Over 60 Million Americans suffer from Adult Acquired Flatfoot (AAF), otherwise known as Posterior Tibial Tendon Dysfunction or PTTD. This condition generally occurs in adults from 40-65 years of age, and it usually only occurs in one foot, not both. The Posterior Tibial (PT) Tendon courses along the inside part of the ankle and underneath the arch of the foot. It is the major supporting structure for the arch. Over time, the tendon becomes diseased, from overuse, and starts to lose it’s strength. As a result, the arch begins to collapse, placing further strain on the PT Tendon, leading to further decrease in tendon strength, which causes further collapse of the arch. This is described as a progressive deformity because it will generally get worse over time.
Adult acquired flatfoot is caused by inflammation and progressive weakening of the major tendon that it is responsible for supporting the arch of the foot. This condition will commonly be accompanied by swelling and pain on the inner portion of the foot and ankle. Adult acquired flatfoot is more common in women and overweight individuals. It can also be seen after an injury to the foot and ankle. If left untreated the problem may result in a vicious cycle, as the foot becomes flatter the tendon supporting the arch structure becomes weaker and more and more stretched out. As the tendon becomes weaker, the foot structure becomes progressively flatter. Early detection and treatment is key, as this condition can lead to chronic swelling and pain.
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 initial diagnosis.
Non surgical Treatment
Medical or nonoperative therapy for posterior tibial tendon dysfunction involves rest, immobilization, nonsteroidal anti-inflammatory medication, physical therapy, orthotics, and bracing. This treatment is especially attractive for patients who are elderly, who place low demands on the tendon, and who may have underlying medical problems that preclude operative intervention. During stage 1 posterior tibial tendon dysfunction, pain, rather than deformity, predominates. Cast immobilization is indicated for acute tenosynovitis of the posterior tibial tendon or for patients whose main presenting feature is chronic pain along the tendon sheath. A well-molded short leg walking cast or removable cast boot should be used for 6-8 weeks. Weight bearing is permitted if the patient is able to ambulate without pain. If improvement is noted, the patient then may be placed in custom full-length semirigid orthotics. The patient may then be referred to physical therapy for stretching of the Achilles tendon and strengthening of the posterior tibial tendon. Steroid injection into the posterior tibial tendon sheath is not recommended due to the possibility of causing a tendon rupture. In stage 2 dysfunction, a painful flexible deformity develops, and more control of hindfoot motion is required. In these cases, a rigid University of California at Berkley (UCBL) orthosis or short articulated ankle-foot orthosis (AFO) is indicated. Once a rigid flatfoot deformity develops, as in stage 3 or 4, bracing is extended above the ankle with a molded AFO, double upright brace, or patellar-tendon-bearing brace. The goals of this treatment are to accommodate the deformity, prevent or slow further collapse, and improve walking ability by transferring load to the proximal leg away from the collapsed medial midfoot and heel.
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.