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 joints, 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. 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 are joint lesions, restricted movement and deformity cannot be reset, it is called rigid flat foot.
Flat feet can be congenital or acquired. The arch of the foot in children 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 in 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 be effectively transmitted to 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. 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 is semi-dislocated posteriorly, and the anterior tuberosity of the heel no longer supports the talar head. In order to adapt to this position, both 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 stress on the posterior tibial tendon is increased and posterior tibial tendon strain is likely to occur. In severe cases, there can be injury to the medial ligament of the foot; 5. The talocrural joint rotates forward and the heel bone turns out; 6. The instability of the midfoot puts the talocrural and talocrural joints in abnormal positions 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 clinically manifested as follows: 1. Pain is usually located on the medial aspect of the plantar aspect of the foot (pain on the posterior medial aspect of the hind foot) and is aggravated after prolonged standing or walking, and can often appear progressively worse. Occasionally, the pain can also 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 and 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 or even walking ability and abnormal gait, such as outward gait.
4.Pain and abnormal gait 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 lead to pain and arthritis in the knee, hip, lower back and other parts. Individual patients with flatfoot may have lower back pain as the only symptom.
5.Severe flatfoot deformity Other joints of the foot and ankle may be seen to be involved, such as reduced flexibility or even stiffness of the subtalar and transverse tarsal joints.
6.Flat foot syndrome may be accompanied by metatarsal fasciitis, tarsal sinus syndrome, etc.