The posterior tibial tendon links the calf muscle and the bones inside the foot. The tendon’s responsibility is to support the foot’s arch when taking a step.

An acute injury, like a fall, or overuse during high impact sports can tear the posterior tibial tendon. A tear will eventually cause the arch of the foot to collapse, resulting in flatfoot.

Posterior tibial tendonitis, also called posterior tibial tendon dysfunction (PTTD) or inside ankle tendonitis, is the most common reason for an adult to develop a flat foot.

This article examines the symptoms, causes, diagnosis process, treatment, prevention, and outlook for someone with posterior tibial tendonitis.

a person with posterior tibial tendonitis is rubbing their footShare on Pinterest
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Symptoms of posterior ankle tendonitis are progressive and change as the condition advances.

Early on, people may have pain inside the foot and ankle. The area may also be warm to the touch, red, or swollen.

Over time, the foot arch may begin to fall and take on a flat appearance. The toes and front of the foot may also start to turn toward the pinky toe, and the ankle rolls inward.

As PTTD develops further, the arch entirely flattens, and the pain moves to the outside of the foot, beneath the ankle. Arthritis may develop in the foot. And in more severe cases, arthritis can form in the ankle.

The posterior tibial tendon makes a sharp turn around the ankle bone, placing it under great pressure at the foot.

When too much pressure pulls on the tendon, as in the case of a fall or repetitive high impact activities, an acute tear or chronic microtears can occur.

To diagnose posterior tibial tendonitis, a doctor will request a complete medical history, including family medical history. They will perform a physical examination looking for specific signs that may indicate this type of injury.

Possible signs of PTTD include:

  • swelling of the posterior tibial tendon, typically seen inside the foot and ankle
  • a collapsed arch on the foot and outward tilt to the heel of the foot
  • the “too many toes” sign when looking at the foot from the back; typically, only the fifth and a portion of the fourth toe are visible
  • inability to stand on tip toes
  • affected range of motion in the foot and ankle

The doctor may also order imaging tests to better help make a diagnosis, such as:

Treatment depends on the severity of the injury.

For all stages, the first step is conservative treatment involving nonsteroidal anti-inflammatory drugs (NSAIDs) and activity modification. When doctors diagnose the condition early, conservative treatment may be enough to heal the injury.

In more advanced cases, nonsurgical options include:

  • orthotic devices or braces to provide arch support
  • immobilizing the foot in a cast or boot
  • physical therapy
  • continuing treatment with NSAIDs
  • specialized shoes or shoe inserts with arch support

Rarely, a doctor may recommend surgery to provide relief. Surgical techniques may include:

  • lengthening the Achilles tendon
  • tenosynovectomy, or cleaning away inflamed tendon tissue
  • tendon transfer, or removal of the affected posterior tibial tendon to replace it with another tendon from the foot
  • osteotomy, or cutting and shifting bones to reshape a foot’s arch
  • fusion, or placing pins or plates in the foot to realign the foot to a more normal position

Addressing the following early on may help prevent or quickly relieve symptoms of PTTD:

  • poor biomechanics
  • excessive training or activity levels
  • inadequate recovery periods between activity
  • inappropriate footwear without proper support
  • muscle weakness in the tibialis posterior, calf, quadriceps, and gluteals
  • muscle tightness in the tibialis posterior and calf
  • joint stiffness in the ankle, foot, knee, hip, and low back
  • too little warm-up time
  • inadequate rehabilitation following an injury
  • change in training surfaces
  • inappropriate running technique
  • poor core stability

When caught early and treated aggressively with rest and anti-inflammatory medications, many people find relief from posterior tibial tendinitis. However, healing may take some time. In some cases, it may even take several months.

Custom orthotics and physical therapy are some of the most effective PTTD treatment options.

Surgery results are less predictable, and fewer people return to full capacity.

The posterior tibial tendon connects the calf muscle to the bones inside the foot. Falls or overuse can cause injuries to the tendon.

When the tendon tears, it cannot support the foot’s arch, and the arch falls, forming a flat foot.

First-line treatments involve NSAIDs and rest.

For more severe injuries, immobilization and physical therapy may be necessary. Several surgical options exist if none of the nonsurgical treatment options work.