Arthroscopic Unicompartmental Knee Instrumentation for Precise Bone Preparation
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Solution Overview
Problem
Current methods for partial knee replacement surgery, such as unicompartmental knee arthroplasty, face challenges in easily creating precise femoral troughs and tibial sockets for secure fixation of biocompatible components, which can complicate the surgical process and recovery.
Innovation Solution
The use of a femoral component with projections for secure fixation in the femur and a tibial component with a threaded baseplate for secure engagement in the tibia, along with a template, drill pins, and cutters to form an hourglass-shaped femoral trough, and a retrograde or flip retrograde cutter to create a tibial socket, facilitating precise bone preparation and component placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional total joint replacement surgery is performed, then complete knee replacement is achieved, but incision size and recovery time increase
Solution Approach 1:
The knee replacement is segmented into a partial replacement (unicompartmental) rather than total replacement, focusing only on the affected compartment. This segmentation allows for smaller incisions, less bone removal, and faster recovery while still providing effective treatment for localized osteoarthritis.
2Manufacturing precision
If precise instruments are used to create femoral trough and tibial socket, then component fixation accuracy is improved, but surgical complexity increases
Solution Approach 1:
The template is applied to the knee joint before surgery to pre-plan and mark the precise locations for femoral trough and tibial socket creation. This preliminary action allows surgeons to accurately locate drilling sites and cutting guides, simplifying the actual surgical procedure while maintaining high placement accuracy.
Solution Approach 2:
A specialized instrumentation system serves as an intermediary between the surgeon's intent and the bone preparation. The system includes a template with guide holes, drill guides, and cutting guides that translate surgical planning into precise execution, reducing the complexity of direct bone work while ensuring accurate component placement.
3Ease of operation
If retrograde drilling is used to create tibial socket, then component insertion is simplified, but drilling precision may be compromised
Solution Approach 1:
The template is applied beforehand to mark the precise center and depth for tibial socket creation. Drill guides attached to the template ensure that retrograde drilling starts from the correct location and follows the accurate trajectory, maintaining precision while allowing the simplified retrograde approach.
Solution Approach 2:
The system replaces complex freehand drilling with a guided mechanical system. The drill guide and cutting guide provide mechanical constraints that ensure accurate socket formation during retrograde drilling, eliminating the need for complex measurements and adjustments during the actual drilling process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for more efficient and secure placement of unicompartmental knee components, reducing surgical complexity and recovery time by enabling precise and stable fixation of femoral and tibial components, enhancing the accuracy and effectiveness of knee reconstruction.
Implementation Method 1
a threaded baseplate member configured to be screwed into the tibial plateau, the tibial articular surface being securely engaged to the tibial baseplate
Implementation Method 2
The cutters are then used to drill into the femoral condyle to form an hourglass-shaped trough in the femur
Implementation Method 3
A cutter, for example, a retrodrill cutter or a flip retrograde cutter is employed to create a tibial socket from outside in
Data Source
AI summary
A method and apparatus for arthroscopic unicompartmental knee surgery which include a femoral component and a tibial component. The femoral component is installed in a trough in the femoral condyle formed by using a template, a plurality of drill pins and a plurality of corresponding cutters. The template is aligned with the curvature of the femoral condyle, the two drill pins are passed through the template and drilled into the femur, cutters are advanced over the corresponding drill pins to make holes in the femur, and the remaining hourglass shaped bone is removed with osteotomy pliers to form the trough. A tibial socket for the tibial component is formed in a retrograde manner.