Kinematic 4-in-1 Femoral Cutting Block With Shims for Cartilage Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional total knee arthroplasty methods rely on mechanical alignment or balanced approaches that do not accurately account for the pre-disease state of the patient's knee anatomy, leading to suboptimal positioning of prosthetic implants.
Innovation Solution
A 4-in-1 femoral cutting block with adjustable shims and alignment paddles that align with the patient's native knee anatomy, allowing for kinematic alignment to compensate for cartilage wear and ensure precise resection planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical alignment or balanced approach is used, then the surgical procedure is simpler, but the accuracy of implant positioning deteriorates
Solution Approach 1:
The alignment instrument is divided into multiple independent components including separate medial and lateral alignment paddles, individual shim packs for each paddle, and modular cutting blocks. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system accuracy.
Solution Approach 2:
The alignment paddles are designed to perform multiple functions: they provide alignment reference surfaces, accept shims for compensation, guide cutting block positioning, and establish resection planes. This multi-functionality reduces the need for separate instruments while maintaining precision.
2Adaptability or versatility
If fixed alignment blocks are used, then the device complexity is reduced, but the adaptability to different patient anatomies deteriorates
Solution Approach 1:
The alignment system transitions from fixed to adjustable through the shim mechanism. Shims of varying thicknesses can be inserted between the alignment paddle and cutting block to dynamically adjust for patient-specific cartilage loss, making the system adaptable to different anatomies.
Solution Approach 2:
The system allows modification of alignment parameters by changing shim thickness. This enables customization of the resection plane orientation and depth to match each patient's native anatomy while using the same basic instrument platform.
3Productivity
If multiple separate alignment blocks are used, then the adaptability to different resection planes is improved, but the device complexity and time required increases
Solution Approach 1:
Multiple alignment functions are merged into a single integrated cutting block assembly. The medial and lateral paddles, along with their respective shims and alignment surfaces, are combined with the cutting block to provide all necessary alignment and cutting guidance in one instrument.
Solution Approach 2:
The cutting block is designed to accommodate multiple cutting guides and alignment references simultaneously, allowing it to perform anterior, posterior, and chamfer cuts while maintaining consistent alignment throughout the procedure.
Data Source
AI summary
An orthopaedic surgical instrument includes a 4-in-1 cutting block and a removable alignment guide. The alignment guide is configured to contact the posterior femoral condyles of a patient's femur so as to kinematically align the 4-in-1 cutting block. A number of shims are selectively installed on the alignment guide to account for any cartilage loss present on the patient's femur. A method of surgically preparing a patient's femur utilizing kinematic alignment is also disclosed.