Dual Tibial Stylus Instrument With Wide Convex Tips
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Solution Overview
Problem
Existing tibial resection guides in knee arthroplasty surgeries face variability in setting the level of tibial resection due to the use of narrow, pointed stylus tips, leading to potential imprecise resection of the proximal tibia, which can compromise the accurate restoration of the patient's natural joint line.
Innovation Solution
The use of wide convex stylus tips with a length and width greater than the minimum dimensions, designed to replicate the curvature of the distal femoral condyle, which provides a more representative area of the irregular tibial plateau, reducing the opportunity for imprecise resection and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If narrow pointed stylus tips are used, then the stylus can access small areas, but measurement precision deteriorates due to variability in placing the tip on the irregular tibial plateau surface
Solution Approach 1:
The stylus tip is designed with a convex surface that has a radius of curvature between 3mm and 10mm, creating a localized contact area that adapts to the irregular tibial plateau surface. This convex geometry provides a consistent reference point for measurement while maintaining the ability to access confined surgical spaces, thus resolving the contradiction between accessibility and measurement precision.
Solution Approach 2:
The stylus tip employs a convex curved surface rather than a sharp point or flat surface. This curvature allows the stylus to make reliable contact with the irregular tibial plateau while providing a reproducible measurement reference, eliminating the variability associated with placing narrow pointed tips on uneven bone surfaces.
2Device complexity
If narrow pointed stylus tips are used, then the stylus structure is simple, but manufacturing precision deteriorates due to variability in resection level setting
Solution Approach 1:
The convex stylus tip with a specifically controlled radius of curvature (3mm-10mm) creates a localized contact area that provides consistent reference points for setting resection levels. This design maintains relatively simple overall device structure while significantly improving the precision of resection level setting through the optimized local geometry of the stylus tip.
3Measurement precision
If wide convex stylus tips are used, then measurement accuracy improves, but device complexity increases due to larger tip dimensions
Solution Approach 1:
The stylus tip dimensions are optimized within specific parameter ranges: a convex radius of curvature between 3mm and 10mm, and a tip width between 2mm and 5mm. These controlled parameter changes provide sufficient contact area for accurate measurement on the tibial plateau while preventing excessive size that would complicate device handling or increase overall complexity.
Data Source
AI summary
Instruments and components for improving the accuracy of resection of the proximal tibia in a kinematic alignment total knee arthroplasty (“TKA”). Instruments include an adjustable double tibial stylus instrument comprising: a first wide convex stylus tip and a second wide convex stylus tip at a second distal end of the second stylus. The wide convex stylus tips may be fixed components of the adjustable double stylus instrument, or the wide convex stylus tips may be detachable.