In a large cohort of twins that included almost 35,000 individuals, the self-reported overall prevalence of Scheuermann disease was 2.8% and the male-to-female ratio was close to 2:1. Because the pairwise and probandwise concordance and the odds ratio were two to three times higher in monozygotic than in dizygotic twins and the heritability was high, we concluded that there is a major genetic contribution to the etiology of Scheuermann disease.

Background and purposeThe genetic/environmental etiology of Scheuermann's disease is unclear. We estimated the heritability of the disease using an etiological model adjusted for sex and time of diagnosis, and examined whether the prevalence of Scheuermann's disease was constant over time.Methods46,418 twins were sent a questionnaire about health and disease. Of these, 75% returned the questionnaire and 97% answered the question “Have you been diagnosed as having Scheuermann's disease by a doctor?”ResultsResponders included 11,436 complete pairs of twins. Data were analysed using classical twin modeling methods. Tetrachoric correlations were used to decide which etiological model to fit. The best-fitting model was the AE model. Heritability was 0.74 (95% CI: 0.65–0.81), while variance explained by environmental factors was 0.26 (95% CI: 0.19–0.35). A threshold of 2.1 (95% CI: 1.9–2.2) was calculated, corresponding to a prevalence of 1.9% (95% CI: 1.3–2.8) for women. Regression coefficients for age and sex were 0.000 (95% CI: –0.003 to 0.002) and –0.32 (95% CI: –0.42 to –0.23).InterpretationWe found a heritability of 0.74 in Scheuermann's disease. The threshold in men was lower than in women, corresponding to a male prevalence that was almost twice that of females. We found no change in the prevalence of Scheuermann's disease throughout the 50-year age span that we examined.

AIM To test the hypothesis that improvements in gait and function following individualized interdisciplinary interventions consisting of physical therapy, orthotics, spasticity management, and orthopaedic surgery using instrumented gait analysis are superior to 'usual care' in children with cerebral palsy (CP).METHOD This was a prospective, single-blind, parallel-group, randomized controlled trial investigating the effectiveness of interventions based on the use of gait analysis. Primary outcome was gait (Gait Deviation Index) and secondary outcomes were walking and patientreported outcome measures of function, disability, and health-related quality of life. Followups were done at 26 weeks (questionnaires) and at the primary end point of 52 weeks (all outcomes). RESULTSSixty participants with CP (39 males, 21 females, mean age 6y 10mo, standard deviation 1y 3mo, range 5y-9y 1mo) in Gross Motor Function Classification System levels I or II, were randomized to interventions with or without gait analysis. No significant or clinically relevant between-group differences in change scores of the primary or secondary outcomes were found. The recommended categories of interventions were dominated by non-surgical interventions and were applied in 36% to 86% of the participants.INTERPRETATION Interventions using gait analysis were not superior to 'usual care' on gait, walking, or patient-reported outcomes in a sample of relatively young and independently walking children with CP not expected to need surgery.

IntroductionThe aetiology of congenital clubfoot is unclear. Although studies on populations, families, and twins suggest a genetic component to the aetiology, other studies have identified environmental factors. The purpose of this study was to calculate heritability in order to determine to what extent genetic and/or environmental factors contribute to the aetiology of congenital clubfoot and to asses whether there was a change in the prevalence over time.Materials and MethodsThe Odense based Danish Twin Registry is unique as it contains data on all the approximately 85,000 twin pairs born in Denmark over the last 140 years. All 46,418 twin individuals born from 1931 through 1982, who had earlier consented to contact, received a 17-page Omnibus questionnaire in the spring of 2002. Data were analysed with structural equation models to identify the best fitting aetiological model based on a balance of goodness-of-fit and parsimony and to estimate heritability.ResultsWe found an overall self-reported prevalence of congenital clubfoot of 0.0027 (95 % confidence interval 0.0022–0.0034). Fifty-five complete (both twins answered the question) twin pairs were identified representing 12 monozygotic, 22 same-sex dizygotic, 18 opposite-sex dizygotic, and 3 with unclassified zygosity. The model with only environmental factors (CE) was best fitting based on AIC, and the model with an additive genetic factor (ACE) came in second. Due to the small statistical power, we hypothesise that the model with both genetic and environmental effects (ACE) was the better model. Choosing the ACE-model we found a heritability of clubfoot of 30 %. Regression coefficient for age was −0.002 (−0.011 to 0.005), indicating that there has been no change in prevalence of clubfoot over the 50-year age span we examined.DiscussionWe conclude that non-genetic factors must play a role, and a genetic factor might contribute, in the aetiology of congenital clubfoot.