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Lateral foot wedging for medial knee OA

Discussion in 'Biomechanics, Sports and Foot orthoses' started by admin, Aug 13, 2005.

  1. admin

    admin Administrator Staff Member

    Members do not see these Ads. Sign Up.
    Good summary in latest Current Opinion in Rheumatology
  2. Craig Payne

    Craig Payne Moderator

    Is anyone actually using lateral foot wedgeing for knee OA? (I know Kevin has written a Precision Intricast Newsletter on the topic)
    Last edited by a moderator: Dec 16, 2007
  3. admin

    admin Administrator Staff Member

    Use of Laterally Wedged Custom Foot Orthoses to Reduce Pain Associated with Medial Knee Osteoarthritis
    Russel Rubin and Hylton B. Menz
    J Am Podiatr Med Assoc 95(4): 347–352, 2005
    Last edited by a moderator: Dec 16, 2007
  5. Craig Payne

    Craig Payne Moderator

    Thinking about and working on a hypothesis that we may have some data on soon.

    A high abductor moment at the knee is probably one of he most important risk factors for medial knee OA..... a lateral foot wedge is one of the more effective ways to reduce that abductor moment ---- problem is, it does not always do so.... so what is being considered is that it might have something to do with STJ ROM. If there is a range of eversion at STJ --> wedge pronates foot and internally rotates knee --> no change in abductor moment. If there is no range of eversion at STJ --> wedge can not pronate foot --> decrease in abductor moment at knee. It is surprising how many people in the age group with knee OA have no or very little eversion from their RCSP.
    Last edited: Aug 14, 2005
  6. Let me clarify what Craig wrote above so that there isn't any confusion for those of you that are following along. We must be careful when we speak of moments at a joint and be certain to distinguish if we are speaking of an internal moment or an external moment. If there is a large magnitude of external knee adduction moment then medial knee OA will be more likely to occur since the internal knee abduction moment will be of greater magnitude.

    A good way to explain whether the knee pain will be relieved by a valgus wedge or not is if the center of pressure (CoP) is shifted laterally or not. In the foot that pronates the CoP will not shift as far laterally with application of a valgus wedge as the foot that does not pronate. Also, it doesn't surprise me how many patients have maximally pronated subtalar joints in relaxed bipedal stance....I see them all day long in my clinic!
  7. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    lateral wedging for medial compartment knee OA


    I have been using lateral wedging / lateral heel skives and similar for many years to treat medial knee compartment OA.

    Typically we all see a genu/tibial varum with this deformity, and I often wonder about the chicken and egg scenario to explain it. My gut tells me these (mostly) men had excessive tibial varum first, which compressed the medial compartment over time, then created a more pronounced genu varum...

    I find this approach very successful, the aim being to transfer CoP forces from the 'damaged' to the relatively 'undamaged' compartment. How you prove this is nigh on impossible, except in a theoretical sense. You would know better than I about such things.

    My usual caveat is we are going to sacrifice 'ideal' foot function to provide symptomatic relief at the knee, also that it wil be a stop-gap measure to delay need for high tibial osteotomy or TKR.

    My 2 cents,

  8. Craig Payne

    Craig Payne Moderator


    None of the studies on lateral wedging reported in the literature and none that I have been involved with has there been reported any foot symptoms developing as the result of the lateral wedge pronating the foot more.
  9. LuckyLisfranc

    LuckyLisfranc Well-Known Member


    I have noted the same in my readings, particularly the Japanese ortho literature...

    However, I still throw this one out there to cover my derriere, for if they shop around to another podiatrist who notes that I am attempting to 'pronate' the STJ - I have no doubt that some would get up in arms about the concept and hoodwink the patient into believing that it is an inappropriate course of action.

    Its funny that we (the podiatry profession) have no hesitation whatsoever in supinating a foot ad nauseum, but when you do the opposite some podiatrists consider it grand herecy!

    I think we may only be teaching our students one half of the pie sometimes...

  10. John Spina

    John Spina Active Member

    I just saw a patientwith medial knee pain and lower leg pain.I applied a lateral wedge to his shoes.I will tell everyone how he made out.I had no idea that these can help,but I know now.As Drs.Kirby& Payne said ,a wedge can shift the center of gravity laterally and this can alleviate pain. :p
  11. pgcarter

    pgcarter Well-Known Member

    Patient responses seem to vary...I have often tried it in my rehab(70+ age group usually ) work...and now I tend to say .." let's see what happens....you will be the best judge of how you feel after a week or three...." I tend to agree with the idea about long term degen often contributed to by greater tib varum...as previously said and I tend to think the respnse you get to lateral wedging depends on how bad it already is and what there is left to work with.
    Regards Phill Carter
  12. davidh

    davidh Podiatry Arena Veteran

    Just to add to this thread...

    I have a note of how Yasuda and Sasaki (1987) used a wedged board, load transducers, and x-rays to demonstrate how a lateral tilt in the weightbearing foot decreased excessive loading on the medial compartment of the knee. I assume that anyone doing work on this subject will have read this paper?

    For those who haven't, its a nice study :) , but the cohort is a little small (n=10).

    The full ref is
    Yasuda k, Sasaki T. The Mechanics of Treatment of the Osteoarthritic Knee with a Wedged Insole. Clin Orth and Related Research. . No 215, 162-172, 1987.

  13. A very nice mechanical explanation, including different types of stress analysis, of how tibial/genu varum deformity causes medial compartment osteoarthritis (OA) was done by Maquet over 20 years ago (Maquet, Paul G.J.: Biomechanics of the Knee. Springer-Verlag, New York, 1984). In one analysis technique, he made photoelastic models of the knee using plexiglass and then observed them under various loading conditions while illuminated by white polarized light. The resultant light and dark lines within the plastic model are indicative of the magnitude and direction of stress within the knee.

    Maquet also calculated loads on the knee using graphic modeling techniques and developed explanations for the cause of medial knee OA with a tibial/genu varum deformity. I use these models in my lectures on varus and valgus wedging for knee OA to this day.

    Currently, within the international biomechanics literature, finite element analysis techniques have been extensively used in designing knee implants and this more advanced modeling technique will certainly be the wave of the future in predicting knee joint loading forces.

    These techniques are not just theoretical. They are scientifically based mechanical analysis techniques used every day by engineers worldwide to design buildings, boats, bridges, automobile engines, etc. The future of advances in podiatric biomechanics will be based on the understanding of these modeling techniques that will ultimately allow podiatrists to better understand the most efficient methods by which to reduce the abnormal stresses on the injured structural components of the foot and lower extemity with in-shoe and/or external shoe modifications, or other treatment techniques.
  14. admin

    admin Administrator Staff Member

    Feet insoles and knee osteoarthritis: evaluation of biomechanical and clinical effects from a literature review.
    Ann Readapt Med Phys. 2005 Jun 13; [Epub ahead of print] [Article in French]
    Gelis A, Coudeyre E, Aboukrat P, Cros P, Herisson C, Pelissier J.
  15. Freeman

    Freeman Active Member

    Hello all,
    I was involved in a study with Dr. W.D. Stanish (orthopaedic surgeon) here in Halifax (back in the 90's)where we did lateral wedging.


    The collected data was interested in that the films showed no appreciable change, but their comfort was almost immediate. 4/7 patients I still see for their lateral wedge orthotics. A couple of them are very active, but avoid any impact actvities. They find the orthotics very comfortable with no foot problems. I use this method of treatment very often with good success.
  16. Atlas

    Atlas Well-Known Member

  17. Atlas

    Atlas Well-Known Member

    No, the reason why the response varies is this. We all seem to think that medial knee pain is caused by medial joint compression/OA alone. Truth be known it is not. Medial knee pain can be caused by a completely 'opposite' pathology...that being MCL tensile pathology.

    Applying a valgus wedge will "open up" the medial compartment. The OA will love it; the MCL will hate it. Hinman can't understand why 33% of "medial knee joint OA's" were worse after lateral wedging. I say that these 33% were suffering clinical medial ligament tensile issues over and above any radiographic and/or rheumatological diagnoses of OA.
  19. the varus deformity of medial compartment osteoarthritis

    The varus deformity that accompanies medial compartment osteoarthritis (MCOA) develops as a result of the disease and is correctable in sitting. It is not the cause. The fact that the lesion of MCOA is so localised within one compartment of the knee within a tricompartmental joint is a pointer to the fact that it is the result of a biomechanical failure not a systemic one or a genetic problem of cartilage. There is some evidence that the development of MCOA is associated with the pronated foot, the tibia being held in internal rotation for too long while the femur rotates externally in late midstance while the knee is extending leading to increased torsion and tissue damage. The rate of repair of tissue diminishes with age and eventually in the elderly this leads to tissue breakdown. There is a link between MCOA and obesity and there is also a link between increased pronation and obesity. If there is an association between the over pronated foot and MCOA it seems unlikely that a lateral wedge which will increase this is likely to lead to any long term improvement. A recent systematic review of lateral wedges has indicated that there really is no evidence that it has any long term positive effects. Also, it must be important to examine the foot before applying a treatment which causes a change in the foot dynamics. An already pronated foot leads to problems of the whole musculo skeletal system - is it ethical to increase this risk. It must surely be relevant to examine the foot carefully before applying any wedging. Medial wedging might seem to be the answer to a pronated foot but because of the varus deformity of the knee in MCOA this may increase the pain - that does not lead to the conclusion that lateral wedging is the answer. Has anyone examined the long term results of the use of lateral wedges ?
  20. Freeman

    Freeman Active Member

    Lateral wedging for medial joint line OA

    Dear Kathleen,

    Thank you for your note. I have been doing lateral (valgus) wedging for 25 years witha a variety of orthopaedic surgeons in Halifax Nova Scotia. I first started it on a research project wityh Dr. Bill Stanish. Xrays confirming medial OA on remarkable tib varum patients with significant pain showed no change on the joint line from the uncorrected standing films to the medially wedged(valgus) films. However instant relief was experienced in 80% of those patients. I am still treating some of those same patients, and buckets more very successfully. There is a compromise to a certain degree becasue I am medially wedging an already pronated foot, however it seems that bigger pain in medial joint line OA which untreated is quite unbearable. I have treated medial OA patients with memdial/varus wedging as per some MD's requests and more often than not they return to have it reversed.

    Freeman churchill, Certified Pedorthist (Canada)
  21. Craig Payne

    Craig Payne Moderator

    What evidence is that? The evidence that I have seen is that it an increase in the adduction moment is the risk factor and NOT the alignment.
    You can't make that leap to come to a conclusion.
    That recent systematic review did not include all the recent studies, most of which are still in press. It did also not break the studies down into OA severity and the effects of lateral wedges (grade does matter). It did also not break the studies down into the type of wedge used (length of wedge does matter)
    What evidence do you have a that a pronated foot is a risk factor for anything? Of the ~25 studies that I have seen on risk factors of lower extremity problems, a pronated foot was only shown to be a minor risk factor in one of them.
    In every study done on lateral wedging for knee OA (and we 24 months into ours with >100 subjects recruited so far), not one of them has reported any subject getting any other symptoms or any foot pain. Its just another of those podiatric myths that pronating a foot more is a problem (the forces associated with pronation are a problem, but not the motion or position of pronation). I thought we had moved on from that mindset.
    Last edited: Nov 9, 2006
  22. Freeman

    Freeman Active Member

    medial OA Valgus wedging

    Dear Kathleen,

    Patients I have seen have ranged from obese to emaciated runners of which I am one. The outcomes are very good. Again I will emphasize that medial OA c an be excruciating and disabling, not that foot pain isn't...but weighing out the bigger picture in terms of nonsurgical relief I have tended to use a heel to forefoot valgus wedge.

    I will aslo say that if I am treating a patient with a foot problem and no medial knee pain who has remakable tib varum I make sure they tell me if they get any medial knee pain with the orthotics...I am very careful to treat the foot with as little as I can get away with, as far as medial posting is concerned so that I do not create problems up at the knee
    I do know some practicioners who cannot bring themselves to placing a valgus wedge or post on any patient for any rerason because they "cannot bring themselves to willfully pronate a foot".

    The last comment in my ranting/raving here, is that when I began to help my colleague Dr. Stanish, I did not understand fully all about why I was doing what he was asking me to do when he asked me to apply lateral (valgus) wedging or posting). It has worked well, and I have learned by faith, moreso than my own understanding.

  23. Craig Payne

    Craig Payne Moderator

    Thats the key - if you look at the literature, the studies that showed no change in abductor moments at the knee used a shorter wedge (thats if you can actually work out from the publication what they actually used as a "wedge". We putting finishing touches to manuscript for submission on "Length Does Matter" (though we suspect that the journal editor will want to change the title :cool: ) - we tested several different length wedges - only the full length reduced knee abductor moment (and abductor moment increase is numero uno risk factor for medial knee OA).
  24. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    The Cochrane Review on this topic, is also worth being aware of:

    Cochrane Database Syst Rev. 2005 Jan 25;(1):CD004020.

    Braces and orthoses for treating osteoarthritis of the knee.

    Brouwer RW, Jakma TS, Verhagen AP, Verhaar JA, Bierma-Zeinstra SM.
    Orthopaedic surgery, Erasmus Medical Centre Rotterdam, Dr. Molewaterplein 40, Rotterdam, Netherlands, 3015 GD. r.w.brouwer@mzh.nl

    BACKGROUND: Patients with osteoarthritis of the knee can be treated with a brace or orthosis (shoe insole). The main purpose of these aids is to reduce pain, improve physical function and, possibly, to slow disease progression. OBJECTIVES: To assess the effectiveness of a brace or orthosis in the treatment of osteoarthritis of the knee. SEARCH STRATEGY: We searched Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE (Current contents, Health STAR) up to October 2002. The reference lists of the publications in the identified trials were also screened. SELECTION CRITERIA: Extracted studies were included in the final analysis if they met the pre-defined inclusion criteria: 1) a randomised controlled clinical trial or a controlled clinical trial, 2) all patients had osteoarthritis of the knee, 3) the intervention in one of the studied groups was a brace or an orthosis. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected the trials and assessed the methodological quality using the Delphi-list and one additional question about care programs. Three reviewers independently extracted the data on the intervention, type of outcome measures, follow-up, loss to follow-up, and results, using a pre-tested standardized form. Study authors were contacted for additional information. MAIN RESULTS: Four trials involving a total of 444 people were included in this review. One study investigated a knee brace and three studies examined different types of orthoses for medial compartment osteoarthritis of the knee. Two studies were of high methodological quality while the other two studies were low. Notably, the randomisation and the blinding procedures were either insufficient or not described. The follow-up period (six weeks to six months) was too short to demonstrate long-term results. Pooling was difficult primarily due to the heterogeneity of the data and the way the information was presented.The pain, stiffness and physical function (WOMAC and MACTAR) scores of a brace group showed greater improvement at six months compared with a neoprene sleeve group, which showed greater improvement compared with a control group.The numbers of days of non-steroidal anti-inflammatory drug (NSAID) intake decreased significantly (relative percentage difference 23.9%) compared with baseline in a group with laterally wedged insoles,and remained unchanged in the neutrally wedged group. Patient compliance with the laterally wedged insole was significantly better compared with the neutrally wedged insole. In one study, the Visual Analogue Pain (VAS) pain score was significantly decreased from baseline in a strapped insole group (RPD - 24%), but not in the traditional lateral wedge group, but this strapped insole showed more adverse effects (popliteal pain, low back pain, and foot sole pain) compared with the traditional lateral wedge insole. Pain during bed rest, after getting up, after getting up from seated position and walking distance was significantly improved in a subtalar strapped group compared with baseline, and no improvement was found in a sock type group. No studies were found that assessed the effectiveness of a brace or orthosis to treat lateral compartment osteoarthritis or general osteoarthritis of the knee, or that compared a knee brace with a wedge insole, or that compared a brace or orthosis with operative treatment. AUTHORS' CONCLUSIONS: Based on one brace study we conclude there is limited evidence that: a brace has additional beneficial effect (WOMAC, MACTAR, function tests) for knee osteoarthritis compared with medical treatment alone.(Silver) a sleeve has additional beneficial effect (WOMAC, function tests) for knee osteoarthritis compared with medical treatment alone.(Silver) a brace is more effective (WOMAC, function tests) than a neoprene sleeve.(Silver) Based on 3 orthoses studies, of which 2 were high quality, (n=2) we conclude there is limited evidence that: a laterally wedged insole decreases NSAID intake compared with a neutral insole. (Silver) patient compliance is better in the laterally wedged insole compared with a neutral insole. (Silver) a strapped insole has more adverse effects than a lateral wedge insole. (Silver).
  25. I have also found over the past 20 years of using valgus wedges for medial knee osteo-arthritis that the full length wedge is most effective for the patient. One of the methods I use in the office for a "quick and dirty test" is to take the sockliner out of the shoe and then place one to two pieces of 1/8" (3 mm) adhesive felt in the shape of a valgus wedge to the sulcus (see illustration below). This works quite well. If necessary, a full length orthosis is prescribed with lateral heel skive and valgus forefoot extension.

    These valgus wedges cause an increase in magnitude of external knee abduction moment (i.e. increase in magnitude of internal knee adduction moment) which will lessen the medial compartmental pressure in the knee and increase the lateral compartment pressure in the knee. I believe that the reason that forefoot valgus wedging is important in treating this problem is that the forefoot is more laterally positioned to the long axis of tibia than the heel is. Therefore, an increase in GRF on lateral forefoot (with a valgus forefoot wedge) has more ability to generate increased knee abduction moments than increases in GRF on the lateral heel (with a valgus heel wedge). This can be easily demonstrated by modelling the foot and knee with the apparent forces and moments applied. I presented these ideas previously in my October 2004 Precision Intricast Newsletter "Foot Orthoses for Medial Compartment Osteoarthritis of the Knee."

    Attached Files:

  26. Working in an orthopaedic hospital I have had the opportunity to look at lots of feet - not to treat them but to observe. The differences in foot type of the patients who were about to have hip replacements and those who were about to have an Oxford unicompartmental knee replacement for end stage arthritis was marked and I published a paper on this in Foot and Ankle international. The hip patients' feet were more homogenous. The OA of those patients with medial compartment problems was often secondary to earlier knee surgery, occupation and it appeared to be excess weight gain. The differences in their feet is what made me doubtful about using lateral wedges indiscriminately. None of the studies seemed concerned about the foot they were applying the wedge to - I thought this should be an initial consideration. Recently I have had the opportunity to review patients 5 years after hip replacement. Some have had leg length discrepancy - in the literature this has been demonstrated to have no ill effects but many of these patients are complaining of severe back ache. This is a topic I hope to investigate - the long term effects have not been fully investigated because no one really cares a few years down the line. But I think that very small changes around the feet can have, over time, major effects further up the musculo skeletal system. Also the knee abduction moment is part of normal gait, there is more pressure in the medial compartment in normal gait that is apparent from the anatomy of the knee. What pronated and supinated feet do is upset normal gait patterns - supinated feet inhibit internal rotation of the tibia, knee flexion and internal rotation of the hip whereas pronated feet inhibit external rotation of the tibia, knee extension and external rotation of the hip. The effects go further but essentially applying wedges to any foot type will not bring about the same results and it may be the reason that the research shows no real lasting changes though of course clinically these may be obvious. Is it possible that the successes with wedges have depended on the foot types they were applied to ?
  27. Craig Payne

    Craig Payne Moderator

    Forget about rotations and motions - knee OA is about moments and forces.
    We testing hypothesis that those with feet at STJ everted end range of motion are more likely to respond to lateral wedging - ie they change the knee adductor moment, but can't change motions/rotations.
  28. Teichtahl et al, J Sci Med Sport 2006, 9(1-2):67-71 "Foot rotation - a potential target to modify the knee adduction moment. This study finds an association between foot rotation and the knee adduction moment during late stance - implying that changing foot kinematics can modify the medial tibiofemoral joint load during gait. Andrews et al, J. Orthop Res 1996, 14(2):289-95 "Lower limb alignment and foot angle are related to stance phase knee adduction in normal subjects: a critical analysis of the reliability of gait analysis data". The study suggests that the alignment of the lower limb and foot progression angle can serve as predictors of knee joint loading in healthy individuals which may have implications for nonsurgical treatment of knee problems. There are people out there who think that foot rotation and obviously subsequent tibial rotation do influence knee loading and the knee adduction moment. It seems that in spite of many years of gait analysis there is still no one answer, probably because there are many answers.
  29. NewsBot

    NewsBot The Admin that posts the news.

    Effects of disease severity on response to lateral wedged shoe insole for medial compartment knee osteoarthritis.
    Arch Phys Med Rehabil. 2006 Nov;87(11):1436-41
    Shimada S, Kobayashi S, Wada M, Uchida K, Sasaki S, Kawahara H, Yayama T, Kitade I, Kamei K, Kubota M, Baba H
  30. Scorpio622

    Scorpio622 Active Member

    I have not applied wedges clinically for OA but have thought about the concept for some time. I have a much more simplistic view of how these work- which is purely in the frontal plane. I feel that the lateral wedges tilt the tibia in the frontal plane when the STJ can't accommodate to the wedge. I don't think much internal leg rotation is happening.

    In view of all the studies, it seems that lateral wedges have more of an affect on the knee then medial. I assume this is because the STJ has the ability to invert much more than evert, esp in the max pronated patient, which can't evert at all. That being said, most can accommodate better to the varus wedge rather than the valgus at the level of the STJ due more available ROM.

    With respects to the max pronated patient (which most knee OA are), they would repond to a lateral wedge much like someone with a triple arthrodesis. Both are standing in heel valgus without the ability to pronate further. As such, the GRF of the lateral wedge must be resolved proximally with little triplanar motion since the STJ has little/no movement. The tibia is thrust medially in the frontal plane and genu valgum is the result.

    This is how I see it, I could be wrong....

  31. From a biomechanical standpoint, it is more accurate to say that the valgus insoles used when treating medial knee OA cause a lateral shift in the center of pressure which will, in turn, cause a decrease in external knee adduction moment. The problem with saying that valgus wedges "tilt the tibia in the frontal plane" is that this does not accurately portray what is happening mechanically. No measureable tibial motion need to occur in order for these valgus wedges to produce the reduction in pressure in the medial compartment of the knee that produces the symptomatic results seen in patients with medial knee OA. One of my previous Thought Experiments explains this mechanical idea more graphically. http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=2110&highlight=Thought experiment

    In addition, I don't believe that the common idea that feet that are maximally pronated are the only ones that will respond successively to valgus wedging for medial knee OA is mechanically accurate either. I could easily make the argument that since a foot that is not maximally pronated has a greater potential to pronate at the STJ (and, therefore, to abduct more laterally to the longitudinal axis of the tibia), then these patients that are not maximally pronated also have the greatest potential to have a more lateral repositioning of their CoP relative to the longitudinal axis of the tibia due to the valgus wedged insole, and, as a result, have the greatest potential to have decreased external knee adduction moment from these valgus wedges.
  32. Craig Payne

    Craig Payne Moderator

    I hear that one of the major running shoe companies has an experimental shoe in development that has a higher density EVA under the lateral side and a softer EVA under the medial side (ie the opposite of the 'motion control' shoe) aimed to mimic the effect of a lateral wedge. If the shoe goes into production, it would be targeted at the medial knee OA group ....
  33. A potential problem with creating a shoe of this type is that it may cause injury unless used in the correct patients that have very certain diagnoses. In other words, if a patient that has medial knee pain is told by the shoe store, or other non-medical, personnel that they would benefit from this type of shoe with increased lateral midsole durometer, but that patient also has some other pathology of the medial knee that is caused by increased external knee abduction moments (i.e. valgus moments), such as medial collateral ligament strain or pes anserinus bursitis, then the shoe would likely increase their symptoms, rather than helping them. I wonder if the shoe manufacturer will, therefore, require a prescription for this shoe or if the shoe store personnel will accept medical liability for harming a patient that has been misdiagnosed as to the correct diagnosis for their medial knee pain???? Do you think the shoe manufacturer has thought about this yet?? I guess it depends on which company it is?! :eek:
    Last edited: Dec 18, 2006
  34. toomoon

    toomoon Well-Known Member

    Some time ago, I completed a study with an orthopaedic colleague looking at the effect of lateral wedging on medial OA. We measured the angle between femur and tibia from erect WB x-rays, and used a Kitaoka pain score to moniter symptomatic changes in a cohort of about 20 subjects who were destined for unicompartmental replacement.
    Neither the tibiofemoral angle nor the pain scores showed any significant change, either positive or negative with rearfoot valgus wedging.
    regards to all
  35. Scorpio 22 suggests that a lateral wedge results in genu valgum and this is what would be expected. Athough Simon states that he looked at 20 subjects with medial compartment OA he does not state what size of wedge was used and whether it was used in shoe or simply place under the foot. The degree of varus deformity present would also be useful information and whether or not it was idiopathic oa or as a result of a football injury or as a result of the patient's employment - carpet fitter, electrician etc. Also more importantly he does not indicate what type of foot was wedged. As Scorpio indicates many of the subjects with MCOA have pronated feet but others who perhaps had meniscal surgery may have supinated or normal feet. The difference in foot type could lead to varying results which would then make the results insignificant. As a physiotherapist I look at the foot as part of the body but would consider any treatment which changes the foot to be subject to an initial examination of the foot itself. The use of a lateral wedge may lock the foot into the overpronated position thus keeping the tibia in internal rotation and maintaining a slightly flexed knee - pronation/internal rotation of the tibia/knee flexion being the pattern of movement of the lower leg. This is seen as decreasing the varus deformity which is present in MCOA and lowering the knee adduction moment because the movement in the knee is restricted but the femur is outwardly rotating. Thus to reduce the adduction moment the hip is under increased torsion the the foot is locked into increased pronation neither of which is part of normal gait and both of which may lead to further trauma in a leg which already has a compromised joint. The use of a lateral wedge may be helpful in the short term reduction of pain and in some instances may not have the adverse effects suggested but it would depend on the foot type and subsequent gait pattern.
    This is why I find some of the research into lateral wedging worrying - the foot type is not discussed or taken into account - does anyone think that this is important.
  36. toomoon

    toomoon Well-Known Member

    I also find the concept very worrying Kathleen, and the reason I wanted to research it further is that at that time, the world of orthopaedics saw long-term lateral wedging of the foot as a viable treatment option for symptomatic medial compartment OA.... but at what cost to the foot? Logically, for any foot type, long term lateral wedging would seem a dangerous thing to do, and even if it did provide symptomatic relief, how long before issues occured at the level of the foot?
    In our study, we were most focussed on whether the wedging provided pain relief to a cohort of symptomatic medial OA subjects, with the diagnosis made radiographically. It did not. Wedge angle was 5 degrees valgus. Foot type was not controlled for, because at this time, the orthopods were wedging everyone, regardless of biomechanical profile. We wanted to investigate whether the wedging supported the claim that the medial compartment would be "opened up" by increased (presumed) tibiofemoral valgus. This could not be established radiographically. As a result of this little study, our orthopaedic group stopped prescribing valgus wedging.
    On the balance, I am pretty sure this was a good thing.
    Regards and happy Christmas to all
    Simon Bartold
  37. kerstin

    kerstin Active Member

    Lateral wedging for patients with medial OA?!? yes when we see it just theoretical I believe we should relieve the medial side of the knee (Simons study shows no you are wrong maybe because it depends of the cause of OA pain, but good to think "out of the box" again). SO when we treat patients with medial knee pain we need to take the patients into account and then I mean the biomechanical outlining of the feet and body and there gait. In my clinical practice most of the patients with medial OA pain has a torsional problem. So there subtalar joint pronates excessively especially in time while the femur exorotates because of several reasons (muscles, femur position, ...). this means that the tibial endorotates while the femur exorotates and yes, meniscus under stress and so the cartilage too. Also of course the patella tendon and the cartilage under the patella. And because most of the patients have a little tibila varum the medial side of the knee undergoes the most stress wich can cause over time osteo arthritis. SO putting a valgus wedge in our insole by this kind patients, will cause more subtalar pronation and more tibial endorotation and when you don't do anything on the femur exorotation: hmmmm "no good".

    Maybe I am wrong so shoot.

    best regards,
  38. Craig Payne

    Craig Payne Moderator

    Summarising this thread and the evidence:

    The evidence is that an increase in the adductor moment is a major risk factor for medial knee OA.

    Lateral wedges have been shown in many lab based studies to reduce the adductor moment at the knee.

    Several studies (including Simon's above and one of ours that is 'in press') have shown no changes in alignment (but we also showed a reduction in the addcutor moment).

    Almost all (with a couple of exceptions) of the clinical studies show an improvement in symptoms in those with medial knee OA and lateral wedges (none reported an increase in symptoms).

    Foot type does appear to be important - it appears that those who are already at end ROM of STJ benefit most (though evidence points to this, it is limited) (...so wedges do not pronate foot more as its already at end ROM).

    The type of wedge does appear to be important - we have a paper in press titled "Length Does Matter" - the adductor moment was most effectively reduced when the wedge extended forward to under the 5th met head.

    In all the studies (including the first 110 subjects of our study), there has not been ONE case in which there was any increase in foot symptoms reported.

    A problem is the podiatric mindset of "pronation = bad", that we have to get over.
  39. kerstin

    kerstin Active Member

    You are right we have to think out of pronation=bad. I believe when we put a valgus wedge, especially when you put it from the rearfoot till just before CM5 that you will decrease the adductor moment of the tibia and so opening the medial side of the knee. So for a certain amount of patient this will work and yes especially when they have used there complete pronation STJ ROM because then you don't increase tibial endorotation and have maximal impact on the adduction tibial moment. But with patients were you increase STJ pronation and where the femur exorotates, will give no release and will gives over time more problems? Maybe I have to try a valgus wedge with one of these patient and see what happens.
    How many of the subjects has no decrease in pain??? What was the degree of the valgus wedges??

  40. Freeman

    Freeman Active Member

    lateral wedging for medial knee OA...like many goodthings in life, there goes a saying, "don't knock it if you haven't tried it...." do try it.

    At the PFOLA conference a few weeks ago in Chicago there were serval speakers who'd done research on wedging and bracing for medial knee OA. Having my notes at the office and me being at home, I must apologize for not being able to say who they were, however, in one particvular study where some patients were given bracing for agiven period of time, then a rest period to let thier knee "go back to the untreated level" and then given a lateral wedged orthotic, the patients had better results in terms of pain releif, I belive, than those with the brace. It was added that the brace was harder to use as well. I believe the valgus wedge was roughly 4-5 degrees from heel to the toes. Perhasp someone who has thier notes with them can give a more accurate account of this.

    Best regards,

    Freeman Churchill, Certified Pedorthist (Canada)
    Halifax, NS

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