Flat foot is a pretty common disorder of the foot, but most of the time merely having a lower mid-foot (arch) or flatter foot is not always an issue. What is a problem is if it is progressive and becomes painful, then it is known as posterior tibial tendon dysfunction or adult acquired flatfoot. In such cases the arch of the foot becomes gradually flatter and the heel rolls inwards. This is usually followed by pain in the arch of the foot and in the ankle area. Those with this also find walking is a lot is a lot and walking consumes a lot of energy leading to a lot of fatigue.
The explanation for posterior tibial tendon dysfunction is not really fully understood, however it is an issue in which the posterior tibial tendon and muscle can't just do the job that it is designed for. The primary role of the posterior tibial tendon is to hold up the arch of the foot and stop the heel rolling inwards. For some reason the muscle and tendon unit can't just do their job any more, resulting in the progressive nature of this condition.
The treatment of posterior tibial tendon dysfunction is sort of urgent and needs to be dealt with as early as it possibly can. This is because the disorder is progressive and it will get to a stage where conservative measures fail to work and surgery is the only choice. Even though the surgical outcomes are likely to be satisfactory, they do include the fusion of some joints to prevent the problem getting worse, that comes with some long term limitations on gait as well as function, so is best avoided. To prevent the surgical treatment, treatment options should be started early. This will consist of foot orthotics that are really supportive and angle the foot back in the correct position. Exercises are also encouraged, but should not be used instead of foot orthotics, as they are vital to stop the flat foot from progressing.