Adult acquired flatfoot deformity (AAFD) is a painful, chronic condition found most often in women between the ages of 40 and 60. AAFD occurs when the soft tissues of the foot are overstretched and torn, causing the arch to collapse. Flatfoot deformities may also be caused by a foot fracture, or may result from long-term arthritis. Once the posterior tibial tendon-the tendon unit that holds up the arch-loses its function, the foot becomes ?flat? as the bones spread out of position during weight bearing. Without an AAFD repair, the condition may progress until the affected foot becomes entirely rigid and quite painful.
Posterior tibial tendon dysfunction is the most common cause of acquired adult flatfoot. Sometimes this can be a result of specific trauma, but usually the tendon becomes injured from wear and tear over time. This is more prevalent in individuals with an inherited flat foot but excessive weight, age, and level of activity are also contributing factors.
As different types of flatfoot have different causes, the associated symptoms can be different for different people. Some generalized symptoms are listed. Pain along the course of the posterior tibial tendon which lies on the inside of the foot and ankle. This can be associated with swelling on the inside of the ankle. Pain that is worse with activity. High intensity or impact activities, such as running and jumping, can be very difficult. Some patients can have difficulty walking or even standing for long periods of time and may experience pain at the inside of the ankle and in the arch of the foot. Feeling like one is ?dragging their foot.? When the foot collapses, the heel bone may shift position and put pressure on the outside ankle bone (fibula). This can cause pain in the bones and tendons in the outside of the ankle joint. Patients with an old injury or arthritis in the middle of the foot can have painful, bony bumps on the top and inside of the foot. These make shoe wear very difficult. Sometimes, the bony spurs are so large that they pinch the nerves which can result in numbness and tingling on the top of the foot and into the toes. Diabetic patients may not experience pain if they have damage to their nerves. They may only notice swelling or a large bump on the bottom of the foot. The large bump can cause skin problems and an ulcer (a sore that does not heal) may develop if proper diabetic shoe wear is not used.
Diagnostic testing is often used to diagnose the condition and help determine the stage of the disease. The most common test done in the office setting are weightbearing X-rays of the foot and ankle. These assess joint alignment and osteoarthritis. If tendon tearing or rupture is suspected, the gold standard test would be MRI. The MRI is used to check the tendon, surrounding ligament structures and the midfoot and hindfoot joints. An MRI is essential if surgery is being considered.
Non surgical Treatment
Nonoperative treatment of posterior tibial tendon dysfunction can be successful with the Arizona AFO brace, particularly when treatment is initiated in the early stages of the disease. This mandates that the orthopedist has a high index of suspicion when evaluating patients to make an accurate diagnosis. Although there is a role for surgical management of acquired flat feet, a well-fitted, custom-molded leather and polypropylene orthosis can be effective at relieving symptoms and either obviating or delaying any surgical intervention. In today's climate of patient satisfaction directed health care, a less invasive treatment modality that relieves pain may prove to be more valuable than similar pain relief that is obtained after surgery. Questions regarding the long-term results of bracing remain unanswered. Future studies are needed to determine if disease progression and arthrosis occur despite symptomatic relief with a brace. Furthermore, age- and disease stage-matched control groups who are randomized to undergo surgery or bracing are necessary to compare these different treatment modalities.
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.