Patient-Specific Trial Repositioning Block for Knee Arthroplasty
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Solution Overview
Problem
Current knee arthroplasty techniques fail to accurately consider ligament conditions during surgery, leading to longer operation times and potential bone loss, as they rely on bony landmarks without real-time monitoring of soft tissue and ligament tension.
Innovation Solution
A patient-specific trial repositioning block that allows for intraoperative assessment and correction of soft tissue and ligament conditions, combining the advantages of 'tibia first' and 'femur first' philosophies, enabling precise planning and execution of knee endoprosthesis implantation with reduced operation time and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bone-referenced techniques are used, then bony landmarks can be easily identified, but ligament conditions cannot be accurately assessed intraoperatively
Solution Approach 1:
Patient-specific cutting blocks are manufactured before surgery based on preoperative CT or MRI data and 3D modeling. The blocks incorporate patient-specific anatomical surface geometry, allowing precise positioning on the femur that automatically accounts for individual ligament conditions, eliminating the need for intraoperative ligament assessment while maintaining measurement precision
Solution Approach 2:
The patient-specific cutting block serves as an intermediary device that translates preoperative planning data into intraoperative guidance. The block's patient-specific proximal reference region acts as a mediator between the surgeon's bone cuts and the final prosthesis positioning, ensuring that ligament conditions are automatically accounted for through the preconfigured reference geometry
2Productivity
If trial repositioning is performed without patient-specific blocks, then standard instruments can be used, but operation time increases and bone loss occurs
Solution Approach 1:
All positioning and measurement calculations are performed in advance during preoperative 3D planning. The patient-specific cutting block is manufactured with pre-configured reference surfaces and geometric features that directly indicate the optimal bone cut positions, eliminating the need for time-consuming intraoperative trial repositioning and subsequent bone removal
Solution Approach 2:
The invention replaces the mechanical trial-and-error approach of conventional trial repositioning with a pre-calculated, patient-specific mechanical guide. The cutting block's geometry is derived from 3D models and replaces the need for iterative mechanical adjustments during surgery, significantly reducing operation time and preventing unnecessary bone loss
3Manufacturing precision
If conventional cutting blocks are used, then standardization is maintained, but precision in defining cutting planes is reduced
Solution Approach 1:
The cutting block features a patient-specific proximal reference region that is uniquely adapted to the individual patient's femoral anatomy, while other portions of the block may use standardized features. This local customization ensures precise cutting plane definition specific to each patient's geometry without requiring complete customization of the entire device
Solution Approach 2:
The optimal cutting plane geometry is calculated in advance during preoperative 3D planning based on patient-specific anatomical data. The patient-specific cutting block is manufactured with these pre-determined geometric features, ensuring manufacturing precision is achieved through digital planning rather than intraoperative adjustment
Data Source
AI summary
A patient specific trial repositioning block is disclosed which extends the know operating technique using patient-specific cutting blocks by virtue of the fact that the soft-tissue situation or ligament tension conditions can be checked and corrected intraoperatively. The trial repositioning block can be dimensioned according to the tibia structure and femur structure. During use of the trial positioning block in an operation, the block can bring the femur to lie in a planned corrected end position on the tibia. Trial repositioning can be performed after the sectioning of the tibia, and the operator, after sectioning of the tibia, can already have an accurate picture of the end result of the operation.