Ultrasonographic study of the femoro-patellar joint and its attachments in infants from birth to 24 months of age. Part II: children with Down syndrome.

An ultrasonographic study was carried out in 25 infants (50 knees) with Down syndrome, whose age ranged from zero to 24 months, average being 13.2 months; 13 were males and 12 were females. The ultrasonographic investigation was performed with the knee being in full extension for the transversal view and in 30 degrees flexion for the sagittal view. The Insall-Salvati index and femoral cartilaginous sulcus angle were measured. Insall-Salvati index values ranged from 1.06 to 1.15 (average 1.10), with standard deviation of 0.16. No significant differences were observed with regard to Insall-Salvati index values in normal children. The femoral cartilaginous sulcus angle in infants with Down syndrome ranged from 152.7 to 155.8 degrees (average 154.3) with standard deviation of 7.959. In Down syndrome we noticed significant difference as compared to the normal values. The authors suggest that ultrasonography is useful in Down syndrome for an early diagnosis of instability of the patella.