Osteonecrosis of the Femoral Head Matthew Orton Radiology Presentation 7/20/2007

HPI A 20 yo male with SLE reports to ER complaining of chronic L hip pain and new L knee pain that has not resolved since fall 1 week ago. A 20 yo male with SLE reports to ER complaining of chronic L hip pain and new L knee pain that has not resolved since fall 1 week ago. PCP diagnosed SLE in PCP diagnosed SLE in Meds: Lisinoprol, Prednisone, Zantac, HCTZ, Imuran, Volteran, Meds: Lisinoprol, Prednisone, Zantac, HCTZ, Imuran, Volteran,

Sclerosis and density changes “Crecent Sign” = subcondral radiolucancy Loss of smooth spherical or collapse of femoral head. Joint space narrowing, degenerative changes.

MRI of Femoral Head Osteonecrosis Coronal T1 MRI of both hips shows diffuse low signal throughout the left femoral head, neck, and proximal shaft. Coronal T1 MRI of both hips shows diffuse low signal throughout the left femoral head, neck, and proximal shaft. Axial T2 MRI of both hips shows diffuse high signal in the left femoral head consistent with the avascular necrosis. Axial T2 MRI of both hips shows diffuse high signal in the left femoral head consistent with the avascular necrosis. Images from: brighamrad.harvard.edu

Osteonecrosis of Femoral Head Osteonecrosis = aseptic necrosis, avascular necrosis, ischemic necrosis and osteochondritis dessicans. Osteonecrosis = aseptic necrosis, avascular necrosis, ischemic necrosis and osteochondritis dessicans. Mechanism  compromise of bone vasculature leading to death of bone and marrow cells and ultimately mechanical failure. Process is often progressive and results in joint destruction in 3-5 years if untreated. Mechanism  compromise of bone vasculature leading to death of bone and marrow cells and ultimately mechanical failure. Process is often progressive and results in joint destruction in 3-5 years if untreated. Exact pathogenesis still under debated. Some theories include intravascular necrosis, increased intraosseous pressure, mechanical stresses, or metabolic factors.Exact pathogenesis still under debated. Some theories include intravascular necrosis, increased intraosseous pressure, mechanical stresses, or metabolic factors. Prevalence is 10,000-20,000 cases diagnosed in US/year. M:F = 8:1. 5% of patients with SLE will develop osteonecrosis. Prevalence is 10,000-20,000 cases diagnosed in US/year. M:F = 8:1. 5% of patients with SLE will develop osteonecrosis. Staging Staging Stage 0 — All diagnostic studies normal, diagnosis by histologyStage 0 — All diagnostic studies normal, diagnosis by histology Stage 1 — Plain radiographs and computed tomography normal, magnetic resonance imaging positive and biopsy positive.Stage 1 — Plain radiographs and computed tomography normal, magnetic resonance imaging positive and biopsy positive. Stage 2 — Radiographs positive but no collapse.Stage 2 — Radiographs positive but no collapse. Stage 3 — Early flattening of dome, crescent sign, computed tomography or tomograms may be needed.Stage 3 — Early flattening of dome, crescent sign, computed tomography or tomograms may be needed. Stage 4 — Flattening of femoral head with joint space narrowing, possible other signs of early osteoarthritisStage 4 — Flattening of femoral head with joint space narrowing, possible other signs of early osteoarthritis Nontraumatic Corticosteroid Sickle cell Systemic lupus erythematosus Gaucher’s Disease Chronic renal failure or hemodialysis Radiation Excessive ETOH Traumatic Femoral Neck Fracture Femoral Dislocation

Treatment of Osteonecrosis of Femoral Head Conservative management ( rest and pain control) if <15% femoral head involved. Conservative management ( rest and pain control) if <15% femoral head involved. Bisphosphonates can slow progression Bisphosphonates can slow progression Core decompression may slow progression. Core decompression may slow progression. Osteotomy move areas of necrosis away from major load bearing and try to redistribute on healthy bone. Osteotomy move areas of necrosis away from major load bearing and try to redistribute on healthy bone. Joint replacements (higher rate of complications and revisions) Joint replacements (higher rate of complications and revisions)

References 1. Donohue, JP.UptoDate: Osteonecrosis (avascular necorsis of bone) Jones LC, Hungerford DS. Osteonecrosis: etiology, diagnosis, and treatment. Curr Opin Rheum 2004; 16: Galindo M, Mateo I, Pablos JI. Multiple avasular necrossis of bone and polyarticular septic arthritis in patients with systemic lupus erythematosus. Rheumatol Int 2005; 25: