The purpose of this study is to examine the blood flow in acetabulum after periacetabular osteotomy by Positron Emission Tomography (PET).

As a consequence of periacetabular osteotomy the blood flow in acetabulum is decreased. After periacetabular osteotomy has been performed there is fine contact between the osteotomised acetabulum and the rest of the pelvis and the potential for healing is good. However, it has not been investigated how much the blood flow in acetabulum is changed after surgery. The blood flow is considered to be vital for how the pelvis heals after surgery. Most likely, the blood flow is important in relation to which degree osteoarthritis can be prevented after periacetabular osteotomy.

It is possible to estimate the blood flow by Positron Emission Tomography of the dysplastic hip joint pre- and postoperatively. In this study the blood flow and fluoride uptake is quantified by Positron emission tomography based on measurements of O-15 water and F-18 fluoride.

Inclusion Criteria:

• Patients with radiologically diagnosed hip dysplasia (CE-angle < 25°).
• Patients with osteoarthritis graded 0, 1 or 2 defined according to Tönnis' classification. Patients with pain from hip
• Age > 18 years.
• Minimum 110° flexion in hip joint and closed growth zones in the pelvic.
• Informed consent.

Exclusion Criteria:

• Patients with neurological diseases
• Patients with calvé-Legg-Perthes syndrome.
• Patients where an femoral intertrochanteric osteotomy is necessary.
• Patients with medical sequelae after earlier hip surgery.
• Females who are pregnant.
• Patients with metal implants.