The majority of people will experience a flattening of the arch of the feet as we age. This is a natural part of the aging process for most, as the years of abuse we put on our feet causes weakening of the soft tissue structures that support the arch of the foot and gravity dictates that the feet tend to flatten out. When flattening of one of the feet occurs rapidly over a relatively short period of time this may signal a more serious problem.
Damage to the posterior tendon from overuse is the most common cause for adult acquired flatfoot. Running, walking, hiking, and climbing stairs are activities that add stress to this tendon, and this overuse can lead to damage. Obesity, previous ankle surgery or trauma, diabetes (Charcot foot), and rheumatoid arthritis are other common risk factors.
Depending on the cause of the flatfoot, a patient may experience one or more of the different symptoms here. Pain along the course of the posterior tibial tendon which lies on the inside of the foot and ankle. This can be associated with swelling on the inside of the ankle. Pain that is worse with activity. High intensity or impact activities, such as running, can be very difficult. Some patients can have difficulty walking or even standing for long periods of time. When the foot collapses, the heel bone may shift position and put pressure on the outside ankle bone (fibula). This can cause pain on the outside of the ankle. Arthritis in the heel also causes this same type of pain. Patients with an old injury or arthritis in the middle of the foot can have painful, bony bumps on the top and inside of the foot. These make shoewear very difficult. Occasionally, the bony spurs are so large that they pinch the nerves which can result in numbness and tingling on the top of the foot and into the toes. Diabetics may only notice swelling or a large bump on the bottom of the foot. Because their sensation is affected, people with diabetes may not have any pain. The large bump can cause skin problems and an ulcer (a sore that does not heal) may develop if proper diabetic shoewear is not used.
Starting from the knee down, check for any bowing of the tibia. A tibial varum will cause increased medial stress on the foot and ankle. This is essential to consider in surgical planning. Check the gastrocnemius muscle and Achilles complex via a straight and bent knee check for equinus. If the range of motion improves to at least neutral with bent knee testing of the Achilles complex, one may consider a gastrocnemius recession. If the Achilles complex is still tight with bent knee testing, an Achilles lengthening may be necessary. Check the posterior tibial muscle along its entire course. Palpate the muscle and observe the tendon for strength with a plantarflexion and inversion stress test. Check the flexor muscles for strength in order to see if an adequate transfer tendon is available. Check the anterior tibial tendon for size and strength.
Non surgical Treatment
In the early stages, simple pre-fabricated orthotics can help improve the heel position to reduce the mechanical load which is contributing to the symptoms. In advanced stages or long term orthotic use, a plaster of paris or foam box cast can be taken and specific bespoke orthotics manufactured. If the condition develops further a AFO (ankle foot orthotic) may be necessary for greater control. In more advanced stages of symptomatic Adult Acquired flat feet, where the conservative methods of treatment have failed there are various forms of surgery available depending upon the root cause of the issue and severity.
For more chronic flatfoot pain, surgical intervention may be the best option. Barring other serious medical ailments, surgery is a good alternative for patients with a serious problem. There are two surgical options depending on a person?s physical condition, age and lifestyle. The first type of surgery involves repair of the PTT by transferring of a nearby tendon to help re-establish an arch and straighten out the foot. After this surgery, patients wear a non-weight bearing support boot for four to six weeks. The other surgery involves fusing of two or three bones in the hind foot below the ankle. While providing significant pain relief, this option does take away some hind foot side-to-side motion. Following surgery, patients are in a cast for three months. Surgery is an effective treatment to address adult-acquired flatfoot, but it can sometimes be avoided if foot issues are resolved early. That is why it is so important to seek help right away if you are feeling ankle pain. But perhaps the best way to keep from becoming flatfooted is to avoid the risk factors altogether. This means keeping your blood pressure, weight and diabetes in check.