Introduction: The management of unstable slipped upper femoral epiphysis (SUFE) is controversial, with a high risk of developing avascular necrosis (AVN). We meta-analysed two areas of concern: reduction of the slip and the timing of treatment.
Methods: A search of Medline, CINAHL and Embase identified only retrospectively relevant studies: four regarding the role of reduction and five regarding the timing of treatment. The incidence of AVN was compared between reduced and unreduced SUFEs, and between those treated within 24 h of symptom onset and those treated thereafter.
Areas of agreement: Analysis of the pooled data gave an odds ratio of 2.20 (P = 0.290) in favour of the unreduced group, who had a lower risk of developing AVN. The odds ratio was 0.50 in favour of the group treated within 24 h from symptom onset (P = 0.441). However, though clinically important, these effects were not statistically significant.
Areas of controversy: The timing of treatment is somewhat inconsistent: two studies favour management more than 24 h after the onset of symptoms, while for three unstable SUFEs are best managed within 24 h.
Growing points: Despite the non-significant results from the meta-analysis, it can be suggested that, if reduction is to be performed, it should be undertaken cautiously, as it may be associated with increased AVN. The ideal time for management of unstable slip is probably within 24 h of symptom onset.
Areas timely for developing research: There is a strong need for multicentre, randomized, controlled trials in this area.