Patient-Specific Joint Prosthesis Design Using Kinematic Data
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Solution Overview
Problem
Conventional knee replacement surgeries require intra-operative adjustments due to the inability of static medical images to account for variations in soft tissues, leading to potential malalignment and the need for variable-sized inserts, which can be limiting when specific sizes are not available intra-operatively.
Innovation Solution
A method for designing a two-part joint prosthesis using kinematic data to create patient-specific implants that do not require intra-operative adjustments, utilizing 3D bioprinted components made from cellular materials like hyaline cartilage and subchondral bone, which account for both bony anatomy and soft tissues, eliminating the need for inserts and allowing precise fitting without adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional three-component knee replacement implants with pre-determined sizes are used, then the implant can be manufactured and stored in advance, but intra-operative adjustments are required to account for soft tissue variations, leading to potential malalignment
Solution Approach 1:
The patent applies preliminary action by performing dynamic kinematic assessment and soft tissue evaluation before implant design. The method captures kinematic data during movement and under load, then uses this data to pre-calculate the optimal insert thickness that will balance the knee, eliminating the need for intra-operative adjustments.
Solution Approach 2:
The patent creates a digital copy or model of the patient's knee joint using medical imaging and kinematic data. This virtual model allows for simulation and optimization of the implant design before manufacturing, ensuring precise fit without requiring multiple physical trial components during surgery.
2Reliability
If variable-sized inserts are prepared for intra-operative adjustment, then the knee can be balanced accurately, but the complexity and cost of producing and storing multiple sizes increases
Solution Approach 1:
The patent changes the approach from having multiple discrete insert sizes to calculating a specific optimal thickness parameter based on the patient's unique kinematics and soft tissue properties. This continuous parameter optimization eliminates the need for a catalog of variable-sized inserts while maintaining or improving balancing accuracy.
3Ease of manufacture
If static medical images are used for implant sizing, then the sizing process is simplified, but variations in soft tissues cannot be accounted for, leading to potential malalignment
Solution Approach 1:
The patent transitions from static imaging to dynamic kinematic assessment. The system captures motion data and evaluates soft tissue behavior during movement and under load, providing a dynamic understanding of knee mechanics that static images cannot reveal, while still maintaining a streamlined digital workflow.
Data Source
AI summary
A method for designing a two-part joint prosthesis (830) comprises: providing kinematic data of a subject's joint under load; and designing the joint prosthesis using the kinematic data, wherein the working surfaces of the two-part prosthesis comprise, consist essentially of or consist of cellular material. Advantageously, the method may not require any intra-operative adjustments to replace one or more of the components (831, 832), e.g. with a component of a different size. In particular, if components are made of biological tissues, such as a patient's own cells, it is advantageous to design and produce an implant that requires no adjustments intra-operatively as each implant may be manufactured specifically for each patient, and the time and costs of producing a range of sizes, most of which would not be required, would otherwise be prohibitive.