Tibia Vara due to Focal Fibrocartilaginous Dysplasia

We present a case of unilateral tibia vara associated with an area of focal fibrocartilaginous dysplasia in the medial aspect of the right proximal tibia. Such a case has not been described previously. The affected child was 8 months old. Deformity resolved without aggressive treatment. The pathogenesis of the focal lesion remains controversial. The most likely explanation is that the mesenchymal anlage of the tibial metaphysis has for unknown reasons, developed abnormality at the insertion of the pes anserinus.