[Perthes disease].

Morbus Perthes today still poses a challenge for the orthopaedic surgeon because of the unclear aetiology as well as the controversial discussion about the role and kind of multiple treatment principles. The prognosis depends upon clinical (e.g. age at onset, reduction of range of motion, gender) and radiological (extent of necrosis, containment) parameters. Of these, only the reduced range of motion and a loss of containment can be adressed therapeutically, be it in a conservative and/or operative concept. Pelvic osteotomies have the advantage of a high potential of correction without the biomechanic disadvantages which are associated with intertrochanteric varus osteotomies. Nowadays, the use of orthoses is considered to be obsolete. Non-containment is targeted mainly on the symptomatic treatment and the correction of residual deformities. Based on the outcome after the final stage there is a risk of premature osteoarthritis with the need of early total hip replacement.