Last updated on May 19 2025
Description
Total Knee Arthroplasty (TKA) involves substituting the knee joint with specialized components for the tibia, patella, and femur. This procedure aims to correct deformities and restore anatomical alignment, which are crucial for extending the lifespan of the new joint components. Each femoral component is tailored to the unique anatomy of the patient, taking into account the availability of healthy bone.
Requirements
This procedure can be performed using CR, CT, and MRI images. Additionally, it is necessary to obtain representations of either the full leg or the knee. For this specific procedure, it is important to note that the CR images should depict the entirety of the patient's leg, while the CT scans will focus exclusively on the anatomical region of the knee.
Measurements
The measurements made by the procedure are displayed in the image:
2D
- Mechanical Tibiofemoral Angle (mTFA): The angle formed by the line connecting the center of the femoral head to the center of the femoral articular surface and the line extending from the center of the tibial plateau to the center of the tibial distal articular surface;
- Lateral Femoral Resection Length (lFRL): Lateral measurement in the femur designated for the resection;
- Lateral Tibial Resection Length (lTRL): Lateral measurement of the tibia designated for the resection;
- Medial Femoral Resection Length (mFRL): Medial measurement in the femur designated for the resection;
- Medial Tibial Resection Length (mTRL): Medial measurement in the tibia designated for the resection.
3D
- Estimated Mechanical Tibiofemoral Angle (emTFA): The angle formed between the estimated mechanical axis of the femur (eMAF) and the mechanical axis of the tibia (MAT).
- Lateral Femoral Resection Length (lFRL): Lateral measurement in the femur designated for the resection;
- Lateral Tibial Resection Length (lTRL): Lateral measurement of the tibia designated for the resection;
- Medial Femoral Resection Length (mFRL): Medial measurement in the femur designated for the resection;
- Medial Tibial Resection Length (mTRL): Medial measurement in the tibia designated for the resection.
Auxiliary references
- Mechanical Axis of the Tibia (MAT): The tibial length is defined as the distance from the tangent line of the distal articular surface of the tibia to the midpoint of the tibial plateau.
- Mechanical Axis of the Femur (MAF): The length of the femur is defined as the distance from the center of the femoral head to the midpoint of the femoral condyle.
How to perform
Pre-op stage
- Validate landmarks and consult measurements
Upon creating the case and uploading the image, the system will automatically place all relevant landmarks, allowing you to view the pre-operative values of each measurement.
If necessary, you can refine the position of these landmarks. Simply click on "Edit landmarks," make the required adjustments, and then save your changes by selecting "Save." The measurements will be updated accordingly, enabling you to continue to the next step by clicking “Approve.”
To reposition the landmarks, simply hover your cursor over the desired landmark and use the left mouse button to adjust each handle to the most appropriate location.
Plan stage
- Template selection and positioning
Upon the approval of the procedure, you will proceed to the templating stage. Here, you can select the manufacturer of your choice. If only one manufacturer is available, it will be automatically selected for you.
During the template configuration phase, you have the flexibility to adjust the properties of the selected template(s) and reposition them as needed.
To finalize the plan, it is essential to click on "Approve plan" and confirm the action in the dialog box that appears.
Export stage
The final stage of the planning process involves the Export step. At this point, you can download a comprehensive PDF report that encapsulates all the planning information, ensuring you have a thorough record of the procedures and measurements taken.
