Overview Adult-acquired flatfoot or collapsed arch occurs because the large tendon on the inside of the ankle - the posterior tibial tendon - becomes stretched out and no longer supports the foot?s arch. In many cases, the condition worsens and and the tendon thickens, becoming painful, especially during activities. Flatfoot or collapsed arch is also known as posterior tibial tendon dysfunction. This condition is different than having flat feet since birth (known as congenital flatfoot), although sometimes these patients develop similar symptoms and require similar treatments. Causes There are numerous causes of acquired adult flatfoot, including fracture or dislocation, tendon laceration, tarsal coalition, arthritis, neuroarthropathy, neurologic weakness, and iatrogenic causes. The most common cause of acquired adult flatfoot is posterior tibial tendon dysfunction. Symptoms PTTD begins with a gradual stretching and loss of strength of the posterior tibial tendon which is the most important tendon supporting the arch of the human foot. Left untreated, this tendon will continue to lengthen and eventually rupture, leading to a progressive visible collapse of the arch of the foot. In the early stages, patients with PTTD will notice a pain and swelling along the inner ankle and arch. Many times, they are diagnosed with ?tendonitis? of the inner ankle. If the foot and ankle are not properly supported during this early phase, the posterior tibial tendon can rupture and devastating consequences will occur to the foot and ankle structure. The progressive adult acquired flatfoot deformity will cause the heel to roll inward in a ?valgus? or pronated direction while the forefoot will rotate outward causing a ?duckfooted? walking pattern. Eventually, significant arthritis can occur in the joints of the foot, the ankle and even the knee. Early diagnosis and treatment is critical so if you have noticed that one, or both, of your feet has become flatter in recent times come in and have it checked out. Diagnosis 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 Options range from shoe inserts, orthotics, bracing and physical therapy for elderly and/or inactive patients to reconstructive surgical procedures in those wishing to remain more active. These treatments restore proper function and alignment of the foot by replacing the damaged muscle tendon unit with an undamaged, available and expendable one, lengthening the contracted Achilles tendon and realigning the Os Calcis, or heel bone, while preserving the joints of the hindfoot. If this condition is not recognized before it reaches advanced stages, a fusion of the hindfoot or even the ankle is necessary. Typically this is necessary in elderly individuals with advanced cases that cannot be improved with bracing. Surgical Treatment For more chronic flatfoot pain, surgical intervention may be the best option. Barring other serious medical ailments, surgery is a good alternative for patients with a serious problem. There are two surgical options depending on a person?s physical condition, age and lifestyle. The first type of surgery involves repair of the PTT by transferring of a nearby tendon to help re-establish an arch and straighten out the foot. After this surgery, patients wear a non-weight bearing support boot for four to six weeks. The other surgery involves fusing of two or three bones in the hind foot below the ankle. While providing significant pain relief, this option does take away some hind foot side-to-side motion. Following surgery, patients are in a cast for three months. Surgery is an effective treatment to address adult-acquired flatfoot, but it can sometimes be avoided if foot issues are resolved early. That is why it is so important to seek help right away if you are feeling ankle pain. But perhaps the best way to keep from becoming flatfooted is to avoid the risk factors altogether. This means keeping your blood pressure, weight and diabetes in check.