Right lateral foot pain (cuboid/ base of 5th metatarsal)

by Daphne

Hello!

I have been a runner for years but have gradually increased my mileage in preparation for my first marathon in April. Yesterday was a day off for me and I noticed a dull ache in my foot as I left work that progressed to stabbing pain by the time I got to my car in the parking lot. 24 hours have passed and I have not been able to bear weight on my right lateral foot or push off normally. I spent the day today walking on my toes as I am not able to get my foot flat because of the sharp pain. It seems to be the area around the 5th metatarsal/ cuboid joint. I have been icing, taking anti-inflammatories, and skipped my runs these last 2 days. I had an X-ray this morning that was negative for stress fracture/ dislocation. Should I be concerned that this could still be a stress fracture that did not show up? Is there anything (taping, arch supports) that I can do in the meantime to help me walk normally? I imagine walking on my tip toes all day isn't wise.

The only other relevant information I can think to tell you is that I do have moderate hallux valgus on this same foot. My opposite foot has a talar-navicular fusion, so I know my mechanics are probably to blame.

Thanks so much for your help!

RESPONSE

Hi Daphne,

Sounds like you do not really need my advice as you seem to be pretty knowledgeable when it comes to foot pathology.
You are right in the sense that sometimes a small fracture may not show up initially on x-ray and either a second x-ray will need to be taken ten days down the road or perhaps a bone scan sooner, if you want to get this problem resolved as quickly as possible.
There is also the possibility that you have a subluxed cuboid bone and of course, that too will not show up on x-ray. That is usually made on clinical grounds.
Another possibility is damage to the peroneus longus tendon which comes down the side of the ankle and into the side of the foot and then takes a quick turn by the cuboid bone and heads underneath the foot. This tendon can easily be injured just by its location and the course that it travels.
So, a fracture of the fifth metatarsal base, a subluxed cuboid and an injury to the peroneus longus tendon are the three most common causes of pain in that part of the foot.
The problem is, I/you do not know which one it is and of course the treatment is basically different for all three.
Depending on your time line for preparing for your marathon you may need a proper diagnosis sooner rather than later and of course the only way that is going to happen is to see a foot specialist who should be able to make the diagnosis and offer appropriate treatment.
If you do have the time to spare, then you could try rest, ice, immobilization and anti-inflammatory medication (if you can tolerate it) to see if the pain resolves itself. If you do not see substantial improvement in lets say ten days, then you may have no other option but to seek medical attention.

Marc Mitnick DPM
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