Tibial Trial Insert Assembly for Stable Shim-Free Spacing Adjustment

Solution Overview

Problem

Existing tibial trial insert systems face issues with dimensional deviations and reduced stability due to the stacking of multiple shims, which complicates the adjustment of proximal/distal spacing during knee joint replacement surgeries.

Innovation Solution

A tibial trial insert system with two distinct spacing adjustment assemblies, each with different adjustment ranges, is designed to prevent shim stacking, featuring unique thicknesses and engagement mechanisms to ensure precise and stable spacing adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple shims are stacked to adjust proximal/distal spacing, then the adjustment range is increased, but dimensional deviations and reduced stability occur

Engineering Contradiction:

Improveadjustment rangeVSAvoiddimensional accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The spacing adjustment mechanism is segmented into two distinct assemblies: a first spacing adjustment assembly with a first adjustment range and a second spacing adjustment assembly with a second adjustment range. Each assembly has unique thickness characteristics, allowing surgeons to select the appropriate assembly for different spacing requirements without stacking multiple shims, thereby maintaining dimensional accuracy while providing comprehensive adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system provides universal spacing adjustment capability through multiple assemblies that can each independently accommodate different spacing requirements. The first and second spacing adjustment assemblies together cover a broad range of proximal/distal spacing needs, eliminating the need to stack shims from a single assembly and thus preventing dimensional deviations while maintaining stability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple shims are stacked to adjust proximal/distal spacing, then the adjustment range is increased, but stability is reduced

Engineering Contradiction:

Improveadjustment rangeVSAvoidsystem stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The spacing adjustment mechanism is segmented into two distinct assemblies: a first spacing adjustment assembly with a first adjustment range and a second spacing adjustment assembly with a second adjustment range. Each assembly has unique thickness characteristics, allowing surgeons to select the appropriate assembly for different spacing requirements without stacking multiple shims, thereby maintaining dimensional accuracy while providing comprehensive adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Rather than using multiple thin shims that must be stacked (which reduces stability), the invention employs distinct spacing adjustment assemblies with different thickness profiles. Each assembly is designed as a stable, self-contained unit that provides the necessary spacing without requiring stacking, thus maintaining system stability while achieving the desired adjustment range.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If multiple shims are stacked to adjust proximal/distal spacing, then the adjustment flexibility is increased, but the surgical process becomes more complex

Engineering Contradiction:

Improveadjustment flexibilityVSAvoidsurgical process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The spacing adjustment mechanism is segmented into two distinct assemblies: a first spacing adjustment assembly with a first adjustment range and a second spacing adjustment assembly with a second adjustment range. Each assembly has unique thickness characteristics, allowing surgeons to select the appropriate assembly for different spacing requirements without stacking multiple shims, thereby maintaining dimensional accuracy while providing comprehensive adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The different thickness configurations of the first and second spacing adjustment assemblies are predetermined and designed in advance. This preliminary configuration allows surgeons to directly select the appropriate assembly for the required spacing without needing to calculate or stack multiple shims during surgery, thereby maintaining adjustment flexibility while simplifying the surgical process.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12502286B2Tibial trial insert system

Publication Date: 2025.12.23 AESCULAP AG

AI summary

A tibial trial insert system includes a bearing having a superior articulating surface and an inferior surface; a plate having a superior surface and an inferior fixation surface; a first adjustment assembly and a second adjustment assembly, each adjustment assembly arrangeable between the inferior surface of the bearing and the superior surface of the plate, and each adjustment assembly having a superior connector to engage the bearing and an inferior base to engage the plate. A plurality of shims are slidable between an inferior surface of the connector and a superior surface of the base of the first and/or second adjustment assembly to adjust a proximal/distal height of the respective adjustment assembly to adjust a proximal/distal spacing between the bearing and the plate. The first adjustment assembly allows adjustment of the spacing within a first range. The second adjustment assembly allows adjustment of the spacing within a second range.