[Congenital absence of the patella: two cases reported]

To remind a rare disease, To emphasize the importance of patellar agenesis because it's a calling sign, To insist on the necessity to know child bony growth.

We reported observations of two negro-african children's, one female and one male, who were both 7-years-old. They were referred for troubles of the walk, knee pains for the male, and for the female frequent falls and hypotonia. We have noted previous history of second degree familial consanguinity and paternal grandfather's ungueal anomalies for the female.

For the female, examination showed ligamentary hyperlaxity, anterior flattening and lateral dimple of the knee, so varied skeletal defects. Skeletal radiographies displayed absence of the patella, "console like" aspect of the superior tibial metaphysis. At the male, examination is normal. Standard radiographies showed semilunar opacities and tomodensitometry showed presence of a tissular formation who looks like the patella. Aplasia of the patellar apparatus is evocated for the female, even though for the male, the diagnosis of hypoplasia seems more probable.

Absence of patella is rare. It can be transient and patellar nucleus appears lately. It can be permanent and in this case, it is isolated whether associated with other osseous malformations. Interest of such observations is in its rarity and its functional impact related to the biomechanical importance of the patella.