Adult acquired flatfoot
deformity (AAFD) is a painful, chronic condition found most often in women
between the ages of 40 and 60. AAFD occurs when the soft tissues of the foot are overstretched and torn, causing the arch to collapse. Flatfoot deformities may also be caused by a foot fracture, or
may result from long-term arthritis. Once the posterior tibial tendon-the tendon unit that holds up the arch-loses its function, the foot becomes flat as the bones spread out of position during
weight bearing. Without an AAFD repair, the condition may progress until the affected foot becomes entirely rigid and quite painful.
Overuse of the posterior tibial tendon is often the cause of PTTD. In fact, the symptoms usually occur after activities that involve the tendon, such as running, walking, hiking, or climbing
Some symptoms of adult acquired flat foot are pain along the inside of the foot and ankle, pain that increases with activity, and difficulty walking for long periods of time. You may experience
difficulty standing, pain on the outside of the ankle, and bony bumps on the top of the foot and inside the foot. You may also have numbness and tingling of the feet and toes (may result from large
bone spurs putting pressure on nerves), swelling, a large bump on the sole of the foot and/or an ulcer (in diabetic patients). Diabetic patients should wear a properly fitting diabetic shoe wear to
prevent these complications from happening.
The adult acquired flatfoot, secondary to posterior tibial tendon dysfunction, is diagnosed in a number of ways with no single test proven to be totally reliable. The most accurate diagnosis is made
by a skilled clinician utilizing observation and hands on evaluation of the foot and ankle. Observation of the foot in a walking examination is most reliable. The affected foot appears more pronated
and deformed compared to the unaffected foot. Muscle testing will show a strength deficit. An easy test to perform in the office is the single foot raise. A patient is asked to step with full body
weight on the symptomatic foot, keeping the unaffected foot off the ground. The patient is then instructed to "raise up on the tip toes" of the affected foot. If the posterior tibial tendon has been
attenuated or ruptured, the patient will be unable to lift the heel off the floor and rise onto the toes. In less severe cases, the patient will be able to rise on the toes, but the heel will not be
noted to invert as it normally does when we rise onto the toes. X-rays can be helpful but are not diagnostic of the adult acquired flatfoot. Both feet - the symptomatic and asymptomatic - will
demonstrate a flatfoot deformity on x-ray. Careful observation may show a greater severity of deformity on the affected side.
Non surgical Treatment
The adult acquired flatfoot is best treated early. There is no recommended home treatment other than the general avoidance of prolonged weightbearing in non-supportive footwear until the patient can
be seen in the office of the foot and ankle specialist. In Stage I, the inflammation and tendon injury will respond to rest, protected ambulation in a cast, as well as anti-inflammatory therapy.
Follow-up treatment with custom-molded foot orthoses and properly designed athletic or orthopedic footwear are critical to maintain stability of the foot and ankle after initial symptoms have been
calmed. Once the tendon has been stretched, the foot will become deformed and visibly rolled into a pronated position at the ankle. Non-surgical treatment has a significantly lower chance of success.
Total immobilization in a cast or Camwalker may calm down symptoms and arrest progression of the deformity in a smaller percentage of patients. Usually, long-term use of a brace known as an ankle
foot orthosis is required to stop progression of the deformity without surgery. A new ankle foot orthosis known as the Richie Brace, offered by PAL Health Systems, has proven to show significant
success in treating Stage II posterior tibial dysfunction and the adult acquired flatfoot. This is a sport-style brace connected to a custom corrected foot orthotic device that fits well into most
forms of lace-up footwear, including athletic shoes. The brace is light weight and far more cosmetically appealing than the traditional ankle foot orthosis previously prescribed.
A new type of surgery has been developed in which surgeons can re-construct the flat foot deformity and also the deltoid ligament using a tendon called the peroneus longus. A person is able to
function fully without use of the peroneus longus but they can also be taken from deceased donors if needed. The new surgery was performed on four men and one woman. An improved alignment of the
ankle was still evident nine years later, and all had good mobility 8 to 10 years after the surgery. None had developed arthritis.