Adult-Acquired Flat Foot Deformity (AAFFD) is most commonly caused by a progressive degeneration of the tendon (tibialis posterior) that supports the arch of the foot. As the tendon ages or is subjected to repetitive trauma, it stretches out over time, the natural arch of the foot becomes less pronounced and the foot gradually flattens out. Although it is uncertain why this occurs, the problem is seen equally among men and women - at an increasing frequency with age. Occasionally, a patient will experience a traumatic form of the condition as a result of a fall from a height or abnormal landing during aerial sports such as gymnastics or basketball.
Overuse of the posterior tibial tendon is often the cause of PTTD. In fact, the symptoms usually occur after activities that involve the tendon, such as running, walking, hiking, or climbing stairs.
PTTD begins with a gradual stretching and loss of strength of the posterior tibial tendon which is the most important tendon supporting the arch of the human foot. Left untreated, this tendon will continue to lengthen and eventually rupture, leading to a progressive visible collapse of the arch of the foot. In the early stages, patients with PTTD will notice a pain and swelling along the inner ankle and arch. Many times, they are diagnosed with ?tendonitis? of the inner ankle. If the foot and ankle are not properly supported during this early phase, the posterior tibial tendon can rupture and devastating consequences will occur to the foot and ankle structure. The progressive adult acquired flatfoot deformity will cause the heel to roll inward in a ?valgus? or pronated direction while the forefoot will rotate outward causing a ?duckfooted? walking pattern. Eventually, significant arthritis can occur in the joints of the foot, the ankle and even the knee. Early diagnosis and treatment is critical so if you have noticed that one, or both, of your feet has become flatter in recent times come in and have it checked out.
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
Nonoperative treatment of posterior tibial tendon dysfunction can be successful with the Arizona AFO brace, particularly when treatment is initiated in the early stages of the disease. This mandates that the orthopedist has a high index of suspicion when evaluating patients to make an accurate diagnosis. Although there is a role for surgical management of acquired flat feet, a well-fitted, custom-molded leather and polypropylene orthosis can be effective at relieving symptoms and either obviating or delaying any surgical intervention. In today's climate of patient satisfaction directed health care, a less invasive treatment modality that relieves pain may prove to be more valuable than similar pain relief that is obtained after surgery. Questions regarding the long-term results of bracing remain unanswered. Future studies are needed to determine if disease progression and arthrosis occur despite symptomatic relief with a brace. Furthermore, age- and disease stage-matched control groups who are randomized to undergo surgery or bracing are necessary to compare these different treatment modalities.
If conservative treatment fails to provide relief of pain and disability then surgery is considered. Numerous factors determine whether a patient is a surgical candidate. They include age, obesity, diabetes, vascular status, and the ability to be compliant with post-operative care. Surgery usually requires a prolonged period of nonweightbearing immobilization. Total recovery ranges from 3 months to one year. Clinical, x-ray, and MRI examination are all used to select the appropriate surgical procedure.