Acetabular dysplasia is a hip deformity that occurs when the acetabulum does not develop well. It is also known as a subluxation of the hip joint. The main pathological alteration is the shallow acetabulum, resulting in inadequate inclusion and coverage of the femoral head by the acetabulum. As a result of these pathological changes, the mechanical conduction of the hip joint becomes abnormal, which gradually causes damage and degeneration of the articular cartilage and eventually leads to the occurrence of osteoarthritis of the hip joint. Therefore, acetabular dysplasia is a disease with a high disability rate. Since there are no obvious symptoms in the early stage of acetabular dysplasia, it is not easy to diagnose early. However, as time goes on, symptoms will develop around the age of 20 to 40. It is more common in females and initially manifests as soreness and swelling of the hip, which is aggravated after prolonged standing or walking and gets better after rest. Afterwards, hip pain gradually appears, mainly in the root of the thigh and groin area, sometimes accompanied by knee pain. Some patients also show mainly knee pain, but the knee examination is often normal. There is no significant impairment of hip joint movement in the early stage. The severity of hip pain is somewhat related to the degree and extent of articular cartilage damage. As the disease progresses, the pain in the hip joint further worsens and the movement of the hip joint is affected. If the symptoms appear at a younger age, it indicates that the degree of acetabular dysplasia is more severe and the prognosis is worse. If detected early and operated early, it can effectively relieve or even eliminate hip pain, preserve joint function, stop or delay the occurrence and development of osteoarthritis, and can eliminate or postpone the time of artificial joint replacement surgery. There are several surgical methods that can be used for the early treatment of acetabular dysplasia. Our department uses the acetabular rotational osteotomy method. The technical principle of this procedure is to correct the hip deformity, increase the coverage of the femoral head, and change the force load on the hip joint by rotational movement of the entire acetabular joint surface. We have been performing this joint preservation surgery for many years and have achieved relatively good results.