Different periacetabular and triple pelvic osteotomies are used to rotate a dysplastic acetabulum to a normal weightbearing position. If the acetabular fragment becomes too small or the acetabular artery is damaged, avascular necrosis (AVN) may result. On the other hand, if the osteotomies are situated too far from the acetabulum, free rotation in all directions may be impeded. In addition, all osteotomies should be clearly visible. Our modification considers these essentials. The osteotomy of the ischium, also leaves the sacral ligaments intact and avoids pseudarthroses by its length. We examined 216 joints of children aged >7 years and adults aged ≤55 years at follow-up of 5–16 years (average 7.7 years). Clinical results were good to very good in 85%. Radiologie results correlated with four degrees of decentration. Fairly centered joints and decentered joints with an elongated acetabulum had a high percentage of normal and slightly pathologic values. In false acetabuli and high dislocations, this rate was diminished. Results were also correlated with arthrosis and deformation of the femoral head and acetabulum. Sixteen percent had moderate and 5% had significant remission of pain. The four degrees of arthrosis were improved in 9.1% and unchanged in 73.2% and had deteriorated in 17.7%. Because of the high percentage of extremely deformed joints, we conclude that our technique provides very good potential for correction and long-lasting good results. Measurements of acetabular rotation that guarantee greatest pain relief have been evaluated for the future.