Hand-held Display Module for Real-time Joint Force Balance

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Solution Overview

Problem

Orthopaedic surgeons face challenges in accurately balancing joint forces during surgical procedures, relying on manual feel or instruments like ligament balancers, which can be inefficient and lack precise feedback, especially in minimally invasive procedures.

Innovation Solution

A hand-held display module with a sensor module that is inserted into the joint to provide real-time visual and data feedback on joint force balance, using pressure sensors and a control circuit to display medial-lateral and anterior-posterior balance through light emitting diodes, and wirelessly transmit data to a computer-assisted surgery system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual feel or ligament balancers are used to balance joint forces, then the surgeon can perform the procedure with simple tools, but the precision and accuracy of joint force measurement is insufficient

Engineering Contradiction:
Improvejoint force measurement precisionVSAvoidmeasurement device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical sensing (ligament balancers and surgeon's manual feel) with electronic pressure sensors that provide quantitative digital measurements of joint forces. This substitution enables precise measurement of medial-lateral and anterior-posterior force distributions without requiring complex mechanical balancing instruments.

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

Solution Approach 2:

The patent implements real-time feedback by displaying measured joint force data on a hand-held device during the surgical procedure. The display shows visual indicators (such as bar graphs or numerical values) that immediately reflect the current joint force balance, allowing the surgeon to make precise adjustments and verify the effects of surgical interventions.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If computer assisted orthopaedic surgery systems are used to improve surgical navigation and alignment, then the accuracy of bone cut planes and implant positioning is improved, but the system complexity and cost increase

Engineering Contradiction:
Improveimplant positioning precisionVSAvoidsurgical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges joint force measurement functionality with existing computer assisted orthopaedic surgery navigation systems. By integrating the pressure sensor data into the CAOS platform, the system provides both spatial navigation guidance and real-time biomechanical feedback, allowing surgeons to optimize implant positioning based on actual joint force distributions rather than relying solely on preoperative planning.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a multi-functional system that combines surgical navigation, joint force measurement, and real-time data visualization into a single integrated platform. The hand-held display device can show multiple parameters simultaneously (alignment data, joint forces, gap measurements), reducing the need for separate specialized instruments and simplifying the overall surgical workflow.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If real-time joint force feedback is provided during surgery, then the surgeon can optimize joint alignment immediately, but the complexity of the surgical instrument increases

Engineering Contradiction:
Improvesurgical procedure efficiencyVSAvoiddisplay module complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the measurement and display functions into a portable hand-held unit that can be easily held and manipulated by the surgeon during the procedure. The device separates force sensing (via pressure sensors in the implant or attached to bone surfaces) from data processing and display, allowing the main computational functions to be housed in a compact form factor that does not interfere with surgical access or workflow.

Inventive Principle:
Principle #1Segmentation

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 precise and immediate feedback on joint force balance, allowing surgeons to adjust and optimize joint alignment and force distribution during procedures, enhancing the accuracy and efficiency of orthopaedic surgeries.

Implementation Method 1

A sensor module is inserted into a joint of a patient to sense a joint force applied to the sensor module. The sensor module includes a sensor array having a plurality of pressure sensors configured to generate sensor signals indicative of the joint force applied to the sensor module.

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 2

A hand-held display module with a sensor module that is inserted into the joint to provide real-time visual and data feedback on joint force balance, using pressure sensors and a control circuit to display medial-lateral and anterior-posterior balance through light emitting diodes

Methodology Applied
Scientific EffectLight emitting diode: Light Emitting Diode

Data Source

PatentEP2237177B1Hand-held device for displaying joint force data
Publication Date: 2017.05.10 DEPUY (IRELAND) LTD
  • EP2237177B1 patent drawingFigure 1
  • EP2237177B1 patent drawingFigure 2
  • EP2237177B1 patent drawingFigure 3~4

AI summary

A hand-held display module includes a housing, a display coupled to the housing, and a circuit positioned in the housing and coupled to the display. The circuit includes a receiver circuit configured to communicate with a sensor module positioned in a knee joint of a patient to receive joint force data indicative of the joint force of the patient's knee joint. In one mode, the circuit is configured to display a visual indication of the medial-lateral balance of the joint force based on the joint force data. In a second mode, the circuit is configured to display a visual indication of the medial-lateral and the anterior-posterior balance of the joint force.