[Anatomic study of the anterior patellar groove in the fetal period].
OBJECTIVE
We performed a biometric analysis of the femoral trochlea in the fetus and compared our findings with those observed in adults in order to search for correlations with other biometric parameters of the femur.


METHODS
Twenty-two fetuses (44 knees) conserved in formol and free of known orthopedic disease were studied. Fetal age ranged from 26 to 40 weeks. After anatomic dissection, digitalized images were used to obtain angle measurements with a dedicated software. Measurements made on the distal epiphyseal view were: anteroposterior dimension of the condyles, medial and lateral protrusion of the trochlear borders, difference in condyle height, length of the trochleal borders, alpha angle of the trochlear groove, trochlear slope. Measurements made on the AP femoral view were: femoral anteversion, length of the femoral neck, neck-shaft angle. Spearman's test was used to search for correlations. Results were compared with measurements obtained under the same conditions in a series of 32 adult knees published by Wanner.


RESULTS
The trochlear alpha angle was 148 degrees (coefficient of variation 4%). The angle was greater than 150 degrees for 18 trochleae. The lateral border of the trochela was higher than the medial border in 37 of the 44 knees. There was no correlation with age and gender. Femoral anteversion was 27.01 degrees, with a high coefficient of variation (46%), and no correlation with the trochlear alpha angle. Comparison with measurements made on the adult knees revealed no significant difference.


CONCLUSIONS
This is the first report of statistically significant biometric data of the fetal trochlea. The morphology of the lower femur observed during the third trimester of fetal live is the same as observed in adults. Morphological changes in the proximal femur occurring during growth do not appear to modify the morphology of the distal femur. The asymmetrical ingression of the patella into the trochlea, characteristic of modern man, is considered to result from bipedalism. Our study would suggest that the anatomic characteristics of the trochlea could have been integrated into the genoma during the course of evolution. This would be in favor of a genetic origin of trochlear dysplasia.
D000328:Adult; D000886:Anthropometry; D005314:Embryonic and Fetal Development; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000196:embryology*; D006801:Humans; D010329:Patella / Q000033:anatomy & histology* / Q000196:embryology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third
Etude anatomique du creusement de la trochlée fémorale chez le foetus.