Adult Aquired Flat Feet

Overview

When we have foot pain, it isn't always easy to pinpoint the source because we can't visualize the structure of all the bones, muscles, and tendons on the inside. The posterior tibial tendon plays an important supportive role within the structure of the foot. It attaches to your calf muscle and then comes down along the inside of your ankle, connecting to the bones inside your foot at the other side. This tendon's main function is to hold up your arch and support your foot during each and every movement. Every step, run, walk, or jump is made possible with the support from this crucial tendon. While it is designed to perform such an important role, it is vulnerable to stress and injury. A tear during a traumatic injury or stress from overuse can injure the tissues within the tendon. This kind of injury is referred to as posterior tibial tendon dysfunction (PTTD). A really hard fall during a sports game or exposure to a repetitive motion, such as the impact on feet during soccer, tennis, football or basketball, can cause an injury. Flat foot and flat feet in adults can exacerbate this condition. The tendon can experience small tears and become inflamed. If the inflammation is allowed to continue and worsen over time, it will weaken further and could rupture completely.Acquired Flat Feet




Causes

There are multiple factors contributing to the development of this problem. Damage to the nerves, ligaments, and/or tendons of the foot can cause subluxation (partial dislocation) of the subtalar or talonavicular joints. Bone fracture is a possible cause. The resulting joint deformity from any of these problems can lead to adult-acquired flatfoot deformity. Dysfunction of the posterior tibial tendon has always been linked with adult-acquired flatfoot deformity (AAFD). The loss of active and passive pull of the tendon alters the normal biomechanics of the foot and ankle. The reasons for this can be many and varied as well. Diabetes, high blood pressure, and prolonged use of steroids are some of the more common causes of adult-acquired flatfoot deformity (AAFD) brought on by impairment of the posterior tibialis tendon. Overstretching or rupture of the tendon results in tendon and muscle imbalance in the foot leading to adult-acquired flatfoot deformity (AAFD). Rheumatoid arthritis is one of the more common causes. About half of all adults with this type of arthritis will develop adult flatfoot deformity over time. In such cases, the condition is gradual and progressive. Obesity has been linked with this condition. Loss of blood supply for any reason in the area of the posterior tibialis tendon is another factor. Other possible causes include bone fracture or dislocation, a torn or stretched tendon, or a neurologic condition causing weakness.




Symptoms

Patients will usually describe their initial symptoms as "ankle pain", as the PT Tendon becomes painful around the inside of the ankle joint. The pain will become more intense as the foot flattens out, due to the continued stretching and tearing of the PT Tendon. As the arches continue to fall, and pronation increases, the heel bone (Calcaneus) tilts into a position where it pinches against the ankle bone (Fibula), causing pain on both the inside and outside of the ankle. As the foot spends increased time in a flattened, or deformed position, Arthritis can begin to affect the joints of the foot, causing additional pain.




Diagnosis

In the early stages of dysfunction of the posterior tibial tendon, most of the discomfort is located medially along the course of the tendon and the patient reports fatigue and aching on the plantar-medial aspect of the foot and ankle. Swelling is common if the dysfunction is associated with tenosynovitis. As dysfunction of the tendon progresses, maximum pain occurs laterally in the sinus tarsi because of impingement of the fibula against the calcaneus. With increasing deformity, patients report that the shape of the foot changes and that it becomes increasingly difficult to wear shoes. Many patients no longer report pain in the medial part of the foot and ankle after a complete rupture of the posterior tibial tendon has occurred; instead, the pain is located laterally. If a fixed deformity has not occurred, the patient may report that standing or walking with the hindfoot slightly inverted alleviates the lateral impingement and relieves the pain in the lateral part of the foot.




Non surgical Treatment

Footwear has an important role, and patients should be encouraged to wear flat lace-up shoes, or even lace-up boots, which accommodate orthoses. Stage I patients may be able to manage with an off the shelf orthosis (such as an Orthaheel or Formthotics). They can try a laced canvas ankle brace before moving to a casted orthosis. The various casted, semirigid orthoses support the medial longitudinal arch of the foot and either hold the heel in a neutral alignment (stage I) or correct the outward bent heel to a neutral alignment (stage II). This approach is meant to serve several functions: to alleviate stress on the tibialis posterior; to make gait more efficient by holding the hindfoot fixed; and thirdly, to prevent progression of deformity. Devices available to do this are the orthosis of the University of California Biomechanics Laboratory, an ankle foot orthosis, or a removable boot. When this approach has been used, two thirds of patients have good to excellent results.

Acquired Flat Foot




Surgical Treatment

Types of surgery your orthopaedist may discuss with you include arthrodesis, or welding (fusing) one or more of the bones in the foot/ankle together. Osteotomy, or cutting and reshaping a bone to correct alignment. Excision, or removing a bone or bone spur. Synovectomy, or cleaning the sheath covering a tendon. Tendon transfer, or using a piece of one tendon to lengthen or replace another. Having flat feet is a serious matter. If you are experiencing foot pain and think it may be related to flat feet, talk to your orthopaedist.

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