Flatfoot may sound like a characteristic of a certain water animal rather than a human problem. Flatfoot is a condition in which the arch of the foot is fallen and the foot is pointed outward. In contrast to a flatfoot condition that has always been present, this type develops after the skeleton has reached maturity. There are several situations that can result in fallen arches, including fracture, dislocation, tendon laceration, tarsal coalition, and arthritis. One of the most common conditions that can lead to this foot problem is posterior tibial tendon dysfunction. The posterior tibial tendon attaches the calf muscle to the bones on the inside of the foot and is crucial in holding up and supporting the arch. An acute injury or overuse can cause this tendon to become inflamed or even torn, and the arch of the foot will slowly fall over time.
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.
The symptom most often associated with AAF is PTTD, but it is important to see this only as a single step along a broader continuum. The most important function of the PT tendon is to work in synergy with the peroneus longus to stabilize the midtarsal joint (MTJ). When the PT muscle contracts and acts concentrically, it inverts the foot, thereby raising the medial arch. When stretched under tension, acting eccentrically, its function can be seen as a pronation retarder. The integrity of the PT tendon and muscle is crucial to the proper function of the foot, but it is far from the lone actor in maintaining the arch. There is a vital codependence on a host of other muscles and ligaments that when disrupted leads to an almost predictable loss in foot architecture and subsequent pathology.
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
Flatfoot can be treated with a variety of methods, including modified shoes, orthotic devices, a brace or cast, anti-inflammatory medications or limited steroid injections, rest, ice, and physical therapy. In severe cases, surgery may be necessary.
Flatfoot reconstruction (osteotomy). This is often recommended for flexible flatfoot condition. Flatfoot reconstruction involves cutting and shifting the heel bone into a more neutral position, transferring the tendon used to flex the lesser toes (all but the big toe) to strengthen the posterior tibial tendon, and lengthening the calf muscle. Fusion (also known as triple arthrodesis). Fusion involves fusing, or making stiff, three joints in the back of the foot the subtalar, talonavicular, and calcaneocuboid joints, to realign the foot and give it a more natural shape. Pins or screws hold the area in place until it heals. Fusion is often recommended for a rigid flatfoot deformity or evidence of arthritis. Both of these surgeries can provide excellent pain relief and correction.