A painful flat foot, or adult acquired flatfoot
deformity, is a progressive collapsing of the arch of the foot that occurs as the
posterior tibial tendon becomes insufficient due to various factors. Early stages may present with only pain along the posterior tibial tendon whereas advanced deformity usually results in arthritis
and rigidity of the rearfoot and ankle.
Rheumatoid arthritis This type of arthritis attacks the cartilage in the foot, leading to pain and flat feet. It is caused by auto-immune disease, where the body?s immune system attacks its own
tissues. Diabetes. Having diabetes can cause nerve damage and affect the feeling in your feet and cause arch collapse. Bones can also fracture but some patients may not feel any pain due to the nerve
damage. Obesity and/or hypertension (high blood pressure) This increases your risk of tendon damage and resulting flat foot.
Not everyone with adult flatfoot has problems with pain. Those who do usually experience it around the ankle or in the heel. The pain is usually worse with activity, like walking or standing for
extended periods. Sometimes, if the condition develops from arthritis in the foot, bony spurs along the top and side of the foot develop and make wearing shoes more painful. Diabetic patients need to
watch for swelling or large lumps in the feet, as they may not notice any pain. They are also at higher risk for developing significant deformities from their flatfoot.
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
Initial treatment consists of supporting the medial longitudinal arch (running the length of the foot) to relieve strain on the medial soft tissues. The most effective way to relieve pain on the
tendon is to use a boot or brace, and once tenderness and pain has resolved, an orthotic device. A boot, brace, or orthotic has not been shown to correct or even prevent the progression of deformity.
Orthotics can alleviate symptoms and may slow the progression of deformity, particularly if mild. The deformity may progress despite orthotics.
Surgical correction is dependent on the severity of symptoms and the stage of deformity. The goals of surgery are to create a more functional and stable foot. There are multiple procedures available
to the surgeon and it may take several to correct a flatfoot deformity. Usually surgical treatment begins with removal of inflammatory tissue and repair of the posterior tibial tendon. A tendon
transfer is performed if the posterior tibial muscle is weak or the tendon is badly damaged. The most commonly used tendon is the flexor digitorum longus tendon. This tendon flexes or moves the
lesser toes downward. The flexor digitorum longus tendon is utilized due to its close proximity to the posterior tibial tendon and because there are minimal side effects with its loss. The remainder
of the tendon is sutured to the flexor hallucis longus tendon that flexes the big toe so that little function is loss.