Lateral foot wedging for medial knee OA

Craig wrote that he has a study - not sure if published yet ?

It was to do with the lenght of the lateral post - the longer the more effective, in some of my patients with O/A Medial knee require full length wedge others not.

 

'Goodaye Michael, are you the new father?
Do you start by giving them all just rearfoot or full length then what? How do you determine which is indicated? Thanks

 

Hiya Mark,

3 months on Wednesday to Oliver - so yep thats me. Oliver has his passport and will see OZ for 3 weeks over Christmas - got get the OZ Education started early.

As for the lateral wedge I usually start with just rearfoot 1st and then if required add more.

Again I think it was Craig who said that people who are maximally pronated ie those who have the ground stopping the motion of pronation have the best result with lateral wedges for medial knee O/A

So this got me thinking, with using lateral wedges 1 the wedge must pronate the foot to end range where the GRF medial to the STJ axis is the opposite reaction to the wedge OR the use of a ORF medial to the STJ axis is certain foot types could have the same effect. But this is just my thinking !!!!

Which seems to work well . So I add the rearfoot wedge intrinsic to the Polypro device, the intrinsic skive I extend past the cuboid and then usually add an EVA post under to reduce the flex of the plastic under the Skive.

Depending on things like navicular drop ROM available will depend on how high the arch of the device is.

When the patient come back for their 1 month review thats when I consider the Full length EVA Wedge which is glue on top of the device. I try to use a step by step process as I found with these patients too much soon can lead to other issues.

As I make My own devices I´ve experimented around a little and have had some success, but it just my interpretation.

Hope that helps some and makes sense

 

Rana S. Hinman, Kelly Ann Bowles, Craig Payne, Kim L. Bennell: Effect of length on laterally-wedged insoles in knee osteoarthritis. Arthritis Care & Research, Volume 59 Issue 1, Pages 144 – 147, 2008

My theory is that a full length wedge has a greater lever arm to the STJ axis to exert a moment up the leg. If thats right, then a heel wedge should be adequate to get a good lever arm if the STJ axis is more medially located ... just a thought.

 

'day Craig, just started reading the article, thanks, and didn't get far before,
"The rearfoot insoles were wedged from the calcaneus to the mid-shaft of the fifth metatarsal base."
Would you re-describe the last bit using simpler words, as I can't imagine where that is exactly, mark

 

It depends how much forefoot varus supinatus. A high degree of varus (tibial varum, rearfoot varus and forefoot varus) will make it so that the range of motion of eversion of the forefoot (at all joints that allow forefoot eversion) will be used up and the pressure will be lateral. The pressure will be lateral because there is not enough range of motion to get significant weight on the medial forefoot. In this case an additional forefoot valgus wedging would not be needed.

On the other hand, a "supinatus" can be caused by high medial forefoot loads. In this foot there is typically enough range of motion to allow significant medial forefoot loads. In this situation a lateral forefoot wedge may help both the knee and the overloaded medial forefoot.

For wedging, it all depends where the load is, and where you want to move it to. The theory is that the further lateral the center of pressure is on the foot, the less knee adduction momnet, the better it is for MEDIAL knee arthritis.

Eric

 

No takers? My problem is if this is describing the distal edge of the rearfoot wedge on the lateral border of the foot then how can you have "mid-shaft" and "base"? It's one or the other isn't it?, mark

 

My clinical experience of using valgus rearfoot and forefoot wedging for the past 20 years to treat medial knee osteoarthritis (OA) is that "foot type" is not that important since all types of feet tend to respond to these valgus wedges with reduced medial compartment pain. As long as the valgus wedge shifts the ground reaction forces more laterally on the plantar foot and/or pronates the subtalar joint, then the medial compartment of the knee will have reduced intracompartmental compression forces and reduced pain. It all comes down to adding just enough valgus wedging to reduce the knee pain but without causing observable gait dysfunction or increased pain elsewhere in the body.

I realize that many believe that different foot types will need different levels of valgus correction to reduce medial compartment OA pain. However, in my clinical experience, I haven't necessarily seen this to be the case.

Is there any research evidence that different "foot types" need different levels of correction to effectively treat medial knee OA......or is this just a guess?

 

Mark:

I don't know what others do in regards to these valgus wedges. However, illustrated below is the shape of the adhesive felt temporary wedges I have been adding to the shoe insoles of my patients with medial knee osteoarthritis for the past 20 years. This design works great and is nearly always very well tolerated by the patient. Lesser or greater valgus wedging may be used depending on the comfort and the gait function of the patient.

 

Thanks Kevin, excellent, that diagram, that's got me thinking!
Love the 'chalet' on the lake!

 

Hi Kevin in my case Just a "guess" with feedback - mainly to do with patients comfort.

I´ve found that the Classic ´pes cavoid´foot type patients did not find the lateral wedge only device as comfortable as a having some arch contour built into the device, ie some navicular push.

As an aside added a posting similar to your picture today - patient " that sharp pain in my knee has gone" only a little walk but nice to get a smile 1st patient of the day.

 

An analysis of the mechanisms for reducing the knee adduction moment during walking using a variable stiffness shoe in subjects with knee osteoarthritis.
Jenkyn TR, Erhart JC, Andriacchi TP.
J Biomech. 2011 Mar 9. [Epub ahead of print]

 

Efficacy of knee braces and foot orthoses in conservative management of knee osteoarthritis: a systematic review.
Raja K, Dewan N.
Am J Phys Med Rehabil. 2011 Mar;90(3):247-6

 

1. A scientist has a theory does experiments and comes to a conclusion, then applies the test "Does this all make sense". Have I applied the test?
2. Open the horses mouth and count the teeth. Have I counted the teeth for myself?
3. Have I locked myself in an "Ivory Tower" of ethical superiority, accusing other caring doctors?
4. Have I missed the big picture by focusing on the angle of the dangle forgetting my job of alleviating pain and suffering?
5. Everyone appears right in their own mind. Can I stop "parenting my positions"?

 

Maybe it my lack of sleep at the minute but can anyone explain what the above means.???

 

Joseph, welcome to podiatry arena. Interesting first post. I'm not quite sure how to interpret it. I'm going to give you my interpretation of what you are trying to say. Let me know if I'm wrong.

It appears you are skeptical of lateral wedging for medial knee OA and are questioning the science. Your post is also confusing in that you use the pronoun "I" when you appear to mean you. Is this interpretation correct?

Well the studies do make sense. You can use the keywords knee abduction or knee adduction moment to help you find why it makes sense.

Joseph, I'll ask similar questions of you. Have you locked yourself in an ivory tower and are you accusing caring scientists. Have you missed the big picture by not exploring new information?

Joseph, I hope I'm wrong, but your post appears to be a rant on those who you feel believe, erroneously, that lateral foot wedging would help medial knee OA. If you feel that our beliefs are incorrect you should clearly state that and explain your reasoning.

Eric

 

Explanation
I read a thread on lateral foot wedging for medial knee OA. While reading the thread I became frustrated with Kathleen Reilly. My frustrations with her posts, I turned into a self examination. I did this in order to see if I had fallen into the same perceived traps. I think I have posted my comments on the wrong lateral foot wedging thread.

 

I think the post which came as a result of frustration with my input is the most unusual response I have heard. There are several more papers recently published which find that there are links between pronated feet and knee pain and even one which finds that people with medial compartment OA exhibit a mor pronated foot type (Foot posture in people with medial compartment knee osteoarthritis - Pazit Levinger, Hylton B menz, Mohammad R Fotoohabadi, Julian A Feller, John R Bartlett, and Neil R Bergman, Foot and Ankle Research 2010: 3.29) so I am no longer alone. My main critisism of lateral wedging research was the lack of examination of the foot to which the wedge was being applied. Can this be justified ?
kathleen reilly

 

Effect of center of pressure modulation on knee adduction moment in medial compartment knee osteoarthritis.
Haim A, Wolf A, Rubin G, Genis Y, Khoury M, Rozen N.
J Orthop Res. 2011 Apr 13. doi: 10.1002/jor.21422. [Epub ahead of print]

 

wedges and knees

netizens

Passed on in good faith
http://www.familypracticenews.com/n...n-t-take-the-load-off-knee-oa/392e68dc0f.html

toeslayer

 

The effect of laterally wedged shoes on the loading of the medial knee compartment-in vivo measurements with instrumented knee implants.
Kutzner I, Damm P, Heinlein B, Dymke J, Graichen F, Bergmann G.
J Orthop Res. 2011 Jun 8. doi: 10.1002/jor.21477. [Epub ahead of print]

 

Lateral wedge insoles for medial knee osteoarthritis: 12 month randomised controlled trial
Kim L Bennell, Kelly-Ann Bowles, Craig Payne, Flavia Cicuttini, Elizabeth Williamson, Andrew Forbes, Fahad Hanna, Miranda Davies-Tuck, Anthony Harris, Rana S Hinman
BMJ 2011; 342:d2912

 

Thx for the diagram Kevin, gives a better better description than just 'lateral wedge' in the literature
just a question here, is there any significant difference b/w having the wedge with or without a CFO in terms of applying a greater moments to the STJ?

 

For milder problems, I will just use an valgus forefoot and rearfoot wedge added to the shoe insole. For moderate medial knee OA, I prefer using a foot orthosis in order to try and limit the subtalar joint pronation from the valgus wedge.

 

Have Craig or his team been able to assess why this study group have had no success with 12 months of lateral wedging?

Should we be increasing the wedge size?

Cheers,
Gareth

 

I am having a hard time understanding this.

Why would you want to reduce the effects of the valgus wedge on moderate medial knee OA.

 

Joe:

What I meant was that with a moderate knee OA, if I increase the lateral forefoot wedging and start getting medial arch strain in the foot, with the foot orthosis I have more control (with the medial arch of the orthosis) over symptoms being produced within the medial arch of the foot than I would if I only had a valgus wedge on the insole. There is often a fine balancing act in treating medial knee OA with a valgus wedged orthosis and not causing pronation related foot symptoms, but it can be highly successful. These orthoses often require a few trial and error adjustments to optimize the symptom relief in the knee, without causing new symptoms in the foot. Hope that makes sense.

 

What?

 

hello all. thanks for an interesting thread. I have two questions really,

Mr Kirby - you say with your diagramme 3mm of wedging here etc : how many degrees of wedging are we in fact talking about??

Mr Payne - in your study : Rana S. Hinman, Kelly Ann Bowles, Craig Payne, Kim L. Bennell: Effect of length on laterally-wedged insoles in knee osteoarthritis. Arthritis Care & Research, Volume 59 Issue 1, Pages 144 – 147, 2008

you used 5 degree lateral valgus wedges, and took readings from the asis and psis in the gait analysis, but didn't include any of the results in the article. was that because there were no changes at the hips with and without valgus wedges?

Beforehand, thanks
Peter

 

I think what Kevin means is that there wont be an increased pronation if the lateral wedge is attached to a CFO and that the foot will be only in a more 'everted' position without encouraging unnecessary pronation., hence attating an increased medial opening of the KJ?? am I understanding it right?

 

If I was to construct an orthotic to act in one plane, I would be back at a lateral wedge.

I think with a triplanar device you are fighting what you are trying to accomplish.

 

I guess this is where my thinking is taking me that lesser or greater valgus wedging maybe used. Thanks Kevin.

 

Kevin:

I have been poking around Podiatry Arena.

You are awesome.

I get to learn from you.

Thanks is too small a word for what you are doing.

 

My wife thinks that what I do here on Podiatry Arena is a disease......just kidding......but poor Pam has to put up with a lot being married to me for 31 years. I couldn't do what I do without her continued support.

Hope all is well.

 

Kevin,

1. I am not practicing at this time.

2. The more I study lateral foot wedging for medial OA, the less sense it is making.

3. I should be talking less.

4. I need to study more.

5. I think I will take another look at my self examination.

Joe

 

Let me explain more clearly so there is no misunderstanding. When we place a valgus wedge on the forefoot and rearfoot inside a patient's shoe to treat medial knee osteoarthritis (OA), the valgus wedge will simultaneously be causing multiple joint moments on the foot and lower extremity as follows:

-external knee abduction moment;
-external subtalar joint pronation moment;
-external forefoot eversion moment.

With a very mild or early medial knee OA condition, I will normally put an 1/8" (i.e. 3 mm) thick rearfoot and forefoot valgus wedge on the patient's shoe insole or shoe sockliner to see how this works. This can be converted to a 1/8" korex wedge that is glued to the shoe insole if the all of the knee pain is relieved by this simple valgus wedge.

With moderate, more advanced, medial knee OA, the valgus correction will need to be greater to be able to reduce the medial knee compartment compression forces sufficiently to get sympomatic relief (by the way, the medial knee joint never "opens" with a valgus wedge-it just is compressed less than normal). Since the valgus wedge needs to be greater in degree, then so will the external STJ pronation and forefoot eversion moments be increased which may cause new symptoms in the foot or other gait pathology.

It is in these cases of moderate knee OA that I will nearly always insist on using a functional foot orthosis for the treatment of the medial knee OA. The functional foot orthosis, in addition to allowing me to vary the degree of rearfoot and forefoot valgus wedging to treat the pathological forces causing the symptoms of the medial knee OA, also allows me to add some support to the medial longitudinal arch of the foot to prevent subtalar or midtarsal joint symptoms that may arise from using larger degrees of rearfoot valgus and forefoot valgus wedging. The use of this type of orthosis, with a flat rearfoot post, lateral heel skive, everted balancing position, stiff lateral arch and valgus forefoot wedging, in my 20 years of clinical experience in treating such conditions with these specially-modified custom foot orthoses, is much better tolerated and more comfortable for the patient than simple valgus wedging alone.

When I lecture in Manchester, UK, in a few days at the Biomechanics Summer School, maybe I can cover these ideas more fully in one of the workshops I will be presenting during the conference, if one of you attending the conference will simply ask me to do so.

 

Sorry, that was a few yrs ago now and I just can't recall. I have emailed the others to check what was actually done.

 

Kevin,

Finally I understand what you are saying. Whew!

Sometimes storming comes before norming and out of chaos comes order.

Why the use of the lateral Kirby skive unless you are increasing the forefoot wedge over the subtalar joint wedge why not just increase both moments with a full length wedge.

Thank you for stating the use of korex.

I have in the past used Hapad, korex and G&W.


Joe

 

Kevin also once the STJ is pronated isn't there less eversion available in the forefoot?

 

The eversion range of motion of the forefoot isn't as critical as moving the ground reaction force on the forefoot more laterally to increase the external knee abduction moment which will, in turn, decrease the compression force within the medial compartment of the knee.