Foot orthoses or gait retraining for patellofemoral pain?

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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Posterior tibial tendon dysfunction

This is the primary cause of acquired flat foot in adults. Essentially the underlying pathomechanics is that the posterior tibial tendon and muscle just give up - they can no longer do their job. Why do they give up? My understanding and experience is that all that all those with posterior tibial tendon dysfunction have a medially located subtalar joint axis. If this is the case, then it means that the posterior tibial tendon will have a much shorter lever arm to the joint axis. This would mean that in these people the muscle would have to work substantially harder than if the tendon had a longer lever arm if the subtalar joint axis was closer to a more normal or average position. After a life time of having to work so much harder, no wonder the tendon and muscle complex just give up. This is becoming more common in runners who start forefoot striking.

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Does genu valgum cause the foot to pronate?

This one has troubled me for a while.

When teaching the pediatrics part of the course here, especially the genu varum and genu valgum, it always comes up about the effect they have on foot function. Genu vaurm affects the foot as it has to pronate to get the foot flat on the ground. According to so many podiatric texts, genu valgum also causes the foot to pronate as the center of body weight is medial to the subtalar joint -- this has always troubled me ... how can opposite alignments at the knee cause the same affect on foot function Is this just another one of those podiatric myths

As part of the lecture, I mention this troubling aspect --- sometimes, I get the students to do this exercise:
Stand up with feet wide apart (simulated genu valgum, due to wide base of gait) -what does your subtalar joint feel as though its doing? -- the answer is always "supinating" ---- so how does a genu valgum pronate a foot, like so many podiatric texts claim??

Now thanks to Bart Van Gheluwe we finally got some real data:

Effects of Simulated Genu Valgum and Genu Varum on Ground Reaction Forces and Subtalar Joint Function During GaitBart Van Gheluwe, Kevin A. Kirby and Friso Hagman
Journal of the American Podiatric Medical AssociationVolume 95 Number 6 531-541 2005
"The mechanical effects of genu valgum and varum deformities on the subtalar joint were investigated. First, a theoretical model of the forces within the foot and lower extremity during relaxed bipedal stance was developed predicting the rotational effect on the subtalar joint due to genu valgum and varum deformities. Second, a kinetic gait study was performed involving 15 subjects who walked with simulated genu valgum and genu varum over a force plate and a plantar pressure mat to determine the changes in the ground reaction force vector within the frontal plane and the changes in the center-of-pressure location on the plantar foot. These results predicted that a genu varum deformity would tend to cause a subtalar pronation moment to increase or a supination moment to decrease during the contact and propulsion phases of walking. With genu valgum, it was determined that during the contact phase a subtalar pronation moment would increase, whereas in the early propulsive phase, a subtalar supination moment would increase or a pronation moment would decrease. However, the current inability to track the spatial position of the subtalar joint axis makes it difficult to determine the absolute direction and magnitudes of the subtalar joint moments." (J Am Podiatr Med Assoc 95(6): 531–541, 2005)

What say you?

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Asymptomatic pediatric flatfoot

This is another one of those perennial issues that keep coming up. Discussing it with some people is like arguing a religion (and because of the $$$ involved). Views are varied from one extreme of leaving them all alone to the other extreme of using expensive custom made orthoses every 6 months in them all. There are divergent views within the podiatric profession and divergent views within the orthopedic profession. There is even a difference between textbooks (usually depending if its published in the UK vs the USA - with the USA approach tending to be more interventionist). The evidence is limited - there is only the Kilmartin et al study. So we have to rely on expert opinion and consensus - bit hard to do when "experts" don't agree.

As an educator, I have a responsibility to expose the students to all views and approaches, and most importantly try and give them the tools to make up their own minds. I spend a great deal of time going over all the issues, especially ethical decision making in the context of the lack of any real evidence for observation vs intervention. Of course, the McDonald & Kidd paper is compulsory reading (I even promise them an exam question on it that more than half fail. HINT for students: READ THE QUESTION)

The notes the students get before the lecture are explicit:

"Considerable debate in literature as to natural history and the need to intervene if asymptomatic - ethical decision to intervene in consultation with parents.

General guidelines - treat if subtalar joint is pronated after heel off; symptomatic; severe; significant medial column collapse; significant transverse plane motion; history of symptomatic problems in parents "


What brought this up today for me, was the latest issue of the Journal of Foot and Ankle Surgery - yes I know there are no students around, but that does not mean the work stops . In it is the clinical practice guidelines from the American College of Foot and Ankle Surgeons on the Diagnosis and Treatment of Pediatric Flatfoot (its only available online to subscribers). Its a weighty 30 page documents, well thought out and the authors/committee are to be congratulated. The most interesting part for me was the flowchart for the asymptomatic flatfoot and a greater emphasis on observation of the asymptomatic physiological flatfoot than I have come to expect from publications out of the USA on this issue.


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Asymptomatic pediatric flatfoot

This is another one of those perennial issues that keep coming up. Discussing it with some people is like arguing a religion (and because of the $$$ involved). Views are varied from one extreme of leaving them all alone to the other extreme of using expensive custom made orthoses every 6 months in them all. There are divergent views within the podiatric profession and divergent views within the orthopedic profession. There is even a difference between textbooks (usually depending if its published in the UK vs the USA - with the USA approach tending to be more interventionist). The evidence is limited - there is only the Kilmartin et al study. So we have to rely on expert opinion and consensus - bit hard to do when "experts" don't agree.

As an educator, I have a responsibility to expose the students to all views and approaches, and most importantly try and give them the tools to make up their own minds. I spend a great deal of time going over all the issues, especially ethical decision making in the context of the lack of any real evidence for observation vs intervention. Of course, the McDonald & Kidd paper is compulsory reading (I even promise them an exam question on it that more than half fail. HINT for students: READ THE QUESTION)

The notes the students get before the lecture are explicit:

"Considerable debate in literature as to natural history and the need to intervene if asymptomatic - ethical decision to intervene in consultation with parents.

General guidelines - treat if subtalar joint is pronated after heel off; symptomatic; severe; significant medial column collapse; significant transverse plane motion; history of symptomatic problems in parents "


What brought this up today for me, was the latest issue of the Journal of Foot and Ankle Surgery - yes I know there are no students around, but that does not mean the work stops . In it is the clinical practice guidelines from the American College of Foot and Ankle Surgeons on the Diagnosis and Treatment of Pediatric Flatfoot (its only available online to subscribers). Its a weighty 30 page documents, well thought out and the authors/committee are to be congratulated. The most interesting part for me was the flowchart for the asymptomatic flatfoot and a greater emphasis on observation of the asymptomatic physiological flatfoot than I have come to expect from publications out of the USA on this issue.


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Quizz on Flat Feet

A clinical quiz on Flat feet at Medscape - you need to sign up for a free log in.

Quizz on Flat Feet

A clinical quiz on Flat feet at Medscape - you need to sign up for a free log in.