A painful flat foot, or adult acquired flatfoot
deformity, is a progressive
collapsing of the arch of the foot that occurs as the posterior tibial tendon becomes insufficient due to various factors. Early stages may present with only pain along the posterior tibial tendon
whereas advanced deformity usually results in arthritis and rigidity of the rearfoot and ankle.
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.
Symptoms of pain may have developed gradually as result of overuse or they may be traced to one minor injury. Typically, the pain localizes to the inside (medial) aspect of the ankle, under the
medial malleolus. However, some patients will also experience pain over the outside (lateral) aspect of the hindfoot because of the displacement of the calcaneus impinging with the lateral malleolus.
This usually occurs later in the course of the condition. Patients may walk with a limp or in advanced cases be disabled due to pain. They may also have noticed worsening of their flatfoot
Looking at the patient when they stand will usually demonstrate a flatfoot deformity (marked flattening of the medial longitudinal arch). The front part of the foot (forefoot) is often splayed out to
the side. This leads to the presence of a ?too many toes? sign. This sign is present when the toes can be seen from directly behind the patient. The gait is often somewhat flatfooted as the patient
has the dysfunctional posterior tibial tendon can no longer stabilize the arch of the foot. The physician?s touch will often demonstrate tenderness and sometimes swelling over the inside of the ankle
just below the bony prominence (the medial malleolus). There may also be pain in the outside aspect of the ankle. This pain originates from impingement or compression of two tendons between the
outside ankle bone (fibula) and the heel bone (calcaneus) when the patient is standing.
Non surgical Treatment
A patient who has acute tenosynovitis has pain and swelling along the medial aspect of the ankle. The patient is able to perform a single-limb heel-rise test but has pain when doing so. Inversion of
the foot against resistance is painful but still strong. The patient should be managed with rest, the administration of appropriate anti-inflammatory medication, and immobilization. The injection of
corticosteroids is not recommended. Immobilization with either a rigid below-the-knee cast or a removable cast or boot may be used to prevent overuse and subsequent rupture of the tendon. A removable
stirrup-brace is not initially sufficient as it does not limit motion in the sagittal plane, a component of the pathological process. The patient should be permitted to walk while wearing the cast or
boot during the six to eight-week period of immobilization. At the end of that time, a decision must be made regarding the need for additional treatment. If there has been marked improvement, the
patient may begin wearing a stiff-soled shoe with a medial heel-and-sole wedge to invert the hindfoot. If there has been only mild or moderate improvement, a longer period in the cast or boot may be
If conservative treatment fails surgical intervention is offered. For a Stage 1 deformity a posterior tibial tendon tenosynovectomy (debridement of the tendon) or primary repair may be indicated. For
Stage 2 a combination of Achilles lengthening with bone cuts, calcaneal osteotomies, and tendon transfers is common. Stage 2 flexible PTTD is the most common stage patients present with for
treatment. In Stage 3 or 4 PTTD isolated fusions, locking two or more joints together, maybe indicated. All treatment is dependent on the stage and severity at presentation with the goals and
activity levels of the patient in mind. Treatment is customized to the individual patient needs.