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
A person with flat feet has greater load placed on the posterior tibial tendon which is the main tendon unit supporting up the arch of the foot. Throughout life, aging leads to decreased strength of
muscles, tendons and ligaments. The blood supply diminishes to tendons with aging as arteries narrow. Heavier, obese patients have more weight on the arch and have greater narrowing of arteries due
to atherosclerosis. In some people, the posterior tibial tendon finally gives out or tears. This is not a sudden event in most cases. Rather, it is a slow, gradual stretching followed by inflammation
and degeneration of the tendon. Once the posterior tibial tendon stretches, the ligaments of the arch stretch and tear. The bones of the arch then move out of position with body weight pressing down
from above. The foot rotates inward at the ankle in a movement called pronation. The arch appears collapsed, and the heel bone is tilted to the inside. The deformity can progress until the foot
literally dislocates outward from under the ankle joint.
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.
Observation by a skilled foot clinician and a hands-on evaluation of the foot and ankle is the most accurate diagnostic technique. Your Dallas foot doctor may have you do a walking examination (the
most reliable way to check for the deformity). During walking, the affected foot appears more pronated and deformed. Your podiatrist may do muscle testing to look for strength deficiencies. During a
single foot raise test, the foot doctor will ask you to rise up on the tip of your toes while keeping your unaffected foot off the ground. If your posterior tendon has been attenuated or ruptured,
you will be unable to lift your heel off the floor. In less severe cases, it is possible to rise onto your toes, but your heel will not invert normally. X-rays are not always helpful as a diagnostic
tool for Adult Flatfoot because both feet will generally demonstrate a deformity. MRI (magnetic resonance imaging) may show tendon injury and inflammation, but can?t always be relied on for a
complete diagnosis. In most cases, a MRI is not necessary to diagnose a posterior tibial tendon injury. An ultrasound may also be used to confirm the deformity, but is usually not required for an
Non surgical Treatment
In the early stages, simple pre-fabricated orthotics can help improve the heel position to reduce the mechanical load which is contributing to the symptoms. In advanced stages or long term orthotic
use, a plaster of paris or foam box cast can be taken and specific bespoke orthotics manufactured. If the condition develops further a AFO (ankle foot orthotic) may be necessary for greater control.
In more advanced stages of symptomatic Adult Acquired flat feet, where the conservative methods of treatment have failed there are various forms of surgery available depending upon the root cause of
the issue and severity.
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.