Last updated on August 1 2024
Description
The Knee Osteotomy procedure could be used to correct an abnormal size, shape, position or composition of the leg, which may be congenital and inherited or an acquired defect. To perform the leg alignment, it is needed to have knowledge of anatomical measurements and provide the anatomical and mechanical axes of deformed limbs, which are compared to standard values, to later simulate corrective procedures.
The Knee Osteotomy procedure will advise the user to perform a correctional procedure depending on the calculated measurements. The first set of points should be marked to determine the deformity (Varus vs Valgus; Tibial vs Femoral). After determining the deformity, a second set of points should be marked according to the type of osteotomy to be performed (Distal Femoral Osteotomy or High Tibial Osteotomy) .
The procedure will correct the deformity detected using a High Tibial Osteotomy (HTO) or a Distal Femoral Osteotomy (DFO) or both combined .
Measurements
The measurements made by the procedure are displayed in the image:
Mechanical Lateral Distal Femoral Angle (mLDFA): the angle between the tangent line to the femoral condyles and the femoral mechanical axis, measured on the lateral side;- Mechanical Tibiofemoral Angle (mTFA): the angle between the line from the center of the femoral head to the center of the femoral articular surface and the line from the center of the tibial plateau to the center of the tibial distal articular surface;
- Joint Line Congruence Angle (JLCA): the angle between the lines of the femur and tibia plateau. If the apex of the angle is medial, the JLCA is positive, if it is lateral, the JLCA is negative;
- Mechanical Medial Proximal Tibial Angle (mMPTA): the angle between the tibial plateau and the tibial mechanical axis, measured on the medial side;
- Weight Bearing Position (WBP): percentage where the mechanical axis line crosses the tibial plateau line;
- Joint Line Obliquity (JLO): the angle between the tibial plateau line and a horizontal line that is perpendicular to the vertical line of the medical image.
Auxiliary references
To show this procedure, PeekMed® needs additional references:
- Mechanical Axis of the Tibia (MAT): is the tibial length, i. e., the length between the tangent line of the tibial distal articular surface and the midpoint of the tibial plateau;
- Mechanical Axis (MA): the total leg length, i. e., the length between the center of the femoral head and the tangent line of the tibial distal articular surface;
- Mechanical Axis of the Femur (MAF): is the femur length, i. e., the length between the center of the femoral head and the midpoint of the femur plateau.
How to perform
With automatic landmark detection
After selecting the procedure in the sidebar, as well as the side where you will perform the procedure, PeekMed will analyse the image and detect the landmarks.
If the detection is successful, the landmarks will be placed automatically. You can adjust them before approving the placement.
If it's not possible to detect the landmarks automatically, you will be prompted to place them manually.
You can enable/disable the automatic landmark detection in Settings.
Without automatic landmark detection
After selecting this procedure in the sidebar, as well as the side where you will perform the procedure, you must mark the points to conclude it. To see the caption of each point you need to click on this button 
Beware: you can change the position of the points at this stage or later. To do this, simply click on each handle with the left mouse button and move them to the most suitable position.
For advanced configuration, please follow the instructions below.
Advanced Configuration
With this procedure, it is possible to evaluate if the patient has a deformity. If so, a Distal Femoral Osteotomy (DFO) or a High Tibial Osteotomy (HTO) can be suggested, depending on the patient's measurements, using its corresponding option in the Object edition.
Based on the values obtained (mTFA, mLDFA, mMPTA and JLCA), the procedure configuration will suggest a type of osteotomy. In case the patient has both femoral and tibial deformities, the configuration will suggest the combination of both HTO and DFO.
After determining the deformity, a second set of points should be marked.
If HTO is to be performed:
Point 12 - Mark a point at the lateral edge for the tibia resection.
Point 13 - Mark a point at the medial edge for the tibia resection.
If DFO is to be performed:
Point 12 - Mark a point at the lateral edge for the femur resection.
Point 13 - Mark a point at the medial edge for the femur resection.
After marking the points, it is possible to perform the Osteotomy by clicking Finish.
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