purple foot

by jamie
(wa)

had ankle fusion surgery 8 weeks ago dr put me in a walking boot a few days ago (still not walking ) but when I put my foot down it turns purple and gets cold, also my foot don't feel like my own (hard to explain) is this all normal?

RESPONSE
Hi Jamie,
This is not a good sign. Anytime a foot turns purple especially when the foot is in a dependent position (down) it means that the blood is not returning properly to the heart and is pooling in the foot causing the foot to turn purple.
There can be a number of reasons for this. The simplest may be due to nothing more than swelling around the surgical site, the ankle, which is causing the poor blood return to the heart. This is a situation that should resolve itself over time.
The second possibility could be that the walking cast is too tight usually further up the leg. this too could put pressure on the veins and thus not allow the blood to flow freely upward and it too could cause the purple discoloration.
A third possibility might be a blood clot in your leg. This would also have an adverse affect on the ability of the veins to pump the blood back up to your heart. In this case your foot would also tend to be swollen. But keep in mind you can have swelling in the foot as well from the other conditions I have mentioned. This is a potential problem that requires immediate medical care.
Another potential cause for the discoloration in your foot is what is known as complex regional pain syndrome.
This can occur after major foot surgery usually from the original cast being too tight. There will usually be symptoms beyond just discoloration in the foot and leg. This is a tough diagnosis to make and usually a neurologist or pain management specialist will be the one to recognize this.
Then condition basically is a result of a neurological short circuit.
So, as you can see there are a multitude of reasons why the foot may be turning purple. There are some other potential reasons based on your age, weight, medical history, etc. but since I know nothing about you, there is no point going into all those possibilities.
In any event it is very important that you bring this problem to the attention of your surgeon. Let he or she decide if the discoloration is a reason or cause for concern as your surgeon is most familiar with your condition.
The best advice I can give you is to not ignore this situation and follow up with your doctor.

Marc Mitnick DPM
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