The Pelvic Changes of Patients with Down Syndrome in Korea

Park, Jong; Oh, Kwan Cheol; Kim, Kyoung Sim; Kim, Ki Bok

Abstract

PURPOSE
Since Caffey et al. first described the anomaly in pelvis among the Down patients, decreased iliac and pelvic indexes have been helpful in diagnosing the syndrome. For Korean cases, however, no definitive data are available as yet, prompting us to evaluate the pelvic changes in Korean Down's patients.
METHODS
Subjected to this study were 68 children with Down's syndrome. As the control group served 126 patients with other diseases that do not affect the pelvis. The acetabular angle (AA) and the iliac angle (IA) were measured, and the iliac and pelvic indexes wer calculated from the following equations : Iliac index (Ii) = X + Y: pelvic index (Pi) = 0.3X + 0.42Y (where X is the mean of both acetabular angles, and Y is the mean of both iliac angles)
RESULTS
1) The sex ratio of the patients was 1.5 to 1, male prepondering. Their ages ranged from 1 day to 13 years, with the mean of 9.5 months, the majority (55.9%) falling under 1 month. The karyotype most frequently found in them was 21-trisomy (97%), followed by translocation (3%). 2) The AA of the Down patients was 18.49+/-4.92 (M+/-SD), significantly lower than that of the control group with 25.21+/-5.73; and the IA of the affected measured 43.53+/- 5.97, also signficantly (p<0.001) lower than the control (52.68+/-7.93). 3) The Ii and Pi of the Down groups were calculated as 62.01+/-9.04 and 23.83+/-3.38; both values were significantly lower than those of the control with 77.87+/-11.28 and 29.69+/-4.26, respectively. 4) The maximum likelihood estimate of Ii for Down syndrome was found to be 64, and at that level, the specificity 87.30%, and the sensitivity 66.18%. 5) In the Neonatal and infantile period, all parameters of Down syndrome were very significantly lower values when compared with those of the control of corresponding age In the childhood age, however, the AA of both groups did not significantly differ from each other, but the Down children had significantly lower values in the other parameters. The Ii decreased in relation to the increasing age in the control group, while no significant correlation was noted in the Down patients. 6) In the control group, a significant gender difference was found in the Ii, with females having higher values. In the Down patients, however, both sex did not significantly differ in the Ii.
CONCLUSIONS
Decreased iliac and pelvic indexes manifested in Korean Down cases were quantitively evaluated in this study and it was found that an iliac index below 64 strongly supports the diagnosis of Down syndrome. For the Down cases, the Ii did not signficantly correlate with age, nor did both sexes differ in the Ii, in contrast to the control group which showed an age-related decrease and higher female values.