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 cause of posterior tibial tendon insufficiency is not completely understood. The condition commonly does not start from one acute trauma but is a process of gradual degeneration of the soft tissues supporting the medial (inner) side of the foot. It is most often associated with a foot that started out somewhat flat or pronated (rolled inward). This type of foot places more stress on the medial soft tissue structures, which include the posterior tibial tendon and ligaments on the inner side of the foot. Children nearly fully grown can end up with flat feet, the majority of which are no problem. However, if the deformity is severe enough it can cause significant functional limitations at that age and later on if soft tissue failure occurs. Also, young adults with normally aligned feet can acutely injure their posterior tibial tendon from a trauma and not develop deformity. The degenerative condition in patients beyond their twenties is different from the acute injuries in young patients or adolescent deformities, where progression of deformity is likely to occur.
The first stage represents inflammation and symptoms originating from an irritated posterior tibial tendon, which is still functional. Stage two is characterized by a change in the alignment of the foot noted on observation while standing (see above photos). The deformity is supple meaning the foot is freely movable and a ?normal? position can be restored by the examiner. Stage two is also associated with the inability to perform a single-leg heel rise. The third stage is dysfunction of the posterior tibial tendon is a flatfoot deformity that becomes stiff because of arthritis. Prolonged deformity causes irritation to the involved joints resulting in arthritis. The fourth phase is a flatfoot deformity either supple (stage two) or stiff (stage 3) with involvement of the ankle joint. This occurs when the deltoid ligament, the major supporting structure on the inside of the ankle, fails to provide support. The ankle becomes unstable and will demonstrate a tilted appearance on X-ray. Failure of the deltoid ligament results from an inward displacement of the weight bearing forces. When prolonged, this change can lead to ankle arthritis. The vast majority of patients with acquired adult flatfoot deformity are stage 2 by the time they seek treatment from a physician.
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
Treating PTTD is almost always easier the earlier you catch it. So, the first step in treatment is to see your doctor as soon as you begin experiencing painful symptoms. However, once your condition has been diagnosed, your podiatrist will likely try to give the upset tendon a bit of a break so it?ll calm down and stop being so painful. This can often be accomplished by immobilizing the foot using tape and padding, braces, or casts, depending on what your podiatrist believes will work best for you, and depending on the severity of your condition. You may also be instructed to reduce inflammation by applying ice to the area (usually 40 minutes on and 20 minutes off, with a thin towel between you and the ice). Or, you might take anti-inflammatory medications like ibuprofen (steroidal anti-inflammatory meds are actually likely to make this problem worse, and are not usually recommended in treating PTTD), or use ultrasound therapy. Once the inflammation has gone down a bit, your podiatrist may recommend using orthotics (prescription shoe inserts) to support your damaged arch. Ankle braces can also be helpful.
Types of surgery your orthopaedist may discuss with you include arthrodesis, or welding (fusing) one or more of the bones in the foot/ankle together. Osteotomy, or cutting and reshaping a bone to correct alignment. Excision, or removing a bone or bone spur. Synovectomy, or cleaning the sheath covering a tendon. Tendon transfer, or using a piece of one tendon to lengthen or replace another. Having flat feet is a serious matter. If you are experiencing foot pain and think it may be related to flat feet, talk to your orthopaedist.