Pes planus, or flat feet, is a common concern addressed during well-child visits. Many parents express concern more because of the appearance of the feet than actual symptomatology. But what is within the realm of normal and what is beyond?
Ninety percent of clinic visits for foot problems are for flat feet.1 Historically, the treatment of flat feet was wearing orthopedic shoes that were unappealing, so parents fear that is the fate of their child. Although the exact incidence rate of flat feet has not been determined, it clearly is quite common. Other contributing factors are joint hypermobility, obesity, and age. All children under the age of 2 years have flat feet because of the fat pad that is present. By the age of 10 years, this fat pad regresses and the normal arch is formed.
Determining the incidence is complicated by the lack of classification of normal versus abnormal. Because flexible flat feet usually are asymptomatic, some authorities have difficulty classifying it as abnormal. Flat feet are classified into three categories; flexible flat feet, flexible flat feet with short Achilles tendon, and rigid flat feet. Flexible flat feet account for two-thirds of diagnosed cases.2
Given that the arch does not fully form until the end of the first decade of life, neither diagnosis nor treatment should be given until after that time. Evaluating for flat feet in the clinic is usually limited to inspection in weight bearing and non-weight bearing. There are more formal procedures using foot prints and x-rays, but practically speaking those are not necessary. It is key to examine the patient while he or she is standing, to see if the arch is present and to gauge the orientation of the talus bone. When the patient is supine, again note if the arch is present and check the degree of dorsiflexion and plantarflexion.
Determine whether the talus bone is straight or in a valgus position, and whether there is a shortened Achilles tendon. This is crucial in predicting whether symptoms will emerge if they haven’t already. Patients with rigid flat feet or flexible flat feet with shortened Achilles tendon usually begin to complain of discomfort with activity in the second or third decade of life. Those symptoms may be limited to pain in the foot near the head of the talus, or can be complaints of knee, hip, or back pain.1
For the asymptomatic patient, no intervention is needed. Although many clinicians recommend orthotics, studies have shown that after years of wearing orthotics, the feet remain flat. For symptomatic patients with flexible flat feet, there is increased intrinsic muscle activity, which can result in soreness and achiness of the feet. Orthotics can offer some relief, but for patients with shortened Achilles tendons, it potentially can cause more discomfort.2 Both OTC and hard custom orthotics have been shown to relieve pain without significant increase in the height of the arch. There is little information to support using one over the other.2
Heel cord stretching is another reasonable intervention to improve any discomfort. It is important to note that the knee must be extended and the subtalar joint must be in the neutral position for the stretch to be effective.
Surgery is reserved for flexible and rigid flat feet that are symptomatic despite conservative treatment. Bone reconstruction and tendon lengthening have shown reduction in symptoms.
In summary, the vast majority of patients with flat feet do not need any intervention. Proper categorization is important to determine if intervention will be needed. The use of orthotics should be reserved for symptomatic patients, but will not alter the height of the arch. Surgery is indicated for those patients with significant symptoms that have not improved with conservative measures. It has been found to be effective if all components of the deformity have been addressed.
Dr. Pearce is a pediatrician in Frankfort, Ill. She said she had no relevant financial disclosures. Email her at email@example.com .