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Avascular Necrosis: Causes and Treatment
Coleman D. Fowble, M.D.
Midlands Orthopaedics, P.A.
Columbia, SC
Introduction
• DefinitionLoss of blood flow to the bone leading to death of
the cellular components of bone.
Bones Affected
• Femoral head – most common by far• Shoulder – humeral head• Odontoid (Neck)• Scaphoid (Wrist)• Lunate (Wrist)• Talus (Ankle)
Etiologies
• Trauma• Alcohol• Steroids• Diving (Caisson’s Disease)• Sickle Cell• Idiopathic (up to 30% of cases)
Classification
• FicatOriginal x-ray classification of hip
• Other classifications exist for talus, scaphoid, etc.
Stage I
• May or may not have symptoms• Radiographs and CT are normal• MRI is abnormal as is bone scan• Microscopic exam confirms diagnosis
Stage II
• Patient is symptomatic• X-rays show osteopenia, sclerosis, cysts• No subchondral lucency or collapse• MRI confirms diagnosis
Stage III
• X-rays show subchondral lucency and collapseCrescent sign
• Shape of femoral head is preserved• Subclassified by extent of crescent
IIIa 15% of headIIIb 15-30% of aheadIIIc greater than 30%
Stage IV
• Flattening or collapse of head on x-ray• Loss of joint space• Subclassified by extent of collapse like Stage III
IVaIVbIVc
Stage V
• Arthritic changes evident on x-rays with loss of joint space and spurring
• May affect acetabular side of the joint
Stage VI
• Extensive destruction of femoral head and joint
• May be indistinguishable from osteoarthritis
Treatment Options
• Stage dependent• Clinical signs and symptoms• Physiologic condition• Age• Medical comorbidities
Free Vascularized Fibular Graft
• Pioneered in 1979 by Dr. Urbaniak at Duke• Over 2500 performed• Multidisciplinary approach• Only center with real consistent results
Summary
• AVN is the disruption of the blood supply to bone
• There are multiple causes• Diagnosis may be delayed• Treatment is dependent on stage and other
factors