[When should secondary procedures be performed in residual hip dysplasia?].

Residual hip dysplasia is one of the most important complications following treatment of developmental hip dysplasia. If untreated, this condition will cause problems during maturity. The acetabulum consists of the ilium, ischium, pubis, and the triradiate cartilage lying between them. Interstitial growth from the growth plates of the triradiate cartilage plays an important role in the development of the acetabulum. Concentricity and congruity should be maintained during this development, which is very fast during the first eight years and continues until maturity. Whether residual hip dysplasia will occur can be anticipated by evaluating the factors that are effective on this development during the treatment of developmental hip dysplasia. The main prognostic factors include the age of the patient, concentricity and congruity of the hip, sphericity of the femoral head, the distance from the center to the head, and the thickness of the acetabular roof. Taking these factors into consideration during the follow-up is important to eliminate overtreatment and to assess the success of treatment.