Even within the medical community, the severity and complexity of this deformity are not fully understood. This adds confusion and misinformation to a potentially devastating problem. There is a certain type of surgical procedure to treat severe flat feet that is performed four times more often in Europe than here in the United States. Statistically, even twice as much would be relevant, but four times is pretty amazing.
One has to understand a little basic terminology and anatomy to comprehend the nuances of this condition.
WHAT DOES THE TERM “FLAT FEET” MEAN?
Flat feet is a description of the appearance of the arch. If the arch is diminished then one is said to have flat feet. The problem is that the arch is often in the normal range but the foot is rotating below the level of the ankle, which gives the appearance of a flat foot. A trained foot and ankle specialist should be able to tell easily what is normal and what is pathologic. Everyone pronates. Everyone should pronate, but if it is too much then the foot “unlocks” and then rotates, giving a flattening appearance.
WHAT IS PRONATION?
In terms of anatomy, the ankle only goes up and down. Point your toes up and then down letting your foot move with this motion. This is the only movement your ankle does. If you move your foot inward (like you are trying to look at the bottom of your foot), this is called supination. If you move your foot in a similar motion but outward (like you are trying to walk on you inner ankle), this is called pronation. The subtalar joint is responsible for this type of movement. This joint is often the real culprit in excessive pronation. As noted previously, one can have a pretty normal arch but with the rotation of the subtalar joint it appears to be obliterated. That is, the arch disappears.
To demonstrate this movement hold your hand in the air making a letter C pointing downward. Now rotate your knuckles toward you without changing the shape of the “C”. If you pretend the “C” is a normal arch and you rotate it without letting the “C” flatten, it looks like it does just that, flatten, but really one is not changing the shape of the “C”. Try this and you will see how this works with considerable similarity on the foot.
WHEN ARE FLAT FEET AND PRONATION NORMAL AND WHEN CAN THEY BE A POTENTIAL ISSUE?
Again, pronation and supination are normal and needed for normal gait. If either of these is excessive then gait is affected and the consequences can be severe. One needs a stable platform to walk off of and propel from. If the foot excessively pronates, the foot unlocks and becomes a “loose bag of bones”. Excessive pronation then causes excessive rotation of the leg which could lead to knee pain and/or damage. Shin splints are common with active children who excessively pronate. Excessive pronation is unfortunately not always painful in children. If pain is present it often begins in the legs and is typically misdiagnosed as “growing pains”. I hear of many parents who give their children Motrin and massage the legs at night to ease pain after an overly active day. If pronation is more severe then posterior heel pain, or less common, plantar heel pain presents. If one has a flat foot with excessive pronation then even inserts may not be tolerated due to the very prominent bone on the inside of the foot (called the Navicular) that drops down and can almost hit the ground. These children often have enlargement of the Navicular which makes fitting into some shoe gear, as well as tolerating orthotics very difficult. Often these children are limited in their participation in sports because of the pain caused when putting a foot with an enlarged Navicular into normal shoe gear. Because of the difficulty fitting into normal shoes I see children with recurrent blisters to the inside of their foot.
Severe pronation can lead to inactivity with obesity a real problem later in life. These children lag behind others when running and even sometimes when walking. This can be frustrating for the parents and the child. Some may think these children are lazy but the actual problem is an inefficient gait, and some children even have pain they are trying to avoid. I liken this to the following: The normal foot structure is walking on a board walk and the severely pronated foot is walking in the sand next to the board walk. Again, the foot “unlocks” and stops being a rigid lever. That is, one can not propulse off loose sand as much as a more rigid board or beam. With excessive pronation the bone that makes up part of the ankle (called the Talus) has to rotate inward. This makes the ankle, and thus the leg, follow suit. The knee is designed to handle a little rotation but not much. The knee is a hinge joint. Bend it back and forth and this motion is clear. If one has repetitive and excessive rotation this will take its toll on this structure. This then leads to the need for arthroscopic procedures and eventual knee replacements. Biomechanically savvy orthopedists are recognizing this and not just looking at the knee when pain is present in this area.
Ultimately excessive pronation’s end result is a condition usually seen later in life called Chronic Posterior Tibial Tendonitis/Dysfunction. The tendon responsible for much of the work holding up the arch simply fails, leading to further dysfunction and secondary changes.
How do we treat excessive pronation? Most children do great in better shoes. Temporary inserts are fine and sometimes a custom orthotic is necessary. The more extensive the deformity the more rigid control one needs. Children should lace up their shoes (good luck!). Often stretching is necessary in the area of the Achilles tendon. This can be due either to secondary contractures or this may actually be the original problem that made the midfoot collapse to begin with. If the problem is caught early one has a better chance of correcting or at least limiting this deformity. If the deformity is severe and the orthotics are either not tolerated or not helping control the deformity or pain, then surgical options should be considered.
If one needs surgery, the earlier the better. Early surgery is often a “balancing” with work to the tendons and/or limiting the motion of the subtalar joint with the use of an MBA or similar implant. After this type of surgery the subtalar joint is free to move as it should but it does not allow the severe motion which is the problem with excessive pronation. The subtalar joint is not prevented from moving as it is in a fusion. The MBA implant is the device that is actually used four times more often in Europe than here in the States. Sad! I would much rather correct tendons early on than have to perform more aggressive bone cuts and or fusions that may be necessary at an older age. The implant can be removed at a later date and the worse scenario is that further surgery may be necessary. Luckily most children do not need surgery.
Take a look at your child’s foot from different angles, especially from behind. Most parents who are concerned with their children’s feet are concerned for good reason. They know that Jimmy’s feet don’t look anything like his sibling’s feet. They have asked the pediatrician several times about the abnormal appearance often being told they will “out grow” it or it’s really no problem. Unfortunately, it can be a real problem and is often under treated or not treated until it is too late. So trust your instincts and consult with a foot and ankle specialist who works with children and treats this type of condition to get the best advice for your child.