The ‘acute’, unstable, slipped upper femoral epiphysis represents an acute fracture. Slipped capital femoral epiphysis is the most common disorder of the hip in adolescence, with an incidence of approximately two per 100,000 people.Minor degrees of slip do not usually result in significant long-term disability, but patients with severe slips in whom the anatomy cannot be restored to normal are at risk of developing severe degenerative changes at an early age.It would seem logical therefore to try to achieve an anatomical result in these hips by open reduction and stabilization, manipulation, or in some cases simply by allowing remodeling to occur.