Couplable Knee Spacer Units for Variable Thickness

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Solution Overview

Problem

Current total knee replacement systems require multiple incrementally sized spacers, which are costly and inefficient for global delivery, as they need to accommodate varying patient anatomies and require extensive inventory and sterilization processes.

Innovation Solution

A total knee replacement kit with couplable spacers of different thicknesses that can be combined to form a single, larger spacer, using a keyed snap-fit engagement mechanism and adhesives for secure alignment and orientation, allowing surgeons to select the desired thickness without needing multiple spacers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple incrementally sized spacers are used to accommodate varying patient anatomies, then the adaptability to different patient sizes is improved, but the device complexity and inventory requirements increase

Engineering Contradiction:

Improveadaptability to different patient sizesVSAvoidinventory complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spacer is divided into multiple couplable units of identical size that can be stacked together. Each unit has the same dimensions and geometry, but they can be combined in different numbers (1, 2, or 3 units) to create spacers of varying thicknesses, thereby achieving adaptability without maintaining complex inventory of differently sized spacers

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple identical spacer units are merged through keyed snap-fit engagement to form a single thicker spacer. The coupling mechanism combines the thickness of individual units while maintaining a unified structure, allowing surgeons to achieve various thickness requirements by combining different numbers of identical units

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple incrementally sized spacers are maintained in inventory, then the versatility for different patient anatomies is improved, but the loss of time and resources for sterilization and delivery increases

Engineering Contradiction:

Improveversatility for different patient anatomiesVSAvoidsterilization and delivery time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

A single type of spacer unit serves multiple functions by being combinable in different quantities. The identical units can be used individually or stacked to create various thickness configurations, eliminating the need to sterilize and deliver multiple different spacer types while maintaining versatility for different patient anatomies

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If traditional arrays of incrementally sized spacers are used, then the ability to replicate natural articulation for different patients is improved, but the manufacturing cost and economic efficiency decrease

Engineering Contradiction:

Improveability to replicate natural articulationVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of manufacturing different spacer designs for different thicknesses, the invention changes the parameter of quantity by allowing multiple identical units to be stacked. This maintains the same manufacturing process and tooling while achieving variable thickness outcomes through simple stacking, significantly reducing manufacturing complexity and cost

Inventive Principle:

Principle #35Parameter changes

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

This solution reduces the number of spacers needed during surgery, decreases inventory costs, and simplifies sterilization and delivery by allowing three to seven thickness options with only two or three physical spacers, enhancing surgical efficiency and cost-effectiveness.

Implementation Method 1

The first spacer and the second spacer may be selectively engageable with one another prior to implantation to form a relatively thicker third spacer

Methodology Applied

Scientific EffectMechanical Fastener: Mechanical Fastener

Implementation Method 2

An adhesive may also be used to adhere the first spacer to the second spacer

Methodology Applied

Scientific EffectAdhesive: Adhesive

Data Source

PatentUS20250009517A1Total knee replacement with couplable spacers

Publication Date: 2025.01.09 JOINT DEVELOPMENT INC

AI summary

The total knee replacement kit includes a femoral component, a tibial component, a patella component, and a set of couplable spacers selectively engageable with one another. The femoral component, the tibial component, and the patella in the kit are each selected based on a predetermined compatible size for implantation together as part of a total knee replacement system along with an implantation spacer that includes one of the set of couplable spacers in the kit having a desired thickness to position the tibial component from a tibia or multiple of the set of couplable spacers in the kit engaged with one another to achieve the desired thickness.