There are four stages of posterior tibial tendon dysfunction. In the first stage the posterior tibial tendon is inflamed but has normal strength. There is little to no change in the arch of the foot. In stage two the tendon is partially torn or shows degenerative changes and as a result loses strength. There is considerable flattening of the arch without arthritic changes in the foot. Stage three results when the posterior tibial tendon is torn and not functioning. As a result the arch is completely collapsed with arthritic changes in the foot. Stage four is identical to stage three except that the ankle joint also becomes arthritic.
The most common cause of acquired adult flatfoot is posterior tibial tendon dysfunction. What causes adult acquired flat foot? Fracture or dislocation. Tendon laceration. Tarsal Coalition. Arthritis. Neuroarthropathy. Neurological weakness.
As different types of flatfoot have different causes, the associated symptoms can be different for different people. Some generalized symptoms are listed. 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 and jumping, can be very difficult. Some patients can have difficulty walking or even standing for long periods of time and may experience pain at the inside of the ankle and in the arch of the foot. Feeling like one is ?dragging their foot.? When the foot collapses, the heel bone may shift position and put pressure on the outside ankle bone (fibula). This can cause pain in the bones and tendons in the outside of the ankle joint. 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 shoe wear very difficult. Sometimes, 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. Diabetic patients may not experience pain if they have damage to their nerves. They may only notice swelling or a large bump on the bottom of the foot. The large bump can cause skin problems and an ulcer (a sore that does not heal) may develop if proper diabetic shoe wear is not used.
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
Non-surgical treatment consists of custom orthoses and or special bracing devices along with supportive measures aimed at reducing the symptoms. While non-surgical treatment helps the majority of patients with PTTD, progressive cases may require surgical treatment including soft tissue tendon transfers, osteotomies and lastly fusion.
For those patients with PTTD that have severe deformity or have not improved with conservative treatments, surgery may be necessary to return them to daily activity. Surgery for PTTD may include repair of the diseased tendon and possible tendon transfer to a nearby healthy tendon, surgery on the surrounding bones or joints to prevent biomechanical abnormalities that may be a contributing factor or both.