Over 60 Million Americans suffer from Adult Acquired Flatfoot (AAF), otherwise known as Posterior Tibial Tendon Dysfunction or PTTD. This condition generally occurs in adults from 40-65 years of age, and it usually only occurs in one foot, not both. The Posterior Tibial (PT) Tendon courses along the inside part of the ankle and underneath the arch of the foot. It is the major supporting structure for the arch. Over time, the tendon becomes diseased, from overuse, and starts to lose it's strength. As a result, the arch begins to collapse, placing further strain on the PT Tendon, leading to further decrease in tendon strength, which causes further collapse of the arch. This is described as a progressive deformity because it will generally get worse over time.
Flat feet causes greater pressure on the posterior tibial tendon than normal. As the person with flat feet ages, the muscles, tendons and ligaments weaken. Blood supplies diminish as arteries narrow. These conditions are magnified for obese patients because of their increased weight and atherosclerosis. Finally, the tendon gives out or tears. Most of the time, this is a slow process. Once the posterior tibial tendon and ligaments stretch, body weight causes the bones of the arch to move out of position. The foot rotates inward (pronation), the heel bone is tilted to the inside, and the arch appears collapsed. In some cases, the deformity progresses until the foot dislocates outward from the ankle joint.
Some symptoms of adult acquired flat foot are pain along the inside of the foot and ankle, pain that increases with activity, and difficulty walking for long periods of time. You may experience difficulty standing, pain on the outside of the ankle, and bony bumps on the top of the foot and inside the foot. You may also have numbness and tingling of the feet and toes (may result from large bone spurs putting pressure on nerves), swelling, a large bump on the sole of the foot and/or an ulcer (in diabetic patients). Diabetic patients should wear a properly fitting diabetic shoe wear to prevent these complications from happening.
Looking at the patient when they stand will usually demonstrate a flatfoot deformity (marked flattening of the medial longitudinal arch). The front part of the foot (forefoot) is often splayed out to the side. This leads to the presence of a ?too many toes? sign. This sign is present when the toes can be seen from directly behind the patient. The gait is often somewhat flatfooted as the patient has the dysfunctional posterior tibial tendon can no longer stabilize the arch of the foot. The physician?s touch will often demonstrate tenderness and sometimes swelling over the inside of the ankle just below the bony prominence (the medial malleolus). There may also be pain in the outside aspect of the ankle. This pain originates from impingement or compression of two tendons between the outside ankle bone (fibula) and the heel bone (calcaneus) when the patient is standing.
Non surgical Treatment
Patients can be treated non-surgically with in-shoe devices and braces to hold their feet in the correct position. This can reduce pain and damage and assist with walking. Physical therapy is also given to improve muscle strength and help prevent injury to the foot. Surgery can be performed if the patient doesn?t find any relief.
Stage two deformities are less responsive to conservative therapies that can be effective in mild deformities. Bone procedures are necessary at this stage in order to recreate the arch and stabilize the foot. These procedures include isolated fusion procedures, bone grafts, and/or the repositioning of bones through cuts called osteotomies. The realigned bones are generally held in place with screws, pins, plates, or staples while the bone heals. A tendon transfer may or may not be utilized depending on the condition of the posterior tibial tendon. Stage three deformities are better treated with surgical correction, in healthy patients. Patients that are unable to tolerate surgery or the prolonged healing period are better served with either arch supports known as orthotics or bracing such as the Richie Brace. Surgical correction at this stage usually requires fusion procedures such as a triple or double arthrodesis. This involves fusing the two or three major bones in the back of the foot together with screws or pins. The most common joints fused together are the subtalar joint, talonavicular joint, and the calcaneocuboid joint. By fusing the bones together the surgeon is able to correct structural deformity and alleviate arthritic pain. Tendon transfer procedures are usually not beneficial at this stage. Stage four deformities are treated similarly but with the addition of fusing the ankle joint.