a case of osteoid osteoma

1. A 21 year Male with
Left knee pain
Department of Orthopaedics,
Apollo Institute of Medical Sciences & Research

2. • A 21 year Male presented with atraumatic severe
left knee pain since 3 months.
• Focal, Dull aching pain over medial knee.
• Nocturnal aggravation.
• Clinically no visible/palpable swelling.
• Localised tenderness medially over distal femur.
• Full Range of motion of knee joint.
• Distal Neurovascularity intact.

6. Computed Tomogram is the Imaging
modality of choice
• Bull’s eye appearance with central nidus &
surrounding reactive bone.
• Helps in Localisation & planning surgery
• Others:
• Technitium – 99 Bone scan – specific

7. CT scan

8. Patient was managed conservatively
with NSAIDS without any relief.

9. Percutaneous Radiofrequency Ablation
• Minimal invasive under CT guidance
• High Cost

11. Surgical
• Enbloc Excision
– requires CT localisation
– greater bone loss - requiring bone grafting &
plating.
• Burr down & curettage
– removes lesser bone , thus doesn’t weaken it.

13. CT guided localisation in our hospital

16. Intra operative

21. Osteoid Osteoma
• Benign bone lesion with well demarcated
osteoblastic mass <2cm- Nidus
• Surrounded by a sclerotic rim.
• 10% incidence
• 2nd decade, (5-30 yrs) M:F – 2:1
• Location- diaphysis or metaphysis of long
bones.
• Proximal femur> Tibia> Spine

22. • X Ray: cortical / medullary location
– Osteolytic with calcified rim.
• MRI: Nidus
– Marrrow & soft tissue Oedema

23. Pathology
• Overlying cortex is pink due to vascularity.
• Nidus is Red in colour
– Early nidus is soft
– Later becomes dense & gritty
• Microscopy: immature bone surrounded by
osteoblasts, osteoclasts & fibroblasts with
capillaries & non myelinated axons.
• High levels of prostaglandins

24. Course
• Mature spontaneously over long time by
calcification & ossification.
• Rarely transform to osteoblastoma.
• No Malignant potential.

25. Thank You