Is There a Relationship Between the Functional Level of Juvenile and Adolescent Patients With Down Syndrome and Hip Dysplasia?

Abstract

The prevalence of hip dysplasia among patients with Down syndrome (DS) is higher than in the general population. We hypothesize that a relationship may exist between functional level and hip dysplasia in DS, but this has not been studied to date. The aim of this study is to evaluate whether there is a relationship between functional level and radiographic parameters of hip dysplasia or other measures. Retrospective cross-sectional comparative study of 652 patients with DS from a pediatric referral center database. Patients over 8 years of age with an anteroposterior pelvis radiograph and with no exclusion criteria were selected, totaling 132 patients (264 hips; 54.55% females; mean age 12.96 ± 2.87 y). Several radiographic parameters of the acetabulum [Sharp angle (SA), Tönnis angle (TA), Wiberg center-edge angle (W-CEA), extrusion index (EI), and acetabular retroversion signs], the proximal femur [neck shaft angle (NSA)], and joint congruence [Shenton line (SL)] were assessed. Patients were classified into 2 levels based on functional skills. A multivariate association analysis was performed between radiographic parameters and functional level. Sixty-one patients were compatible with a functional level I and 71 with a level II. Forty-six hips were dysplastic and 60 were borderline according to the W-CEA. A statistically significant relationship was found between the categorical distribution of certain radiographic measurements of hip dysplasia (EI, SA, TA, W-CEA, SL, and classification by functional level ( P < 0.0005). A significant receiver operating characteristic curve was obtained for W-CEA with a cutt-off point at 26.4 degrees for level I (area under the curve = 0.763; P < 0.005; sensitivity = 0.800 and specificity = 0.644). There was a fairly high correlation between EI and TA (0.749; P < 0.0005), EI and W-CEA (-0.817; P < 0.0005), and TA and W-CEA (-0.748; P < 0.0005). Numerous hips showed signs of acetabular retroversion, with no significant differences found between functional levels or association with hip dysplasia measures. The present study reveals a relationship between an increased risk of hip dysplasia and reduced functional levels in DS children older than 8 years. These findings may guide individualized clinical follow-up of hip development in DS children considering their functional level. Level III, retrospective comparative study.