Developmental dysplasia of the hip (DDH), formerly known as congenital dislocation of the hip (CDH), is a developmental abnormality of the hip joint that occurs at birth and continues to deteriorate after birth. The main manifestation is an abnormal matching and accommodative relationship between the acetabulum and the femoral head. The pain and deformity of the hip joint usually become more serious when the symptoms appear in adulthood, and surgery is often required to improve the quality of life. The clinical manifestations and secondary manifestations of adult DDH are usually seen in women, and the symptoms of the hip joint usually appear between the ages of 20 and 40. In the early stages of the disease, the main symptoms are fatigue, soreness and vague pain in the affected hip joint, but they can also occur in other areas such as the groin area, anterior thighs and buttocks. Local pressure pain, percussion pain and rotation pain in the hip joint, with normal mobility. In the middle and late stages, the clinical symptoms are mainly increased hip pain, followed by claudication, rest pain, hip subluxation or total dislocation and limb shortening deformity, with gradual aggravation of osteoarthritis leading to varying degrees of limitation of hip joint movement. A small number of patients have no symptoms and are found incidentally on X-ray. Hip dysplasia or dislocation can lead to a change in the body’s center of gravity and lower extremity force lines and limb inequality, resulting in lower back pain. Correction of hip dislocation, stabilization of the hip joint, and improvement of bilateral lower extremity inequality can improve and relieve low back symptoms and delay the progression of lumbar spine osteoarthritis. For patients with unilateral DDH, total hip arthroplasty should be performed as soon as possible in order to avoid continuous aggravation of low back symptoms, which may lead to serious irreversible spinal deformation. Misconception 1, hip joint “aging”: Adult DDH usually develops symptoms around the age of 40, and many people mistake hip pain for hip joint “aging” and think that it will improve with some medication. The anatomical characteristics of the hip joint determine that the direction of onset of DDH is different from that of ordinary hip degeneration, and often the only way to solve the problem is through surgery. 2, delay may be good: reduce the activity and use of drug treatment for early adult DDH hip symptoms have obvious relief, so some patients will have a certain fluke mentality “delay may be good”. In fact, in addition to the bony structure of the adult DDH hip, soft tissue problems may develop as the disease progresses, which may also lead to osteoarthritis of the opposite hip and bilateral knee joints due to stress factors. At the same time, some patients have problems with the lumbar spine because of the pelvic tilt, so delaying the disease often leads to more “trouble”. 3. Can a decades-old problem be cured? Many patients with DDH start to have symptoms at a very early age, and the development process of the disease is relatively long, many of them may have decades of “disease age”, and they are already familiar with “cripples”, so they are skeptical about the effect of surgery. The bony structure of the hip of adult DDH patients is different from that of normal people, and the lack of bone volume also makes the surgery difficult. However, the perfect design of the artificial hip prosthesis and the maturity of hip replacement surgery technology nowadays can accomplish such a challenge well, allowing patients to achieve the surgical objectives of relieving hip pain, restoring the function of the hip joint, restoring the length of the lower limb, and reducing claudication.