Knee Arthroplasty Digital Twin for Implant Positioning

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Solution Overview

Problem

Current knee replacement surgeries face challenges such as inadequate post-operative pain relief, limited functional improvement, faulty implant positioning, excessive soft tissue releases, one-size-fits-all approach, and high surgeon-specific subjectivity, leading to patient dissatisfaction due to the inability to assess knee mechanics pre-operatively and reliance on intraoperative trial-and-error.

Innovation Solution

The creation of a computer-based functional digital twin of the knee joint using pre-operative sensor data and medical imaging, allowing surgeons to plan surgical procedures pre-operatively by simulating bone cuts and soft tissue releases, reducing intraoperative trial-and-error and improving implant sizing precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional instruments and trial-and-error approach are used for knee replacement surgery, then surgical experience and judgement can be applied, but implant positioning accuracy and functional outcomes deteriorate due to subjectivity and variability

Engineering Contradiction:
Improveimplant positioning accuracyVSAvoidsurgical planning complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary surgical planning and simulation before the actual surgery. A functional digital twin is created preoperatively to simulate bone cuts, ligament releases, and implant positioning, allowing surgeons to optimize the surgical plan without intraoperative trial-and-error, thereby improving implant positioning accuracy while reducing surgical complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a functional digital twin (virtual copy) of the patient's knee joint that replicates its biomechanical properties. This digital copy allows for virtual surgical trials and predictions of postoperative function without requiring physical trial implants, reducing subjectivity and improving positioning precision

Inventive Principle:
Principle #26Copying

2Adaptability or versatility

If one-size-fits-all approach is used for total knee replacement, then surgical procedure is simplified, but patient-specific functional outcomes deteriorate due to lack of customization

Engineering Contradiction:
Improvesurgical procedure adaptabilityVSAvoidsurgical procedure complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system enables customization of surgical procedures for each patient by analyzing their specific knee biomechanics, alignment, and functional requirements. The functional digital twin allows surgeons to tailor bone cuts, ligament releases, and implant positioning to each patient's unique anatomy, improving adaptability while managing complexity through automated simulations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system transitions from static, standardized surgical approaches to dynamic, patient-specific planning. The functional digital twin simulates how each patient's knee will respond to different surgical interventions, allowing the surgical plan to be dynamically optimized based on predicted functional outcomes rather than following fixed protocols

Inventive Principle:
Principle #15Dynamics

3Productivity

If intraoperative assessment is performed when patient is under anesthesia, then surgical decisions can be made, but real-time knee behavior and proprioceptive responses cannot be assessed

Engineering Contradiction:
Improvesurgical decision-making efficiencyVSAvoidproprioceptive response information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The system performs preliminary assessment and prediction before surgery by creating a functional digital twin that captures the patient's baseline knee mechanics and proprioceptive responses while awake. This preoperative data is used to predict postoperative function, eliminating the need for intraoperative assessment under anesthesia and preserving proprioceptive information

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If trial-and-error approach with physical trial implants is used, then implant fit can be assessed, but operating time increases and surgeon subjectivity remains

Engineering Contradiction:
Improveimplant fit precisionVSAvoidoperating time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system replaces physical trial implants with a virtual trial in the functional digital twin. Surgeons can test different implant sizes, positions, and configurations in the simulation, achieving precise implant fit assessment without the time-consuming process of trying multiple physical implants during surgery, thereby reducing operating time while maintaining or improving precision

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system substitutes the mechanical trial-and-error process with computer-based simulations and predictive analytics. Instead of physically trying implants and assessing fit mechanically, the system uses digital twins to simulate implant behavior and predict outcomes, reducing operating time while maintaining precision through automated calculations

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

Data Source

PatentEP3992978A1Knee arthroplasty functional digital twin
Publication Date: 2022.05.04 ZIMMER INC
  • EP3992978A1 patent drawingFigure 1
  • EP3992978A1 patent drawingFigure 2
  • EP3992978A1 patent drawingFigure 3

AI summary

The present disclosure describes technical solutions to various technical problems facing knee surgery surgical procedures. In an embodiment, this solution includes prediction of postoperative knee functionality by creating a functional digital twin computer-based model of the patient knee joint. The functional digital twin may be based on medical imagery and preoperative joint sensor data, such as motion and position data. This functional digital twin is used for digital mirroring of the knee joint functionality, and this digital mirroring enables the surgeon to determine knee functionality before and after planned surgical bone cuts, soft tissue releases, or other surgical procedure steps. This digital mirroring is performed preoperatively to determine an optimal set of surgical procedures, which improves the patient's satisfaction in the functional outcome by reducing or eliminating the surgeon-specific subjectivity and intraoperative trial-and-error approaches.