Adult flatfoot may be due to multiple problems including a dysfunctional posterior tibial tendon (PTT), hypermobility and ligamentous laxity, or possibly a coalition that becomes symptomatic. For a vast majority of patients, posterior tibial tendon dysfunction (PTTD) is the cause of symptomatic flatfoot and is the main trigger of surgical reconstruction in flatfoot. The common presenting scenario for adult flatfoot is a case of unilateral flatfoot with pain. Patients will often confirm they ?always had flat feet? but have noticed increased pain and additional collapse in the past few months to years. They may also note increased swelling and a possible concern over one foot increasing in shoe size. After a comprehensive dermatologic, neurologic and vascular assessment, one should direct his or her attention to the musculoskeletal portion of the exam. It is key to examine the foot and leg as a whole in order to determine the proper procedure and consider each phase of the corrective surgery.
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 types of symptoms that may indicate Adult-Acquired Flat Foot Deformity include foot pain that worsens over time, loss of the arch, abnormal shoe wear (excessive wearing on the inner side of shoe from walking on the inner side of the foot) and an awkward appearance of the foot and ankle (when viewed from behind, heel and toes appear to go out to the side). It is important that we help individuals recognize the early symptoms of this condition, as there are many treatment options, depending upon the severity, the age of the patient, and the desired activity levels.
Clinicians need to recognize the early stage of this syndrome which includes pain, swelling, tendonitis and disability. The musculoskeletal portion of the clinical exam can help determine the stage of the disease. It is important to palpate the posterior tibial tendon and test its muscle strength. This is tested by asking patient to plantarflex and invert the foot. Joint range of motion is should be assessed as well. Stiffness of the joints may indicate longstanding disease causing a rigid deformity. A weightbearing examination should be performed as well. A complete absence of the medial longitudinal arch is often seen. In later stages the head of the talus bone projects outward to the point of a large "lump" in the arch. Observing the patient's feet from behind shows a significant valgus rotation of the heel. From behind, the "too many toes" sign may be seen as well. This is when there is abducution of the forefoot in the transverse plane allowing the toes to be seen from behind. Dysfunction of the posterior tibial tendon can be assessed by asking the patient to stand on his/her toes on the affected foot. If they are unable to, this indicates the disease is in a more advanced stage with the tendon possibly completely ruptured.
Non surgical Treatment
Although AAF is not reversible without surgery, appropriate treatment should address the patient?s current symptoms, attempt to reduce pain, and allow continued ambulation. In the early stages, orthotic and pedorthic solutions can address the loss of integrity of the foot?s support structures, potentially inhibiting further destruction.3-5 As a general principle, orthotic devices should only block or limit painful or destructive motion without reducing or restricting normal motion or muscle function. Consequently, the treatment must match the stage of the deformity.
Surgical correction is dependent on the severity of symptoms and the stage of deformity. The goals of surgery are to create a more functional and stable foot. There are multiple procedures available to the surgeon and it may take several to correct a flatfoot deformity. Usually surgical treatment begins with removal of inflammatory tissue and repair of the posterior tibial tendon. A tendon transfer is performed if the posterior tibial muscle is weak or the tendon is badly damaged. The most commonly used tendon is the flexor digitorum longus tendon. This tendon flexes or moves the lesser toes downward. The flexor digitorum longus tendon is utilized due to its close proximity to the posterior tibial tendon and because there are minimal side effects with its loss. The remainder of the tendon is sutured to the flexor hallucis longus tendon that flexes the big toe so that little function is loss.