The concept of DDH (developmental dysplasia of the hip) will have what manifestations The femoral head prolapses from the acetabulum to form a joint dislocation This is the previous concept, but now DDH includes: acetabular dysplasia, subluxation, and total dislocation three different degrees of lesions. It is more common in Caucasians and less common in Blacks, and the incidence is higher in cold regions than in warm regions. Clinical manifestations: unequal lower extremities, limp or duck walk, pelvic tilt scoliosis. How to detect DDH early Focused screening for certain high-risk infants: (1) family history (2) high incidence areas (3) asymmetrical thigh skin pattern (4) infants with joint laxity (5) breech births and cesarean deliveries (6) girls. Nowadays, early detection is possible through physical examination of 42-day-old infants to see if the skin lines are symmetrical, physical examination by a pediatrician or even a pediatric orthopedic surgeon, and auxiliary examinations such as ultrasound and x-ray. DDH prevention and treatment After birth, the most stable position is to create conditions for the infant’s hip joint to be flexed and abducted in an externally rotated position. In the north, we advocate the use of diaper bibs and the abandonment of the traditional method of binding the lower limbs in the extended position. If the diagnosis is clear, a Pavlik sling can be used. If the diagnosis is clear, it can be treated conservatively with a Pavlik sling, a human position cast, a human position brace, an abductor walking brace, etc. At 18 months, children who still have dislocation or good residual acetabular dysplasia are recommended to undergo surgery, and the timing of surgical treatment is better from 18 months to five years of age; over 6 years of age, surgery is very difficult with many complications and less effective.