Trial Patella Component Kit for Sensor-Guided Joint Balancing

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Solution Overview

Problem

Existing knee replacement surgeries face challenges in accurately positioning implant components due to measurement errors and limited implant sizes, leading to imbalanced collateral ligaments and potential changes in the patella-femoral joint balance, which can result in reduced joint function and pain.

Innovation Solution

A trial patella component kit is used during surgery, comprising a patella implant and a trial patella component with adjustable thickness and inclination, equipped with sensors to measure soft tissue tension, allowing for precise resection planning to maintain quadriceps balance and soft tissue tension similar to pre-surgery levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the patella resection is based on measurement of patella thickness before surgery, then the patella can be replaced with an implant component, but the patella-femoral joint balance changes leading to reduced joint function and pain

Engineering Contradiction:
Improvepatella resection accuracyVSAvoidjoint function and pain
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The trial patella component is used during surgery to preliminarily establish the correct resection depth and positioning before finalizing the patella implant. This allows the surgeon to verify joint balance and soft tissue tension in real-time, ensuring the final implant will restore proper patella-femoral joint mechanics without causing pain or dysfunction

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Sensors integrated into the trial patella component provide real-time feedback on soft tissue tension and joint balance during surgery. This feedback enables the surgeon to adjust the resection depth and implant positioning to maintain optimal quadriceps balance and patella tracking, preventing long-term joint problems

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the implant components are positioned based on linear measurements during surgery, then the components can be positioned, but measurement errors compound resulting in inaccurate positioning

Engineering Contradiction:
Improvecomponent positioningVSAvoidcomponent positioning accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The trial patella component serves as a temporary copy or prototype that replicates the final implant's function. By using sensors on this trial component, the surgeon can accurately measure soft tissue tension and joint balance before installing the permanent implant, eliminating the need for complex intraoperative measurements and reducing positioning errors

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces traditional mechanical measurement methods with sensor-based detection systems. Sensors embedded in the trial patella component electronically detect soft tissue tension and joint mechanics, providing precise data that guides accurate implant positioning without relying on error-prone manual measurements

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

3Reliability

If the femoral component size is adjusted to balance ligaments, then the collateral ligaments can be balanced, but the positions of the external surfaces of the femoral implant component differ from the patient's natural femur

Engineering Contradiction:
Improveligament balanceVSAvoidfemoral component positioning
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The trial patella component with adjustable thickness allows dynamic adjustment of the patella-femoral joint geometry during surgery. This enables the surgeon to optimize ligament balance while maintaining accurate representation of the patient's natural anatomy, as the trial component can be configured to match different patellar sizes and shapes before final implant installation

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4157156B1A trial patella component kit
Publication Date: 2025.07.02 EVENTUM ORTHOPAEDICS LTD
  • EP4157156B1 patent drawingFigure 1~2
  • EP4157156B1 patent drawingFigure 3~4
  • EP4157156B1 patent drawingFigure 5~6

AI summary

A kit for use in knee replacement surgery includes a trial patella component and a patella implant component. The trial patella component includes a backing plate (122) having a backing surface for positioning against a patient's patella, and at least one sensor (130, 132, 134, 136) which can generate a signal corresponding to the compressive load applied to the trial patella component, and a first bearing plate (150, 152, 154) which can be fitted to the backing plate and which, when fitted to the backing plate, provides a bearing surface for articulation against a bearing surface on the patient's femur. The patella implant component has a backing surface for fixation to a patient's patella instead of the backing surface of the trial patella component, and a bearing surface for articulation against a femoral bearing surface. The thickness of the patella implant component is greater than the thickness of the trial patella component when the first bearing plate is fitted to the backing plate, the difference between the said thicknesses being at least about 1 mm.