Katy Pattie

Overview
Adult-Acquired Flat Foot Deformity (AAFFD) is most commonly caused by a progressive degeneration of the tendon (tibialis posterior) that supports the arch of the foot. As the tendon ages or is subjected to repetitive trauma, it stretches out over time, the natural arch of the foot becomes less pronounced and the foot gradually flattens out. Although it is uncertain why this occurs, the problem is seen equally among men and women - at an increasing frequency with age. Occasionally, a patient will experience a traumatic form of the condition as a result of a fall from a height or abnormal landing during aerial sports such as gymnastics or basketball.


Causes
Several risk factors are associated with PTT dysfunction, including high blood pressure, obesity, diabetes, previous ankle surgery or trauma and exposure to steroids. A person who suspects that they are suffering from PTT dysfunction should seek medical attention earlier rather than later. It is much easier to treat early and avoid a collapsed arch than it is to repair one. When the pain first happens and there is no significant flatfoot deformity, initial treatments include rest, oral anti-inflammatory medications and, depending on the severity, a special boot or brace.

Symptoms
At first you may notice pain and swelling along the medial (big toe) side of the foot. This is where the posterior tibialis tendon travels from the back of the leg under the medial ankle bone to the foot. As the condition gets worse, tendon failure occurs and the pain gets worse. Some patients experience pain along the lateral (outside) edge of the foot, too. You may find that your feet hurt at the end of the day or after long periods of standing. Some people with this condition have trouble rising up on their toes. They may be unable to participate fully in sports or other recreational activities.

Diagnosis
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
A patient who has acute tenosynovitis has pain and swelling along the medial aspect of the ankle. The patient is able to perform a single-limb heel-rise test but has pain when doing so. Inversion of the foot against resistance is painful but still strong. The patient should be managed with rest, the administration of appropriate anti-inflammatory medication, and immobilization. The injection of corticosteroids is not recommended. Immobilization with either a rigid below-the-knee cast or a removable cast or boot may be used to prevent overuse and subsequent rupture of the tendon. A removable stirrup-brace is not initially sufficient as it does not limit motion in the sagittal plane, a component of the pathological process. The patient should be permitted to walk while wearing the cast or boot during the six to eight-week period of immobilization. At the end of that time, a decision must be made regarding the need for additional treatment. If there has been marked improvement, the patient may begin wearing a stiff-soled shoe with a medial heel-and-sole wedge to invert the hindfoot. If there has been only mild or moderate improvement, a longer period in the cast or boot may be tried.


Surgical Treatment
If initial conservative therapy of posterior tibial tendon insufficiency fails, surgical treatment is considered. Operative treatment of stage 1 disease involves release of the tendon sheath, tenosynovectomy, debridement of the tendon with excision of flap tears, and repair of longitudinal tears. A short-leg walking cast is worn for 3 weeks postoperatively. Teasdall and Johnson reported complete relief of pain in 74% of 14 patients undergoing this treatment regimen for stage 1 disease. Surgical debridement of tenosynovitis in early stages is believed to possibly prevent progression of disease to later stages of dysfunction.