Unstable slipped capital femoral epiphysis

The unstable slipped capital femoral epiphysis (SCFE) continues to be associated with occasional but severe complications such as osteonecrosis of the femoral head. Persistent deformity of the proximal femur, a previously accepted outcome, is now believed to hold an uncertain prognosis. The concept of femoroacetabular impingement and the persistence of occasional severe complications have prompted rapid change in the treatment of unstable SCFE. A recent retrospective review suggested that osteonecrosis occurs more frequently in patients treated with in situ pinning between 24 and 72 hours of the onset of symptoms. Its incidence also was found to be associated with intra-operative reduction of the slip angle of more than 10°, anterior physeal separation of 4mm or more, and intra-operative reduction of anterior physeal separation. Interestingly, a recent MRI study suggested that not all patients who cannot bear weight have evidence of mechanical instability. Although in situ pinning remains the standard treatment in North America, surgical hip dislocation for unstable SCFE is reviewed in concert with the presentation of early promising results in a case series. The growing list of risk factors for the development of osteonecrosis in patients with unstable SCFE continues to be modified. Surgical hip dislocation remains an enticing management option but its ability to prevent impingement symptoms, resultant arthrosis and maybe even osteonecrosis has yet to be proven by a large series or randomized trial.