Twisted Bone Plate Joining Portion Resists Tibial Load

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Solution Overview

Problem

Conventional bone plates used in high tibial osteotomy tend to bend and dislodge artificial bones when a vertical load is applied, leading to potential retroversion of the joint surface.

Innovation Solution

A bone plate system with a strip-shaped main-body portion secured to an oblique anterior inner surface of the tibia and a transverse portion secured above the cut, joined by a twisted portion that prevents bending by distributing load across intersecting planes, using screws that intersect at specific angles to secure the plate effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bone plate is placed along substantially the same plane for both the main-body portion and transverse portion, then the structure is simple and easy to manufacture, but the bone plate bends and dislodges artificial bone when vertical load is applied

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The joining portion is twisted by a twist angle of 10° to 25° about the longitudinal axis, transitioning the structure from a planar configuration to a three-dimensional twisted configuration. This dimensional change allows the bone plate to resist bending moments while maintaining structural integrity under vertical loads, thereby improving reliability without significantly complicating manufacturing

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the joining portion is twisted by 10° to 25°, then the bone plate resists bending and prevents dislodging of artificial bone, but the structure becomes more complex

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The twist angle of the joining portion is optimized within a specific range of 10° to 25°. This parameter change provides the optimal balance between resistance to bending moments and manufacturing feasibility. The specified range ensures sufficient structural stability while avoiding excessive complexity in fabrication and installation procedures

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the transverse portion is positioned to bridge the cut, then the artificial bone is supported at three points, but the bone plate may cause retroversion of the joint surface under vertical load

Engineering Contradiction:
ImprovestabilityVSAvoidretroversion of joint surface
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The twisted joining portion creates a three-dimensional configuration that prevents the transverse portion from rotating or tilting under vertical loads. This spatial arrangement ensures that the artificial bone remains properly positioned and the joint surface maintains its correct orientation, eliminating the harmful retroversion effect while preserving the three-point support stability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3123971B1Bone plate and bone plate system
Publication Date: 2020.04.22 OLYMPUS TERUMO BIOMATERIALS CORP
  • EP3123971B1 patent drawingFigure 1
  • EP3123971B1 patent drawingFigure 2A
  • EP3123971B1 patent drawingFigure 2B

AI summary

A bone plate (1) is provided with: a strip-shaped main-body portion (1a) that is secured, along a longitudinal direction of a tibia, to an oblique anterior inner surface of the tibia below a cut formed in an inner surface of the tibia; a transverse portion (1b) that is secured to an inner surface of the tibia above the cut along a direction that intersects the longitudinal direction of the tibia; and a joining portion (1c) that joins the main-body portion (1a) and the transverse portion (1b), wherein the transverse portion (1b) and the main-body portion (1a) are provided with a plurality of screw holes (5, 6, and 7) that are arrayed with spaces between each other and that pass therethrough in plate-thickness directions.