Adult flatfoot (adult acquired flatfoot) or posterior tibial tendon dysfunction (PTTD) is a common pathology presented to foot and ankle specialists. PTTD is characterized by a valgus (everted) hindfoot, flattening of the longitudinal arch of the foot (collapse) and abduction of the forefoot. This is a progressive deformity that begins flexible and can become rigid over time. The posterior tibial tendon (PT) is one of the main supporting structures of the foot arch. Changes within this tendon cause flattening of the foot. There are four stages of this deformity that begins flexible and progressives, with no treatment, to a rigid deformity and with time may involve the ankle joint. Patients usually present with pain in the foot or ankle stating the ?ankle? is rolling. It?s also common for patients to state they have difficulty walking barefoot. Pain is exacerbated after physical activities. Pain is usually isolated to the inside of the foot along the course of the PT tendon.
Several risk factors are associated with PTT dysfunction, including high blood pressure, obesity, diabetes, previous ankle surgery or trauma and exposure to steroids. A person who suspects that they are suffering from PTT dysfunction should seek medical attention earlier rather than later. It is much easier to treat early and avoid a collapsed arch than it is to repair one. When the pain first happens and there is no significant flatfoot deformity, initial treatments include rest, oral anti-inflammatory medications and, depending on the severity, a special boot or brace.
Patients often experience pain and/or deformity at the ankle or hindfoot. When the posterior tibial tendon does not work properly, a number of changes can occur to the foot and ankle. In the earlier stages, symptoms often include pain and tenderness along the posterior tibial tendon behind the inside of the ankle. As the tendon progressively fails, deformity of the foot and ankle may occur. This deformity can include progressive flattening of the arch, shifting of the heel so that it no longer is aligned underneath the rest of the leg, rotation and deformity of the forefoot, tightening of the heel cord, development of arthritis, and deformity of the ankle joint. At certain stages of this disorder, pain may shift from the inside to the outside aspect of the ankle as the heel shifts outward and structures are pinched laterally.
Posterior Tibial Tendon Dysfunction is diagnosed with careful clinical observation of the patient?s gait (walking), range of motion testing for the foot and ankle joints, and diagnostic imaging. People with flatfoot deformity walk with the heel angled outward, also called over-pronation. Although it is normal for the arch to impact the ground for shock absorption, people with PTTD have an arch that fully collapses to the ground and does not reform an arch during the entire gait period. After evaluating the ambulation pattern, the foot and ankle range of motion should be tested. Usually the affected foot will have decreased motion to the ankle joint and the hindfoot. Muscle strength may also be weaker as well. An easy test to perform for PTTD is the single heel raise where the patient is asked to raise up on the ball of his or her effected foot. A normal foot type can lift up on the toes without pain and the heel will invert slightly once the person has fully raised the heel up during the test. In early phases of PTTD the patient may be able to lift up the heel but the heel will not invert. An elongated or torn posterior tibial tendon, which is a mid to late finding of PTTD, will prohibit the patient from fully rising up on the heel and will cause intense pain to the arch. Finally diagnostic imaging, although used alone cannot diagnose PTTD, can provide additional information for an accurate diagnosis of flatfoot deformity. Xrays of the foot can show the practitioner important angular relationships of the hindfoot and forefoot which help diagnose flatfoot deformity. Most of the time, an MRI is not needed to diagnose PTTD but is a tool that should be considered in advanced cases of flatfoot deformity. If a partial tear of the posterior tibial tendon is of concern, then an MRI can show the anatomic location of the tear and the extensiveness of the injury.
Non surgical Treatment
Conservative treatment also depends on the stage of the disease. Early on, the pain and swelling with no deformity can be treated with rest, ice, compression, elevation and non-steroidal anti-inflammatory medication. Usually OTC orthotic inserts are recommended with stability oriented athletic shoes. If this fails or the condition is more advanced, immobilization in a rigid walking boot is recommended. This rests the tendon and protects it from further irritation, attenuation, or tearing. If symptoms are greatly improved or eliminated then the patient may return to a supportive shoe. To protect the patient from reoccurrence, different types of devices are recommended. The most common device is orthotics. Usually custom-made orthotics are preferable to OTC. They are reserved for early staged PTTD. Advanced stages may require a more aggressive type orthotic or an AFO (ankle-foot orthosis). There are different types of AFO's. One type has a double-upright/stirrup attached to a footplate. Another is a gauntlet-type with a custom plastic interior surrounded be a lace-up leather exterior. Both require the use of a bulky type athletic or orthopedic shoes. Patient compliance is always challenging with these larger braces and shoes.
Many operations are available for the treatment of dysfunction of the posterior tibial tendon after a thorough program of non-operative treatment has failed. The type of operation that is selected is determined by the age, weight, and level of activity of the patient as well as the extent of the deformity. The clinical stages outlined previously are a useful guide to operative care (Table I). In general, the clinician should perform the least invasive procedure that will decrease pain and improve function. One should consider the effects of each procedure, particularly those of arthrodesis, on the function of the rest of the foot and ankle.