Ultrasonographic study of the femoropatellar joint and its attachments in normal infants from birth to 24 months of age: part I.

Eighty knees of 40 musculoskeletally normal infants whose age ranged from 0 to 24 months (average 9.65 months) were ultrasonographically analyzed. The lengths of the patella, patellar ligament - and the Insall-Salvati index, knee being flexed at 30 degrees , were assessed. The angles of the femoral cartilaginous sulcus knee flexed at 0, 30, 60, and 90 degrees were also defined. Patellar length varied from 1.84 to 2.02 cm (mean, 93.3 cm; standard deviation, 0.35); patellar ligament length varied from 1.67 to 1.86 (mean, 1.76 cm; standard deviation, 0.25); the Insall-Salvati index varied from 1.04 to 1.13, (mean, 1.09; standard deviation, 0.14); and femoral cartilaginous sulcus angle ranged from 148.7 to 149.3 degrees (average, 148.9 degrees and standard deviation, 6.20). Statistical tests showed no significant difference in the proposed measures according to sex and side (right/left). Moreover, we did not observe significant difference in the femoral cartilaginous sulcus angle with respect to the various degrees of knee flexion. Thus, we conclude that ultrasonography is useful for determining the normal values of the Insall-Salvati index and femoral cartilaginous sulcus angle in infants from 0 to 24 months. Then, we suggest standardization of this imaging procedure for the early diagnosis of deformities, which might impair the knee in infants within this range of age.

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.