Slipped capital femoral epiphysis: a population-based study.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in children 9-15 years old. This is a population-based study in Sweden presenting the epidemiology for SCFE. METHODS: In a prospective cohort study, we analysed pre- and postoperative radiographs, medical records for all children treated for SCFE in Sweden 2007-2013, demographic data, severity of slip and surgical procedures performed. RESULTS: We identified 379 Swedish children with primary SCFE 2007-2013; 162 girls, median age 11.7 (7.2-15.4) years, and 217 boys, median age 13 (3.8-17.7) years. The average annual incidence was 4.4/10000 for girls and 5.7/10000 for boys 9-15 years old. Obesity or overweight was found in 56% of the girls and in 76% of the boys. As an initial symptom, 66% of the children had hip/groin pain and 12% knee pain. At first presentation, 7% of the children had bilateral SCFE. Prophylactic fixation was performed in 43%. Of the remaining children, 21% later developed a contralateral slip. Fixation with implants permitting further growth was used in >90% of the children. Femoral neck osteotomy was performed for 11 hips. CONCLUSIONS: The annual average incidence 2007-2013 in Sweden showed a mild increase for girls. The male-to-female ratio was lower than previous regional data from Sweden. Overweight or obesity is one major characteristic for boys with SCFE but to a less extent for girls. Knee pain as initial symptom cause a delay in diagnosis. Most hospitals in Sweden treat <2 children annually.