The beautiful, tall Ms. Wang is 47 years old, two years ago, she likes shopping often feel sore, painful and other discomfort in the knee joint, has been to a number of hospitals, after the film, CT and MRI examination, no clues, eat a lot of medicine, plus the external ointment, but also no effect. Six months later, pain appeared at the root of her thighs, which affected her walking and going up and down stairs, and then she went to the hospital and had a pelvic film taken. Ms. Wang was confused: she was almost five years old, where did she get the “dysplasia”? As the pain had a great impact on her life and work, she had no choice but to follow the doctor’s advice and underwent surgery at the orthopedic department of Xinhua Hospital. After the surgery, she recovered well, and the pain in her hip disappeared completely, so she could go shopping again. A year later, her son, who had returned to Shanghai to visit his family after studying in England, accompanied her mother to the hospital for a review and everything was as usual. When she was leaving, Ms. Wang asked the doctor inadvertently: Is this problem hereditary? Will her son also have hip dysplasia? The son was very resistant: I am not sore or in pain, where is the problem? But at his mother’s insistence, the doctor took a picture of his pelvis. The result was very surprising, the son did have hip dysplasia, and still had problems on both sides! It is no coincidence that Ms. Xiao from Nanping, Fujian Province, also had hip dysplasia and went to several provincial and municipal hospitals for medical treatment. She was not worried about her daughter, so she asked her daughter to take a film as well, not realizing that her daughter also had hip dysplasia. Ms. Xiao’s tears fell quietly: she suffered a lot because of hip dysplasia, and her child, who was not yet an adult, would also suffer from psychological and physical trauma! Developmental dysplasia of the hip (also known as DDH) is a developmental hip deformity. Its incidence varies greatly among different races and regions, ranging from 4 to 50 per 1,000 in Europe and the United States. In China, there is no comprehensive census data, and the average incidence is about 3.9 per 1,000. The cause of DDH is not fully understood, but it is believed that genetic factors play a major role, and about 1/4 of the patients have a family history of DDH. DDH can occur alone or in association with other malformations, and can also be associated with chromosomal abnormalities such as trisomy 21, trisomy 18, etc. As a polygenic genetic disease, the causative genes are distributed on multiple human chromosomes, and there may be three genetic systems that influence the development of DDH. Early diagnosis of DDH with complete subluxation is relatively easy, due to the accompanying symptoms such as limb length discrepancy and claudication. In contrast, when DDH manifests as a subluxation, early detection is less easy. The initial symptoms are mostly soreness and swelling in the knee or thigh root after prolonged walking. This can progress to pain at the base of the thigh or buttocks, which can affect walking and walking up and down stairs. Because it is more common in women, most of the time the joint is sore and swollen after a long period of shopping, and it gets better after rest, so it is often not noticed and not taken seriously by patients. Once the pain worsens, the damage to the joint cartilage is more serious and the best time for treatment may be missed. Therefore, patients who experience discomfort or pain in the knee, hip or buttock should be alerted and go to an experienced hospital for timely examination. Once diagnosed, early treatment is advisable, and screening should also be done for children to rule out hip dysplasia.