The hip is a ball and socket joint consisting of the acetabulum (socket) and the
femoral head (ball). Acetabular dysplasia (abnormal formation of the socket) is an
under-development of the hip socket where the acetabulum, or cup, is shallow or/and aligned poorly with the femoral head. In cases of poor alignment the upper portion or roof of the acetabulum is obliquely inclined outward, rather than having the normal horizontal concave orientation. Because of these abnormalities the femoral head is incompletely covered and abnormally high stresses on the outer rim of the socket lead to premature degeneration of the articular cartilage and labral tears.

The Periacetabular Osteotomy (PAO) is a surgical procedure aiming to correct this
deficiency of the hip socket. If the dysplasia is significant and is left untreated then there is a strong likelihood for early onset of hip osteoarthritis.

A Periacetabular Osteotomy involves performing several bone cuts (osteotomies) around  the acetabulum and redirecting it in an optimal position so that the femoral head is adequately covered. The osteotomy is then stabilized with screws. Of note, the PAO can’t add volume to a shallow socket but rather concentrate on orienting the existing socket in a way which would correspond best with the femoral head for optimal stress distribution and joint biomechanics.