Sagittal Saw Guide for Knee Arthroplasty Alignment
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Solution Overview
Problem
Current knee arthroplasty procedures lack accurate and cost-effective methods for positioning and orienting prosthetic components during distal femur and proximal tibial resections, often relying on complex and expensive navigation systems or inaccurate visual alignment.
Innovation Solution
A system and method utilizing guide pins, sagittal saw guides, and inertial sensors to accurately position and orient cutting blocks and implants, ensuring precise alignment based on the mechanical axis of the femur and tibia, and using orientation devices with processors to gather and analyze kinematic data for optimal implant placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex computer navigation systems are used to track spatial location and movement of surgical instruments, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The navigation system is segmented into separate functional components: a guide pin embedded in the femur to establish a reference axis, a sagittal saw guide that couples with the guide pin, and a saw registration feature for cutting the tibia. This segmentation eliminates the need for complex computer navigation systems while maintaining alignment precision through mechanical reference structures.
Solution Approach 2:
The guide pin acts as an intermediary element that transfers the mechanical axis reference from the femur to the sagittal saw guide, which in turn positions the saw registration feature over the tibia. This mechanical intermediary chain replaces complex optical or computer-based navigation intermediaries.
2Device complexity
If simple visual alignment methods are used to align rods with anatomical features, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The guide pin is pre-placed in the femur to establish a mechanical reference axis before the tibial cutting procedure. This preliminary action creates a fixed reference that guides subsequent positioning of the sagittal saw guide, eliminating the need for complex real-time navigation while ensuring accurate alignment.
3Manufacturing precision
If expensive navigation systems with three dimensional imaging are used, then manufacturing precision is improved, but cost increases
Solution Approach 1:
The system uses simple, inexpensive mechanical components (guide pin, sagittal saw guide, and saw registration feature) that can be easily manufactured and disposed of, replacing expensive, complex navigation systems with three-dimensional imaging capabilities. The low-cost mechanical references provide sufficient cutting precision without the high cost of advanced navigation equipment.
Data Source
AI summary
The present invention provides, in certain embodiments, a device for positioning and orienting the femoral cutting block. The present invention also provides a device for setting rotation of sagittal resection for unicompartmental knee arthroplasty. The present invention further provides methods for setting the rotation of the tibial implant by kinematic measurements.