Tapered Bone Fixation Plate Design for Stress Reduction

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Solution Overview

Problem

Existing bone fixation plates used in tibial osteotomy are thick, heavy, and have sharp transitions between sections, which can lead to weak areas and potential breakage, as well as reports of increased tumor occurrences due to their material composition.

Innovation Solution

A bone fixation plate with a base section that tapers smoothly to join a leg section, both sections being anatomically pre-contoured and made of machined implant-grade stainless steel, with no sharp transitions and a maximum thickness of 0.275 inches, ensuring strength and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the fixation plate is made thick to ensure strength, then the strength is improved, but the weight increases and the plate becomes more invasive

Engineering Contradiction:

Improveplate strengthVSAvoidplate weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by transitioning from cast construction to machined construction, which allows for thinner plate thickness (0.175-0.275 inches versus 5mm in prior art) while maintaining strength through precise geometric control and material optimization. The machined construction enables optimized thickness parameters that reduce weight without compromising structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes implant-grade stainless steel with specific material properties (austenitic or martensitic structure) to achieve high strength-to-weight ratio. The material selection and processing create a composite-like performance where the machined metal structure provides both lightweight properties and exceptional strength.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the fixation plate has a sharp transition between wide and narrow sections, then the manufacturing is simpler, but a weak stress zone is created subject to breakage

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidresistance to breakage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature principles by designing a smooth, continuous transition between the wide base section and narrow leg section. The plate features a tapered configuration with no sharp angles or abrupt changes in cross-section, creating a streamlined geometry that eliminates stress concentration zones and prevents breakage while maintaining manufacturing feasibility through CNC machining.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters along the plate length, creating a gradual variation in cross-sectional dimensions. The smooth transition is achieved through controlled parameter changes in the tapering sections, where the width and thickness vary continuously rather than abruptly, eliminating weak stress zones.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the fixation plate is made thick to ensure strength, then the strength is improved, but the plate becomes more invasive and tumor risk increases

Engineering Contradiction:

Improveplate strengthVSAvoidtumor occurrence risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by reducing plate thickness to 0.175-0.275 inches through machined construction, which maintains strength while minimizing the plate's invasive presence in the bone. The optimized thickness parameters reduce the plate's interaction with surrounding tissue and eliminate the need for thick, tumor-associated cast plates.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable, single-use machined plate that is precision-manufactured and sterilized, eliminating the need for repeated sterilization of cast plates. This approach reduces the overall invasive burden and associated health risks while maintaining structural integrity throughout the device's service life.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If the fixation plate uses cast construction, then the manufacturing is simpler, but the plate becomes thicker and heavier

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidplate weight

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent replaces the cast construction mechanical process with a machined construction process. Instead of forming the plate through casting molds, the plate is precision-machined from solid stock using CNC equipment. This substitution enables thinner, lighter plates with controlled geometry while maintaining manufacturing efficiency through automated machining processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8177818B2Fixation plate

Publication Date: 2012.05.15 SECUROS

AI summary

A fixation plate with a base section including apertures for fixation to one bone segment and a leg section extending from the base section and including apertures for fixation to another bone segment. The expanse of the base section tapers gradually to smoothly cojoin with the leg section and the expanse of the leg section continues to taper to a distal rounded end of the leg section.