Most cases of flatfeet are simply the result of normal development. When that is not the case, the condition can be caused by a number of factors, including the following:
- Physical abnormality
Flattened arches in adults may result from the stresses of aging, weight gain, and the temporary increase in elastin (protein in connective tissue) due to pregnancy.
In some cases, flatfeet are caused by a physical abnormality, such as tarsal coalition (two or more bones in the foot that have grown together) or accessory navicular (an extra bone along the side of the foot).
The effects of diseases such as diabetes and rheumatoid arthritis can lead to flatfeet. An injury (e.g., bone fracture, dislocation, sprain or tear in any of the tendons and ligaments in the foot and leg) also can cause flatfeet.