Dianzhong Luo, Hong Zhang, Weijia Zhang Division of Joint Surgery and Sport Medicine, Department of Orthopaedics, First Affiliated Hospital of Chinese PLA General Hospital, Beijing, People’s Republic of China Background: Developmental dysplasia of the hip is a common disease and treated with various surgical approaches. Improved ilioinguinal (I-I) approach, two-incision Smith-Peterson (TSP) approach, and modified Smith-Peterson (MSP) approach are three main approaches; however, they are rarely compared. The present study compared the operative time, blood loss, intraoperative and postoperative allogeneic blood transfusion, and postoperative complications of these three different approaches. Hypothesis: Surgical approach does not influence the operation time, blood loss, and complications of periacetabular osteotomy. Level of evidence: Level III. Case–control study. Patients and methods: In a total of 101 hips of 95 cases, from February 2010 to July 2011, three different approaches of Bernese periacetabular osteotomy, I-I, TSP, and MSP, were conducted. The operation time, intraoperative bleeding, allogeneic blood transfusion, and early complications in different operation approaches were compared by a retrospective study when there were similar ages, genders, and lesions. Results: Among the three approaches, I-I had less operation time and more blood loss (P<0.05), TSP had less blood loss (P<0.05) but more complications, and MSP had less blood loss (P<0.05) and less complications. Discussion: The MSP approach is superior to the other two approaches in doing periacetabular osteotomy. Keywords: periacetabular osteotomy, operation approaches, complications