed connection.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If different bearing designs are used with the same femoral component, then patient needs can be accommodated, but multiple insert and baseplate sets are required, increasing inventory complexity

Engineering Contradiction:
Improvebearing design compatibilityVSAvoidinventory management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single tibial baseplate design with the standardized connection mechanism can accommodate multiple different bearing designs and configurations. The universal recess-post interface allows different bearing geometries, materials, and mobility characteristics to be used with the same baseplate and insert, eliminating the need for multiple baseplate variants.

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

Data Source

PatentEP3551136B1Tibial insert
Publication Date: 2023.09.06 ZIMMER INC
  • EP3551136B1 patent drawingFigure 1
  • EP3551136B1 patent drawingFigure 2
  • EP3551136B1 patent drawingFigure 3A~3C

AI summary

Systems and apparatuses including a tibial insert (506) for replacement of a knee joint of a patient are disclosed. The insert can comprise a proximal surface configured to interface with a bearing (504), a post (510) and a distal surface. The post can extend from the proximal surface and can be configured to be received in a recess (508) in the bearing. The bearing can be configured to pivot about the post to move relative to the proximal surface. The distal surface can be spaced from the proximal surface and can be configured to interface with a tibial baseplate (502). The distal surface can be configured with a connection mechanism to connect with the tibial baseplate.