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. Flat feet (flat feet) refer to the absence of a normal arch, or a collapsed arch. It is important to note that flat feet are not the same as flatfoot syndrome, and not all flat feet require treatment. When a person with flat feet has a combination of symptoms such as pain, they are said to have flat feet and may only need treatment. In fact, people with flat feet are very common, while flatfoot syndrome is not. Many people with flat feet, especially children, have no symptoms and do not need treatment. Only a small percentage of children with flat feet may gradually cause changes in their entire body posture, and some flat feet may be combined with abnormalities in the bone structure of the foot, such as the vertical talus and tarsal coalition. In adults with flat feet, there are more women over 50 years old. When adult flatfoot first occurs, the arch of the foot exists in the non-weight-bearing state, and disappears after weight-bearing. At this time, because the mobility of the joints still exists, it is called reversible flatfoot or flexible flatfoot. If there is joint lesion, restricted movement and deformity cannot be reset, it is called rigid flat foot.
Etiology
Flat feet can be congenital or acquired. In children, the arch is often formed at the age of 4 to 6 years, and most children and adolescents with flat feet are congenital. Adult flat feet can be a continuation of childhood flat feet or can be secondary to other causes, resulting in a collapsed arch. Symptomatic adults with secondary flat feet are referred to as adults with acquired flatfoot syndrome. There are many causes of secondary arch collapse such as joint degeneration, trauma, diabetes mellitus, rheumatoid arthritis, neuropathic lesions, tumors, and posterior tibial tendon insufficiency.
Arch collapse can cause the following structural changes of the foot.
1, Achilles tendon contracture: after the collapse of the medial longitudinal arch, the moment of the Achilles tendon acting on the ankle joint is reduced, and the pulling force of the Achilles tendon cannot effectively reach the forefoot through the stiff arch, in order to push the body forward and lift the heel, the Achilles tendon needs to become shorter, tighter and more powerful;
2. Laxity of the midfoot. Causing the mid-tarsal joint to fail to lock;
3, forefoot displacement: after the collapse of the medial longitudinal arch, the metatarsals are plantarflexed, the heel bone is semi-dislocated posteriorly, and the anterior tuberosity of the heel bone no longer supports the talar head. In order to adapt to this position, the forefoot and midfoot are displaced dorsally and laterally around the talus. The forefoot is abducted and the lateral column of the foot is shortened;
4, the posterior tibial tendon stress increases, and posterior tibial tendon strain is likely to occur. In severe cases, there can be damage to the medial ligament of the foot;
5, the lower talofibular joint rotation, heel exostosis;
6.The instability of the midfoot makes the talofibular joint and talofibular joint in an abnormal position for a long time, and over time, these joints degenerate and become fixed deformities. This will put the ankle joint under greater stress and eventually lead to ankle degeneration.
The above pathological changes can be manifested clinically as follows
1. pain. It is usually located on the medial aspect of the plantar aspect of the foot (posterior medial pain of the hindfoot) and increases after prolonged standing or walking, and can often be progressively worse. Occasionally, the pain can be located near the lateral lateral ankle joint. This is the result of the collapse of the arch of the foot causing the hindfoot to turn out, followed by the impact of the fibula with the heel bone.
2. Swelling. Painful extra-articular swelling, especially at the navicular tuberosity of the foot.
3, abnormal gait. Pain and arch collapse of the affected foot can cause a decrease in running and even walking ability, and abnormal gait, such as an outward gait.
4.Pain and abnormal gait. It may affect other joints of the body, such as compensatory valgus of the knee joint and compensatory external rotation of the hip joint due to excessive valgus and internal rotation of the affected foot, which may then cause pain and arthritis in the knee, hip and lower back. Individual patients with flat feet may have lower back pain as the only symptom.
5.Severe flatfoot deformity. Involvement of other joints in the foot and ankle may be seen, such as reduced flexibility or even stiffness of the subtalar and transverse tarsal joints.
6.Flatfoot syndrome. It may be accompanied by metatarsal fasciitis, tarsal sinus syndrome, etc.
Examination
During the initial examination, let the patient take a standing position and check the overall force line relationship between the hindfoot and forefoot from the anterior and posterior visualization of the ankle. Note the morphology of the longitudinal arch of the foot in the weight-bearing position. The structure of the foot may appear normal in the sitting position but be significantly altered after weight-bearing stress, which is common in patients with hyperlaxic flatfoot deformity, soft toe deformity, and hyperlaxic metatarsophalangeal joints. On posterior examination, the affected hindfoot is usually valgus, as well as “polydactyly” due to forefoot abduction. The patient is observed posteriorly on a unilateral or bilateral heel lift test with knee extension. Failure to perform a unilateral heel lift or lack of symmetrical inversion of the hindfoot suggests the presence of posterior tibial tendon disease.
Auxiliary examinations are mainly x-ray examinations, which should be taken under weight-bearing conditions to measure the angular changes in the arch of the foot, mainly in the lateral view of the foot.
Diagnosis
1.History of congenital abnormal foot bone alignment or foot trauma, overload, and weakness of foot muscles and ligaments.
2, collapse of the longitudinal arch of the foot and flattening of the sole. Heel valgus, walking or standing for a long time is easy to feel fatigue, pain and pressure pain.
3, footprint examination without arch defect area, and determine the flat foot type and degree.
4.X-ray film shows the collapse of the longitudinal arch of the foot and the change of the tarsometatarsal axis relationship.
Treatment
Early detection of flatfoot syndrome is very important, and active examination and treatment should be carried out after detection to clarify the cause and prevent possible irreversible lesions of bone and joint, not only for adults, but also for children and adolescents with flatfoot syndrome. Foot pads are more commonly used as a non-surgical treatment to relieve pain and also to support the arch of the foot and improve the position of the dislocated joint. In addition, wearing shoes with hard soles can achieve strong support for the sole of the foot, and shoes with rocker soles can reduce stress on the ankle during walking. For those with ankle lesions, walking boots can be worn to alleviate symptoms, but orthotics such as foot pads cannot completely correct the abnormal position of the talus and fully restore the normal arch. For those with severe deformities, if non-surgical treatment fails, surgery may be chosen accordingly to the type of lesion. A series of soft tissue and bone reconstructive surgeries can be performed to rebuild the arch position. In recent years, the more commonly performed subtalar joint stabilization procedure can effectively reset and stabilize the talus by placing a subtalar joint brake in the tarsal canal. The appropriate age for placement of a subtalar joint stabilizer for flatfoot syndrome in pediatric patients is 6 to 12 years of age. This is because the subsequent plastic modification of the organism allows the child to rebuild the arch of the foot and maintain it for life even after the stabilizer is removed. The operation is simple, less invasive, with fewer complications and more definite and satisfactory results. However, for adult patients with flatfoot syndrome with fixed foot deformity or arthropathy, the subtalar joint stabilizer needs to be used in combination with other bony or soft tissue procedures to achieve the desired results.
Prevention
Perform functional exercises for the intrinsic and extrinsic muscles of the foot, such as plantar walking, plantar flexion exercises, and heel lifting and external rotation exercises. Also, choosing shoes with good arch support and avoiding prolonged standing are important for the prevention of flatfoot syndrome.