Stackable Knee Implant Spacers for Anatomical Fit and Lower Inventory

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Solution Overview

Problem

Existing knee replacement implants face challenges in minimizing inventory and cost while accommodating the variability in anatomical characteristics of patients, necessitating a need for implant solutions that reduce component numbers while expanding adaptability.

Innovation Solution

The implementation of stackable spacers for both tibial and distal femoral implants, which can be securely attached to the baseplate and femoral head portion, respectively, allowing for adjustable spacing to accommodate varying patient anatomies with a reduced number of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional knee replacement implants use fixed, non-stackable spacers, then the implant structure is simpler and manufacturing is easier, but the ability to accommodate variability in patient anatomies is limited and inventory requirements increase

Engineering Contradiction:

Improveability to accommodate variability in patient anatomiesVSAvoidimplant structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spacer is divided into multiple stackable units that can be combined in different configurations. Each spacer unit can be independently manufactured and then stacked to create the desired total spacer thickness, allowing a single baseplate design to accommodate multiple patient anatomies through modular assembly rather than requiring multiple different baseplate designs

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The spacer system transitions from a fixed, static thickness to a dynamic, adjustable configuration where spacers can be stacked in varying numbers and arrangements. This allows the spacer assembly to adapt its total thickness and geometry to match different patient anatomical requirements while using the same standardized component

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple different spacer designs are manufactured to fit various patient anatomies, then patient-specific anatomical variability is better accommodated, but inventory requirements and manufacturing costs increase

Engineering Contradiction:

Improveaccommodation of patient anatomical variabilityVSAvoidinventory requirements

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

A single standardized spacer design serves multiple functions by being stackable in different configurations. The same spacer unit can be used alone or combined with other identical units to create various total spacer thicknesses, eliminating the need to manufacture and inventory multiple different spacer designs while still accommodating diverse patient anatomies

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple spacer units are combined through stacking to achieve the desired total spacer thickness. Instead of manufacturing separate spacers for different thickness requirements, the system merges identical spacer units in series, reducing inventory diversity to a single spacer design while providing multiple effective thickness options through combination

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If stackable spacers are used to reduce inventory, then manufacturing costs and inventory requirements decrease, but the complexity of assembly and selection increases

Engineering Contradiction:

Improvemanufacturing cost and inventory efficiencyVSAvoidassembly and selection process

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The spacer units are pre-manufactured as standardized components with predetermined geometries and thicknesses. During assembly, the surgeon simply needs to select and stack the appropriate number of pre-fabricated units rather than custom-manufacturing or complexly assembling different spacer designs, which streamlines the surgical process despite the modular approach

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250352348A1Knee replacement implant having stackable spacers

Publication Date: 2025.11.20 ENCORE MEDICAL L P (D B A DJO SURGICAL)

AI summary

A knee replacement prosthesis includes a distal femoral implant, including a femoral head portion, including an outer arcuate surface, and interior posterior surface, an interior distal surface disposed at a first angle with respect to the interior posterior surface, and a first interior intermediate surface joining the interior posterior surface and the interior distal surface and being disposed at a second angle with respect to the interior posterior surface and at a third angle with respect to the interior distal surface. The distal femoral implant includes stackable femoral spacers secured to at least one of the interior posterior surface and the interior distal surface, thereby adjusting an aggregate spacing between the interior posterior surface and/or the interior distal surface and a resected surface of a distal femur of the patient. A tibial implant is also provided. Related methods of use of either implant or both are also provided.