I assume we are talking about tibias here. What about femurs? In the case of genu varum, the femurs are straight but need to be slanted. How would it work with Precice, if it will work at all?
You should read the Paley institute booklet.
https://paleyinstitute.org/wp-content/uploads/Cosmetic-Stature-Lengthening-FAQs.pdfOn page 23, it says the following
Axial deviation is a more common problem in the tibia. the tibia tends to lengthen into valgus and procurvatum.
To prevent this the nail should be inserted at the correct starting point, which is very high and as posterior as possible on the tibia on the lateral and To prevent this the nail should be inserted at the correct starting point, which is very high and as posterior as possible on the tibia on the lateral and the frontal plane.
If the nail has space between it and the lateral cortex above the osteotomy, a blocking screw should be inserted in this space.
In other words, the proximal bone fragments are unstable because the diameter of the tibial osteotomy site is larger than the nail.
During the lengthening phase, the proximal fragment is prone to displacement due to muscle forces, and the tibia is prone to valgus deformity.
Blocking screws are used to prevent this, but if the patient originally has Bow-legs and does not use blocking screws, the Bow-legs will be corrected.
However, this is about the tibia, so if your bow-legs are associated with femoral deformity, you will need different approach.