Controversy remains whether the contralateral hip should be fixed in patients presenting with unilateral slipped capital femoral epiphysis (SCFE). This retrospective study compares the outcomes and cost of those patients who had prophylactic fixation with those who did not.

Between January 2000 and December 2010 a total of 50 patients underwent unilateral fixation and 36 had prophylactic fixation of the contralateral hip. There were 54 males and 32 females with a mean age of 12.3 years (9 to 16). The rate of a subsequent slip without prophylactic fixation was 46%. The risk of complications was greater, the generic health measures (Short Form-12 physical (p < 0.001) and mental (p = 0.004) summary scores) were worse. Radiographic cam lesions in patients presenting with unilateral SCFE were only seen in patients who did not have prophylactic fixation. Furthermore, prophylactic fixation of the contralateral hip was found to be a cost-effective procedure, with a cost per quality adjusted life year gained of £1431 at the time of last follow-up.

Prophylactic fixation of the contralateral hip is a cost-effective operation that limits the morbidity from the complications of a further slip, and the diminished functional outcome associated with unilateral fixation.

Cite this article: Bone Joint J 2015;97-B:1428–34.

Aim: Since obesity is thought to be an aetiological factor for SCFE we have looked to see if the ‘Obesity epidemic’ in children has been associated with a similar trend in SCFE.

Method: A population based study, using a national database of NHS Scotland activity, was undertaken to analyse trends in SCFE from 1981 to 2005 and to look for a relationship with changes in obesity in Scotland. Data on the body mass indices of Scottish school children have been collected as part of the child Health Surveillance Programme.

Results: We found that the incidence of SCFE increased from 3.78 per 100,000 children in 1981 to 9.66 per 100,000 children in 2000 (R² = 0.715) – a two and a half fold increase over two decades. Furthermore, SCFE was seen at younger ages with a fall in the average age at diagnosis from 13.4 to 12.6 years for boys (p=0.007) and 12.2 to 11.6 for girls (p=0.047). SCFE is rare in young children – for 1981–1990 only two children presented with the diagnosis between the ages of six and eight; however for 1991–2000 seven presented in this age group. Along with the rest of the UK, the two decades we studied had seen markedly rising childhood obesity rates in Scotland. The prevalence of overweight (BMI> 85^th centile) 13–15 year old children doubled from 15% in 1981 to 29% in 2001 and the problem extends to 4 and 5 year olds, although it is not of the same severity.

Conclusion: The incidence of SCFE has increase two and a half times in two decades and may well be a consequence of the worsening obesity rates that have occurred over the same period.

Obesity is thought to be an aetiological factor for slipped capital femoral epiphysis (SCFE). We analysed changes in the incidence of SCFE in Scotland over the last two decades. During this period rates of childhood obesity have risen substantially and evidence for a relationship between these changes and the incidence of SCFE was sought.

We found that the incidence of SCFE increased from 3.78 per 100 000 children in 1981 to 9.66 per 100 000 in 2000 (R² = 0.715): a two and a half times increase over two decades. It was seen at a younger age, with a fall in the mean age at diagnosis from 13.4 to 12.6 years for boys (p = 0.007) and 12.2 to 11.6 for girls (p = 0.047). More children under eight years old were seen with SCFE in Scotland in the decade to 2000 than in the previous decade (p = 0.002, R² = 0.346).

A close correlation was observed between rising childhood obesity over the last 20 years in Scotland and an increasing incidence of SCFE.