Rotating Latch Tibial Bearing Insert for Size-Matched Knee Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing knee implant systems face challenges in achieving optimal tibiofemoral articular congruency and stability due to size mismatches between femoral and tibial implants, leading to instability, particularly during mid-flexion phases of movement, and the removal of cruciate ligaments during surgery contributes to further instability.

Innovation Solution

A modular implant system featuring a baseplate, bearing insert, and a rotating latch that allows easy attachment and detachment without damaging the baseplate, ensuring compatibility across different sizes and providing enhanced stability through interference fits and a locking mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single tibial baseplate design is used to accommodate multiple femoral component sizes, then versatility and adaptability are improved, but tibiofemoral articular congruency and joint stability deteriorate due to size mismatches

Engineering Contradiction:

Improvecompatibility across different implant sizesVSAvoidtibiofemoral articular congruency

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The tibial implant is divided into two separable components: a baseplate and a bearing insert. The baseplate provides bone anchorage and is sized for optimal fit on the resected tibia, while the bearing insert provides the articular surface and is sized to match the specific femoral component. This segmentation allows each component to be independently optimized for its specific function, resolving the contradiction between versatility and congruency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The baseplate is designed with a universal interface that can accommodate bearing inserts of different sizes through a standardized locking mechanism. The baseplate serves multiple functions: bone anchorage, structural support, and interface for various bearing insert sizes. This universality allows a single baseplate design to work with multiple femoral component sizes while maintaining optimal articular congruency through the interchangeable bearing inserts.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If a locking mechanism is added to secure the bearing insert to the baseplate, then joint stability is improved, but device complexity increases

Engineering Contradiction:

Improvebearing insert attachment stabilityVSAvoidlocking mechanism structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The locking mechanism is designed to be self-aligning and self-locking through an interference fit between the bearing insert and baseplate. The geometric arrangement of the interface surfaces automatically guides proper alignment during assembly, and the interference fit provides inherent locking without requiring additional complex fasteners or adjustment mechanisms. This self-service approach maintains stability while minimizing complexity.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If traditional attachment methods are used to secure the bearing insert, then joint stability is improved, but ease of revision surgery deteriorates due to difficulty in removal

Engineering Contradiction:

Improvebearing insert fixationVSAvoidease of insert removal for revision

Core Design Contradiction:

Stability of the object's compositionVSEase of repair

Solution Approach 1:

The attachment mechanism transitions from a static, permanent fixation to a dynamic, controllable connection. The interference fit provides stable fixation during the normal function of the implant, while the designed interface allows for controlled separation during revision surgery. The geometric design enables the bearing insert to be easily detached from the baseplate when needed, providing both stable fixation and ease of revision without requiring complex removal tools or procedures.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4427708B1Universal insert-baseplate interface and insert for tibiofemoral articular congruency

Publication Date: 2026.03.18 HOWMEDICA OSTEONICS CORP

Figure 1~2
Figure 3~4
Figure 5~6

AI summary

A modular implant system (50) includes a baseplate (100), a bearing insert (200, 200") and a latch (260, 260"). The baseplate is adapted to receive the bearing insert. The bearing insert has an articular surface (220, 220") and a plate-contacting surface (240) opposite the articular surface and the latch is adapted for disposal through a hole (246, 246") in the bearing insert. The system is adapted so that when the plate-contacting surface (240) of the bearing insert is disposed on the baseplate (100) and the latch (260, 260") is disposed through the hole (246, 246") in the bearing insert, the latch is rotatable from a first position to a second position. In the first position, the bearing insert is removable from the baseplate. In the second position, the bearing insert is held in place on the baseplate.