What condition may result from a posterior tibial tendon rupture?

A posterior tibial tendon rupture can lead to acquired adult flatfoot because the posterior tibial tendon plays a crucial role in maintaining the medial arch of the foot. When this tendon is ruptured, it loses its ability to support the arch effectively, resulting in a collapse of that arch over time. This condition is characterized by the flattening of the foot, which can lead to additional problems such as pain and instability during walking.

In contrast, congenital flatfoot is a condition present at birth and is not caused by tendon rupture. Cavus foot involves an increased arch height and may not be directly related to the posterior tibial tendon's function. Equinus foot describes a foot position where the heel does not touch the ground when standing, which is also unrelated to tendon ruptures. Understanding the function of the posterior tibial tendon is key to recognizing how its rupture can lead to conditions like acquired adult flatfoot.