pain at base of 5th metatarsal

by wilkies5
(UK)

over last year have suffered pain at base of right 5th MT. I had a congenital 6th toe at birth which was excised at 2 days old. This was at 4/5 web space.

Question: would I still have an extra 6th metatarsal bone running alongside my 5th metatarsal, which may explain the pain ?

RESPONSE

Hi Wilkies5,

I would be curious to know how old you are presently because if you are an adult and therefore it has been a number of years since you had your sixth toe amputated, then it would be a safe guess that you probably do not have a sixth metatarsal bone.
Having said that, the easiest way to find out if you have an extra metatarsal bone would be simply to have an x-ray. An x-ray would tell you whether or not there is an additional bone.
Assuming you did not have an extra toe on the other foot, another thing you could do is compare the width of one foot to the other. In theory if there is an additional metatarsal bone on one foot, then it should be wider than the other foot.
Here is the important message to take away from this discussion. A fifth metatarsal bone has a unique shape to it compared to the other metatarsal bones in your foot. The uniqueness lies at the level of the metatarsal base. In almost every individual there is a flare or widening of the fifth metatarsal base. Some individuals have a wider flare than others. Those with a wider flare have a greater prominence protruding from the side of their foot. The consequence of this is that the wider the flare, the greater the chance that there will be trauma to the base of the metatarsal simply because it "sticks" out further.
If nothing else, pressure from the side of the shoe directly on the metatarsal base can cause pain. I see this all the time.
Because of the prominence of the fifth metatarsal bone and simply because it is located on the side of the foot, this particular bone at the level of the base is subject to fracture.
It can result from anything ranging from direct trauma, to jumping off a ladder, to jogging, to nothing more than a stress fracture from simple walking.
The scenario worsens because unfortunately, this particular part of the fifth metatarsal bone is poorly vascularized, meaning the blood supply to the bone at this level is poor. This is true in everyone.
What this means is that typically people who fracture their fifth metatarsal base have a difficult time of healing. Even with immobilization, in many instances the fracture site will not heal because of the poor circulation to the area.
I am not saying that you a definitive fracture, but the fact that you have had pain in the area for a year is somewhat suggestive of that possibility.
There are a few other causes of pain in that region of the foot, including tendonitis of the tendons that attach and pass by that area, as well as the possibility of a subluxed cuboid bone that is being mistaken for pain in the fifth metatarsal base.
Factors such as your activity, work, types of shoes that you wear, may all be contributing to pain in that area of the foot without an actual fracture being present.
So, as you can see, the diagnosis is not a simple one to make on your own. The best advice I could give you would be to see a foot specialist in your area and have an x-ray as well as a proper examination to determine the exact cause of your pain.

Marc Mitnick DPM
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