Adjustable Cut Block and Sizer for Arthroplasty
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Solution Overview
Problem
In revision knee surgery, achieving precise measurements and cuts on bones during arthroplasty procedures is challenging due to the complexity of referencing natural joint lines and accommodating varying femoral anatomy, leading to potential malposition of the joint line.
Innovation Solution
An adjustable 4-in-1 cut block and sizer instrument that allows for precise sizing and cutting by adjusting the relative positions and angles of anterior and posterior cut guides, chamfer blocks, and shims, enabling accurate alignment with femoral anatomy for optimal implant placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate instruments are used for sizing, cutting, and referencing, then each function can be performed with dedicated tools, but the overall procedure becomes more complex and time-consuming
Solution Approach 1:
The patent combines multiple separate instruments (AP sizer, knee tensor, cutting guides, and referencing tools) into a single integrated instrument assembly. The femoral tool includes integrated components for anterior-posterior sizing, knee balancing, and cutting guidance, all referenced to common anatomical landmarks. This merging reduces the number of separate instruments needed while maintaining the reliability of each function through shared reference points and coordinated design.
2Ease of operation
If approximate referencing landmarks are used for joint line positioning, then the procedure is simpler, but the precision of joint line restoration deteriorates
Solution Approach 1:
The patent introduces an intermediary referencing system that uses multiple anatomical landmarks (epicondyles, patella, fibular head) in combination with mechanical reference features on the instrument. The femoral tool includes reference surfaces and alignment features that mediate between simple landmark identification and precise joint line positioning, allowing the surgeon to achieve accurate restoration through the intermediary mechanical guidance system.
3Ease of operation
If fixed-position cut guides are used, then the cutting procedure is simpler, but the adaptability to varying femoral anatomy is reduced
Solution Approach 1:
The patent employs dynamic, adjustable cut guides that can be positioned and configured to accommodate varying femoral anatomy. The femoral tool includes adjustable cutting guides with movable components that can be adapted to different anatomical configurations while maintaining ease of use. The guides can be repositioned along the femur and adjusted to match individual patient anatomy, providing both simplicity and adaptability.
4Adaptability or versatility
If multiple adjustment mechanisms are added to accommodate varying anatomy, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The patent designs the femoral tool with universal, multi-functional components that can accommodate varying anatomy without requiring numerous separate adjustment mechanisms. The integrated instrument assembly includes components that serve multiple functions: the same reference landmarks are used for sizing, balancing, and cutting; the cutting guides can accommodate different resection depths and angles; and the overall assembly can be adapted to various femoral geometries. This multi-functionality reduces device complexity while maintaining high adaptability.
Data Source
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AI summary
An integrated instrument for arthroplasty planning comprises a cutting block having an adjustable distance between an anterior cut guide and a posterior cut guide, and a sizer mounted to the cutting block, the sizer comprising medial and lateral posterior feet having an adjustable distance from one of the cut guides and an adjustable angular position relative to the one of the cut guides.