Accessory Navicular: An Accessory You May Want To Do Without

Dr Blake's Note: This email was received several days ago from a patient suffering from a syndrome of pain produced by a weakened attachment of the posterior tibial tendon into the navicular. The posterior tibial tendon is the strongest supporter of the arch. The weakened attachment is due to an extra bone next to the navicular at the height of the arch. This extra bone occurs in probably 5% of the population and is called accessory navicular, os navicularis, os tibial externum, and the extra ankle bone. In only 10% of those patients with it does it occur on the other side also (bilatteral).


Hello Dr. Blake,


I am a 29 year old who has been suffering from a lot of foot pain
since early childhood-- it wasn't until I was in highschool that the
Dr. examined me standing and realized that my arches "collapse".
Finally they took an x-ray and found that I have bilateral accessory
naviculars. I have since worn orthotics and attempt to wear very
stable shoes (i.e. Saucony Hurricane). Due to the pain, I cannot do
high impact sports, and walking long distances usually results in pain
and limping. (I will also get shooting pain up my shins, in my knees,
or in my thighs/hips). There are not too many shoes I can wear
comfortably, and even with my orthotics I will have pain if I walk
more than a mile or so.

Xray shows accessory navicular under the navicular at the height of the arch.

Dr Blake's Note: The os tibial externum begins to form around 8-9 years old, and should be fully formed at 16 years old. It can fully attach bone wise, or partially attach with cartilage or fibrous tissue. These last 2 attachments are particularly weak and can cause pain.

This MRI view of an Accessory Navicular shows it inferior and  closer to the heel than the big toe. 

In the past, my foot doctor has suggested that if pain cannot be
improved with orthotics, I should consider having them surgically
removed. The Dr. mentioned that most people have pain from the bones
rubbing on shoes, etc, which I have never found rubbing to be a
problem, more like pain from disalignment. I did so PT for a while,
and much of the focus was on stretching and strengthening muscles,
especially my hips. While this did help with aches in
knees/hips/thighs at the time, I don't really feel like my overall
strength or balance has improved.

Dr Blake's Note: I have never had a patient with this syndrome with pain limited to shoe rubbing, since orthotic devices, shoe padding, and taping all take the pressure off the outside of the bone. The real pain is from something else, and that is what needs to be discovered . Discovering where the pain is coming from hopefully will enable the patient to avoid surgery, since the treatment can be directed at that, or if surgery is necessary, make sure the right surgery is performed.

I also have very poor balance, tight achilles tendons and hamstrings,
and weak muscles.I did so PT for a while, and much of the focus was on
stretching and strengthening muscles, especially my hips. While this
did help with aches in knees/hips/thighs at the time, I don't really
feel like my overall strength or balance has improved.

Dr Blake's Note: If you read the sections on posterior tibial and arch strengthening, you will understand the complexity to strengthening through pain. If the tendon is damaged, you will not be able to strengthen it, and surgery may be necessary. If the tendon is not damaged, it is vitally important to attempt to isolate it and strengthen it, painfree, and not strengthen the peroneals at all.

I also apparently have possibly pinched nerves between my big
toe/second/possibly third toe at times when walking-- the area above
and between by big and second toe will swell a bit and I get
tingling/pain//numbness in my third toe sometimes when walking.

Dr Blake's Note: The significance of this statement is Lindsey may have a version of Tarsal Tunnel syndrome which gives posterior tibial symptoms, and also superficial toe nerve symptoms. This would be a rare situation, so I will ignore it right now.

Recently, I made the silly mistake of wearing sandals to the mall.
After walking around, my right foot began paining, and has been
getting worse (now on day two night). The pain is located directly
below my ankle on the inside in a very localized spot, and has been
swollen. I have been icing it and it helped minimally (I also tried
tylenol). It hurts regardless of movement, bearing weight, etc.

Dr Blake's note: also perhaps Tarsal Tunnel??

Dr Blake's note: Like many of these chronic problems, they can become acute at times. The mistake made now is not to recognize that you have to treat this acute injury first, and deal with the chronic injury after. Lindsey is now in the Acute Phase of Rehabilitation (for this chronic injury). The treatment is immobilization and anti-inflammatory. Get yourself into a removable Anklizer Boot (see referenced in blog search) and ice 3 to 4 times a day for 15 minutes. If the ice irritates the local nerves, ice 3 inches above the area, and consider a Rx of voltaren gel 4 times daily or Flector Patches every 12 hours. Should be better in 1 to 2 weeks.


I tend to "hold my arches up" and transfer more weight to the outside
edges of my feet, because letting my arches collapse immediately
causes pain and irritation.

Dr Blake's Note: This is what the orthotic devices must do for a patient. They must be designed to hold up the arch, perhaps along with Kinesiotape, so that the patient doesn't strain the tissue further doing it using muscles and tendons abnormally.

I was told by my Dr. that the tendon holding my arch up is partially
connected to the accessory navicular, making my arch unstable and
collapse. ( I have also been told in the past that I have "loose
ligaments-- but I have noticed that while I am very flexible in some
joints, I am extremely tight elsewhere)

Dr Blake's Note: If you image that only 1/2 of your achilles tendon attached where it should, and the other 1/2 attached into a soft ligament, you would not have only 1/2 the strength, you would have next to nothing. As the achilles pulls, the weakest link in the chain (the part not attaching into solid bone) would begin to strain, and the whole achilles begin to hurt. Same with the accessory navicular, the part of the posterior tibial tendon that does not attach into solid navicular begins to strain trying to stabilize the foot, slow down pronation of the foot, ankle, knee, and pain ensues. It can not do it's job properly.

I am not sure what sort of direction is best with this problem. I
don't know if this swelling/pain is from the extra bones and would
diminish with surgery, or not. The pain is so frustrating and keeps me
from being active too much at all-- I enjoy dance, walking, yoga,
cycling and swimming-- but often walking and dance are limited (and
running out of the question) due to the pain it will cause.

Dr Blake's Note: Once the acute pain is gone, and you are back to the chronic pain, you need to get this worked up. I will give my final recommendations below, but you must know my recommendations center around a world that I would like, maybe not practical.

It seems like my pain is not the usual for accessory navicular (as
according to Dr.) so I am not sure if this is an unusual case? Any
advice or information on this would be great. This has been causing
trouble for most of my life (i.e. being unable to enjoy
walks/hikes/sports, having trouble falling asleep due to pain, pain
and limping at work).

Thanks,

Lindsey 

Lindsey, Most of the pain from this syndrome can be from inflammation at the attachment of the posterior tibial into the accessory navicular, actual tearing of the tendon itself, injury to the spring ligament just under this bone, chronic movement of the accessory bone on the parent bone (navicular) like in a fracture non-union, or orginating from another structure (both tarsal coalition and tarsal tunnel syndromes can have similiar presentations at times. Please read the post entitled (Tip of the Iceberg) since sometimes the apparent problem is actually not what is producing pain.

     You are definitely a surgical candidate due to the length of time you have had this. That being said you need a good workup to make sure they operate on the right area and do the right thing for you. And, you may find along the way that you don't need surgery.

     So, if I could prioritize wish lists for you, they would like this:

Orthaheel Wave Sandal which can be varus wedged on the outersole

MRI view on the partial bone attachment of the accessory navicular. 

1.  Get the acute pain calmed down with an Anklizer Boot, an EvenUp for the other side, anti-inflammatory. You will need the boot and EvenUp again. 
2. Get an MRI to look at the tendon, attachment of the bones, spring ligament, tarsal coalition, and tarsal tunnel areas.
3. If the MRI shows alot of bone activity, get a bone scan.
4. Talk to a Physical Therapist about isolating the posterior tibial tendon. Can you do at least isometrics without pain? Begin strengthening the tendon, same exercises are needed post operatively. Strengthening should only be done in the hour before bed, and ice after even if it does not hurt.
5. Get an orthotic that is comfortable, but supports your arch. Are there doctors or therapists in your area that use a version of the Inverted Orthotic Technique? You must feel that the orthotic works so well that you do not need to pull up your arch. 
6. Ice three times daily period. For 15 minutes each. Since you can wrap ice around the top and inside of your foot and walk around the house, at least you can do other things. 
7. Learn to Kinesiotape your arch (see separate post). Tape daily. You can ice through it.
8. Do not go around with sandals or barefoot. Dansko clogs may work. A compromise may be an Orthaheel or Chaco Sandal with Kinesiotape.
9. Feel free to send me any tests along the way. You have a big journey. Hang in there. Be Logical. I hope this has helped. Rich