The posterior tibialis muscle originates on the bones of the leg (tibia and fibula). This muscle then passes behind the medial (inside) aspect of the ankle and attaches to the medial midfoot as the
posterior tibial tendon
. The posterior tibial tendon serves to invert (roll inward) the foot and maintain the arch of the foot.
This tendon plays a central role in maintaining the normal alignment of the foot and also in enabling normal gait (walking). In addition to tendons running across the ankle and foot joints, a number
of ligaments span and stabilize these joints. The ligaments at the medial ankle can become stretched and contribute to the progressive flattening of the arch. Several muscles and tendons around the
ankle and foot act to counter-balance the action of the posterior tibial tendon. Under normal circumstances, the result is a balanced ankle and foot with normal motion. When the posterior tibial
tendon fails, the other muscles and tendons become relatively over-powering. These muscles then contribute to the progressive deformity seen with this disorder.
Damage to the posterior tendon from overuse is the most common cause for adult acquired flatfoot. Running, walking, hiking, and climbing stairs are activities that add stress to this tendon, and this
overuse can lead to damage. Obesity, previous ankle surgery or trauma, diabetes (Charcot foot), and rheumatoid arthritis are other common risk factors.
Depending on the cause of the flatfoot, a patient may experience one or more of the different symptoms here. Pain along the course of the posterior tibial tendon which lies on the inside of the foot
and ankle. This can be associated with swelling on the inside of the ankle. Pain that is worse with activity. High intensity or impact activities, such as running, can be very difficult. Some
patients can have difficulty walking or even standing for long periods of time. When the foot collapses, the heel bone may shift position and put pressure on the outside ankle bone (fibula). This can
cause pain on the outside of the ankle. Arthritis in the heel also causes this same type of pain. Patients with an old injury or arthritis in the middle of the foot can have painful, bony bumps on
the top and inside of the foot. These make shoewear very difficult. Occasionally, the bony spurs are so large that they pinch the nerves which can result in numbness and tingling on the top of the
foot and into the toes. Diabetics may only notice swelling or a large bump on the bottom of the foot. Because their sensation is affected, people with diabetes may not have any pain. The large bump
can cause skin problems and an ulcer (a sore that does not heal) may develop if proper diabetic shoewear is not used.
It is of great importance to have a full evaluation, by a foot and ankle specialist with expertise in addressing complex flatfoot deformities. No two flat feet are alike; therefore, "Universal"
treatment plans do not exist for the Adult Flatfoot. It is important to have a custom treatment plan that is tailored to your specific foot. That starts by first understanding all the intricacies of
your foot, through an extensive evaluation. X-rays of the foot and ankle are standard, and MRI may be used to better assess the quality of the PT Tendon.
Non surgical Treatment
What are the treatment options? In early stages an orthotic that caters for a medially deviated subtalar joint ac-cess. Examples of these are the RX skive, Medafeet MOSI device. Customised de-vices
with a Kirby skive or MOSI adaptation will provide greater control than a prefabricated device. If the condition develops further a UCBL orthotic or an AFO (ankle foot orthotic) could be necessary
for greater control. Various different forms of surgery are available depending upon the root cause of the issue and severity.
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.