This condition is characterized by a progressive flattening or falling of the arch. It is often referred to as posterior tibial tendon dysfunction (PTTD) and is becoming a more commonly recognized foot problem. Since the condition develops over time, it is typically diagnosed in adulthood. It usually only develops in one foot although it can affect both. Since it is progressive, it is common for symptoms to worsen, especially when it is not treated early. The posterior tibial tendon attaches to the bones on the inside of your foot and is vital to the support structure within the foot. With PTTD, changes in the tendon impair its ability to function normally. The result is less support for the arch, which in turn causes it to fall or flatten. A flattening arch can cause the heel to shift out of alignment, the forefoot to rotate outward, the heel cord to tighten, and possible deformity of the foot. Common symptoms include pain along the inside of the ankle, swelling, an inward rolling of the ankle, pain that is worse with activity, and joint pain as arthritis sets in.
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.
Initially, flatfoot deformity may not present with any symptoms. However, overtime as the tendon continues to function in an abnormal position, people with fallen arches will begin to have throbbing or sharp pain along the inside of the arch. Once the tendon and soft tissue around it elongates, there is no strengthening exercises or mechanism to shorten the tendon back to a normal position. Flatfoot can also occur in one or both feet. If the arch starts to slowly collapse in one foot and not the other, posterior tibial dysfunction (PTTD) is the most likely cause. People with flatfoot may only have pain with certain activities such as running or exercise in the early phase of PTTD. Pain may start from the arch and continue towards the inside part of the foot and ankle where the tendon courses from the leg. Redness, swelling and increased warmth may also occur. Later signs of PTTD include pain on the outside of the foot from the arch collapsing and impinging other joints. Arthritic symptoms such as painful, swollen joints in the foot and ankle may occur later as well due to the increased stress on the joints from working in an abnormal position for a long period of time.
Examination by your foot and ankle specialist can confirm the diagnosis for most patients. An ultrasound exam performed in the office setting can evaluate the status of the posterior tibial tendon, the tendon which is primarily responsible for supporting the arch structure of the foot.
Non surgical Treatment
In the early stages, simple pre-fabricated orthotics can help improve the heel position to reduce the mechanical load which is contributing to the symptoms. In advanced stages or long term orthotic use, a plaster of paris or foam box cast can be taken and specific bespoke orthotics manufactured. If the condition develops further a AFO (ankle foot orthotic) may be necessary for greater control. In more advanced stages of symptomatic Adult Acquired flat feet, where the conservative methods of treatment have failed there are various forms of surgery available depending upon the root cause of the issue and severity.
Many operations are available for the treatment of dysfunction of the posterior tibial tendon after a thorough program of non-operative treatment has failed. The type of operation that is selected is determined by the age, weight, and level of activity of the patient as well as the extent of the deformity. The clinical stages outlined previously are a useful guide to operative care (Table I). In general, the clinician should perform the least invasive procedure that will decrease pain and improve function. One should consider the effects of each procedure, particularly those of arthrodesis, on the function of the rest of the foot and ankle.