PAO followed by rehabilitation At PAO, the pubic bone is osteotomized and under fluoroscopic control, the ischial osteotomies and the posterior iliac osteotomy are performed. The acetabular fragment is repositioned to optimise coverage of the femoral head. The repositioning is very challenging and clearly the most demanding aspect of the procedure18. Four weeks after discharge, the rehabilitation is initiated and carried out by two physiotherapists specialised in orthopaedics. The patients come to the hospital for physiotherapy twice a week and each exercise session is 1 hour with a 30-minute aerobic and strength program followed by a 30-minute program of mobility and gait training. Physiotherapy is ended 2-3 months after PAO when the physiotherapists assess that the patient has achieved predetermined functional goals e.g. walking at speed without crutches and ability to run. As a result of the patients' young age, they have had a high physical function and it is the aim, that they will regain this level of function after PAO. It is not yet examined whether PAO patients after surgery attain the functional capacity comparable to the age- and gender-matched population.