Tibial Resection Guide Alignment Using Distal Femur Reference
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Solution Overview
Problem
Existing femoral resection assisting devices in total knee arthroplasty require resecting the proximal tibia using the distal femur as a reference surface, which is inefficient and does not account for the flexion axis of the knee joint, necessitating a device that can utilize the distal femur's resection surface as a reference.
Innovation Solution
A tibial resection assisting device with a base, femoral and tibial paddles, a movable body, and a reference guide that allows the tibial paddle to be swung and positioned orthogonally to the femoral paddle, enabling the use of the distal femur's resection surface as a reference for setting the tibial resection surface, while applying tensile force to soft tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the proximal tibia is resected first using the distal femur as a reference surface, then the surgical procedure can be completed, but the flexion axis of the knee joint is not properly accounted for and the surgical precision is reduced
Solution Approach 1:
The device employs a movable body that can be positioned at different locations along the mechanical axis of the tibia, allowing dynamic adjustment of the reference point. This enables the surgeon to switch between using the proximal tibia resection surface as a reference (when the movable body is positioned proximally) and using the distal femur resection surface as a reference (when the movable body is positioned distally), thereby resolving the contradiction between surgical precision and operational efficiency
Solution Approach 2:
The device changes the reference surface parameter dynamically during the surgical procedure. By moving the movable body along the tibia's mechanical axis, the system transitions from one reference configuration (proximal tibia) to another reference configuration (distal femur), allowing optimal precision for different surgical stages without compromising overall operational efficiency
2Manufacturing precision
If the femoral paddle is made swingable to apply tensile force to soft tissues, then the position of the resection surface can be accurately set, but the device complexity increases
Solution Approach 1:
The device is segmented into functionally independent components: a base, a movable body, a femoral paddle mounted on the movable body, and a tibial paddle. This segmentation allows the femoral paddle to be swingable independently to apply tensile force to soft tissues for accurate resection surface positioning, while the tibial paddle remains stable on the tibia, thus achieving high positioning accuracy without excessive overall device complexity
Solution Approach 2:
The movable body serves multiple functions: it supports the femoral paddle, provides the swinging mechanism for applying tensile force to soft tissues, and allows positional adjustment along the tibia's mechanical axis. This multi-functionality reduces the need for separate components, thereby achieving accurate resection surface positioning without proportionally increasing device complexity
Data Source
AI summary
A tibial resection assisting device includes: a femoral paddle including a first contact surface brought into contact with a resection surface of a distal portion of a femur; and a tibial paddle including a second contact surface brought into contact with a proximal portion of a tibia that is unresected. The femoral paddle is mounted to a base disposed at an anterior side of a knee joint. A movable body mounted to the base is movable in an orthogonal direction to the first contact surface. The tibial paddle is mounted to the movable body and is swingable about a swing shaft that extends in an anterior-posterior direction of the knee joint, the anterior-posterior direction being parallel to the first contact surface. Further, a reference guide mounted to the base is movable in the orthogonal direction and is intended for positioning a tibial cutting guide.