Page 20 - Slipped Capital Femoral Epiphysis Pathogenetic and Clinical aspects

Chapter 2
Results.
The literature search generated a total of 434 references in PubMed, 47 additional studies identified through reference checking were included. 481 Papers were selected based on title and abstract. 314 Papers were excluded based on the above-mentioned criteria. 167 Papers were included in this review.
Epidemiology.
The average age at diagnosis of SCFE is 13.5 years for boys and 12.0 years for girls [68].
Previous reviews found an incidence of 0.2 to 10.08 per 100,000 population [69]. New data showed that the incidence of SCFE differs among countries. The numbers of incidence in the literature are difficult to compare because age group criteria and methods of estimation differ among studies. In the Western world (Europe and USA) the incidence seems to be higher than in Asian countries like Japan. This may be related to the difference in average child body weight among races [69]. Increased SCFE incidence were found in African American and Polynesian populations, with the Maori population having the highest incidence, 81:100,000 [101]. Recent studies show that globally, there is an increase in children with SCFE and obesity [15, 90, 92, 129]. Interestingly, the children who have bilateral disease seem to have a higher BMI [17]. The literature suggests a male predominance in SCFE cases. The sex ratio in children with SCFE, however, seems to have changed over time, from 90% male during the 20th Century to 60% recently [44]. In the Netherlands the change is more pronounced, with an equal number of boy to girl ratio in SCFE cases being recorded in the past decade [153].
Wabitsch et al. [145] examined 411 overweight and obese children. Of these patients, 54 had either hip or knee pain or limited motion of the hip (< 90° flexion and < 10° internal rotation). These 54 patients underwent anteroposterior (AP) and axial radiographs of the pelvis and femoral head. Of this clinically conspicuous group, 11 patients had signs of SCFE (based on an abnormal head-neck angle), i.e. 20% in this group and 2.7% of the total cohort. Lehmann et al. [63] examined a population based cohort of 2072 patients between 2007 and 2009, all born in 1989. His radiological findings were consistent with possible prior SCFE (based on the Lateral radiograph headshaft angle > 13°) in 6.6% of these asymptomatic young adults. Based on these two conclusions, we can assume that the incidence of SCFE might be even higher than suggested by the literature.
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