Flatfoot syndrome

　　The etiology of this disease has not been elucidated, but epidemiological studies have found that the disease has a significant genetic predisposition. Pathological observation shows that the tarsal bones do not have developmental deformities, but the ligaments connecting the talus, calcaneus, and navicular and cuneiform joints are looser than normal, causing the calcaneus to rotate inward below the talus when the foot bears weight, with its front moving medially and laterally. The talus moves to the plantar and medial side, causing the loose calcaneonavicular plantar ligament to become even more relaxed and unable to support the talus head, leading to a decrease in the longitudinal arch of the foot. The calcaneocuboid ligament becomes loose, causing the calcaneus to turn outward, which further exacerbates the decrease in the longitudinal arch of the foot. Clinically, the etiology of the disease is divided into four types of factors:

　　1. Genetic factors;

　　2. Congenital foot bone deformity;

　　3. Foot trauma or chronic strain;

　　4. Weakness or paralysis of the intrinsic or extrinsic muscles of the foot.

　　Prolonged standing can cause pain in the Achilles area, leading to flat feet with outwardly turned feet, swelling and tenderness at the navicular tuberosity of the forefoot, and even local muscle strain. In severe cases, it can cause local skeletal deformation, which may affect the normal gait. Therefore, after confirming that it is flatfoot, it is advisable to take active symptomatic treatment, which can include the use of corrective insoles, corrective instruments, or even surgical treatment to restore normalcy.

　　1. Postural flatfoot syndrome:It is the initial stage, and there is no abnormality in the appearance of the arch of the foot. However, after walking and fatigue, there is a feeling of foot fatigue and pain, and there is pain in the lateral ankle of the lower leg. There may be swelling in the center of the sole and the top of the foot, and the navicular tubercle is swollen and painful. The local skin may become red, and the internal inversion of the foot is slightly limited when standing. After rest, the symptoms and signs may disappear.

　　2. Spastic flatfoot syndrome:It is prevalent in young and middle-aged adults, part of which develops from improper treatment of postural flatfoot. The main symptoms are severe pain during standing or walking, which can present as a bowlegged gait. The gastrocnemius muscle is in a rigid spasm, and the internal and external inversion and abduction movements of the foot are limited. The heel becomes wider, the sole of the foot is outwardly deviated, the Achilles tendon is laterally deviated, the metatarsal head of the forefoot is completely collapsed, and it bulges inward. Severe cases may result in stiffness of the foot. The activity of inversion, abduction, and extension is significantly limited, even after a long period of rest, the symptoms are difficult to improve, and some patients may develop lumbar, back, and hip and knee joint pain.

　　1. The emphasis of this disease is on prevention, and the purpose of treatment is to improve standing and walking. Those with a genetic predisposition or those who stand frequently should often practice walking with the outer edge of the sole of the foot on the ground to avoid the foot being in one position for a long time, preventing fatigue.

　　2. Early adoption of physical therapy can also be effective, walk with the toes, and also perform toe flexion exercises.

　　3. You can wear flatfoot insoles or flatfoot orthopedic shoes, elevate the inner side of the heel, shift the load line outward, and thereby prevent and alleviate foot fatigue. The commonly used method is to elevate the inner side of the heel in a wedge shape (0.3~0.5 cm), the purpose is to make the hindfoot pronate.

　　4. Support pads made of felt, leather, or rubber (0.9 cm) can be placed under the longitudinal arch of the foot. If the deformity is severe or non-surgical treatment is ineffective, various surgical treatments can be adopted.

　　5. Physiotherapy, massage, strengthen the exercise of the intrinsic and extrinsic muscles of the foot, wear flatfoot orthopedic shoes or flatfoot insoles for correction.

　　The auxiliary examination method for this disease is mainly X-ray examination, and foot anteroposterior and lateral X-ray films should be taken under load conditions, mainly measuring the change in the angle of the arch of the foot on the lateral foot film.

　　1. Draw a straight line through the center of the navicular bone, the first cuneiform bone, and the metatarsal long axis. Then, draw a line through the center of the navicular bone that is parallel to its anterior and posterior articular surfaces and intersects with each line. Generally, the two lines of the arch of the foot intersect at a right angle. If there is a lesion or ligament laxity in the talonavicular joint, the median axis of the navicular, first cuneiform, and metatarsal does not align with the median axis of the talus, forming an angle on the plantar side of the foot. The median axis of the talus passes through the plantar side of the navicular at 1/4 of its length. If ligament laxity occurs at the naviculocuneal joint, the median axis of the talus is located on the plantar side of the first cuneiform, forming a right angle with the perpendicular line from the center of the navicular bone. When the line through the center of the navicular bone is extended forward and backward, it is located on the plantar side of the talus and first metatarsal, indicating that there is ligament laxity in both the talonavicular and naviculocuneal joints.

　　2. Talus plantar flexion angle: Draw a horizontal line along the plantar side of the foot and intersect it with the midline of the talus. The normal value is 26.5°±3.5°. When the talus has a plantar deformity, this angle increases.

　　3. Talus plantar angle: Draw a parallel line along the distal joint of the navicular bone on the weight-bearing anteroposterior radiograph, and then draw a line along the midline of the talus. The inner angle formed by the intersection of the two lines is called the talus plantar angle. An angle greater than 60° indicates talus displacement.

　　1. Firstly, encourage children to participate in moderate physical exercise regularly, so that their muscles and ligaments receive appropriate stimulation. Activities such as skipping rope, high jump, and long jump can exercise the arches of the feet well. When engaging in physical exercise, try to wear soft-soled shoes, and it is best to wear professional sports shoes. Avoid letting children wear too small shoes.

　　2. Do not let infants under 9 months old walk too early on the ground or stand for too long. After children are eleven or twelve years old, although they are in a period of rapid growth and development, since the development of muscle strength is slower than that of bones, do not arrange adult work frequently due to their tall stature.

　　3. If flatfoot is already quite obvious, let the child practice walking on the tips or outer side of the feet, which can achieve certain correction effects. Flatfoot that cannot be corrected should be treated in the orthopedic department of a hospital.

　　Patients with mild to moderate flat feet without symptoms do not require treatment. For children under 10 years old with symptomatic moderate to severe flat feet, passive or active stretching of the gastrocnemius muscle of the lower leg and relief of discomfort caused by muscle spasm can be adopted. Wearing Thomas orthopedic shoes with a thickened insole of 0.3 to 0.6 cm on the posterior-medial side, or adding a thick support pad of 0.5 to 0.75 cm on the inside of the sole to support the longitudinal arch of the foot, can alleviate or eliminate pain and discomfort, but has no corrective effect.