Adult-acquired flatfoot (Posterior Tibial Tendon Dysfunction, PTTD) and flexible flatfoot are conditions that may cause the flattening of the arches.

When changes are made to the posterior tibial tendon -- the major tendon that supports the foot -- the ability to support the arch is impaired. If left untreated the condition will worsen. The tendon can be damaged from overuse such as running, long-distance walking, hiking, or climbing stairs. Pains on the inside of the ankle, foot, and along the tendon are indications that there may be an issue. Other symptoms of PTTD may include:

• Swelling
• Flattened arch
• Inward rolling of the ankle

Advancement of the condition can lead to pain migrating from the inside to the outside of the foot, arthritis, and tendon deterioration. Custom orthotic devices, immobilization casts or boots, and strengthening exercises through physical therapy can correct the condition during the early stages of PTTD. In extreme cases, surgery may be required to correct the issue and alleviate pain.

Flexible flatfoot shares the same common characteristic as PTTD, partial or full loss of the arch. When no weight is put on the foot, there is still an arch; when weight is put on the foot that the arch disappears. Progression of this condition will lead to ligament and tendon damage. Symptoms include:

• Heel pain
• Rolled in ankle
• Foot/leg fatigue
• Shin spints

Avoid prolonged walking and lose weight if overweight to treat the condition. In some cases, immobilization may be required.