Adult acquired flatfoot is characterized by a fallen arch and outward pointed toes. This condition is a gradual progression in most cases, as the posterior tibialis tendon becomes weakened and loses the ability to maintain the height of the arch over time. Adult acquired flatfoot is different from a flatfoot condition in children. Adults with flatfeet remain permanently flat without surgical intervention, while children usually outgrow the condition on their own with or without treatment.
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Symptoms
Patients typically present with pain along the course of the posterior tibialis tendon, which is on the inside of the foot and ankle. However, the muscle belly originates in the lower leg and can cause some discomfort. Pain is usually worse with activities, especially high impact like running and jumping. The heel bone can shift toward the outside of the foot putting more pressure on the outside ankle bone. Patients that develop arthritis and joint spurring may have nerve impingement (trapping/pinching of the nerve) which can lead to numbness, tingling or burning in the arch and toes of the foot. Diabetic patients may notice swelling or a bump on the bottom of the foot if the condition progresses. Due to the presence of diabetic neuropathy in some patients, pain is not always an indicator of this condition.
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Causes
The most common cause of adult acquired flatfoot is damage to the posterior tibial tendon. This tendon starts at the calf and travels down to the inside of the foot. If the tendon becomes swollen, irritated or torn, the arch will begin to collapse due to lack of support and strength from the tendon. Studies have shown that women over 40 years of age are the most likely to develop an issue with the posterior tibialis tendon. Risk factors that can increase the chances of posterior tibialis tendon dysfunction include but are not limited to obesity, diabetes, hypertension. There is a small population of patients with inflammatory arthritis such as rheumatoid arthritis, that develop a painful flatfoot condition. Inflammatory arthritis typically causes dysfunction of the tendon, ligaments and joints leading to a more severe flatfoot deformity. Diabetic patients can progress to a condition called Charcot foot which is severe flattening and rocker bottom deformity of the midfoot. Bones can break and coalesce as the arch collapses, requiring an even more specialized brace in order to maintain weight bearing.
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Treatment
Patients with adult acquired flatfoot deformity are often treated with orthotics and braces.. Often patients require nonsteroidal anti-inflammatory medication due to pain and swelling, which can limit mobility. Patients also benefit from physical therapy to help treat and prevent further injuries with the tendon involved. Patients that do not respond to conservative therapy may require surgical intervention.
