ADULT ACQUIRED FLATFOOT

POSTERIOR TIBIAL TENDON DYSFUNCTION

WHAT IS ADULT ACQUIRED FLATFOOT?

There are two kids of flatfoot - flatfoot from childhood and there is one other type- the flatfoot that appears later in life. We commonly call this adult acquired flatfoot. This can be caused by a few different situations- one of those is an injury to a structure called the posterior tibial tendon. This tendon and muscles job is to help hold up the arch against the force of the body weight, injuries to this tendon can be chronic (meaning happen over time) or acute (like a tear). If you want to read about children’s (pediatric flatfoot CLICK HERE, otherwise keep reading for adult flatfoot below.) Since damage to this tendon - either chronic over an extended period of time or acute is the most common cause of this condition we also call this posterior tibial tendon dysfunction or PTTD.

WHAT ARE THE SIGNS AND SYMPTOMS?

PAIN - Patients usually complain that there is pain on the inside of the ankle. At first this may be only while walking but may become a constant pain at some point. In later stages people may develop pain on the outside of the ankle as well near the outside ankle bone ( fibula). This usually happens as the ankle and foot become flatter.

APPEARANCE - In many cases people say the arch is getting lower , they are getting a flat foot they never had before. On occasion they may say the front of their feet are pointing outward changing the way they walk. Also they describe it as “their ankle is rolling in”. Also many times patients can have a bunion condition develop because of the anatomy of the joints and how the arch collapses.

WEAKNESS - patients relate weakness in the foot when walking especially when they are pushing off with their foot to move forward.

WHAT DOES POSTERIOR TIBIAL TENDON TENDONITIS HAVE TO DO WITH IT?

If the posterior tibial tendon has chronic inflammation from a constant recurring injury or even an acute injury like an ankle sprain that never healed it will weaken over time . This weakening may allow it to stretch and force the arch to lower- creating a flat foot. Important - if someone has flatfeet since childhood they can still get more flatfeet if the tendon is injured.

HOW DOES A DOCTOR DIAGNOSE IT?

A history of the foot as told by the patient is the most important way for a doctor to figure out if there is damage to the posterior tibial tendon. Recent injury or sprains can give us a clue as well as a change in the shape of the foot. Thats a very common problem people notice when they try to put on their regular shoes. During the physical examination we look for swelling and tenderness over the area where the posterior tibial tendon lies just on the inside of the ankle joint.

Then we do a common and simple test - the single leg raise. The doctor will ask you to get up on your toes with both feet at once, after that you will be asked to get up on the toes one foot at a time. Usually in cases of PTTD the patient will not be able to get up on the toes on the affected side.

The doctor will then determine the strength of the tendons in the foot and ankle again specifically the posterior tibial tendon and see if there is pain in the area the posterior tibial tendon lives.

The examination is quite simple and any well trained diagnostician should be able to give a proper diagnosis.