Flatfoot (Adult)

Posterior tibial tendon dysfunction is one of several terms to describe a painful, progressive flatfoot deformity in adults. Other terms include posterior tibial tendon insufficiency and adult acquired flatfoot.

The term adult acquired flatfoot is more appropriate because it allows a broader recognition of causative factors, not only limited to the posterior tibial tendon, an event where the posterior tibial tendon looses strength and function.

The adult acquired flatfoot is a progressive, symptomatic (painful) deformity resulting from gradual stretch (attenuation) of the tibialis posterior tendon as well as the ligaments that support the arch of the foot.

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.