[Tibialis posterior tendon dysfunction. An often neglected cause of painful adult flatfoot].

The posterior tibialis tendon is the most important dynamic stabilizer of the medial longitudinal arch of the foot. Posterior tibial tendon dysfunction (PTTD) may result from an acute trauma or a progressive degeneration of the tendon and should be suspected in painful flatfoot. The diagnosis is largely clinical, based on pain, tenderness and swelling along the tendon underneath the medial malleolus, the too-many-toes sign and persistant hindfoot valgus during heel rise. Untreated PTTD often results in total collapse of the longitudinal arch and severe osteoarthritis of the ankle or hindfoot. In traumatic cases acute repair of the tendon should be considered.