Patient-Specific Hip Resection Guide for Accurate Femoral Alignment

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Solution Overview

Problem

Current methods for total hip replacement surgery, such as hand measuring and x-ray scans, are inaccurate, leading to potential errors in positioning prosthetic devices, which can result in improper alignment, leg length changes, hip dislocation, or femur perforation.

Innovation Solution

A customized surgical guide tool is developed using 3D computer modeling and CNC machining, featuring a mating region with customized indexing surfaces and a saw guide, which is preoperatively planned to ensure accurate resection and alignment of the femoral component, reducing human error and surgical time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If hand measuring techniques and x-ray scans are used for preoperative planning, then the surgical process is simple and quick to perform, but the measurement precision and positioning accuracy deteriorate, leading to potential errors in prosthetic device placement

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsurgical guide tool complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The surgical guide tool is preoperatively planned and manufactured based on patient-specific 3D bone models obtained from CT scans. The guide tool incorporates pre-calculated resection planes, component positioning parameters, and alignment data, allowing the surgeon to simply attach the guide to the bone and perform the surgery without complex intraoperative measurements or calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A customized surgical guide tool serves as an intermediary device between the preoperative 3D planning data and the actual surgery. The guide physically translates the virtual planning into surgical reality by providing mechanical constraints for resection planes and component positioning, eliminating the need for complex hand measurements during surgery.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If hand measuring techniques are used during surgery, then the surgical time is reduced and the process is simpler, but the reliability of prosthetic device positioning deteriorates, increasing the risk of complications

Engineering Contradiction:
Improvepositioning reliabilityVSAvoidsurgical time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

All critical positioning decisions, resection plane angles, and component alignment parameters are determined and locked into the surgical guide tool before surgery. This eliminates time-consuming intraoperative measurements and calculations while ensuring consistent, reliable positioning that matches the preoperative plan.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The surgical guide tool is designed to be self-aligning and self-positioning on the patient's anatomy through unique bone surface matching. Once attached, the guide automatically provides the correct orientation and positioning without requiring additional surgical time for alignment adjustments or complex measurement procedures.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If customized surgical guide tools are manufactured using 3D modeling and CNC machining, then the positioning precision and alignment accuracy are significantly improved, but the device complexity and manufacturing process become more complex

Engineering Contradiction:
Improveguide tool fabrication accuracyVSAvoidguide tool manufacturing ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Traditional manual measurement and layout methods are replaced with automated 3D imaging (CT scanning), computer-based 3D modeling, and CNC machining. This substitution of mechanical processes with automated digital systems achieves superior manufacturing precision while the standardized workflow and software automation actually simplify the overall manufacturing process despite the advanced technology involved.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2265194B1Total hip replacement surgical guide tool
Publication Date: 2023.05.24 HOWMEDICA OSTEONICS CORP
  • EP2265194B1 patent drawingFigure 1A
  • EP2265194B1 patent drawingFigure 1B
  • EP2265194B1 patent drawingFigure 1C

AI summary

Disclosed herein is a surgical guide tool for use in total hip replacement surgery. The surgical guide tool may include a customized mating region and a resection guide. The customized mating region and the resection guide are referenced to each other such that, when the customized mating region matingly engages a surface area of a proximal femur, the resection guide will be aligned to guide a resectioning of the proximal femur along a preoperatively planned resection plane.