Members do not see these Ads. Sign Up.

I've been asked to make orthotics for a patient, referred by an orthopedist, to help relieve "runner's knee" -- his pain is at the lateral, upper part of the knee cap. He pronates excessively in that foot, a little in the other foot. His non-weight bearing cast of that foot, taken by dorsiflexing the 4th and 5th maximally, still shows varus of about 3-4 degrees. Should this be treated by an extrinsic forefoot post to close the gap between his foot and the ground when the STJ is in neutral? If I posted this intrinsically, I'm worried it would lead to blistering in the medial arch. If I simply posted the heel to neutral and made the shell according the cast, I'm concerned that in order for the 1st met to eventually contact the ground, the orthotics is going to have to tip down medially, pulling the lateral side of the heel up -- effectively still allowing his foot to pronate and not curing his problem.... Any advice welcome....

If an extrinsic varus forefoot post is the answer, should that be tapered from 3-4 degrees at the 1st met head to nothing by the end of the great toe, or should the 3-4 degrees continue forward constantly out to the end of the great toe?

Thank you.

 

My criteria for forfoot varus posts: Have the patient stand relaxed and then try and get your fingers under one side of the foot and then the other. A foot that is functioning in a partially compensated varus will have little weight on the first met head and you will easily be able to get your fingers under the first met head. In that foot it will be nearly impossible to get your fingers under the lateral side of the foot. If you see that then add a forefoot varus extension. If the first met is well loaded, do not add a varus extension. I don't know if the distal taper of the extension really matters in terms of function. The big problem with a full length extension is getting the orthotic, and the foot, into multiple shoes.

You are correct in noting that a forefoot varus intrinsically posted orthotic, made with the classic Root protocol, will tend to have a high medial arch. A high medial arch will tend to cause blistering along the edge of the orthotic. What a lot of labs do is add enough medial arch fill to lower the height of the arch to where it would be if there were no varus correction. This usually works quite in preventing symptom relief and preventing blisters. Of course, this really puts into question the explanation of how orthotics work. Do you really need to capture the foot in neutral position when you cast? Is it just enough to have some pressure in the arch. I ask for a specific arch height. Have the patient stand and press comfortably into the arch and measure the height of your finger off of the ground. This is not neutral position this is resting stance. You don't need to worry about neutral position. You just need to worry about the orthotic applying tolerable forces to the foot.

Eric

 

Thank you very much, Eric, that is very clear/helpful. Andoni