Late-onset pseudarthrosis of the dysplastic tibia.

Eleven children in whom a tibial fracture occurred after minor trauma had pre-existing dysplastic changes evident radiographically. These changes included cortical tapering, sclerosis, and formation of a cyst in the region of the medullary canal. Ten of the eleven patients had had no more fractures an average of fifteen years after the most recent fracture. Six of the fractures healed following prolonged immobilization in a cast, but four of the six tibiae were abnormally bowed anteriorly, and it was thought that a stress fracture could occur in the future. Four of the patients had a clinically straight tibia and radiographic evidence of thick cortices following corrective osteotomy, intramedullary fixation with bone-grafting, and prolonged immobilization in a cast. At the most recent follow-up examination, the eleventh patient had a persistent pseudarthrosis despite several operative procedures. While there were too few patients in this series for us to draw definite conclusions, our findings suggest that late-onset pseudarthrosis of a dysplastic tibia has a better prognosis than does congenital pseudarthrosis.