Hindfoot flatfoot occurs when the arch of the foot collapses, causing the hindfoot to roll inward and the heel outward. This can lead to pain and swelling in the foot and ankle and may contribute to problems in the knees, hips, or lower back. Flatfoot may be the result of a congenital condition, injury, or overuse. In some cases, the foot's deformity may worsen over time, making it difficult to walk or stand for extended periods. Treatment often starts with conservative approaches like orthotics, but in severe cases, surgical reconstruction may be needed to restore the arch and improve foot function.