Flatfoot deformity is a general term used to describe a person whose arches are slowly dropping to the ground, aka ?fallen arches.? Adult-acquired flatfoot deformity can be caused by several factors, but the most common is abnormal functioning of the posterior tibial tendon in the foot and ankle. The posterior tibial tendon is the primary tendon that supports the arch. If this tendon begins to elongate from a sustained, gradual stretch over a long period of time, then the arch will progressively decrease until full collapse of the arch is noted on standing. What makes this tendon elongated? Biomechanical instability of the foot such as over-pronation or an accessory bone at the insertion site of the tendon are the primary causes for posterior tibial tendon dysfunction.
The cause of posterior tibial tendon insufficiency is not completely understood. The condition commonly does not start from one acute trauma but is a process of gradual degeneration of the soft tissues supporting the medial (inner) side of the foot. It is most often associated with a foot that started out somewhat flat or pronated (rolled inward). This type of foot places more stress on the medial soft tissue structures, which include the posterior tibial tendon and ligaments on the inner side of the foot. Children nearly fully grown can end up with flat feet, the majority of which are no problem. However, if the deformity is severe enough it can cause significant functional limitations at that age and later on if soft tissue failure occurs. Also, young adults with normally aligned feet can acutely injure their posterior tibial tendon from a trauma and not develop deformity. The degenerative condition in patients beyond their twenties is different from the acute injuries in young patients or adolescent deformities, where progression of deformity is likely to occur.
Your feet tire easily or become painful with prolonged standing. It’s difficult to move your heel or midfoot around, or to stand on your toes. Your foot aches, particularly in the heel or arch area, with swelling along the inner side. Pain in your feet reduces your ability to participate in sports. You’ve been diagnosed with rheumatoid arthritis; about half of all people with rheumatoid arthritis will develop a progressive flatfoot deformity.
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
Get treated early. There is no recommended home treatment. While in stage one of the deformity, rest, a cast, and anti-inflammatory therapy can help you find relief. This treatment is followed by creating custom-molded foot orthoses and orthopedic footwear. These customized items are critical in maintaining the stability of the foot and ankle. Once the tendon has stretched and deformity is visible, the chances of success for non-surgical treatment are significantly lower. In a small percentage of patients, total immobilization may arrest the progression of the deformity. A long-term brace known as an ankle foot orthosis is required to keep the deformity from progressing. The Richie Brace, a type of ankle foot orthosis, shows significant success as a treatment for stage two posterior tibial dysfunction. It is a sport-style brace connected to a custom corrected foot orthodic that fits into most lace-up footwear (including athletic shoes). It is also light weight and more cosmetically appealing than traditionally prescribed ankle foot orthosis. The Arizona Brace, California Brace or Gauntlet Brace may also be recommended depending on your needs.
Surgery is usually performed when non-surgical measures have failed. The goal of surgery is to eliminate pain, stop progression of the deformity and improve a patient?s mobility. More than one technique may be used, and surgery tends to include one or more of the following. The tendon is reconstructed or replaced using another tendon in the foot or ankle The name of the technique depends on the tendon used. Flexor digitorum longus (FDL) transfer. Flexor hallucis longus (FHL) transfer. Tibialis anterior transfer (Cobb procedure). Calcaneal osteotomy – the heel bone may be shifted to bring your heel back under your leg and the position fixed with a screw. Lengthening of the Achilles tendon if it is particularly tight. Repair one of the ligaments under your foot. If you smoke, your surgeon may refuse to operate unless you can refrain from smoking before and during the healing phase of your procedure. Research has proven that smoking delays bone healing significantly.