Tibialis Posterior Tendon Dysfunction (Acquired Flatfoot)

What is Tibialis Posterior Tendon Dysfunction (Acquired Flatfoot)?

Tibialis Posterior Tendon Dysfunction, also known as Posterior Tibial Tendon Dysfunction (PTTD) or Acquired Flatfoot, is a condition where the tibialis posterior (TP) tendon, which is responsible for supporting the arch of the foot, becomes damaged or weakened.

This can lead to a collapse of the arch and a flattening of the foot, causing pain, instability, and difficulty walking. It often occurs due to overuse, injury, or aging, and can result in significant discomfort and functional impairment if left untreated.

Damage to the TP tendon can occur due to wear and tear over time, overuse, or acute trauma.

While acquired flatfoot is the most common form of tibialis posterior tendon dysfunction, there are also congenital and degenerative forms.

  • Acquired Flatfoot (PTTD):
    • This is the most common type of posterior tendon dysfunction, where the tibialis posterior tendon becomes weakened or damaged over time, leading to a collapse of the arch and flattening of the foot. It often occurs due to overuse, injury, or ageing.
  • Congenital Flatfoot:
    • This type of posterior tendon dysfunction is present at birth and may be associated with other foot deformities. It can result from abnormal development of the foot structures during fetal development.
  • Degenerative Flatfoot:
    • Degenerative flatfoot develops gradually over time, often due to aging and wear and tear on the tendon. It may occur as a result of chronic stress or strain on the tendon, leading to its weakening and eventual dysfunction.

Acquired Flatfoot can be caused by a variety of factors, including:

  • Doing repetitive activities that stress the tendon, like running, walking long distances, or standing for a long time, can make the tendon weak over time.
  • Getting hurt, like twisting an ankle or having a bad fall, can damage the tendon and make it weaker.
  • As we get older, our tendons naturally weaken and can wear out, which can lead to PTTD.
  • Carrying extra weight puts more pressure on the feet and ankles, which can strain the tendon and cause problems.

Tibialis Posterior Tendon Dysfunction can lead to a range of symptoms affecting the foot and ankle, including:

  • Pain along the inside of the ankle. Individuals may experience pain along the length of the tendon behind the medial malleolus (the bump on the inside of the ankle) as the condition progresses.
  • Flattening of the foot. As the tibialis posterior tendon weakens, the arch of the foot may collapse, resulting in a flattening of the foot structure.
  • Outer ankle pain. Pain may develop on the outer side of the ankle as the foot flattens and the bones shift out of alignment.
  • Difficulty walking or standing. Patients may have difficulty walking or standing for long periods, especially on uneven surfaces or inclines, due to pain and instability in the affected foot.
  • Swelling and redness. Inflammation of the tendon and surrounding tissues can lead to swelling and redness in the affected area.
  • Limited range of motion. Reduced flexibility and range of motion in the foot and ankle may occur due to tendon dysfunction and associated pain and stiffness.
  • In severe cases, the joints in the hindfoot may become affected, leading to arthritis and further pain and disability.

Foot Anatomy

The foot is a complex structure composed of bones, muscles, tendons, ligaments, and other tissues that work together to support body weight, absorb shock, and facilitate movement. In the context of PTTD, understanding the anatomy of the foot is crucial.

One of the key structures involved in PTTD is the tibialis posterior (TP) tendon. This tendon originates from the back of the tibia (shinbone) and fibula (smaller bone in the lower leg) and runs down the inside of the ankle, passing behind the medial malleolus (the bump on the inside of the ankle). The TP tendon then inserts into multiple bones of the foot, including the navicular bone and several cuneiform and metatarsal bones.

The primary function of the TP tendon is to support the arch of the foot and control its inward position during walking and other weight-bearing activities. It helps maintain the stability and alignment of the foot’s structure, preventing excessive flattening of the arch and inward rolling of the foot (pronation).

Treatment & Surgery Options

Non-surgical treatments for PTTD offer options to ease discomfort and aid healing without surgery.

Physiotherapy uses exercises and techniques to improve muscle strength and foot function. Additionally, orthotic devices like arch supports, ankle braces and custom-moulded splints provide support, while footwear adjustments and activity modifications help reduce strain. Painkillers, including medication and therapies like ice or heat packs, complement these treatments.

Non-surgical options are suitable for mild forms of the condition however, if symptoms persist or worsen, surgery may be recommended.

Surgery typically involves removing damaged tissue from the TP tendon and surrounding structures, and repairing the damaged TP tendon. It often needs to be strengthened by using another tendon, flexor digitorum longus (FDL).

To enhance the biomechanics of the tendon transfer, a procedure known as calcaneal osteotomy is performed. This involves moving the heel bone inward towards the foot’s centre and securing it with a screw. Furthermore, a plug is inserted into the outer portion of the foot (sinus tarsi) to support the arch. Typically, the plug and screw are removed in a follow-up operation once the transferred tendon has sufficiently strengthened, usually around 6 months after the initial surgery. This procedure is often performed as a day case operation, and recovery is generally quick.

In advanced cases where multiple foot joints have become arthritic, a triple fusion procedure may be necessary. This involves stabilising and fusing three specific joints (subtalar, talo-navicular, and calcaneocuboid) using screws and bone grafts taken from either the heel or the hipbone.

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Downloadable info sheets related to Tibialis Posterior Tendon Dysfunction (Acquired Flatfoot)

These notes from OrthoSport Victoria are for educational purposes only and are not to be used as medical advice. Please seek the advice of your specific surgeon or other health care provider with any questions regarding medical conditions and treatment.


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