Adjustable Arm Depth Indicator for Femoral Head Cutting

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Solution Overview

Problem

Sleeve cutters used to prepare the femoral head can overshoot and notch the femoral neck, leading to potential fractures and the need for surgical revision.

Innovation Solution

A device with adjustable arms that indicate the cutting depth of a cutting tool, allowing for precise alignment and prevention of over-shooting by aligning with the object to be cut, ensuring the cutting tool reaches the correct depth without notching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a sleeve cutter is used to prepare the femoral head, then the cutting operation can be performed efficiently, but the cutter may over-shoot and notch the femoral neck causing fractures

Engineering Contradiction:
Improvecutting efficiencyVSAvoidrisk of over-shooting and notching
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device marks the cutting depth on the bone surface before the actual cutting operation. By pre-marking the target depth position, the surgeon can stop the cutting at the correct depth, preventing over-shooting and notching of the femoral neck while maintaining efficient cutting progression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The device provides visual feedback by marking the bone surface at the intended cutting depth. This feedback mechanism allows the surgeon to monitor the cutting progression and stop at the precise marked position, eliminating the risk of exceeding the safe cutting depth.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the cutting depth is not precisely controlled, then the cutting operation is simple and fast, but over-shooting occurs leading to notching and fractures

Engineering Contradiction:
Improvesimplicity of cutting operationVSAvoidcutting depth precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The device pre-marks the exact cutting depth position on the bone surface before cutting begins. This preliminary marking provides a clear visual guide that maintains operational simplicity while ensuring precise depth control, eliminating the need for complex measurement procedures during the cutting process.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a depth indication device is added to control cutting depth, then over-shooting is prevented, but the device complexity increases

Engineering Contradiction:
Improveprevention of over-shootingVSAvoidcomplexity of cutting system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The depth indication device is designed as a separate, standalone component that can be independently attached to the cutting guide. This segmentation allows the indication function to be added without complicating the basic cutting tool design, maintaining system simplicity while enhancing safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The depth indication device acts as an intermediary between the cutting tool and the bone surface. It provides the depth information through a simple marking mechanism rather than requiring complex integrated measurement and control systems, thus preventing over-shooting without significantly increasing overall device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS9332997B2Medical device
Publication Date: 2016.05.10 SMITH & NEPHEW PLC

AI summary

A device (1) for indicating on an object to be cut the cutting depth of a cutting tool, the device comprising: a first arm (2) having a first end (3) and a second end (4), a second arm (5) having a first end (6) and a second end (7), wherein the first arm (2) and the second arm (5) are joined together such that the distance between the first end (3) of the first arm (2) and the first end (6) of the second arm (5) is equal to the length of the cutting tool so that when, in use, the device (1) is aligned with an object to be cut the device indicates the cutting depth of the cutting tool. A method of indicating on an object to be cut the cutting depth of a cutting tool using such a device.