Dual-Material Bone Anchor with Rigid Core and Flexible Interface

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Solution Overview

Problem

Existing bone anchors either lack flexibility, leading to reduced bone growth due to non-yielding interfaces, or compromise on strength and load-carrying capabilities when made semi-rigid to promote bone integration, resulting in increased fracture risks. Additionally, assembling bone anchors from multiple materials increases costs and risks loosening or separation.

Innovation Solution

A bone anchor design featuring a core portion made of a rigid material and a bone interface portion made of a less rigid material, which extends along the core to provide a buffer between the core and adjacent bone tissue, enhancing bone integration while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If bone anchors are formed of rigid materials, then strength and load carrying capabilities are improved, but bone growth around the bone anchor decreases due to non-flexible interface

Engineering Contradiction:

Improvestrength and load carrying capabilitiesVSAvoidbone growth

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The bone anchor employs different materials with different rigidity properties in different regions: a rigid material (first material) for the load-bearing portions and a more flexible material (second material) for the bone interface portion. This local differentiation allows the anchor to provide both strength where needed and flexibility at the bone interface to promote bone growth.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bone anchor is constructed as a composite device combining two different materials with complementary properties. The first material provides structural strength and rigidity, while the second material provides flexibility and biocompatibility at the bone interface, creating a composite structure that achieves both strength and promotes bone growth.

Inventive Principle:

Principle #40Composite materials

2Reliability

If bone anchors are formed of semi-rigid materials, then bone growth around the bone anchor increases due to flexible interface, but strength and load carrying capabilities are reduced

Engineering Contradiction:

Improvebone growthVSAvoidstrength and load carrying capabilities

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If bone anchors include multiple pieces or components formed of different materials, then different performance characteristics are achieved, but fabrication and assembly costs increase

Engineering Contradiction:

Improvedifferent performance characteristicsVSAvoidfabrication and assembly costs

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functional components into a single integrated bone anchor structure. The first material and second material are formed together as one unitary component, eliminating the need for separate assembly steps and reducing manufacturing complexity while maintaining the different performance characteristics needed in different regions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If bone anchors include multiple pieces or components, then different performance characteristics are achieved, but components are subject to loosening and separation

Engineering Contradiction:

Improvedifferent performance characteristicsVSAvoidcomponent stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7850717B2Bone anchors having two or more portions exhibiting different performance characteristics and method of forming the same

Publication Date: 2010.12.14 WARSAW ORTHOPEDIC INC

AI summary

A bone anchor including a bone engaging element and an implant engaging element. The bone engaging element includes a first portion formed of a first material and a second portion formed of a second material and extending at least partially along a length of the first portion, and with the second portion of the bone engaging element positioned between the first portion and adjacent bone tissue when the bone engaging element is engaged with the bone to provide an interface with the adjacent bone tissue. In one embodiment, the first portion of the bone engaging element exhibits a first level of rigidity and the second portion exhibits a second level of rigidity less than the first level of rigidity. In another embodiment, the bone engaging element includes external threads, with the second portion of the bone engaging element defining at least a portion of the external threads.