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.
As discussed above, many different problems can create a painful flatfoot. Damage to the posterior tibial tendon is the most common cause of AAFD. The posterior tibial tendon is one of the most important tendons of the leg. It starts at a muscle in the calf, travels down the inside of the lower leg and attaches to the bones on the inside of the foot. The main function of this tendon is to support the arch of your foot when you walk. If the tendon becomes inflamed or torn, the arch will slowly collapse. Women and people over 40 are more likely to develop problems with the posterior tibial tendon. Other risk factors include obesity, diabetes, and hypertension. Having flat feet since childhood increases the risk of developing a tear in the posterior tibial tendon. In addition, people who are involved in high impact sports, such as basketball, tennis, or soccer, may have tears of the tendon from repetitive use. Inflammatory arthritis, such as rheumatoid arthritis, can cause a painful flatfoot. This type of arthritis attacks not only the cartilage in the joints, but also the ligaments that support the foot. Inflammatory arthritis not only causes pain, but also causes the foot to change shape and become flat. The arthritis can affect the back of the foot or the middle of foot, both of which can result in a fallen arch. An injury to the tendons or ligaments in the foot can cause the joints to fall out of alignment. The ligaments support the bones and prevent them from moving. If the ligaments are torn, the foot will become flat and painful. This more commonly occurs in the middle of the foot (Lisfranc injury), but can also occur in the back of the foot. Injuries to tendons of the foot can occur either in one instance (traumatically) or with repeated use over time (overuse injury). Regardless of the cause, if tendon function is altered, the forces that are transmitted across joints in the foot are changed and this can lead to increased stress on joint cartilage and ligaments. In addition to tendon and ligament injuries, fractures and dislocations of the bones in the midfoot can also lead to a flatfoot deformity. People with diabetes or with nerve problems that limits normal feeling in the feet, can have collapse of the arch or of the entire foot. This type of arch collapse is typically more severe than that seen in patients with normal feeling in their feet. In addition to the ligaments not holding the bones in place, the bones themselves can sometimes fracture and disintegrate without the patient feeling any pain. This may result in a severely deformed foot that is very challenging to correct with surgery. Special shoes or braces are the best method for dealing with this problem.
Symptoms shift around a bit, depending on what stage of PTTD you?re in. For instance, you?re likely to start off with tendonitis, or inflammation of the posterior tibial tendon. This will make the area around the inside of your ankle and possibly into your arch swollen, reddened, warm to the touch, and painful. Inflammation may actually last throughout the stages of PTTD. The ankle will also begin to roll towards the inside of the foot (pronate), your heel may tilt, and you may experience some pain in your leg (e.g. shin splints). As the condition progresses, the toes and foot begin to turn outward, so that when you look at your foot from the back (or have a friend look for you, because-hey-that can be kind of a difficult maneuver to pull off) more toes than usual will be visible on the outside (i.e. the side with the pinky toe). At this stage, the foot?s still going to be flexible, although it will likely have flattened somewhat due to the lack of support from the posterior tibial tendon. You may also find it difficult to stand on your toes. Finally, you may reach a stage in which your feet are inflexibly flat. At this point, you may experience pain below your ankle on the outside of your foot, and you might even develop arthritis in the ankle.
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
Flatfoot deformity can be treated conservatively or with surgical intervention depending on the severity of the condition. When people notice their arches flattening, they should immediately avoid non-supportive shoes such as flip-flops, sandals or thin-soled tennis shoes. Theses shoes will only worsen the flatfoot deformity and exacerbate arch pain. Next, custom orthotics are essential for people with collapsed arches. Over-the-counter insoles only provide cushion and padding to the arch, whereas custom orthotics are fabricated to specifically fit the patient?s foot and provide support in the arch where the posterior tibial tendon is unable to anymore. Use of custom orthotics in the early phases of flatfoot or PTTD can prevent worsening of symptoms and prevent further attenuation or injury to the posterior tibial tendon. In more severe cases of flatfoot deformity an ankle foot orthosis (AFO) such as a Ritchie brace is needed. This brace provides more support to the arch and hindfoot rather than an orthotic but can be bulky in normal shoegear. Additional treatment along with use of custom orthotics is use of non-steroidal anti-inflammatories (NSAIDS) such as Advil, Motrin, or Ibuprofen which can decrease inflammation to the posterior tibial tendon. If pain is severe, the patient may need to be placed in a below the knee air walker boot for several weeks which will allow the tendon to rest and heal, especially if a posterior tibial tendon tear is noted on MRI.
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.