The foot’s arched structure is what allows it to comfortably flex and distribute weight. Force generated in the calf muscles transfers through the long bones of the foot’s midsection to its front, allowing a person to walk normally. But fallen arches are a common problem, particularly as people age. Although some people are born with flat feet, fallen arches acquired in adulthood are usually caused by correctable factors such as dysfunction in certain tendons, arthritis, or bone weakness.
The Function of the Posterior Tibial Tendon
The shape of the foot’s arch is maintained by tendons, the most important being the posterior tibial tendon. The tibialis posterior muscle connects from the tibia and fibula bones of the lower leg and runs down the calf. Its tendon continues down behind the bony protrusion on the inside of the ankle and branches off under the arch to other parts of the underside of the foot. Most cases of fallen arches are due to overuse and wear to the posterior tibial tendon. Initially, patients will feel pain on the inside of the foot and notice inflammation. As their feet flatten, pain migrates to the outward-facing side of the foot.
Less Common Causes of Fallen Arches
Posterior Tibial Tendon Dysfunction often contributes to and is worsened by arthritis. But arthritis, or joint inflammation, can also result from an autoimmune condition. Damage to cartilage and ligaments at the back or middle of the foot weakens the arch’s structure, and damage to blood vessels causes bones to soften by restricting their nutrition.
The arch’s supporting structures can be injured by an acute injury. Known as Lisfranc injuries, these occur in the middle of the foot when it twists during a fall. Lisfranc injuries can result in arthritis, even years after the injury healed.
Foot bones also could weaken as a result of osteoporosis or vascular problems caused by diabetes. If a person has nerve damage, they might not realize that there is a problem in their foot, and they may aggravate it by continuing to put weight on it. This could cause bone fragments to become displaced, causing several foot deformities in addition to fallen arches.
Podiatrists determine the severity of fallen arches by having the patient demonstrate their foot strength and flexibility. Imaging tests such as ultrasounds and x-rays may reveal problems such as bone spurs that develop in response to arthritis. The patient will also be examined for skin infections on the underside of the foot.
Fallen arches incurred through overuse can usually be treated with minimal intervention. The patient is provided with customized shoe inserts and a brace for when not engaged in physical therapy. They should avoid high-impact exercises while they recover. There are anti-inflammatory injections, as well.
In more severe cases, it is necessary for a doctor to surgically remove a bone spur. If the bones are broken, a doctor may perform surgery to realign or join them. When the posterior tibial tendon is inflamed, it may need to be cleaned of synovium, its cushioning tissue. Fallen arches usually will not progress this far if a patient seeks help for pain quickly and keeps their leg muscles strong without overusing them. They should also wear supportive shoes that they replace as needed.
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