Flat feet can be a problem or just a normal finding. It is important to note when painful flat feet hurt and are left untreated, it usually leads to additional problematic conditions. While it is difficult for a patient to know what is normal and what is not, here are a few points to consider:
A normal flat foot (pes planovalgus) is a mild collapse or flattening of the arch of the foot. The motion in the joints that move the foot from a higher arch to a lower arch is called pronation. Too much pronation leads to a flat foot. While a pronated foot is not a cause for concern, a painful flat foot is, and fortunately it can often be easily treated.
A moderate collapse of one foot is when the flattening of one foot is more pronounced than the other, it is often due to a tendon tear on the arch side of the foot (posterior tibial tendon tear). This painful collapse can lead to arthritis and further collapsing of the arch.
A fixed flat foot is when the foot is permanently fixed in a flat position. This condition, known as coalition, happens when two bones in the foot grow together and cannot move, resulting in a lack of motion. Over time, the flat foot position causes painful arthritis due to the abnormal position of the foot.