Medial tibial stress syndrome (MTSS) is something that has always bugged me, mostly as I never actually knew what it was! There were (and still are) many conflicting opinions as to the actual pathological process. I read them all and think about them trying to sort out what it is and I still don’t get it.
Clinically, those that use foot orthoses for MTSS are in no doubt that they help and are an important part of the rehabilitation process (and include me in the group that believes that). However, like my previous views on foot orthoses for Achilles tendonitis, I was always concerned about the rationale for foot orthotics in medial tibial stress syndrome. It would make sense to use foot orthoses if there was some involvement of the posterior tibial muscle in medial tibial stress syndrome, as foot orthoses have a major impact in reducing the load that this muscle has to carry. The problem with this idea, is that I can’t find any information that implicates this muscle in the pathological process. How then can we explain how and why foot orthoses work in MTSS?
A recent concept that caught my eye was the proposal that medial tibial stress syndrome is due to increased bending moments in the tibia. When we run, there is a narrower base of gait, which will place the tibia in a more varus position (the so called, runners varus). As a result, there will be greater bending moments going through the tibia; combine that with higher activity levels; etc, then there should be an increased risk for MTSS. The effect of foot orthoses would be to reduce that bending moment (nothing to do with foot pronation!).
As a result of this hypothesis, I have started using varus wedging along the whole medial border of the foot in those with medial tibial stress syndrome to reduce the bending moments. More often than not they also still get a foot orthoses. The other option is to increase the rearfoot and forefoot varus posting on foot orthotics for runners, but I am always reluctant to include any forefoot varus posting on anyone due to the consequences of it on windlass mechanics. The full length varus wedge does not seem to interfere with windlass function as the rearfoot is inverted as well and the wedge is not that thick.
All I need to now is wait for the randomised controlled trial on this! Which raises the question we discuss at the Boot Camps about when should be implement a good idea into clinical practice when more and more people are doing it and find it helpful, when there is no evidence for it?