Complex deformities of the acetabulum are one of the most common reasons for secondary pelvic osteoarthritis. One option of treatment is osteotomy of the acetabulum close to the joint. The correction of the spatially reduced roof of the femoral head resulting from pelvic dysplasia can minimize the risk of developing secondary osteoarthritis or reduce the progression of an already existing osteoarthritis. The Ganz periacetabular osteotomy (PAO) and Tönnis triple osteotomy procedures are the predominant methods used to correct hip dysplasia in adolescents. Both are complex procedures which bear specific risks and complications, thus requiring very experienced surgeons.