Orthopedics
InShort
AKA
Aseptic Necrosis
AVN
Bone Infarct
Avascular necrosis (AVN) denotes death of bone due to insufficient or interrupted blood supply. As the bone dies, it causes transient pain. Dead bone does not undergo the usual repair mechanisms of living bone and is subject to fracture and collapse.
Causes and Risk Factors
Use of bisphosphonates has been associated with AVN of the jaw. Steroid use, radiation, and cassion's disease (decompression sickness) also are associated with AVN development.
Most cases of pediatric AVN still are considered to be idiopathic in nature.
Diagnostic Evaluation
Plain films generally are sufficient to diagnose AVN. Early in the disease process, before bone collapse, magnetic resonance imaging is a more sensitive imaging test.
Pearls
Any bone may undergo avascular necrosis, but some anatomic locations (eg, the scaphoid, elbow, talus, capitellum, and the head of the femur or humerus) are more commonly affected than are others.
Legg-Calve-Perthes disease, a form of AVN of the hip seen in the pediatric population, may lead to life-long disability if not recognized early and treated.
Treatment and Recommended Follow-Up
Initial treatment depends upon the bone involved. In large, weight-bearing joints (eg, hip, knee), joint replacement arthroplasty may be needed to correct vast areas of AVN. In smaller joints, a period of reduced activity followed by proper rehabilitation may suffice. Joint-sparing surgery may be possible, as well.
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