It is also known as developmental hip entropion and is a deformity caused by a progressive decrease in the stem angle of the femoral neck that occurs in early childhood. The normal neck stem angle is 120° to 140° in adults and 135° to 145° in children. If the neck stem angle is less than 120°, it is called hip entropion.
The most prominent manifestation of the disease is increasing claudication. In infants, the symptoms are not obvious. In the early stage, hip pain is the main cause, after which the affected limb is weak and easily fatigued, and the body sways and limps when walking. When standing, the affected limb is externally rotated and mildly internalized, the pelvis is inclined to the affected side, and the spine has a lateral convexity deformity, with the lumbar segment convex to the affected side and the thoracolumbar segment convex to the healthy side. The gluteal muscles on the affected side were atrophied, and the gluteal pattern was lower than that of the healthy side. When the patient was in supine position, the hyperplastic femoral head and neck could be palpated in his groin. The apex of the greater trochanter was above the Nelaton line, and the abduction, internal rotation and posterior extension of the affected hip were significantly limited. The sleeve test was negative.
The treatment method should be chosen according to the age of the child, the degree of hip inversion and the condition affecting the function.
1.”Y”-shaped osteotomy
It is suitable for infants and young children with neck stem angle between 80° and 100°.
2.Borden osteotomy
This method is suitable for older children with a cervical stem angle of less than 80°.
Pathogenesis
The cause of congenital hip entropion is unknown, and a variety of factors may be associated with its development. Some believe that it is a growth disorder, which is a kind of incomplete development of the proximal femoral segment; some believe that it is caused by trauma; others emphasize that it is endocrine related; and it may also be related to family inheritance.
Pathogenesis
During fetal development, the proximal epiphyseal plate of the femur extends over the upper end of the femur and manifests as a crescent-shaped cartilaginous column, which soon divides into the epiphyseal portion of the femoral neck and the epiphyseal portion of the greater trochanter. The medial portion of the femoral neck matures earlier, allowing the femoral neck to lengthen, while the epiphysis of the femur will emerge as an ossification center by 6 months of life. When the femoral head and epiphyseal cartilage of the neck become diseased, the lesion is formed as fibrous tissue replaces the normal endochondral ossification, resulting in the fracture and disappearance of the epiphyseal plate, often as a separated triangular bone mass. As the child walks and bears weight, it gradually develops into hip entropion.
Disease diagnosis
1.Osteochondrosis
Patients with osteochondrosis have similar medical history, limited hip movement and limb shortening as mild congenital hip entropion, but both have their own characteristics on X-ray. In osteochondrosis, there is no separation of the femoral head and neck, the head is dense and flat, and the neck is thick and short.
2, congenital hip dislocation
The lameness of patients with congenital hip dislocation appears earlier, starting from early childhood when they are toddlers. Examination shows that the femoral head is outside the acetabulum, and most patients have a positive nesting test.
Examination methods
Laboratory tests: no relevant laboratory tests.
There is a triangular bone block separated by a cleft in the femoral neck near the head of the femur, and two translucent bands cross the femoral neck, forming a “Y” shaped cleft. As the bone grows, the inversion becomes more pronounced and the acetabulum becomes adaptive. The degree of hip inversion can be assessed by measuring the HE angle, which is the angle between the “Y” shaped cartilage line and the extension line of the epiphyseal plate of the femoral head, and is normally 25°.
Complications: pelvic tilt and scoliosis deformity may occur.
Prognosis: Surgical treatment is effective. However, there is still a certain recurrence rate.