Posterior Tibial Tendon Dysfunction (PTTD)

Overview
Adult-acquired flatfoot is a challenging condition to treat. It is defined as a symptomatic, progressive deformity of the foot caused by loss of supportive structures of the medial arch. It is becoming increasingly frequent with the aging population and the obesity epidemic. Patients commonly try to lose weight by exercising to improve the condition. This often leads to worsening of symptoms and progression of the disorder. Early recognition of this complex disorder is essential, if chronic pain and surgery are to be avoided.

Causes
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
Pain and swelling around the inside aspect of the ankle initially. Later, the arch of the foot may fall (foot becomes flat), this change leads to walking to become difficult and painful, as well as standing for long periods. As the flat foot becomes established, pain may progress to the outer part of the ankle. Eventually, arthritis may develop.

Diagnosis
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 stage 1 and 2 acquired adult flatfoot deformity can be successful. General components of the treatment include the use of comfort shoes. Activity modification to avoid exacerbating activities. Weight loss if indicated. Specific components of treatment that over time can lead to marked improvement in symptoms include a high repetition, low resistance strengthening program. Appropriate bracing or a medial longitudinal arch support. If the posterior tibial tendon is intact, a series of exercises aimed at strengthening the elongated and dysfunctional tendon complex can be successful. In stage 2 deformities, this is combined with an ankle brace for a period of 2-3 months until the symptoms resolve. At this point, the patient is transitioned to an orthotic insert which may help to support the arch. In patients with stage 1 deformity it may be possible to use an arch support immediately.

Surgical Treatment
If conservative treatments don?t work, your doctor may recommend surgery. Several procedures can be used to treat posterior tibial tendon dysfunction; often more than one procedure is performed at the same time. Your doctor will recommend a specific course of treatment based on your individual case. Surgical options include. Tenosynovectomy. In this procedure, the surgeon will clean away (debride) and remove (excise) any inflamed tissue surrounding the tendon. Osteotomy. This procedure changes the alignment of the heel bone (calcaneus). The surgeon may sometimes have to remove a portion of the bone. Tendon transfer: This procedure uses some fibers from another tendon (the flexor digitorum longus, which helps bend the toes) to repair the damaged posterior tibial tendon. Lateral column lengthening, In this procedure, the surgeon places a small wedge-shaped piece of bone into the outside of the calcaneus. This helps realign the bones and recreates the arch. Arthrodesis. This procedure welds (fuses) one or more bones together, eliminating movement in the joint. This stabilizes the hindfoot and prevents the condition from progressing further.