Dysplastic hips wear out because there is insufficient coverage of the femoral head (ball) by the acetabulum (socket). This mechanical derangement can be altered by dividing the pelvis and tilting the socket over the femoral head. This operation is called a Triple Pelvic Osteotomy (TPO) or peri acetabular osteotomy. After the bone has been moved it is held with plates and/or screws. Patients will generally be in hospital for 4-5 days and will be partial weight bearing with the aid of crutches for 6 weeks. TPO should be considered a major operation and patients may take 3 to 4 months before they feel the benefit of such surgery. Risks for this procedure are similar to other major hip operations. They include thrombosis of the leg veins, damage to nerves and delayed bone healing. Smokers are strongly advised to try and give up prior to this type of surgery since smoking is known to slow bone healing. This operation has the advantage over hip replacement that it preserves the patients own joint. Although joint replacement and resurfacing can be performed in young patients there is a strong possibility that any artificial joint will either wear out or wear loose over a period of time. If however there is already some early arthritis the results of TPO are less predictable. In Mr Bache’s experience (over 100 cases)TPO is rarely indicated after the age of 40. In patients where there may be a suggestion of early arthritis hip arthroscopy may be offered to the patient in order to assess the joint for its suitability for TPO.