Non-Ossifying Fibroma


Non Ossifying Fibroma




A localised defect in the cortex of the metaphysis

- failure of bone to form

- skeletally-immature adolescents


Fibrous cortical defect 

- < 2cm in diameter


Non ossifying fibroma (NOF)

- > 2cm




Most common skeletal lesion

- 30% of young children

- most common cause of pathological fracture in children


Multiple NOF

- Neurofibromatosis 1

- Jaffe-Campanacci syndrome




Distal femur

Distal tibia


Goldin et al J Child Orthop 2017

- 68 NOF of the femur

- 60% medial at origin of medial head of gastrocneumius or adductor magnus

- 40% lateral at the origin of the lateral head of gastrocnemius


Muzykewicz et al J Child Orthop 2017

- 48 distal tibia NOF

- 96% distal lateral tibia

- in direct communication distal interosseous membrane


Natural history


Self limiting

- usually ossify by early adulthood

- move further from physis as growth occurs

- ? become bone islands


Fracture risk if large


United Non Ossifying Fibroma




Ritschl et al Skeletal Radiol 1988

- stage A: eccentric lesion near physis

- stage B: lesion with thin sclerotic margin, further from physis

- stage C: increasing sclerosis

- stage D: complete sclerosis





- incidental finding

- pain if large

- pathological fracture




Solitary, eccentric lytic lesion


Fibrous Cortical Defect

- < 2 cm

- small cortical lucency 

- sharply defined border


Non-Ossifying Fibroma (NOF)

- > 2 cm

- eccentric metaphyseal lesion

- sclerotic margin

- slight expansion of cortex

- usually < 1/3 diameter of bone


Differential diagnosis


Unicameral bone cyst

Aneurysmal bone cyst




Biopsy usually not necessary


Fibroblasts proliferation with multinucleated giant cells

- no bone formation


Fracture risk


Herget et al BMC Musculoskeletal Disord 2016

- 87 patients with 103 NOF

- 89% asymptomatic and incidental findings

- 10 patients symptomatic

- 6/10 symptomatic patients had a fracture

- all had bone diameter involvement 75% or more


Goldin et al J Paediatr Orthop 2020

- 32 patients with NOF of the tibia

- measured > 50% involvement sagittal and coronal, cortical breach and no neocortex

- those with all 4 risk factors had 100% fracture risk






Small defects


Incidental finding


Curettage and Bone graft



- large lesions > 1/2 diameter of bone

- symptomatic

- significant cortical thinning




Andreacchio et al Eur J Orthop Surg Traumatol

- 9 patients with symptomatic NOF mean age 10 years

- average size > 2/3 diameter bone
- curette and graft with Calcium Sulphate bone substitute

- all 9 healed


Pathological fracture




1.  Nonoperatively

- fracture heals in normal length of time

- lesion may heal with fracture union


2.  Operative management

- failure to obtain or maintain an adequate reduction


2.  Persistent post fracture

- curettage and bone graft


Fibrous Cortical Defect Femur FractureNon Ossified Fibroma ORIFNon Ossified Fibroma United