What's Adult Aquired Flat Foot ?

Overview

Adult acquired flatfoot is a progressive disorder that involves a compromise of soft tissue supports of the medial arch. The condition most commonly affects middle aged women and is characterized by lowering of the arch, turning out of the forefoot, and a sideways angulation of the heel. There are five stages of the disorder that becomes progressively disabling. The end stage can potentially compromise the ankle joint along with the joints in the hindfoot.Adult Acquired Flat Foot




Causes

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.




Symptoms

The symptom most often associated with AAF is PTTD, but it is important to see this only as a single step along a broader continuum. The most important function of the PT tendon is to work in synergy with the peroneus longus to stabilize the midtarsal joint (MTJ). When the PT muscle contracts and acts concentrically, it inverts the foot, thereby raising the medial arch. When stretched under tension, acting eccentrically, its function can be seen as a pronation retarder. The integrity of the PT tendon and muscle is crucial to the proper function of the foot, but it is far from the lone actor in maintaining the arch. There is a vital codependence on a host of other muscles and ligaments that when disrupted leads to an almost predictable loss in foot architecture and subsequent pathology.




Diagnosis

Starting from the knee down, check for any bowing of the tibia. A tibial varum will cause increased medial stress on the foot and ankle. This is essential to consider in surgical planning. Check the gastrocnemius muscle and Achilles complex via a straight and bent knee check for equinus. If the range of motion improves to at least neutral with bent knee testing of the Achilles complex, one may consider a gastrocnemius recession. If the Achilles complex is still tight with bent knee testing, an Achilles lengthening may be necessary. Check the posterior tibial muscle along its entire course. Palpate the muscle and observe the tendon for strength with a plantarflexion and inversion stress test. Check the flexor muscles for strength in order to see if an adequate transfer tendon is available. Check the anterior tibial tendon for size and strength.




Non surgical Treatment

Treatment depends very much upon a patient?s symptoms, functional goals, degree and specifics of deformity, and the presence of arthritis. Some patients get better without surgery. Rest and immobilization, orthotics, braces and physical therapy all may be appropriate. With early-stage disease that involves pain along the tendon, immobilization with a boot for a period of time can relieve stress on the tendon and reduce the inflammation and pain. Once these symptoms have resolved, patients are often transitioned into an orthotic that supports the inside aspect of the hindfoot. For patients with more significant deformity, a larger ankle brace may be necessary.

Adult Acquired Flat Foot




Surgical Treatment

If surgery is necessary, a number of different procedures may be considered. The specifics of the planned surgery depend upon the stage of the disorder and the patient?s specific goals. Procedures may include ligament and muscle lengthening, removal of the inflamed tendon lining, tendon transfers, cutting and realigning bones, placement of implants to realign the foot and joint fusions. In general, early stage disease may be treated with tendon and ligament (soft-tissue) procedures with the addition of osteotomies to realign the foot. Later stage disease with either a rigidly fixed deformity or with arthritis is often treated with fusion procedures. If you are considering surgery, your doctor will speak with about the specifics of the planned procedure.

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