[Evolution of post-fracture bone deformities in an infant with hepatic osteodystrophy on Alagille syndrome].

INTRODUCTION: This case report describes the evolution of postfractural axial bone deviations that occurred in a child with hepatic osteodystrophy due to an Alagille Syndrome. Postfractural bone deformities in children trend to spontaneous correction if there is a remaining growth potential. In case of severe hepatic osteodystrophy correlated by liver transplantation, we have observed spontaneous correction of a posttraumatic valgus deformity of the leg, as well as worsening of a diaphyseal femoral bowing. We tried to explain this apparently paradoxal evolution. CASE REPORT: Andrea St. is born in 1984 with multiple malformations corresponding to Alagille Syndrome: ductulus paucity, pulmonary arterial hypoplasia, posterior embryotoxin and "butterfly vertebrae". She has developed a cholostatic icterial and a portal hypertension due to a hepatic cirrhosis which needed an hepatic transplantation at the age of 8 years. Before her transplantation, Andrea St developed postfractural axial bone deviations. At the age of 7 years, she had a tibia valgum of 20 degrees and a femoral bowing of 50 degrees. With the normalization of the metabolism due to the hepatic transplantation, the osteopenia as well the tibia valgum of 20 degrees has been corrected spontaneously up to 8 degrees and there was a worsening of the femoral bowing up to 50 degrees. DISCUSSION: The physiopathology of the hepatic osteodystrophy is not yet perfectly known. Treatment with Vitamin D and Calcium doesn't seem to prevent hepatic osteodystrophy. Salter reported that postfractural bone angulation in children will spontaneously correct itself if on one hand it is not far from the growth cartilage and on the other hand if it is in the same mobility plane than the adjacent articulation. Postfractural diaphyseal bone deformities tend to correct spontaneously if the angulation is less than 20 to 30 degrees. Concerning fractures of the proximal tibia in children, they develop frequently a progressive tibia valgum deformity, even if the fracture was not primary displaced. However we know that all proximal tibial fractures in children don't give residual valgus deformities, and that several postfractural tibia valgum correct spontaneously. This has been explained by a temporary growth acceleration of the medial part of the proximal tibial growth plate. In this case, the femoral bowing worsened. This is explained by the mediodiaphyseal location of the deformation, and the importance of the bone deviation much bigger than the threshold of 20 to 30 degrees that may not be overtaken to hope a spontaneous correction. The evolution of the proximal metaphyseal tibial fracture consisted firstly in a progressive valgus deformation that resolved spontaneously after hepatic transplantation.