The arch of the foot is an important structure of the human foot. With the arch, the foot is elastic. It absorbs the impact force of the ground on the foot and locks the midfoot joint, making the foot stiff and better able to propel the body’s activities.
Flat feet (flat feet) refer to the absence of a normal arch, or a collapsed arch. When a person with flat feet has a combination of symptoms such as pain, it is called flatfoot syndrome.
Flat feet can be congenital or acquired later in life. In children, the arch is often formed between the ages of 4 and 6 years. Most children and adolescents with flat feet are congenital, and many of them have flat feet for life without symptoms, but some of them may be combined with abnormalities in the bone structure of the foot, such as the vertical talus and tarsal coalition. Adult flatfoot may be a continuation of childhood flatfoot or may be secondary to other causes, such as joint degeneration, trauma, diabetes, rheumatoid arthritis, neurological lesions, tumors, and posterior tibial tendon tears.
Although most flat feet are asymptomatic, a proportion of more severe flat feet in both children and adults end up with pain that interferes with life and work. Patients with flat feet may have fatigue when walking in mild cases, and in severe cases, the morphology of the foot changes significantly, such as heel exostosis, forefoot abduction, and medial protrusion of the foot to the ground. The walking gait changes, such as an outwardly oriented gait. The most common symptom is pain, which starts on the medial side of the foot and shifts to the lateral side of the foot as the heel exostosis increases. At the beginning of the foot in the non-weight-bearing state, the arch exists, and after weight-bearing the arch disappears. At this time, because the mobility of the joint still exists, it is called reversible flat foot or flexible flat foot. If the joint movement is restricted and the deformity cannot be reset, it is called rigid flatfoot. With flat feet, tears of the posterior tibial tendon and spring ligament can occur, and dislocation of the periprosthetic talus joint can cause arthritis in multiple joints.
In some flat feet, bunion deformity may be caused or aggravated by abnormal rotation of the medial structures of the foot. Collapse of the arch of the foot can also increase the stress on the plantar metatarsal tendon membrane, leading to tendon membrane tears causing achalasia.
Flatfoot syndrome not only has a significant impact on the function of the foot, but can also impair the function of other parts of the body. For example, internal rotation of the knee joint causes knee pain; increased anterior lumbar physiological protrusion causes low back pain.
Whether and when to treat flat feet in children and adolescents is a concern for many parents. Active intervention is needed for flat feet with pain, flat feet with progressive development of deformity, and flat feet with more severe deformities that may have an impact on growth and development. Foot pads are a more commonly used non-surgical treatment. Foot pads can relieve pain and also support the arch of the foot, allowing the position of the dislocated joint to improve. However, foot pads do not completely correct the abnormal position of the talus, heal the flatfoot, and restore it to a normal arch. The fundamental treatment is surgery. Although there have been many soft tissue and bone reconstructive surgeries in the past, the high surgical trauma and inexact efficacy have made many doctors reluctant to treat these children. In recent years, clinical studies in China and abroad have demonstrated that subdiscal joint stabilization has achieved very satisfactory results in the treatment of children and adolescents with reversible flat feet. This procedure is simple, less invasive, with fewer complications and more definite results.