Prenatal ultrasound diagnostic clues of congenital dislocation of the knee

Abstract

Objective To explore prenatal ultrasound diagnostic clues of congenital dislocation of the knee(CDK). Methods The prenatal ultrasonographic features of 13 CDK fetuses diagnosed from January 2013 to December 2018 in the Third Affiliated Hospital of Zhengzhou University were retrospectively analyzed, combined with the results of gene detections and pathological findings. Results Thirteen fetuses were diagnosed by prenatal ultrasound during the second trimester. Two-dimensional and three-dimensional ultrasound showed dislocation of the knee(unilateral in 3 cases and bilateral in 10 cases). All cases were accompanied with multiple abnormalities, including talipes(5 cases), overlapping fingers(2 cases), short nasal bone(1 case), thicken nuchal fold(1 case), narrow thorax(1 case), abnormal vertebral development(1 case), etc. Ultrasound diagnosis included Larsen syndrome in 2 cases, arthrogryosis multiplex congenital in 3 cases, asphyxiating thoracic dysplasia in 1 case, and congenital dislocation of the knee in 7 cases. CDK was confirmed in all fetuses after termination of pregnancy. Three of them were known to undergo chromosome examinations with normal chromosomal microarray analysis (CMA). One case was confirmed to be Larsen syndrome by further second-generation sequencing combined with first-generation sequencing screening, suggesting there was FLNB gene mutation. Conclusions CDK can exist isolated, and it can also be a common manifestation of various diseases. Therefore, attention should be paid to other associated abnormalities in the prenatal detection of knee flexion, and further detection of related genes can provide valuable information for genetic counseling. Key words: Prenatal ultrasonography; Fetal; Congenital dislocation of the knee; Gene