Focal cartilaginous dysplasia is a rare condition associated with unilateral tibia vara in young children. The authors report 2 cases. In one patient spontaneous correction occurred at the age of 18 months. In the other case the patient's deformity persisted, and an osteotomy was performed at the age of 36 months. Through these 2 cases and 26 cases of the literature, the authors discuss the healing process and etiology. The most likely exploration is an abnormal development at the insertion of the pes anserinus inducing epiphysiodese like effect. In most cases, the growth plate of the proximal tibial appears to correct the deformity. Surgical correction is necessary after the age of 36 months, if the angular deformation is up to 30 degrees of varus.