Tibialis posterior tendon rupture.

Rupture of the tibialis posterior (TP) tendon occurs most commonly in adult women. It evolves as an insidious, painful, and progressive flatfoot deformity. Watching for such deformities as too many toes and including the single heel rise test in the examination will facilitate an accurate diagnosis. The treatment rationale should consider the site and extent of tendon disruption, as well as the presence of secondary deformity. Early treatment will help to prevent long-term functional impairment.