Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

Sciatic nerve damage > foot drop > pressure lesion sub 5th mpj

Discussion in 'Biomechanics, Sports and Foot orthoses' started by markjohconley, Oct 7, 2010.

  1. markjohconley

    markjohconley Well-Known Member

    Members do not see these Ads. Sign Up.
    Appreciate any input

    There are two new pts, coming to see me, both of whom have had a hx of damage to sciatic nerve, as a result of car collision accidents, b/left/side with resultant foot drop and ulcerative pressure lesions sub 5th mtpj's.

    What shall I see (in static stance and gait), what should i look at/test, what should i consider (apart from leaving podiatry as a profession)

    Thanks to all that consider the query, mark
  2. Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    Don´t leave Mark

    Heres what I would do Break your thinking into 3 different areas

    1 Drop foot gait related issues

    2 Foot biomechanical changes due to Sciatic nerve related issues

    3 Deal with the Ulcer - this I will not give any advice on as I´ve seen 1 ulcer in 4 years and I´m sure you have forgotten more about treating ulcerated lesions than I know.

    Think Tissue stress they will be different from each other.

    You will also need to do a whole heep of muscle testing to work out how much damage has been done and how weak the muscles are and the effect this has on there gait. Consider the compensation from the good side as well.

    area 1 Drop foot - clearly a foot and ankle orthotic to deal with it,

    I work with something like this but with a flatter foot plate - http://www.orthoticshop.com/custom-orthotics/ossur-generation-ii-afo-dynamic.html Its great when you want to add and orthotic over the top.

    area 2 deal with the pressure and friction issues related to the foot biomechanics, ie increase lateral support, cut outs for the 5 mtp and lesion from covers. Shoes will be important too. You may have to remove some of the foot and ankle plate if the 5th weightbears on the carbon plate.

    But if you break it down into the 3 area for assessment, treatment should be easier.

    Hope that helps some.
  3. Griff

    Griff Moderator

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    Hey Mark,

    Just thought I'd add some thoughts, and will try not to repeat any of Mike's good advice. Most of the foot drops I see come direct from a Consultant Neurologist, and tend to be relatively young (25-55 year old) patients with common peroneal nerve neuropraxia.

    I have also not seen an ulcer for many years (so unlikely to be able to help with that I'm afraid) although I assume they are primarily neuropathic in origin? In which case the mechanical considerations will be of direct benefit I'm sure.

    Often (but not always) they will be in a maximally pronated position at the sub talar joint of the affected side when in relaxed stance. I suspect this will rather depend on the extent/location of nerve pathology, and whether the extrinsic muscles which supinate the foot when they concentrically contract (Tibilias Anterior to name the key one) are sufficiently innervated.

    Dynamically I would expect to see an asymmetrical stride pattern. They usually feel quite unstable during stance on the affected side (see above point for possible explantion as to why) and tend to shorten the time they spend on this foot to avoid falling over. In addition to this when the limb is in swing phase they will have to modify its position to achieve adequate ground clearance so that they do not trip over the foot (as it tends to stay in a plantarflexed position due to gravity). This is often most easily achieved with an increase in hip flexion. The Physio's I work with term this a 'hip hitch'. This aforementioned altered stride pattern, combined with a hip hitch can make gait look quite limpy/antalgic.

    With the patients I am referred, I'm often trying to make their gait a bit more efficient in order to reduce symptoms they are experiencing at hip level. If they are 55 and just want to be able to play golf they tend to do very well with a Foot-Up from Ossur. If they are younger and more athletic, and there are no contra-indications, I have had good success with the Richie Brace (Dynamic assist with a tamarac hinge). Lucky for me though I don't have a plantar ulceration to contend with as well ;)

    Not sure what your options will be, and I guess this will depend on the clinical findings, not to mention the exact location, size and status of the ulceration. A total contact cast in combination with a Foot-Up perhaps? Or as Mike suggested an AFO with an orthotic device ontop? N.B the Richie Brace may be more of an all in one solution in which case?

    Good luck boss - keep us updated
  4. pgcarter

    pgcarter Well-Known Member

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    I have dealt with a few of these long term. Depending on how long ago the nerve damage occurred you may not be seeing the full extent of the muscle loss yet. In some cases it is years before the full extent of "withering" is actually shown. Foot anatomy can actually change over time due to the long term effects of muscular imbalances due to loss of tone and function in certain muscles. I have seen a 4 to 5 yr case where neural plasticity effects appear to be improving function a bit again after 5 years (this is my Mum). You'll need to deal with foot drop and swing ,plantar pressure, lateral stability and strength and decreased proprioceptive awareness, shoe fit and type of AFO, do you need a separate foot orthosis or can it be incorporated into the AFO and if so how and what materials? these cases tend to be dynamic over time, so what ever appears to be the best answer this month may not be in 6 to 12 months or 2 to 5 years. One of the traps can be that because the patient keeps changing your answers need modifying and patients can tend to think this means you don't know what you are doing, so explaining these issues up front can be good strategy
    good luck
    regards Phill Carter
  5. markjohconley

    markjohconley Well-Known Member

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    Thanks messrs Weber, Ian and Carter, plenty to ponder

    ...this is worthy of a thread by itself as I am much more confident treating medial lesions, specifically sub 1st mtpj and sub hall ipj when there is little apparent restriction to 1st mtpj rom.
    What i see from others is usually a full width 1-5 felt pad (either forefoot or fullfoot) with cutouts beneath the lesion. What i have found forefoot valgus wedges only, with NO material beneath the 1st met shaft, have had noticable success.
  6. David Wedemeyer

    David Wedemeyer Well-Known Member

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    Mark I would consider a total contact, unweighting AFO such as the one by Arizona. You can mark the cast and have the ulcerous area completely offloaded to heal. I've used them for ulceration before with excellent results. You can address the foot drop with a device such as Michael posted after the patients heal.

  7. efuller

    efuller MVP

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    In the absence of nerve damage, there are two foot types that will tend to have high pressures laterally. A drop foot/nerve damage on top of this would not necessarily change the problems from the underlying foot type. There is the partially compensated varus foot type where there is insufficient range of motion of the STJ to fully load the medial forefoot in stance. In gait, this type of foot will tend to abduct and roll off of the medial side of the foot. The other foot type is the laterally positioned STJ axis foot where there is not very much foot on the lateral side of the STJ axis. (This would be classically considered to be the rigid forefoot valgus foot.) In this foot type, to achieve STJ equilibrium the moments from the lateral side of the axis have to equal the moments from the medial side of the axis. Moment = force x distance. In the laterally positioned STJ axis foot the fifth met head is closer to the axis (distance is smaller) so the forces have to be higher. There is usually, but not always, additional range of motion in the direction of pronation in the rigid forefoot valgus foot type. Use the coleman block test and palpation of the axis to help differentiate between the two.

    The partially compensated varus foot needs a forefoot varus wedge to increase load on the medial forefoot.

    The rigid forefoot valgus foot could use a forefoot valgus wedge to pronate the STJ axis to rotate it more medially. This wedge could have a cut out sub fifth met head if that is where the lesion is.

    Good Luck,

  8. Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    As you should when thinking about anatomy, windlass, GRF etc, but these patients have pathological gait, also think about friction - where is comes from in these patients verse a person without neuroligical affected gait.

    Mark I had a whole post written and realised we dont know if they ff load with dropped foot or heel strike and load the forefoot fast with a slap. If you want when you find out got some school of funny walk experiments - if you want.
  9. Boots n all

    Boots n all Well-Known Member

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    The only a couple of things l would think to add to the above advice given would be a lateral flare to the sole.

    This foot would most likely(and we haven't seen it to know yet) make a mid-foot strike on the lateral border.

    The lateral flare will help move the load more centrally before the full weight is taken up by the foot, the amount of flare is related to the amount of the "inversion" at foot strike, l would start at about 1.5cm and see how you go, l dont think a buttress is needed but then again we are seeing blind with this client.

    We are also going to want at a rocker sole to help off load the ulcer, the fulcrum may need to run 1st to 4th then extreme proximal for the 5th, more of an excavation under the 5th
  10. Admin2

    Admin2 Administrator Staff Member

    Related threads:
    Other threads tagged with drop foot
  11. RobinP

    RobinP Well-Known Member

    Re: sciatic n damage > foot drop > pressure lesion sub 5th mpj

    Hi Mark,

    Given that you haven't seen the patient, much of what we can discuss will be hypothetical as the nerve lesion may affect each patient differently and as Phil said, the presentation will be subject to change.

    I would expect to see a completely flaccid foot drop. The patient will probably actively "flick" the foot into dorsiflexion at initial contact. Loading response will be rapid plantarflexion due to pre tibial muscle loss with probable audible foot slap. 2nd rocker will probably involve either; an element of hyperextension of the knee(if there is a midfoot equinous and laterally deviated STJ axis) or rapid and unopposed progression of the tibia over the stationary foot into excessive dorsiflexion. This will probably be what determines the frontal plane alignment that is leading to the lesion.

    Terminal stance may involve excessive dorsiflexion at the ankle before an apropulsive toe off. In swing phase, expect to find excessive hip and knee flexion as the swing phase limb attempts to clear the ground. Look out for all methods of compensation for insufficient swing phase clearance : circumduction(abduction of the hip causing an effective shortening of the leg at mid swing), hip hitching(as Ian pointed out), vaulting(going up on to the tips of the toes on the sound side to make the contralateral limb longer to compensate). At terminal swing phase, many patients fire the quads rapidly to extend the knee and to flick the foot into dorsiflexion, prepositioning for stance phase.......however, it could be completely different!

    It seems that offloading the lesion site will be a major part of the treatment in the initial phase. Altering the forces to reduce the biomechanical reason for the lesion will be critical and locally offloading will be required. This should be done by whatever means necessary and what will inevitably influence your decision is the set up that provides stance phase stability and swing phase assistance. It is only product knowledge that will allow you to adapt whatever the device is to accommodate/offload the lesion.

    My 2p for what it is worth is to look at immediate, short term and long term strategy

    Immediate: offload the ulcer site and offer some swing phase clearance. Use a prefab such as a formthotic and post/wedge to resolve the biomechanics and window out the lesion site. Use in combination with a foot up. Chairside instant improvement albeit not particularly flashy, but lightweight and inexpensive.

    Short term: Take a cast and use a set up suggested earlier of the carbon fibre AFO(point of note on this one - if the patient has a pronating foot at midstance, use a CF AFO with a lateral strutt such as a Toe Off http://www.gilbert-mellish.co.uk/products/lower-limb/ToeOFF/toeoff-original.php and if the patient supinates at midstance, use an AFO DYnamic or Ypsilon by Ossur which has a medial strutt http://www.ossur.co.uk/Products/Ankle/anklefootorthoses/AFO-Dynamic)

    Use in combination with a custom FFO with lesion accomodation. It there is greater coronal plane deviation eg excessive supination and lateral instability, then a Ritchie brace may be better. The beauty of the CF AFO set up is that if knee hyperextension is present, the GRV in the sagittal plane can be "tuned" using heel wedges to reduce hyperextension.

    Long Term: Depending on the degree of alignment problems, completely opposing solutions may be definitive.

    If there are major alignment issues such as excessive supination that cannot be controlled by an in shoe device, then consider a custom made AFO(with or without ankle joints) to optimise coronal plane control. A rigid AFO will always give the best control as Tamarak hinges will be subject to excessive torsional forces and are not stable in the transverse plane. However, this is again dependent on the degree of defomity. Metal joints are more stable in the transverse plane but there is then little room for error in joint placement otherwise the joints wear and fail rapidly.

    If there are no major alignment issues, and the lesion heals well and the only problem is swing phase clearance, then you could consider somethins like a SAFO
    This will give excellent swing phase clearance, can give a little stance phase control, is very cosmetic and is completely bespoke so can include lesion/prominance accommodations. However, the absolute best thing about about it is that it can be worn barefoot which none of the other suggestions I have made can be. It allows patients to wear flip flops, slippers, sandals etc and is cosmeticlaly superior. they are however, quite pricey so that is why i consider it a long term definitive device. Speak to Matthew at Dorset Orthopaedic for advice.

    It wasn't my intention to turn this into an essay so sorry for the legthy answer but I hope it helps. You could also refer to a friendly Orthotist and if they are any good should have some suggestions about how best to treat and may have some other products in their arsenal not mentioned here as there are so many options.


  12. markjohconley

    markjohconley Well-Known Member

    The gent who presented to the clinic for 9 treatments over 4 months(under different podiatrists, but I kept shoving my not inconsiderable head into the cubicle) was finally diagnosed with osteomyelitis of the distal l/5th metatarsal. The vascular surgeon at the base hospital amputated, his lesions resolved in 2/52.
    Various modifications were used to transfer GRF from the lesion with a full valgus wedge with a 7mm? poron plug beneath the lesion seemingly the most efficacious.
    Thanks to all those contributing posters, Mark

Share This Page