Arthritis can cause joint deformities in the foot and ankle. Severe deformities can require surgery. One cause of arthritis in the foot is Charcot foot.

Charcot foot occurs when the foot bones weaken due to conditions such as arthritis and nerve damage. Diabetics who have neuropathy can suffer from Charcot foot. The weakened bones become susceptible to fractures in the feet or ankles, which can cause bone deformities that alter the shape and form of the foot. Fallen arches and collapsed joints result in changes in foot shape; this can lead to wounds and ulcers as pressure causes friction on the misshapen areas. Charcot foot can affect one or both feet as well as the ankles. The onset of Charcot foot occurs at the average age of 40.

Charcot foot can be treated through rest, elevation, and immobilization to halt pain and allow the fractures and wounds to heal. However, many cases require surgery to correct the deformities and fix the fractures, particularly in patients that have chronic or significant deformity alongside instability, extreme pressure, and/ or severe ulcers. The surgery may involve hindfoot, ankle, and midfoot realignments to improve stability and reduce the pressure that can cause wounds and ulcers. Internal fixation devices can be inserted within the foot, and ostectomies can be performed to remove bony protrusions on the bottom of the foot.