Overview Adult acquired flatfoot is often a complex disorder, with diverse symptoms and varying degrees of deformity and disability. There are several types of flatfoot, all of which have one characteristic in common-partial or total collapse (loss) of the arch. Other characteristics shared by most types of flatfoot include ?Toe drift,? where the toes and front part of the foot point outward. The heel tilts toward the outside and the ankle appears to turn in. A short Achilles tendon or calf muscle, which causes the heel to lift off the ground earlier when walking and may act as a deforming force. In addition, other deformities such bunions and hammertoes can occur and cause pain in people with flexible flatfoot. Health problems such as rheumatoid arthritis, diabetes and obesity can increase the risk of developing flatfoot and may (or may not) make it more difficult to treat. This article provides a brief overview of the problems that can result in AAFD. Further details regarding the most common conditions that cause an acquired flatfoot and their treatment options are provided in separate articles. Links to those articles are provided. Causes Many health conditions can create a painful flatfoot, an injury to the ligaments in the foot can cause the joints to fall out of alignment. The ligaments support the bones and prevent them from moving. If the ligaments are torn, the foot will become flat and painful. This more commonly occurs in the middle of the foot (Lisfranc injury), but can also occur in the back of the foot. In addition to ligament injuries, fractures and dislocations of the bones in the midfoot can also lead to a flatfoot deformity. Symptoms Posterior tibial tendon insufficiency is divided into stages by most foot and ankle specialists. In stage I, there is pain along the posterior tibial tendon without deformity or collapse of the arch. The patient has the somewhat flat or normal-appearing foot they have always had. In stage II, deformity from the condition has started to occur, resulting in some collapse of the arch, which may or may not be noticeable. The patient may feel it as a weakness in the arch. Many patients initially present in stage II, as the ligament failure can occur at the same time as the tendon failure and therefore deformity can already be occurring as the tendon is becoming symptomatic. In stage III, the deformity has progressed to the extent where the foot becomes fixed (rigid) in its deformed position. Finally, in stage IV, deformity occurs at the ankle in addition to the deformity in the foot. Diagnosis The diagnosis of posterior tibial tendon dysfunction and AAFD is usually made from a combination of symptoms, physical exam and x-ray imaging. The location of pain, shape of the foot, flexibility of the hindfoot joints and gait all may help your physician make the diagnosis and also assess how advanced the problem is. 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. Surgical Treatment For those patients with PTTD that have severe deformity or have not improved with conservative treatments, surgery may be necessary to return them to daily activity. Surgery for PTTD may include repair of the diseased tendon and possible tendon transfer to a nearby healthy tendon, surgery on the surrounding bones or joints to prevent biomechanical abnormalities that may be a contributing factor or both.