One-Handed Surgical Alignment Guide With Elastic Restraint

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Solution Overview

Problem

In orthopaedic knee surgery, inserting an intramedullary rod into the femur typically requires two hands to secure the alignment guide and insert the rod, making it cumbersome and inefficient.

Innovation Solution

A restraining system comprising a resilient element and recess or protrusion on the intramedullary rod and alignment guide, which securely maintains the alignment guide's position relative to the rod, allowing for one-handed insertion and removal by restraining it towards the proximal end, preventing longitudinal and rotational movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the alignment guide is secured to the rod during insertion, then the alignment guide remains stable relative to the rod, but two hands are required to perform the insertion operation

Engineering Contradiction:
Improverelative position stabilityVSAvoidoperational simplicity
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The restraining system is segmented into distinct components: a resilient element (such as a spring or elastic component) and a corresponding recess or engagement feature. This segmentation allows the system to provide stable restraint while enabling one-handed operation through simple engagement and disengagement motions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The resilient element introduces dynamic characteristics to the restraining system, allowing it to flexibly engage and disengage from the alignment guide. This dynamic property enables the surgeon to easily secure or release the alignment guide with one hand during insertion or removal operations.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the alignment guide is free to move along the rod, then one-handed operation is possible, but the alignment guide cannot maintain accurate position during insertion

Engineering Contradiction:
Improveone-handed operation capabilityVSAvoidalignment accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The restraining system is designed to be preliminarily positioned on the rod before the alignment guide is attached. The resilient element is pre-configured in a state that allows easy engagement with the alignment guide, enabling the surgeon to quickly secure the alignment guide at the correct position during one-handed operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The resilient element acts as an intermediary between the rod and the alignment guide, providing a flexible connection that maintains alignment accuracy while allowing for easy engagement and disengagement. This intermediary component translates the surgeon's simple hand motion into secure positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If a complex restraining system is used to prevent rotation, then rotational stability is improved, but device complexity increases

Engineering Contradiction:
Improverotational stabilityVSAvoidrestraining system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The restraining system applies local quality by concentrating the rotational prevention function at specific locations on the rod and alignment guide. The resilient element and engagement features are positioned at key points to provide rotational stability without requiring complex mechanisms throughout the entire device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The resilient element provides self-service by automatically engaging with the alignment guide and providing both longitudinal and rotational restraint without requiring additional adjustment mechanisms. The system self-regulates to maintain stability while remaining simple in design.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables secure and efficient one-handed operation during the insertion and removal of the intramedullary rod, simplifying the surgical process and reducing the risk of misalignment, while allowing for precise alignment of the cutting guide.

Implementation Method 1

The restraining system includes a resilient element and recess configured to engage the resilient element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2640282B1Surgical instrument system, surgical alignment guide and surgical rod
Publication Date: 2014.05.28 DEPUY (IRELAND) LTD
  • EP2640282B1 patent drawingFigure 1
  • EP2640282B1 patent drawingFigure 2
  • EP2640282B1 patent drawingFigure 3

AI summary

A surgical instrument system is described which comprises an alignment guide (6,100) comprising a body section having a through bore (50) defining a longitudinal axis (122); and a rod (40) comprising a cylindrical member (2) for insertion into the through bore; and a restraining system (46, 52, 48, 94) for preventing relative movement of the alignment guide and rod along the longitudinal axis, when the cylindrical member is inserted into the through bore, and the alignment guide is located towards the proximal end of the rod. The restraining system may comprise a resilient element (46) and a recess (52) configured to engage the resilient element. In a preferred embodiment, a resilient member is disposed on the surface of the rod. Such a system allows the alignment guide to be restrained towards the proximal end of the rod so that the rod can be inserted to a patient using one hand, rather than requiring two hands (one to secure the alignment guide relative to the rod and one to insert the rod).