Patellar Fixing System for Accurate Resection
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Solution Overview
Problem
Current total knee joint replacement surgeries face challenges in accurately replacing the patella due to the lack of appropriate alternative patellar jigs that can guide surgeons in aligning the patella with the femoral and tibial components, leading to inconsistencies in the patello-femoral gap, flexion gap, and extension gap.
Innovation Solution
A patellar fixing system that stabilizes the patella in situ using a patella jig with a clamp mechanism and a femur referencing component, allowing accurate cutting by referencing the femoral prosthesis or trial component, accommodating various patella sizes and ensuring precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the patella is cut in isolation separate from the femoral and tibial components, then the surgical procedure is simpler and faster, but the accuracy of patella resection and alignment with the femoral prosthesis deteriorates
Solution Approach 1:
The patent combines the patella resection process with the femoral prosthesis by integrating a patella guide into the femoral component. This merging allows the patella to be resected in direct reference to the femoral prosthesis, ensuring accurate alignment and proper spacing while maintaining surgical efficiency. The guide is attached to the femoral prosthesis and provides a reference surface for cutting the patella, eliminating the need for separate, isolated cutting procedures.
2Device complexity
If standard patellar jigs are used that do not reference the femoral prosthesis, then the device complexity is lower, but the alignment accuracy of the patella with the femoral and tibial components deteriorates
Solution Approach 1:
The patent merges the patella guide with the femoral prosthesis into a single integrated unit. The guide is directly attached to or formed as part of the femoral prosthesis, eliminating the need for separate, complex jigs. This integration provides a reference surface that is inherently aligned with the femoral component, ensuring accurate patella alignment without adding significant device complexity.
Solution Approach 2:
The patent introduces a reference surface or guide element that acts as an intermediary between the femoral prosthesis and the patella. This intermediary provides a physical reference for cutting and positioning the patella, ensuring proper alignment and spacing relative to the femoral and tibial components. The guide translates the positional relationship between components into a tangible cutting reference.
3Loss of time
If the patello-femoral gap is not adequately addressed during surgery, then the surgical time is reduced, but the functional outcome and balance of the knee joint deteriorates
Solution Approach 1:
The patent incorporates the patella guide into the femoral prosthesis before the actual patella resection. This preliminary positioning and reference establishment ensures that when the patella is cut, the correct spacing and alignment are already predetermined by the guide's position on the femoral component. This preliminary action eliminates the need for time-consuming measurements and adjustments during the resection process.
Solution Approach 2:
By merging the guidance function with the femoral prosthesis, the system ensures that the patello-femoral gap is automatically addressed through the fixed geometric relationship between the guide and the prosthesis. This integration makes proper gap management an inherent part of the resection process rather than a separate, time-consuming step.
Data Source
AI summary
Disclosed is a patellar cutting jig for use in a knee joint surgical procedure. The jig grips and holds a patella in situ in spatial reference to the femur to enable the appropriate cut to be made to the patella to accurately accommodate the patello-femoral gap at the replacement knee joint. The patella jig has a referencing component that provides a landmark connection between the patella jig and the femur which enables the patella clamp of the jig to be oriented relative to the reference feature prior to gripping the patella. Thus a patella held in the clamp is fixed in the cutting jig an appropriate orientation relative to the femur prior to its resection. Cutting the patella while it is referenced to the patellar groove on the femur increases the accuracy of the resection.