Another common term for this condition is Posterior Tibial Tendon Dysfunction (PTTD). There is a cause-effect relationship between pronation, flatfoot deformity and subsequent tenosynovitis of the posterior tibial tendon. Mechanical irritation of the tendon may lead to synovitis, partial tearing and eventually full rupture of the tendon. Other structures, including ligaments and the plantar fascia, have also been shown to contribute to the arch collapsing. As the deformity progresses, these structures have been shown to attenuate and rupture as well. In later stages, subluxation of various joints lead to a valgus rearfoot and transverse plane deformity of the forefoot. These deformities can become fixed and irreducible as significant osteoarthritis sets in.
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.
Pain along the inside of the foot and ankle, where the tendon lies. This may or may not be associated with swelling in the area. Pain that is worse with activity. High-intensity or high-impact activities, such as running, can be very difficult. Some patients can have trouble walking or standing for a long time. Pain on the outside of the ankle. When the foot collapses, the heel bone may shift to a new position outwards. This can put pressure on the outside ankle bone. The same type of pain is found in arthritis in the back of the foot. Asymmetrical collapsing of the medial arch on the affected side.
Observe forefoot to hindfoot alignment. Do this with the patient sitting and the heel in neutral, and also with the patient standing. I like to put blocks under the forefoot with the heel in neutral to see how much forefoot correction is necessary to help hold the hindfoot position. One last note is to check all joints for stiffness. In cases of prolonged PTTD or coalition, rigid deformity is present and one must carefully check the joints of the midfoot and hindfoot for stiffness and arthritis in the surgical pre-planning.
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.
Surgery should only be done if the pain does not get better after a few months of conservative treatment. The type of surgery depends on the stage of the PTTD disease. It it also dictated by where tendonitis is located and how much the tendon is damaged. Surgical reconstruction can be extremely complex. Some of the common surgeries include. Tenosynovectomy, removing the inflamed tendon sheath around the PTT. Tendon Transfer, to augment the function of the diseased posterior tibial tendon with a neighbouring tendon. Calcaneo-osteotomy, sometimes the heel bone needs to be corrected to get a better heel bone alignment. Fusion of the Joints, if osteoarthritis of the foot has set in, fusion of the joints may be necessary.