I have begun a discussion on patients with both tendencies to abnormally pronate and abnormally supinate in the same foot. These are my Medial/Lateral Instability Patients. At times, pronation is the key to control, and at other times, it is the abnormal contact phase supination that is the major issue. The effect on the foot from Genu Varum and Valgum is very powerful and can produce this problem (as mentioned in my last post). Pes Cavus feet with their narrow balancing points can be prone to pronate and supinate. However, you can take any foot with a tendency to pronate, and add a severe ankle sprain with torn lateral ankle ligaments, and you are set up for this problem. Recognizing these feet should first be addressed with shoe inspection. They should bring in their top 5 for your evaluation of the biomechanics. Of course, heels are a whole other issue, and can be addressed separately.
In the case that the 5 pairs of shoes are all unstable either medially or laterally, you then have to decide if inserts can help. If 4 of the 5 shoes are pronators, then varus wedging of some sort can be helpful. If only one shoe out of 5 is lateral unstable, it is the easiest to recommend that they discontinue them, but this one may do fine with a valgus wedge of some sort.
After you think you have a handle on the shoes, and your patient’s are only wearing stable shoes for the most part, you then have to access stability. I always watch them walk and ask myself 2 questions initially: “Are they stable right versus left foot?” and “If they are not stable, how can I make them stable?” No matter what problem I am treating, I always want to make them stable. It may not be as simple as taking a good image of the foot and ordering a pair of orthotic devices, although that can be a big help.
Right now, I am happy with you beginning to recognize these patients. When I talk about patients with KevinRoot clients, I am very pleased when they can discuss the general categories of abnormal biomechanics (one of which is this Medial/Lateral Instability). Of course, our pronators are generally just medially unstable, and our supinators are generally just laterally unstable. Here is a group of interesting patients that are both medial and lateral unstable in the same foot (see image with both wedges).
Since the lateral instability is the most damaging to the body, you have to fight off that aggressively, but without making them into moderate to severe pronators. The general approach is to rate their pronation at first when you start writing your prescription. After you have written your Rx for pronation, drop the medial arch 2 mm, raise the heel cups 4-6 mm from your starting point, add a lateral phalange and Denton modification (lateral frame support). Now you have a decent orthotic device for this medial lateral unstable patient.
Next week I will discuss this further and add some exercises.
