Pathologic fractures through nonossifying fibromas: is prophylactic treatment warranted?

Twenty-two patients with large nonossifying fibromas (NOFs) in weight-bearing bones were studied to evaluate risk of pathologic fracture. Previous reports suggest an absolute size threshold for NOFs beyond which there is a reasonable chance of impending fracture. In this series, 13 (59%) large NOFs had not had pathologic fracture despite exceeding the previously established size threshold. Four of the patients had fractures of the long bone in which the NOF was located without the fracture involving the lesion. In the nine (41%) patients in whom pathologic fracture occurred, healing was uneventful after closed reduction and cast immobilization. Whereas absolute size parameters may be useful in predicting pathologic fracture rate, they do not imply a requirement for prophylactic curettage and bone grafting. The majority of patients with large NOFs can be monitored without surgical intervention, and fractures can be successfully managed with nonoperative treatment.