A question from a client:
In patients with a pediatric flat foot or a young adult with flat foot deformity …..with the STJ in neutral upon standing and the first ray doesn’t touch the ground, do you add a forefoot extension, first ray cut out or to get the forefoot on the ground?
If it is a RIGID varus, meaning you can’t push the first met head to touch the ground when the STJ is in NCSP, then I will usually add a Morton’s extension (ME) to bring the ground up to meet the first met head. I like to prescribe the orthosis with the cover glued on the posterior half only and then add a temporary Morton’s extension using 1/8″ felt in the office. I bevel it onto the orthosis. I then increase the thickness of the ME by 3mm each week, up to about 12mm. We find out what thickness feels best to the patient and then replace the temporary ME with a permanent one made of Korex. If you are able to plantarflex the first ray so that the first met head touches the ground, then I would not add a ME, but rather, just make sure you are plantarflexing the first ray to the end of the ROM during casting. Also, a first met cut-out can be added later if necessary.