Here is the patient with knock knees or Genu Valgum and Rear Foot Valgus deformities. In an ideal world, the subtalar joint could stay in neutral where the foot and ankle lined up although everted.
If we were to measure this patient, the heels would be everted to the ground the same degrees of genu or tibial valgum.
However, reality sets in, and one of two things happens. The subtalar joint supinates to bring the heel vertical or close to that position (as shown on the right side), or the foot collapses more medially with subtalar joint pronation getting more everted than the tibial valgus position as seen on the left side. The right foot needs an orthotic that allows for contact phase pronation and I set it to typically pronate from 6 everted to 10 everted by using the inverted orthotic device of 20 degrees or a 4 degree change and then grinding 4 degrees of motion into the rear foot post. The left foot needs to get them close to their everted neutral position of 10 degrees everted typically with a 25 degrees inverted orthotic device.
