Avascular necrosis
Background
- Also called osteonecrosis, ischemic necrosis, bone infarction
- Interruption in vascular supply leads to death of osteocytes and marrow, necrosis, and (eventually) collapse of dead segment
Causes/Risk factors
Nontraumatic
- Sickle cell disease
- Exogenous corticosteroids, Cushing's disease
- Collagen vascular disease (e.g. SLE)
- Chronic kidney disease (renal osteodystrophy), post-renal transplant
- Pancreatitis
- Radiation therapy
- HIV
- Caisson Disease (aka dysbarism)
- Legg-Calve-Perthes disease
- Slipped capital femoral epiphysis (may be atraumatic or minor trauma)
- Idiopathic
Traumatic
- Hip dislocation
- High risk if not reduced within 6h
- Femoral neck fracture
- Major talus fracture (talar head/neck)
- Navicular fracture (central part of bone is avascular)
- Proximal humerus fracture
- Risk factors: 4 part fractures, head split, short calcar segments, disrupted medial hinge
- Elbow fractures
- Trochlear fracture
- Lateral or medial epicondyle fracture
- Lunate fracture, Capitate fracture
Clinical Features
- Depends on cause and location
Differential Diagnosis
Sickle cell crisis
- Vaso-occlusive pain crisis
- Bony infarction
- Dactylitis
- Avascular necrosis of femoral head
- Acute chest syndrome
- Asthma
- Pulmonary hypertension
- Gallbladder disease
- Acute hepatic sequestration
- Infection
- Parvovirus B19
- Splenic sequestration
- CVA
- Cerebral aneurysm and ICH
- Priapism
- Papillary necrosis
Evaluation
- Plain films generally first step
- Further evaluation depends on cause/location
Management
- Ortho consult
- Usually splint, non-weightbearing