Adult acquired flatfoot, or posterior tibial tendon dysfunction, is a complex disorder that results in a gradual loss of the foot arch.

The posterior tibial muscle is the muscle responsible for stabilizing the arch. If injury or illness damages the tendon connected to the posterior tibial muscle, the arch can fall, resulting in a flatfoot. Surgery can be performed to repair the tendon and improve bone alignment, which gives patients more stability when running and walking.

Reasons for treatment

Flatfoot may not be a problem in itself, but it can contribute to more serious conditions throughout the body, most commonly the legs, hips, ankles, and lower back. A painful flatfoot is a sign of injury to the tendons and muscles of the foot. Flatfoot does not necessarily get worse over time, but it can lead to the following: 

• Arthritis of the foot and ankle. 
• Bunions and hammertoes. 
• Corns and calluses. 
• Difficulty walking and running. 
• Knee pain. 
• Lower back pain.
• Pain and swelling in the heel and arch. 
• Stiffness and limited mobility.

The symptoms of flatfoot can be managed with anti-inflammatory drugs, but these medications fail to address the underlying cause of flatfoot. The best long-term solution is surgery that repairs the tendon.

How flatfoot correction is performed

Flatfoot can be treated with shoe modifications, custom orthotics, physical therapy, and steroid injections. When the pain associated with flatfoot becomes severe, surgery is required.

Surgical correction of flatfoot may include any of the following procedures: 

• Fusion of the bones in the foot and ankle. 
• Osteotomy (cutting and reshaping bone to improve alignment).
• Removal of bone spurs. 
• Repair of the tibial tendon. 
• Synovectomy (cleaning the tendon sheath). 
• Tendon transfer.

Most flatfoot procedures involve cleaning and repairing damaged tendons. In rare cases, joint fusion is required. Fusion helps improve the alignment and stability of the foot.

Surgery can reduce the pain associated with flatfoot, but it may not work for everyone. There is also a risk of infection following surgery. The earlier flatfoot is treated, the better chance there is of repairing the damage to the tendon.