[Fibrous metaphyseal defect (fibrous cortical defect, non-ossifying fibroma) (author's transl)]

Fibrous cortical defect and non-ossifying fibromas can be classified together as fibrous metaphyseal defects (FMD) since they have the same pathological substrate, with a tendency to the same localisation around the knee, and occurring at the same age. They have a tendency to spontaneous healing, are clinically silent and are usually discovered accidentally during radiological examination. A radiological survey of 5.674 metaphyseal regions in the upper and lower extremities of 2.065 unselected patients aged one to 20 years revealed an incidence of 1.8%; exclusive examination of the distal femur showed an incidence of 2.7%. 96% of all lesions were in the lower extremities and only 4% in the upper. The marked discrepancy in the incidence rate between American and German publications is discussed.