Customized Knee Arthroplasty Spacer Fabrication
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Solution Overview
Problem
Current knee arthroplasty procedures face challenges in achieving an optimal fit between the femoral and tibial components due to variations in patient anatomy, leading to compromised prosthetic joint longevity and patient comfort.
Innovation Solution
A system and method for customizing a knee prosthesis by measuring the gap space between the femoral and tibial components during surgery and fabricating a spacer construct of optimal size using a spacer blank, which is shaped and cut on-demand using a jig and various tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard sized spacers are used in knee arthroplasty, then the procedure is simple and quick, but the fit is not optimal and prosthetic joint longevity is compromised
Solution Approach 1:
The patent combines the spacer blank storage, cutting guide positioning, and spacer fabrication functions into an integrated system. The cutting guide attaches to the tibial component and provides reference surfaces for positioning the spacer blank, ensuring precise customization while maintaining procedural efficiency.
Solution Approach 2:
The system uses pre-fabricated spacer blanks of various thicknesses that are prepared in advance. During surgery, the appropriate blank is selected and quickly customized to the exact required thickness using the cutting guide, eliminating the need for complex real-time manufacturing while achieving precise fit.
2Adaptability or versatility
If multiple standard sized spacers are kept available, then various gap sizes can be accommodated, but inventory management becomes complex and optimal fit is still not achieved
Solution Approach 1:
The cutting guide serves multiple functions: it attaches to the tibial component, provides positioning references for the spacer blank, guides the cutting tool, and ensures proper orientation. This single universal tool enables customization of any spacer blank to any required thickness, eliminating the need for multiple specialized spacers.
Solution Approach 2:
Instead of having multiple spacers with fixed thicknesses, the system uses a single cutting parameter (cut depth) to adjust the spacer thickness. By changing the cutting depth parameter, any spacer blank can be customized to the exact required thickness, providing infinite adaptability with minimal inventory.
3Reliability
If a spacer is damaged or contaminated during surgery, then the surgeon must use a different sized spacer, but the fit becomes less optimal
Solution Approach 1:
The system enables the surgeon to self-service and customize spacers in the operating room using the cutting guide and standard tools. If a spacer blank is damaged or contaminated, the surgeon can immediately fabricate a replacement with the correct specifications rather than being forced to use a suboptimal pre-made spacer.
Solution Approach 2:
The cutting guide acts as an intermediary tool that transfers the required spacer dimensions from the surgical plan to the physical spacer blank. It ensures that even in the operating room environment, precise measurements and cuts can be achieved, maintaining fit optimization despite unexpected situations.
4Manufacturing precision
If custom femoral and/or tibial components are used to compensate for gap variations, then gap space can be controlled, but the complexity and cost of the procedure increases
Solution Approach 1:
The patent extracts the gap compensation function from the custom femoral/tibial components and places it in the spacer. By using standard off-the-shelf femoral and tibial components combined with a customized spacer, the solution achieves the same gap control effect with reduced overall system complexity and cost.
Data Source
AI summary
A system and method for customizing a knee prosthesis that has a femoral component, a tibial component, and a spacer construct. A gap space exists between the femoral component and the tibial component that is measured in vivo. A spacer blank is provided. The spacer blank is shaped into a spacer construct on-demand during the surgical procedure. The spacer construct that is produced matches the optimal size needed for the gap space that was measured. The spacer blank is shaped by being placed in a jig. Various tools are then used to cut features into the spacer blank, wherein the tools are guided by the jig. This produces the spacer construct of the proper size.