Spinopelvic Alignment in Subjects With Down Syndrome

Scoliosis in Adolescent Patients With Down Syndrome: Correlation Between Curve Magnitude and Functional Level

STUDY DESIGN

This is a retrospective, observational comparative study.

OBJECTIVE

The aim of this study is to determine whether a relationship exists between the functional level and spinal deformity in patients with Down syndrome (DS).

SUMMARY OF BACKGROUND DATA

Patients with DS have a higher incidence of scoliosis than the general population; however, it is unknown whether functional level influences the characteristics and severity of the deformity.

MATERIALS AND METHODS

Of 649 patients with DS included in a pediatric referral center database, we identified 59 with a diagnosis of scoliosis (59.32% female; mean age, 14.19±1.82 y); the 46 patients who met the inclusion criteria comprised the study cohort. According to their functional gait skills and gross motor skills, they were classified into 2 levels. Different coronal and sagittal parameters were measured using full-spine standing radiographs. The need for surgical treatment and history of thoracotomy were recorded as well. Finally, a multivariate association analysis was performed between radiologic parameters and functional level.

RESULTS

Twenty-two patients had a functional level consistent with level I and 24 with level II. Twelve curves were thoracic, 10 thoracolumbar, and 24 lumbar. A statistically significant relationship was found between functional level I and II and curve magnitude: 18.9 degrees (6.8) versus 36.9 degrees (20.3) ( P =0.001) with a cutoff point at 22.3 degrees (area under the curve=0.919, P <0.005, sensitivity=0.917 and specificity=0.818). The relationship between patients who required surgery and level II was also significant ( P =0.016). No relationship was found between functional level and coronal and sagittal balance, nor with other radiologic parameters or with curve location, or between the history of thoracotomy and thoracic curves.

CONCLUSIONS

DS adolescents with poorer functional level were associated with larger curves and greater risk for surgery. These findings may provide valuable guidance for the follow-up of scoliosis in patients with DS based on their functional level.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Combining acetabular and femoral morphology improves our understanding of the down syndrome hip

BACKGROUND

Hip instability is frequent in patients with Down syndrome. Recent studies have suggested that skeletal hip alterations are responsible for this instability; however, there are currently no studies simultaneously assessing femoral and acetabular anatomy in subjects with Down syndrome in the standing position. The aim was to analyze the three-dimensional anatomy of the Down syndrome hip in standing position.

METHODS

Down syndrome subjects were age and sex-matched to asymptomatic controls. All subjects underwent full body biplanar X-rays with three-dimensional reconstructions of their pelvises and lower limbs. Parameter means and distributions were compared between the two groups.

FINDINGS

Forty-one Down syndrome and 41 control subjects were recruited. Acetabular abduction (mean = 52° [SD = 9°] vs. mean = 56° [SD = 8°]) and anteversion (mean = 14° [SD = 8°] vs. mean = 17.5° [SD = 5°]) as well as posterior acetabular sector angle (mean = 91° [SD = 7°] vs. mean = 94° [SD = 7°]) were significantly lower in Down syndrome subjects compared to controls (P < 0.01). Anterior acetabular sector angle (mean = 62° [SD = 10°] vs. mean = 59° [SD = 7°]; P < 0.01) was significantly higher in Down syndrome compared to controls. The distributions of acetabular anteversion (P = 0.002;V = 0.325), femoral anteversion (P = 0.004;V = 0.309) and the instability index (P < 0.001;V = 0.383) were significantly different between the two groups, with subjects with Down syndrome having both increased anteversion and retroversion for each of these parameters.

INTERPRETATION

Subjects with Down syndrome were found to have a significantly altered and more heterogeneous anatomy of their proximal hips compared to controls. This heterogeneity suggests that treatment strategies of hip instability in Down syndrome should be subject-specific and should rely on the understanding of the underlying three-dimensional anatomy of each patient.