Focal Fibrocartilaginous Dysplasia ("Fibrous Periosteal Inclusion")

Abstract

Focal fibrocartilaginous dysplasia (FFCD) is a benign condition first described in 1985 as a cause of tibia vara. We are reporting on 11 cases. The lesions involved proximal tibia (9 cases), distal femur (1 case), and distal ulna (1 case). We believe that this entity represents a bony anchor preventing natural sliding of the periosteum during growth (an "epiphysiodesis-like" effect). For the tibia, we believe this is the pes anserinus. We are suggesting that this entity be called a "fibrous periostal inclusion." Treatment indications result from this concept: (1) for tibial lesions with a metaphyseal-diaphyseal angle less than 20 degrees observation for 6 to 12 months; (2) if the deformity improves, the tether likely broke spontaneously, and no treatment is required; and (3) curettage early if the deformity worsens. This will be followed by rapid correction into physiological valgus (tibia) and prevent the need for osteotomy. Early curettage for other less common locations is recommended.