Posterior tibial tendon dysfunction is a common problem because we use our feet continuously. It is a common example of an overuse injury. One of the most frequently affected tendons is the posterior tibial tendon, a structure that is normally hard at work, helping to hold the arch up and prevent over-pronation or rolling in of the foot.
Posterior tibial tendon dysfunction actually runs the gamut from initial strain and minor degeneration of the posterior tibial tendon to frank rupture. It is now known that the problem is caused by a degenerative tendinosis rather than inflammation. Inflammation when it does occur is secondary.
The symptoms of tendonitis of the posterior tibial tendon include pain in the instep area of the foot and swelling along the course of the tendon. The patient may also experience pain and swelling right behind the inner ankle bone. There is pain upon palpation along the course of the posterior tibial tendon behind the inner ankle. There may also be burning, shooting, tingling, stabbing pain, because the nerve is inflamed inside the tarsal tunnel. Patients experience significant pain when walking, steadily worsening toward the end of the day. There is significant pain when the patient inverts his/her foot, as well as pain upon passive stretching of the posterior tibial tendon, and on eversion or flattening of the foot. In some cases the tendon may actually rupture or tear, due to weakening of the tendon by the inflammatory process. Rupture of the tendon leads to a fairly pronounced flatfoot deformity that is easily recognizable.
When the foot is acutely painful, rest, ice, nonsteroidal anti-inflammatory drugs like Advil are recommended, and a compressive dressing may be applied.
Cast immobilization holding the foot in slight inversion and plantar flexion for 4-6 weeks may be started. After the acute period, a custom orthosis or brace may be fitted. An air stirrup brace or lace-up ankle support is beneficial during the rehabilitation period. Your foot doctor may prescribe special shoes with external additions to the medial side (.i.e., medial heel wedge), to support the foot and prevent arch collapse. Your podiatrist may prescribe a custom foot orthotic based on the flexibility of the foot. If the foot becomes both flat and rigid, an Ankle-foot orthosis may become necessary.
If the condition becomes severe and chronic, your podiatrist may suggest a referral for surgical intervention is required, which consists of tendon transfers and osteotomies to improve function, and parts of the thickened tendon may be removed, to decrease symptoms.
If the tendon has ruptured, surgery may be required to either repair the ruptured tendon – or to replace it with a tendon graft. Most tears will not simply be repairable, unless they only recently occurred. Usually, another tendon in the foot, such as the tendon that flexes the four lesser toes (bends them down) is used as a tendon graft to replace the function of the posterior tibial tendon.
Finally, in cases which have been neglected, and a fixed flatfoot deformity is present, a fusion (or arthrodesis) of the foot may be required. A fusion is an operation where a joint between two bones is removed and the two bones on either side of the joint are allowed to grow together – or fuse. This type of operation is used to stop pain from joints that are worn out and can be used to realign the bones when the normal mechanisms for maintaining normal alignment are deficient – such as when the tendons and ligaments no longer work properly. Usually, several joints must be fused to control the flatfoot deformity occurring after posterior tibial tendon rupture.