The femoral head is not smooth to consider the developmental abnormality, traumatic hip arthritis, rheumatoid arthritis, femoral head necrosis and so on. 1. Abnormal development of the femoral head: congenital dysplasia of the femoral head can occur because the femoral head is not smooth due to the development of the femoral head. 2. Traumatic hip osteoarthritis: generally seen in traumatic fracture of the femoral head, as it involves the hip joint, the healing of the fracture may lead to the wear and tear of the local articular cartilage, resulting in deformity of the hip joint and deformation of the femoral head. 3. Rheumatoid arthritis: generally considered to be a chronic autoimmune inflammatory disease involving multiple joints, symmetrical and invasive joints caused by streptococcal infection. If it involves the hip joint and is not properly treated, the femoral head may remain deformed with non-smooth surface in the later stage. 4. Necrosis of the femoral head: generally seen in more than 3 stages, due to ischemia can lead to necrosis and collapse of the femoral head, resulting in local cartilage loss and uneven surface. The surface of femoral head is not smooth, it is recommended to actively consult the doctor and treat under the guidance of the doctor.