A 19-year-old man with neither trauma nor predisposing factors to nont
raumatic osteonecrosis developed increasing pain in both knees. Radiog
raphs of both knees and arthroscopy of the left knee were normal. Bone
scintigraphy initially showed reduced activity distal to the epiphyse
al line in both femora. Core biopsies from the distal part of the left
femur six months after the onset of pain showed partial osteonecrosis
with signs of revascularization. The patient was treated with partial
weight-bearing and physiotherapy. Recovery followed after 26 months.
We suggest that the symptoms were linked with the epiphyseal closure i
n the distal femur and proximal tibia.