Patient-Specific Knee Surgical Device Design for Alignment and Soft Tissue Balance
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Solution Overview
Problem
Current methods for designing surgical devices for total knee replacement (TKR) fail to consistently achieve optimal soft tissue balancing and joint line restoration throughout the range of knee motion, leading to issues like stiffness, pain, and prosthesis failure due to improper alignment and balancing.
Innovation Solution
A method for designing patient-specific surgical devices that involves determining alignment axes in both extension and flexion using patient-specific anatomical data to precisely realign and tension the knee joint, incorporating three-dimensional modeling and anatomical indicators to guide resection planes and ensure balanced soft tissue tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard adjustable instruments are used for universal application, then device versatility is improved, but manufacturing precision and alignment accuracy deteriorate
Solution Approach 1:
The surgical system is divided into two segments: a universal adjustable instrument for initial positioning and a patient-specific cutting block for precise resection. This segmentation allows the universal instrument to provide versatility while the patient-specific component ensures manufacturing precision and alignment accuracy.
Solution Approach 2:
The cutting block is customized with patient-specific anatomical parameters and resection planes, providing local quality tailored to individual patient needs. This ensures high alignment accuracy for each patient while the universal instrument maintains overall system versatility.
2Manufacturing precision
If patient-specific customized resection guides are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Patient-specific anatomical data and resection parameters are determined preoperatively through imaging and planning. This preliminary action creates a customized guide that simplifies the actual surgical procedure, reducing intraoperative complexity while maintaining high resection accuracy.
Solution Approach 2:
The cutting block is created as a physical copy or representation of the patient's unique anatomy and desired resection planes. This copying approach translates complex preoperative planning into a simple, ready-to-use surgical guide, maintaining precision while managing device complexity.
3Manufacturing precision
If alignment is optimized in extension position, then manufacturing precision for extension gap is improved, but soft tissue balance in flexion deteriorates
Solution Approach 1:
The alignment optimization is extended from a single position (extension) to multiple positions (extension and flexion). The cutting block incorporates parameters for both positions, ensuring that soft tissue balance and gap accuracy are maintained across the full range of motion rather than just in one dimension or position.
Data Source
AI summary
Provided is a method for designing a patient-specific surgical device for performing knee surgery, which includes determining a first alignment axis and/or a second alignment axis from a knee joint in extension and/or flexion respectively and subsequently designing said surgical device based on the first and/or second alignment axes. Also provided is a method of manufacturing a patient-specific surgical device designed by the aforementioned method. A patient-specific surgical device designed and/or manufactured by the above methods and a method of performing knee surgery with said patient-specific surgical device is further provided.