Femur Cutting Template System for Knee Replacement
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Solution Overview
Problem
Current methods for preparing the femur for artificial knee implants require multiple pin repositioning of cutting blocks and templates, increasing surgical time and complexity, and custom jigs are time-consuming and costly to produce.
Innovation Solution
A positioning and template system using a datum block and cutting template assembly that eliminates the need for pin repositioning by providing a single cutting template for all femoral cuts, attached to a datum block placed relative to the transepicondylar axis, allowing precise and adjustable cuts without repositioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple cutting blocks and templates are used with pin repositioning, then femoral cuts can be made for knee replacement, but surgical time increases and procedure complexity increases
Solution Approach 1:
The patent combines multiple cutting blocks and templates into a single integrated cutting block with multiple templates that can be positioned at different locations simultaneously. This merging eliminates the need to remove and reposition pins between cuts, as all templates remain fixed to the femur during the entire cutting procedure, thereby reducing surgical time while maintaining the capability to make all necessary femoral cuts
Solution Approach 2:
The cutting block is designed as a universal device that can perform multiple functions by accommodating different templates for various cutting locations (distal cut, anterior cut, posterior cut, chamfer cuts). This multi-functional design allows a single device to replace multiple separate cutting blocks, eliminating repeated pinning operations and reducing surgical time
2Ease of manufacture
If multiple cutting templates are used with pin repositioning, then all required femoral cuts can be made, but the number of operations increases
Solution Approach 1:
The patent merges multiple separate cutting templates into a single integrated cutting block where all templates are simultaneously attachable to the femur. This eliminates the need for multiple pinning and unpinning operations, reducing the number of operations from seven or more to a single pinning event, thereby simplifying the procedure while maintaining comprehensive cutting capability
Solution Approach 2:
The cutting block serves as a universal platform that can accommodate multiple templates for different cutting locations. This multi-functional design allows all required cuts to be made from a single attached device, eliminating the need for repeated pinning operations and reducing procedural complexity
3Manufacturing precision
If custom jigs are fabricated based on CT or MRI imagery, then precise and adjustable femoral cuts can be made, but production time and cost increase
Solution Approach 1:
The cutting block is designed with preliminary reference surfaces and alignment features that can be directly registered to standard anatomical landmarks on the femur (such as the transepicondylar axis). This preliminary preparation allows for accurate positioning without requiring time-consuming custom fabrication based on imaging studies, achieving both precision and efficiency
Solution Approach 2:
Instead of creating custom physical jigs based on patient-specific imaging data, the invention uses a standardized cutting block that copies and applies general anatomical reference systems. This approach achieves sufficient precision for femoral cuts without the time and cost of custom fabrication, while still allowing adjustment based on patient anatomy
Data Source
AI summary
A positioning and template system for preparing a femur for knee replacement. The system includes a datum block, a datum block placement assembly, and a cutting template assembly. The datum block placement assembly is reversibly attachable to the datum block. Further, the datum block placement assembly positions the datum block on the femur in a measured position relative to the transepicondylar axis of the femur when the datum block placement assembly is attached to the datum. Finally, the cutting template assembly is reversibly attachable to the datum block in place of the datum block placement assembly to correctly position the cutting template assembly for guiding femoral cuts in a knee replacement surgery.