Orthopedic Impactor Force Sensor for Implant Stability

Solution Overview

Problem

Surgeons face challenges in accurately assessing the degree of insertion and primary stability of orthopedic implants during surgery, relying on empirical methods that may lead to insufficient or excessive force application, potentially causing bone fractures or implant instability.

Innovation Solution

A device equipped with a force sensor that measures the impaction force and its temporal variation, providing real-time feedback on the degree of insertion through an indicator calculated from the average impaction force over a programmable time window, helping surgeons achieve optimal primary stability without risking bone fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher impact energy is applied to achieve good primary stability, then the degree of insertion and contact surface between bone and implant is improved, but the risk of per-operative fractures of the recipient bone increases

Engineering Contradiction:

Improveprimary stabilityVSAvoidbone fracture risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The device incorporates a force sensor that measures the impaction force in real-time and provides feedback to the surgeon through a display unit. This allows the surgeon to monitor the degree of insertion and adjust the impact energy accordingly, ensuring optimal primary stability while avoiding excessive force that could cause bone fractures.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the traditional empirical mechanical assessment method (relying on surgeon experience and sound of impact) with a sensor-based measurement system. The force sensor quantitatively measures the impaction force, and the processing unit calculates the degree of insertion, substituting subjective mechanical judgment with objective digital measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If empirical methods are used to assess insertion degree, then the surgical procedure is simple, but the accuracy of assessing the degree of insertion and primary stability is insufficient

Engineering Contradiction:

Improvesurgical procedure simplicityVSAvoidinsertion degree assessment accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional empirical mechanical assessment method (relying on surgeon experience and sound of impact) with a sensor-based measurement system. The force sensor quantitatively measures the impaction force, and the processing unit calculates the degree of insertion, substituting subjective mechanical judgment with objective digital measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device introduces a force sensor as an intermediary between the impactor and the bone-implant interface. This sensor acts as a mediator that captures the mechanical interaction data and transmits it to the processing unit, enabling precise measurement without directly interfering with the surgical procedure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If insufficient impact energy is applied, then bone fractures are avoided, but the implant insertion degree and primary stability are compromised

Engineering Contradiction:

Improvebone fracture preventionVSAvoidimplant stability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The device incorporates a force sensor that measures the impaction force in real-time and provides feedback to the surgeon through a display unit. This allows the surgeon to monitor the degree of insertion and adjust the impact energy accordingly, ensuring optimal primary stability while avoiding excessive force that could cause bone fractures.

Inventive Principle:

Principle #23Feedback

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

The device allows for precise evaluation of implant stability, ensuring optimal insertion and reducing the risk of bone fractures by providing real-time data on the degree of insertion and pull-out force, thus enhancing surgical success and reducing the need for additional interventions.

Implementation Method 1

a force sensor able to measure, during each impact, said impaction force applied by the impactor on said impact surface

Methodology Applied

Scientific EffectForce sensing: Force

Data Source

PatentEP2923677B1Device for assisting with the placement of an orthopaedic instrument

Publication Date: 2016.11.09 CENT NAT DE LA RECH SCI (C N R S)

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Figure 3~5

AI summary

The invention relates to a device (1) for assisting in the placement of an orthopedic instrument (2) intended to be inserted into a recipient bone (3) by impaction, using an impactor (10) comprising at least one striking surface (11) adapted to make contact with an impact surface coupled to said orthopedic instrument to apply an impaction force to said orthopedic instrument (2), said device being characterized in that it comprises a force sensor (12) capable of measuring, at each impact, said impaction force applied by the impactor (10) on said impact surface and of providing a measurement signal indicative of the temporal variation of said applied impaction force, said force sensor (12) being connected to processing means (30) designed to determine, from the temporal variation of said impaction force provided for each successive impact,a representative indicator of the degree of insertion of said orthopedic instrument (2) into the receiving bone (3).