Its long been held that excessive foot pronation causes the tibia to rotate excessively internally causing a misalignment of the patella and results in patellofemoral pain syndrome or anterior knee pain in runners. Therefore, based on this you use foot orthotics to correct the foot pronation to treat the problem. Two reasonably well conducted RCT’s shows that foot orthotics are successful at that.
However:
1. Almost the cross sectional and prospective evidence shows that foot pronation is not associated with patellofemoral pain (despite the fact that foot orthotics been shown to help).
2. Even though the foot and tibia are coupled, the research as to which is the driving force, shows that it is tibial internal and external rotation that drive foot pronation and supination. It is not foot motion that drives leg motion, it is the other way around (see this discussion). This is so counter-intuitive to what podiatrists, in general, have believed.
3. More and more physiotherapists are using proximal control exercises and gait retraining to treat patellofemoral pain without the use of foot orthotics, and the evidence shows that this is just as effective as foot orthotics in treating this problem.
What is going on? Is it proximal or distal that the problem is coming from? Should we really be using foot orthotics is the problem is proximal? Should physiotherapists be using proximal control exercises if the problem is distal?
I have been in a couple of conference debates with physiotherapists at both a physiotherapy and a podiatry conference. I have learnt a lot through that and I genuinely do believe that the solution to patellofemoral pain syndrome is proximal control exercises. However, I also believe that this proximal control will not work if the ankle inversion moment (or supination resistance) is above a certain threshold (which will probably vary from individual to individual). For example, if the ankle inversion moment is low (i.e. supination resistance is low), then the proximal control exercise should work easy to help and they may not even need foot orthotics. However, if the ankle inversion moment is high (i.e. supination resistance is high), then it does not matter what you do proximally, it’s not going to work as the foot won’t move. So, therefore the role of foot orthotic in patellofemoral pain could be to reduce the ankle inversion moment to below a certain threshold, so the proximal control can work. This theory makes sense to me and is consistent with the most recent evidence.
For more see:
Foot Orthoses for Knee Pain
Foot orthoses and patellofemoral pain syndrome
Foot pronation and knee pain
Does the tibia drive the foot or does the foot drive the tibia?
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