Sudden onset supinated foot post ankle fusion on other leg

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The picture attached is the posterior view of a right foot! Yes its the lateral border, although it looks like a charcot foot with complete medial colapse.
The pt is an early 40's female with no relevant medical history. She underwent an ankle fusion 3 years ago on the L/ankle after a bad sprain. About 18 months ago the deformity and pain started in the R/anke. She has virtually no movement in the hind foot.
Can anybody suggest a reason why this would happen and how it progressed so fast?

 

Two major ankle issues?..is this a pattern?, what triggered the other?.....looks like some significant change to this foot. And how did you decide there was no relevant background?..what is there?
Phill

 

Re phrase...... no medical history at all, no arthritis, diabetes, neurological problems, no medication, no history of breaks or soft tissue injuries. Seemingly healthy apart from the ankles. She said the 1st injury was a severe sprain. She seems to have had an ankle fusion as 1st line of treatment, no phsio, no other surgical procedures. She maintains nothing had ruptured.

 

Very odd....what's her ligamentous tone like? It's sounding like someone I have seen who has subsequently been diagnosed with Marfans syndrome...lig laxity and various other things that go along with it. Proprioception is probably no good at all, joint stability poor, balance poor etc?
regards Phill

 

Please give us a photograph of the patient from the shoulders down while standing in relaxed bipedal stance. A video of her walking barefoot would also help. What is her weight and height? Is she obese? Is there any peroneal brevis or peroneus longus muscle strength?

 

I'm wondering if, due to postop sequella, a short limb was creeated on the non operated side that caused a supinatory influence that then after a couple of years of compensation along with underlying biomechanical weaknesses (mentioned previously) would have caused this situation.
I would ckeck for The Inclioned Posture (TIP) and also consider placing lift under the rigid rearfoot as a test to see if there is any improvement in symptom and function.
Dennis

 

Thanks Dennis, that definitely makes the most sense.
Kevin, im afraid I dont have video gait analysis or full body picture. I have referred the pt to a surgeon due to the almost complete lack of movement at the rearfoot. Also I am unfortunitely not in a position to request any kind of imaging. The pictures I took were just for my own interest and the reason for the posting on the arena was retrospective learning exercise. To answer your questions, She is aprox 5'8 and 17 stone (which she attributes to not being able to exercise since recovering from the anke fusion 3 years previosly and the onset of symptoms of the R/ankle 18 months ago) The peroneals were weaker on the affected side but not markedly so.

 

An ankle fusion will shorten the limb, not lengthen it. The patient's obesity (about 75 pounds over ideal body weight), which should be included in your initial presentation of any patient, may have caused a wider base of gait which can make a foot supinate more. The weak peroneals may also allow the foot to supinate more. Without any more information, that's all I can think of.

 

I agree with Dr, Kirby that a well performed ankle fusion creates a short operated side. This always would make the non operated side long and it would pronate or go into valgus as compensation which in this interesting case it has not.
A poorly performed ankle fusion may result in a fixed equinus or fixed varus or both which could lengthen the leg and produce the bizarre picture shown.

Clinically, what would be the harm in trying a simple gait evaluation with pads placed under to non operated foot to see if it improved? No better, no foul.
Dennis

 

Dr. Kirby wrote:
The patient's obesity (about 75 pounds over ideal body weight), which should be included in your initial presentation of any patient, may have caused a wider base of gait which can make a foot supinate more.
Is Dr. Kirby trying to imtimate that overweight people, as compensation for weight alone (wider base of gait) get higher arched and more supinated? [B]Clinicians know that the vast majority of overweight people compensate by collapsing, not elevating the arch.[/B] They get genu valgum, internal femaoral and lumbar lordosis compensations, not the opposite.
Dennis

 

Having an ankle fusion for a sprain seems absurd. Any surgeon with the ability to perform an ankle fusion should have the know-how to perform a stabilization procedure. Why this was not attempted does not fit this scenario. I would request all medical records, pre-op and peri-op, before pondering why the contralateral side is supinated. Her past may hold the answer.
Nick

 

I think it would be unusual for the subtalr joint to adopt a supinated position of "almost no movement" over this time period though I suppose it is possible for this degree of degenerative change to set in over this time if the patient os overweight.

If there is a change ibn position there must have been a reasonable range of motion initailly otherwise it would have nowhere to move to. This could be an insidious of onset of pathomechanics but I would not expect this degree of compensation for a leg length differnce in an overweight patient.

More likley the surgery is a red herring and she has an upper motor nneuron lesion causing an increasein tone in the invertor musclature. This would account for an apparnet decrese in subtalar ROM secondary to the hypertonicity rather than and "actual" reduction in subtalar joint ROM.

I dont want to apppear too critical as I used to operate like this as well. I think these days it is not adequate when to see something we don't understand to refer on without exmaining thoroughly, having an idea what do you have in mind as possible diagnoses and what you might expect the next clinican to do. i.e some clinical reasoning based on your assessment. That way the patient is going to end up with the best treatment in the shortest possible time scale. A surgeon may not represent this.

Simon

 

Very Interesting case, indeed. Sudden onset of a rigid supinated hindfoot: my 'guess' would be spastisity of either PTT or ATT. The cause is what is perplexing, especially w/minimal clinical info other the prior contralateral ankle arthrodesis. Either it is pain (like peroneal spastic flatfoot) in the subtalar joint for example or overcompensation for peroneal tendinopathy.

 

I would think that one of the goals of a well performed fusion would be to get leg lengths as even as possible although this is not always possible due to insufficient bone stock.

I thought that studies have shown the opposite to be the more frequent finding the long side supinates, and the short side pronates.

 

Peter96 Wrote:
I thought that studies have shown the opposite to be the more frequent finding the long side supinates, and the short side pronates.
Dr Sha Replies:
Using generalities like "more frequent" doesn't serve many patients when confronted with specific cases (practice) . What if he/she is of a more rare foot type that does'nt follow the rules of the "more frequent".
Summarily, one must ask what type and amount of closed chain compensatory motion is available in every case and avoid generalities.
Focusing on the short side, if there is no motion available and the rearfoot is in varus (rigid rearfoot types) there would be no compensatory movement and the rearfoot would remain inverted and therefore the limb longer. If there is pronatory motion available (stable and flexible rearfoot types) then the rearfoot would evert in closed chain and therefore the limb shorter. If there is no motion vailable and the rearfoot is in valgus (flat rearfoot types) there would be no compensatory movement and the rearfoot would remain everted and therefore the limb shorter.
I think this case, there is a foot type that is less frequest and profiling into into a specific functional foot type would enable a more sophisticated diagnosis as well as exposing treatments that when applied to the "more frequest" group would fail to help (or even hurt) the average patient but would work very well in this case.
Foot Typing improves outcomes, reduces complications and failure rates and allows for an expansion of the choices for care.
Treating all feet as if they were the "more frequent" does just the opposite.

“Crude classifications and false generalizations are the curse of organized life.”
George bernard Shaw
Dennis

 

Dennis/Peter,

It was my understanding that research has not really shown any significant causal relationships between long/short sides and pronation/supination moments as compensations one way or the other. I seem to remember that what has been shown is that the longer leg will often exhibit a more flexed knee.

The fact that a longer limb will present with a more pronated foot beneath it is one of those great 'podiatric fallacies' (see thread of same title on this forum)

Ian

 

Ian:

You are correct. There is absolutely no research that supports the commonly believed podiatric myth that the long leg causes increased subtalar joint pronation and/or the short leg causes increased subtalar joint supination. This is just another podiatric myth that is perpetuated from one generation of podiatrists to another without any research evidence to support it.

 

Ian and Kevin thank you! I have discussed this issue with my DPM friends ad nauseum and we have had to agree to disagree. I often see a pronated foot on the short leg side and this has perturbed me no end reading constantly on the arena that the long leg side always pronates.

What about STJ axis and ground reactive force? Muscular involvement and compensation? Overall gait pattern? Foot morphology and possibly congential factors?

Without full history and exam findings I think this case is difficult to assess.

 

David:

Actually, in podiatry school, I was taught that the long leg pronates and the short leg supinates. However, in the thousands of patients I have examined, I have found nearly equal numbers of long legs that have a more pronated foot as short legs that have a more pronated foot when compared to the contralateral foot. This to me points toward the fact that there is probably little to no correlation between leg length and foot pronation.

 

My observations are that the assymettry of a short leg (the Inclined Posture or TIP for short) causes specific compensation within the ankle/subtalar joint complex (The Joints of the Ankle of Mann and Inmann).
If there is no compensation, then the unequal limb has not gone beyond the compensatory threshhold of the patient (until they overstress as per exercise or sports).
In compensation to even very small amounts of assymettry, the short sided rearfoot is in relative varus when compared to its mate and the ankle joint of the short side is in relative equinus.
I have expanded this observation into a test called FEJA ( F unctional
E quinovarus of the J oints of the A nkle for unequal limbs.

If there is a positve FEJA Test and associated assymettry in complaint, deformity or the existence of lower back problems I lift the short side.

I would be interested in reaction to this as my findings seem to conflict with the last few posts.
Dennis

 

I just reread my post and will correct it Kevin. I meant the long held theory that the long limb pronates. I wonder if this is unique to podiatric education?

On the face of it I feel that a common sense argument could be made that the long leg supinates and the short leg pronates to meet the ground given the strong lever arms created by the pronatory muscles in many individuals but I feel this is a very simplistic overview and does not take into account the many factors responsible for human gait.

Thank you for the response and correction Kevin.

Regards,

 

Interesting thoughts Dennis. I feel that often we are so focused on the feet that we overlook those patients with compensatory spinal or muscular involvement, especially with regard to a non-anatomical leg length inequality (LLI) where you always find compensation within the patient's compensatory threshold as you term it.

LLD certainly changes gait patterns but it also has a profound effect on the postural and phasic musculature proximal to the STJ, which I feel can influence the whole, obviously.

I wonder if podiatry is as focused on these questions as say a PT or DC would be and vice-versa if PT's and DC's possess the available knowledge and training to recognize the current podiatric paradigm to correct such a discrepancy?

This is why I feel that our fields should work more closely in sharing ideas. Can anyone point me to any current research on this subject that I may have missed?

Regards,

 

Clover:

There aren't many underlying causes for a deformity such as this.

If she already had a supinated foot and her ankle fusion resulted in added weight to her right foot (lots of stones, whatever they are!!!) then this progression of a supinatus would be expected (read some of Dr. Kirby's posts on does gravity causing supination)

If indeed she did not have a supinated foot then some other force is a work; i.e., neuromuscular, neurological, traumatic, infectious, etc..... there just are not that many causes for this kind of deformity.

I would continue to expand my history and examination. The answer is there.

Steve