Sequential slipped capital femoral epiphyses: who is at risk for a second slip?

The purpose of this study was to determine as to which of the children who present to our unit with a unilateral slipped capital femoral epiphysis (SCFE) are most at risk of presenting with a subsequent contralateral SCFE. Between 1988 and 2000, 171 patients presented with unilateral SCFE to our unit, whereas 40 presented with bilateral SCFE. At a minimum of 3 years follow up, 56 of the 171 patients had re-presented with a contralateral SCFE (31%). Age less than 12 years at the time of the first SCFE (odds ratio (OR) = 3.809, 95% confidence interval (CI) = 1.631-8.891, P < 0.002) and New Zealand European ethnicity (OR = 3.989, 95%CI = 1.824 to 8.720, P < 0.001) were significantly predictive of a second SCFE. Sex (OR = 0.722, 95%CI = 0.326-1.601, P = 0.4) and stability of the first slip (OR = 1.558, 95%CI = 0.582-4.172, P = 0.38) were not significantly associated with an increased probability of a second SCFE.