Bi-Planar Wedge Osteotomy Cut Guide for Foot Alignment

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Solution Overview

Problem

Current methods for bi-planar wedge osteotomy in Charcot foot deformity lack precision in aligning planar cuts, leading to inconsistent restoration of a plantigrade foot structure and incomplete reduction of Meary's angle.

Innovation Solution

A cut guide and method involving the use of wires to pivot and align a cutting guide with the longitudinal axes of foot bones, allowing precise guidance of a cutter to make planar cuts that reduce Meary's angle by forming a bi-planar wedge osteotomy, with the cut guide having a slot for guiding a blade and alignment holes for wire fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional cutting methods are used for bi-planar wedge osteotomy, then the surgical procedure can be performed, but the alignment precision of planar cuts is insufficient leading to inconsistent restoration of plantigrade foot structure

Engineering Contradiction:
Improvealignment precision of planar cutsVSAvoidconsistency of plantigrade foot restoration
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The cut guide is pre-configured with slots and alignment features that establish the precise orientation of cuts before the actual cutting process. The guide is positioned and secured to the bone surface in advance, ensuring that subsequent cuts follow the predetermined accurate path, thereby achieving consistent plantigrade foot restoration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cut guide acts as an intermediary tool between the surgeon and the cutting instrument. It translates the desired cut orientation into physical guidance through its structured geometry, mediating the transfer of precise alignment from the guide body to the cutting blade, thus ensuring accurate and reproducible planar cuts.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If manual alignment methods are used, then the surgical procedure can be completed, but Meary's angle reduction is incomplete due to imprecise alignment

Engineering Contradiction:
ImproveMeary's angle reduction accuracyVSAvoidbone repositioning accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The cut guide incorporates radiopaque members that appear distinct under imaging modalities, enabling precise visualization and verification of the guide's alignment with the bone's longitudinal axis. This visual feedback mechanism allows the surgeon to accurately assess and achieve the desired Meary's angle reduction.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The cut guide extends alignment control from a single plane to multiple dimensions by incorporating features that constrain orientation in both the coronal and sagittal planes. This multi-dimensional guidance ensures that cuts are precisely oriented to achieve accurate bone repositioning and complete Meary's angle correction.

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

3Manufacturing precision

If a simple cutting guide is used, then the device is easy to manufacture, but it lacks the alignment features needed for precise bone cutting

Engineering Contradiction:
Improvecut alignment precisionVSAvoidcut guide structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cut guide is designed as a modular structure with distinct functional segments: a body portion for positioning, slot features for blade guidance, alignment features for orientation, and fixation means for securing to bone. This segmentation allows each component to be optimized independently while maintaining overall precision, balancing manufacturing feasibility with functional requirements.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3138518B1Cut guide and surgical set for bi-planar wedge osteotomy
Publication Date: 2024.04.03 WRIGHT MEDICAL TECHNOLOGY INC
  • EP3138518B1 patent drawingFigure 1~3
  • EP3138518B1 patent drawingFigure 4
  • EP3138518B1 patent drawingFigure 5~6

AI summary

The cut guide comprises a body having a first face, a second face opposite the first face, and a straight slot therethrough for guiding a blade, the slot extending from the first face to the second face and being perpendicular to a first axis of the body. The body has a row of holes extending therethrough from the first face to the second face, the row of holes being parallel to the slot. The body is designed to receive or have an elongated member aligned with the first axis.