Epiphysiodesis Bone Plate with Recessed Screw Holes

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Solution Overview

Problem

Existing bone plates for epiphysiodesis in pediatric orthopedics face issues such as screw breakage and insufficient angular correction, requiring repositioning and potentially causing inflammatory reactions due to complex manufacturing and design encumbrances.

Innovation Solution

A bone plate with bilobal figure-eight shape featuring cup-shaped screw housings and recesses that expand the exit section, allowing increased screw divarication range and preventing breakage, manufactured from a single piece of biocompatible material like titanium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the fixing screws are loosely fastened to allow angular divarication during bone growth, then the bone realignment function is improved, but the screws may break when reaching the abutment position

Engineering Contradiction:

Improveangular divarication rangeVSAvoidscrew breakage risk

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a recess with different geometric properties at a specific location in the screw hole. The recess features a first portion with a first diameter and a second portion with a second diameter, creating a localized geometric discontinuity that serves as a stop for the screw. This allows the screw to tilt within the recess without breaking, while maintaining structural integrity of the rest of the bone plate.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a mechanical hinge is added to the bone plate to follow screw divarication movement, then the adaptability is improved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:

Improvescrew divarication accommodationVSAvoidmechanical hinge structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the hinge function from a separate mechanical component and integrates it directly into the bone plate structure through the recess geometry. The recess itself acts as the hinge mechanism, eliminating the need for additional mechanical hinge elements. This reduces device complexity while maintaining the ability to accommodate screw divarication movement.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If the screw hole is enlarged to increase divarication range, then the angular correction capability is improved, but the screw retention capability deteriorates

Engineering Contradiction:

Improvedivarication rangeVSAvoidscrew retention

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

4Reliability

If complex manufacturing processes are used to create recesses and cup-shaped seats, then the functional performance is improved, but the ease of manufacture deteriorates

Engineering Contradiction:

Improvescrew stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by defining specific geometric parameters for the recess (first diameter, second diameter, depth) and the cup-shaped seat (spherical geometry). These parameter specifications enable standardized manufacturing processes while achieving the desired functional performance. The geometric discontinuity is created through controlled material removal or forming operations with defined dimensions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11229463B2Bone plate for epiphysiodesis

Publication Date: 2022.01.25 ORTHOFIX SRL

AI summary

The present invention relates to a bone plate (1, 21) for epiphysiodesis, which has been advantageously improved to allow better articulation of the fixing screws engaged with the bone plate (1, 21), comprising: a first portion (4) and a second portion (6) joined by a connecting portion (5), intersected by a first (9) and a second opening (10), respectively, structured to receive the same number of fixing screws; the bone plate having a bilobal figure, such as an eight shape; at least one of said first (9) and second (10) openings comprising: a cup-shaped seat (12) for housing a fixing screw head in a tillable manner, and at least one recess (14″) which merges into the cup-shaped seat (12) expanding an exit section (12b) away from the connecting portion (5).