The Difference Between Flexible and Rigid Flatfoot in Children

Flatfoot in adolescents

When understanding the condition of flatfoot in children, it is important to recognize the differences between the two types of flatfoot; flexible and rigid. The two types of flatfoot are very different from one another and require different treatment plans that can include both nonsurgical and surgical options. Because flatfoot is typically the normal foot shape in infants, physicians will wait to diagnose a child with flatfoot until they have developed past the age of two years old.

Flexible Flatfoot

Within the first decade of a child’s life, the arch of the foot develops along with the bones, muscles, and ligaments within the foot. In flexible flatfoot, the arch is present when the foot is not bearing any weight, but disappears when standing or walking. Infants are typically born with flexible flat feet, but the condition usually resolves by age ten. In preschool children aged three to six years, studies have shown that higher joint laxity (loose ligaments), W-sitting (a child sitting on their bottom with both knees bent and their legs turned out away from their body), male gender, obesity, and younger age can all be associated with a higher risk of having flatfoot. In some patients, flexible flatfoot will continue into adolescence and adulthood.

When flat fleet become symptomatic, patients can experience persistent and debilitating pain that can limit participation in sports, recreation, and enjoyment of every-daily activities. In the case of symptomatic flexible flatfoot, it is recommended to see an orthopedic specialist. If the child is showing no symptoms, evidence suggests that treatment is typically unnecessary, and simply observing the child is suitable.

When a child or adolescent is being seen for flatfoot, the physical examination starts with a generalized musculoskeletal examination. Examination will most likely include inspection of the feet in both the standing and sitting positions and while walking. The physician should also examine the feet from the front and the rear while the patient stands.

The decision to simply observe versus treat a child with flexible flat feet is based on the patient’s symptoms and what the physician finds during the exam. For patients with pain-free, flexible flat feet, there is no concrete evidence that any available intervention can alter the natural course of foot shape development. Observation is generally the best course of treatment. Referral to a pediatric orthopedist is encouraged for patients with pain, fatigue, or concerns regarding malalignment. Treatment options for symptomatic patients include physical therapy, shoe wear modification, orthotics, and, occasionally, surgery.

Rigid Flatfoot

In rare cases, flatfoot can become painful and rigid. In rigid flatfoot, the arch is never present, whether bearing weight or not. The foot remains flat during sitting, tip-toe standing, and the tow raise test due to the relative immobility of the subtalar joint (joint positioned directly below the ankle joint).  

Rigid flatfoot is often associated with abnormal foot development caused by a more serious underlying pathology, such as a neuromuscular condition. The vast majority of patients with neuromuscular flatfoot will have rigid flatfoot. Management of neuromuscular flatfoot differs from management of idiopathic flexible flatfoot because it often requires more invasive treatment, such as surgery.