Adult-acquired flatfoot (AAF) is the term used to describe the progressive deformity of the foot and ankle that, in its later stages, results in collapsed and badly deformed feet. Although the condition has been described and written about since the 1980s, AAF is not a widely used acronym within the O&P community-even though orthotists and pedorthists easily recognize the signs of the condition because they treat them on an almost daily basis. AAF is caused by a loss of the dynamic and static support structures of the medial longitudinal arch, resulting in an incrementally worsening planovalgus deformity associated with posterior tibial (PT) tendinitis. Over the past 30 years, researchers have attempted to understand and explain the gradual yet significant deterioration that can occur in foot structure, which ultimately leads to painful and debilitating conditions-a progression that is currently classified into four stages. What begins as a predisposition to flatfoot can progress to a collapsed arch, and then to the more severe posterior tibial tendon dysfunction (PTTD). Left untreated, the PT tendon can rupture, and the patient may then require a rigid AFO or an arthrodesis fixation surgery to stabilize the foot in order to remain capable of walking pain free.
The most common cause of acquired adult flatfoot is posterior tibial tendon dysfunction. What causes adult acquired flat foot? Fracture or dislocation. Tendon laceration. Tarsal Coalition. Arthritis. Neuroarthropathy. Neurological weakness.
Most people will notice mild to extreme pain in their feet. Below outlines some signs and symptoms of AAFD. Trouble walking or standing for any duration. Pain and swelling on the inside of the ankle. Bump on the bottom of the foot. Ulcer or wound developing on the outer aspects of foot.
The adult acquired flatfoot, secondary to posterior tibial tendon dysfunction, is diagnosed in a number of ways with no single test proven to be totally reliable. The most accurate diagnosis is made by a skilled clinician utilizing observation and hands on evaluation of the foot and ankle. Observation of the foot in a walking examination is most reliable. The affected foot appears more pronated and deformed compared to the unaffected foot. Muscle testing will show a strength deficit. An easy test to perform in the office is the single foot raise. A patient is asked to step with full body weight on the symptomatic foot, keeping the unaffected foot off the ground. The patient is then instructed to “raise up on the tip toes” of the affected foot. If the posterior tibial tendon has been attenuated or ruptured, the patient will be unable to lift the heel off the floor and rise onto the toes. In less severe cases, the patient will be able to rise on the toes, but the heel will not be noted to invert as it normally does when we rise onto the toes. X-rays can be helpful but are not diagnostic of the adult acquired flatfoot. Both feet – the symptomatic and asymptomatic – will demonstrate a flatfoot deformity on x-ray. Careful observation may show a greater severity of deformity on the affected side.
Non surgical Treatment
Although AAF is not reversible without surgery, appropriate treatment should address the patient?s current symptoms, attempt to reduce pain, and allow continued ambulation. In the early stages, orthotic and pedorthic solutions can address the loss of integrity of the foot?s support structures, potentially inhibiting further destruction.3-5 As a general principle, orthotic devices should only block or limit painful or destructive motion without reducing or restricting normal motion or muscle function. Consequently, the treatment must match the stage of the deformity.
If conservative treatments don?t work, your doctor may recommend surgery. Several procedures can be used to treat posterior tibial tendon dysfunction; often more than one procedure is performed at the same time. Your doctor will recommend a specific course of treatment based on your individual case. Surgical options include. Tenosynovectomy. In this procedure, the surgeon will clean away (debride) and remove (excise) any inflamed tissue surrounding the tendon. Osteotomy. This procedure changes the alignment of the heel bone (calcaneus). The surgeon may sometimes have to remove a portion of the bone. Tendon transfer: This procedure uses some fibers from another tendon (the flexor digitorum longus, which helps bend the toes) to repair the damaged posterior tibial tendon. Lateral column lengthening, In this procedure, the surgeon places a small wedge-shaped piece of bone into the outside of the calcaneus. This helps realign the bones and recreates the arch. Arthrodesis. This procedure welds (fuses) one or more bones together, eliminating movement in the joint. This stabilizes the hindfoot and prevents the condition from progressing further.