Hip Dysplasia: Abnormal development of the hip joint, known as hip dysplasia, can be corrected through joint preservation surgery, such as periacetabular osteotomy (PAO), to restore normal joint mechanics and prevent arthritis. Hip Dysplasia: Abnormal development of the hip joint, known as hip dysplasia, can be corrected through joint preservation surgery, such as periacetabular osteotomy (PAO), to restore normal joint mechanics and prevent arthritis.