Orthoses vs. Footbeds. A Podiatrist's view

[Podski]

A (one week a year) skiier for almost 30 years and Podiatrist for over 20 years, I have more than a passing interest in the biomechanics of skiing and techniques to help the skier having difficulty and fine tune the proficient skier.

Orthoses are generally used to help the foot function around its neutral position during gait and because this neutral position is where we want the foot at mid-stance, it is also appropriate for skiing as this is effectively how we should stand whilst skiing.

Granted the knees and ankles are flexed but the sub talar joint is in neutral and the mid tarsal joint maximally pronated.

How do we assess the subtalar neutral? Usually with the subject prone and the foot hanging over the end of the examination couch with the leg internally rotated so that the foot is hanging straight down (not adducted and, most importantly, not abducted) we feel for congruency of the talo-navicular joint, ie the talar head is neither prominent on the medial nor lateral aspect of the navicular. Observation of the concave curves above and below the medial malleolus for when they are similar can also be employed.

With the sub talar joint in neutral, the midtarsal joint is maximally pronated to resistance by dorsiflexing the fourth and fifth metatarsal heads gently.

Assuming the a bisection of the lower third of the leg is perpendicular to the ground, if you were to observe bisections of the posterior aspect of the lower leg and calcaneus, they should be parallel and similarly the plantar surface of the heel and plantar surface of the forefoot should be parallel. Any variations from this will require the foot to compensate by pronation or supination around the subtalar and/or mid tarsal joints and this results in compromised foot function.

To be effective orthoses need to address the alignment issues outlined above to support the foot in neutral.

Skiing requires relatively small degrees of pronation and supination of the subtalar joint to place pressure on the inside or outside of the ski to effect a turn and if the foot has used most of its pronation range to compensate for a forefoot varus you will have to employ other less efficient methods to maintain pressure on the inside edge of the downhill ski. Like internally rotating the leg and tucking the knee behind the uphill knee. Other foot pathologies result in other compensations.

Do Podiatrists have a role to play here? I believe we do, particularly in the pathological foot type.

I'd like to know more about footbeds and their prescription before commenting. My guess is that is very dependent upon the skill and knowledge of the fitter.

Cheers smile.gif

[ 13.07.2007, 08:40 AM: Message edited by: Podski ]

[SA]

Wow. Fantastic first post Podski. graemlins/snow.gif

Your contribution here is going to be invaluable.

[Paul Oberin]

Thanks Podski, it is good to get a confirmation that what I have been doing for a few years now is the same as what you podiatrists also do when finding sub talar neutral, the other area we need to pay special attention too because of the constrictions ski boots place on feet is the pressure on both the Deep peroneal and superficial peroneal nerve, but also being aware of the need for met domes on a regular basis, with dropped met heads. last week we had to make provision for the Plantar fascia tendon for a customer as well.
Forefoot stabilisation is an area where footbeds also play a part now in a ski boot, and there is becoming an increased demand for canting as well as cuff alignment, so the standard keeps on getting better.

[ 13.07.2007, 01:13 PM: Message edited by: Paul Oberin ]

[Podski]

Thanks SA, I do hope I can use my professional expertise to contribute.

On further reflection I have to acknowledge that whilst the vast majority of feet that come through my door have pathologies, this is by no means representative of the general population who would be skiing.

As I stated in my first post, the pathological foot that either pronates or supinates excessively to the point of developing symptoms will benefit most from prescription orthoses.

But what about the normal foot? The foot that has a normal range of motion around all joints and functions around its neutral position? Given that the ski is sensitive to small degrees of inversion (supination) and eversion (pronation), will a footbed that can translate the foot motions to the ski quickly be noticeably better to the expert? I'm not sure.

BUT... 80% of the population have some sort of lower limb mis-alignment ranging from so minor so as not to cause symptoms to severe. It is these minor mis-alignments that will be beneficiaries of improved control the footbed provides. Note that I don't limit the mis-alignments to the foot, you also need to look as high as the pelvis and everything in-between.

So if you're lucky enough to be one of the minority with the perfect alignment, you won't benefit form orthoses or footbeds. If however you're like the rest of us there is probably room for improvement in your biomechanics.

Comments?

[Podski]

Yes good to hear Paul, I'm interested that you needed an plantar fascial accommodation as we regularly put these in orthoses as the fascia bowstrings with flexion of the first metatarso-phalangeal (MTP) joint during the propulsive phase of gait, which of course does not happen whilst skiing.

What I have seen more of recently are Plantar Fibromas within the Plantar fascia which are generally pea sized lumps about mid arch. These are perfectly benign and are generally not excised but would need to be accommodated for in the orthosis or footbed.

With regards to forefoot posting, you'd need to look at the relationship between the forefoot and rearfoot in neutral to see what was appropriate but in a relatively normal foot have you tried adding a small (< 4 deg) valgus post under the fifth met head? The rational here is to make sure the mid-tarsal joint is maximally pronated and thereby locked. Make sure it doesn't pronate the sub-talar joint however.

[Rednut]

Podski i'm the PITA with plantar fasciitis however you spell it ;)

I wear an orthotic daily, and without the accomodation in my footbed it was creating pain through the tendon...

Paul had a great time trying to work out the best way to deal with it :D but had the best foot day on snow i've had for a long time sunday after he fixed them!

[ 13.07.2007, 01:47 PM: Message edited by: Rednut ]

[John Deere]

Aparently I also have carpola feet (a technical term I believe!)

Recommend a Podiatrist/skier in Sydney Podski????

[Rednut]

ian thomas i think his name is jd...

[Podski]

Top of the class for spelling Rednut! Certainly if you have an inflamed plantar fascia it is wise to make an accommodation for it.

Is it just one foot or bilateral?

[Rednut]

both feet, but worse in the left

[Podski]

This is useful for searching for Podiatrists,

http://www.findapodiatrist.org/index.asp

I know Paul Bours is a skier and is in the Sydney CBD. Michael Kinchington was heavily involved in sports podiatry and the 2000 Olympics and so knows his biomechanics. Otherwise contact the Podiatry Association.

[dopestyle]

Podski, it's really good to have you here.

I have a few comments and questions for you.

I am a snowboarder, riding over 100 days a year. I have used orthoses since I was a kid. I get new ones made every year or so. In my snowboard boots, I use custom made footbeds (with additional support (d-block)). I get these fitted by an expert boot fitter. The difference they have made for me is incredible. I couldn't imagine riding without it. Not only does it support my foot, but I also feel I get better performance in my riding.

Now it gets interesting.

Firstly, I have been told on numerous occasions (from snowboarders to chiropractors, and even podiatrists)... wearing orthoses for a high impact sport like snowboarding, especially on heavy landings etc... can be damaging to your foot to have them in. Footbeds in material are more suited to high impact sports. From what I have felt under my foot, I tend to agree.

Now, after having my first pair of custom footbeds fitted, which I used for over 200 days problem free... I thought it might be a good idea to get a footbed made by my podiatrist, instead of a ski shop. I took in my old footbeds to show him. So he made a cast and we had it made. Unfortunately, they didnt feel nearly as good in my boots as the footbeds. I just couldnt get the same board feel with the ones made by my podiatrist. After going abck to the podiatrist, we both came to the conclusion that the footbeds made by the ski shop, were actually better and more suited for snowboarding. He actually sent me back to the ski shop to get another pair. So I got another pair of footbeds made. Of course, as stated before, getting them made properly is obviously essential.

Personally, from what I have seen, orthoses are too rigid for riding, and the footbed made by the podiatrist was too floppy. The footbeds at the ski shop seem to be the perfect rigidity. It's a bit disappointing.

I guess I didn't really have a question for you... Im sure i'll come up with something ;) Just thought I would share my experience with orthoses and footbeds as a snowboarder.

[ 13.07.2007, 07:21 PM: Message edited by: dopestyle ]

[Podski]

That is interesting dopestyle.

I can imagine the thicker (5mm+) polypropylene orthoses would be too rigid. We are more often using EVA full length now in densities from 220 - 400 durometer, but mostly 260 or 350.

What material are footbeds generally made from?

With regards to boarding I would have thought that you would use more ankle joint plantarflexion and dorsiflexion and relatively little inversion / eversion so I'm intrigued that the footbed helps as much.

Is there more frontal plane motion used in boarding than I realise?

I'll post some pics of an EVA device later on for interest.

I'm skiing at Falls in the third week of August, is there a boot fitter there I could visit so I could better understand and compare footbeds?

Thanks.

[Rednut]

I believe there is a masterfit trained bootfitter at the falls creek motel i think... maybe drop paul an email, he's about 90 minutes away in wodonga

[dopestyle]

The footbeds I have are made by footworx. Im not exactly sure what they are mad of. They are quite rigid, but still softish to touch. I'll take a photo when I have time and post. What density would you recommend for a full length orthoses for boarding? I would really like to get a set made by my podiatrist, but I want to get it right this time. The ones he made me were more foam like with a soft, floppy material glues on top (and the foam wasn't full length, only the material was).

I guess they helped me a lot, because it gives me support all the way through to my knees, and excellent feel under my feet. Advanced snowboarding uses the joints closer to the board (foot, ankles) for more precise riding. A lot of pressure goes through the inside of the legs, up to the knees. And as I mentioned, I ride a lot, so I feel things a bit more than the week a year boarder.

[loc]

i found my orthotics hamper my foot movement in my snowboard boots as they are hard an inflexible (half shoe type). I find the same when doing calf raise in the gym. I get better extension through ankle etc with out them. But they are invaluable to my running etc!!

Podski - i tend to get cramps through the arch of my foot when doing strenuous exercise. Not all the time but everynow and then it hits. Get it in rugby boots, runners, and my snowboard boots. I don't think shoe tightness is a problem as they r never done up super tight. any ideas?

[Podski]

With regards to cramping, I assume it is a genuine muscle cramp which resolves fairly quickly with stretching the muscle (flexing the big toe up and holding) as opposed to a strain of the plantar fascia or some other more rare condition such as compartment syndrome or intermittent claudication.

I really need more info and shouldn't really attempt to diagnose something remotely.

Here's a pic of a typical flexible EVA device with met dome and plantarfascial groove.

http://i141.photobucket.com/albums/r80/OzSTi/Orthosis.jpg

[dopestyle]

whats the point of that bump in the middle?

[Taxman]

dopestyle the dome is a met(atarsal) dome. Richard Mould added a met dome (not as prominant) to my foot beds. My cycling shoes (Specalized Tahoe) came with a met dome built in.

They work, not sure how but they do (reduced fatigue & cramping). Perhaps podski or Paul would care to explain.

[ 16.07.2007, 12:48 PM: Message edited by: Taxman ]

[John Deere]

How does a podiatrist decide what size met dome is required?

[John Deere]

The mrs says I should throw a spoon in my shoe graemlins/big_laugh.gif

[Taxman]

Pebbles, Grasshopper, pebbles.

[Podski]

Metatarsal domes are used for a few reasons. Placed centrally as shown they support the second and third met heads to maintain the transverse arch and encourage plantarflexion (downwards motion) of the first metatarsal. This is particularly important during gait but even with the relative static stance of skiing it would facilitate inner edge control.

The material is quite soft and size is relative to the foot and contour of transverse arch of the individual. Not all feet lend themselves to these.

The domes may also be place more lateral under the third/fourth met heads with a Morton's neuroma to reduce the compression on the nerve.

Larger ones and even a slightly wider shape are good to unload painful met heads and inflamed joint capsules.

[Taxman]

Thanks for the explanation Podski.

[tambo]

Wow. I'm impressed! This is very technical! Love the explanations and the chance to understand more. All I want are ski boots that I'm able to wear day after day, and that don't give me pins and needles in my toes. I'm still struggling with that. And I still haven't been able to get custom foam liners (Strolz?)

[John Deere]

Paul O does foam liners I think (sidas???). Strolz aint the only ones!

[Taxman]

Foam may be overkill with the availablility of Thermofit liners.

[tambo]

Originally posted by John Deere:
Paul O does foam liners I think (sidas???). Strolz aint the only ones! went for a visit... sadly he didn't have the size I needed and there's a time to warm the foam. We are 3 hrs from him, and I'd left the kids at home. Would have to be an overnighter for me to get back to Paul for the liners :(
Had booked the chopper to Falls, but also :( both the chopper and the fitter cancelled. He couldn't do it either. So I still have sore feet and need to unbuckle after every run :(

[Caboose]

i have had Heel Spurs (Planta Fascilitis??) & now wear orthodics all day and while riding (boarding)

Due to the fact of having a high arch and therefore a large knuckle supporting that arch

i haven't found any problems with riding and landing with these foot beds (made by Poddy not boot fitter)& think actually it feels better becuase of the support

[ 17.07.2007, 11:16 AM: Message edited by: Caboose ]

[Caboose]

hmmm alot of I's in that post ..... :rolleyes:

[SA]

Can footbeds help you get an edge in?

graemlins/outtahere.gif

[Podski]

Originally posted by SA:
Can footbeds help you get an edge in?

graemlins/outtahere.gif Footbeds / Orthoses will help set and maintain an inside edge particularly if you have a problem foot.

Either the flat pronated foot that has already used up its pronation range to get the forefoot plantargrade and in full contact with the ground and has no more range left to put pressure under the 1st met head to evert the ski to get the inner edge. 1st ray (1st metatarsal and medial cunieform) will dorsiflex up and most pressure will be under the second met head.

Peroneus Longus muscle that originates from the lateral leg and its tendon that ducks under the cuboid before inserting under the base of the first ray to provide a plantar-flex force, only has an effective force vector in the neutral foot. In a pronated foot what was a plantar flexor can become a dorsiflexor and totally in-effective.

The high arched cavus foot is supinated and Peroneus Brevis (next to P Longus but inserts into base of fifth met) is overused and may not be able to effectively evert the foot to set the edge.

Foot mechanics are fun!

[Rednut]

that's certainly one way of describing them podski ;)

[tambo]

I think i have some readiang to do.
Can you reccommmend a basic site, Podski?
Thanks!

[Podski]

Originally posted by tambo:
I think i have some readiang to do.
Can you reccommmend a basic site, Podski?
Thanks! Charles Sturt Uni at Albury-Wodonga has a Podiatry course, not too far from you!

http://www.csu.edu.au/courses/undergraduate/podiatry/
;)

[kazo0]

Hi podski,

I'm a bootfitter in Brisbane, just joining in on the conversation! RE: your post about the 20% of people with normal feet, as a boot fitter (who is masterfit trained, but not a podiatrist!), by knowing that your customer is being supported inside a ski boot and is consistently standing in the correct position inside the boot (with heel firmly in the back of the boot), you can then turn your attention to the boot for necessary modications. We won't address upper cuff alignment and canting in a boot without a footbed. Sometimes, by simply adding a footbed can help anchor the heel in the back of the boot without the need of adding foam wraps etc.

In saying all this though- I am my own worst nightmare when it comes to footbeds. Boots too actually, which is why i became a boot fitter. I'm currently on a search for a podiatrist with a firm skiing knowledge to help me!

What state are you in Podski?