Evidence based treatment for unstable slipped upper femoral epiphysis: Systematic review and exploratory patient level analysis.

The management of slipped upper femoral epiphysis is controversial and evolving as insight into the condition develops. Loder introduced the concept of slip stability and demonstrated a strong association between poor outcome and instability. Almost half of patients with unstable slip developed femoral head osteonecrosis. This has been influential in surgeons' choice of treatments. Some surgeons have adopted a minimal intervention approach such as pinning in situ or gentle reduction and pinning whereas others advocated an urgent open reduction and stabilisation of slip using various surgical techniques. In this review we analysed the influence of various interventions, timing of surgery and severity of the slip on the outcome of unstable slip.