Ultrasound hip joint screening in newborn infants. Correlation of anamnestic risk factors and hip dysplasia

Abstract

Congenital dysplasia of the hip (CDH) is the most frequent inborn deformity of the locomotor apparatus. Hereditary, pelvic respectively breech presentation or abdominal delivery, premature as well as post-term birth and twin pregnancy are considered to be anamnestic risk factors for congenital dysplasia of the hip. The results of ultrasound hip screening from July 87 until December 94 are presented with special regard to the correlation of these risk factors and the occurrence of pathologic hips. 19 different orthopaedic surgeons examined the hips of 3739 newborns (female: 1837-49.1%; male: 1902-50.9%) by ultrasound (screening). 96% of the examinations were performed within a period of 5 days after birth, in a few cases the babies were up to 19 days old. The ultrasound examinations, the assessment of the echograms and classification into types of hip were performed according to Graf's technique. Two types of ultrasonographs were used: SL-1, Siemens--5 MHz scanner; LSC 7500, Picker--7.5 MHz scanner). All investigations were assessed retrospectively over the period of time with the help of documentation forms (data of newborn baby, case history, clinical and sonographical findings, kind of therapy and procedure) and statistically checked (program SPSS 7.5, Chi-Quadrate-Test, logistic regression). In 239 children (6.4%) we found hips required therapy respectively control investigations (type IIa, alpha < 55 degrees or worse; Graf's classification). For the entire group we achieved the following types of hips (right/left side): Ia--214 (5.7%)/224 (6.0%); Ib--2069 (55.3%)/2008 (53.7%); IIa (> or = 55 degrees)--1318 (35.3%)/1322 (35.4%); IIa (< 55 degrees)--65 (1.7%)/74 (2.0%); IIc--45 (1.2%)/71 (1.9%); D--18 (0.5%)/30 (0.8%); IIIa--8 (0.2%)/7 (0.2%); IIIb--1 (< 0.1%)/2 (0.1%); IV--1 (< 0.1%)/1 (< 0.1%). With regard to the risk factors the distribution was as follows: hereditary--302 babies (8.1%), pelvic respectively breech presentation--149 (4%), abdominal delivery--359 (6.5%), premature birth--188 (5.0%), post-term birth--164 (4.4%), twin pregnancy--73 (2%). In newborn babies with cases of hip dysplasia in their family (heredity) and pelvic respectively breech presentation at birth we found a significant higher rate (p < 0.05) of hips required therapy respectively control investigations (type IIa, alpha < 55 degrees or worse; Graf's classification). Also, for girls and the left hip a significant higher rate was achieved. A correlation of the other mentioned risk factors abdominal delivery, premature and post-term birth as well as twin pregnancy was not evident.