Osteonecrosis: Overview of New Paradigms in the Etiology and Treatment.

Osteonecrosis is a pathological condition in which the cellular elements of bone die. It is generally a progressive disease, unless the lesions are very small. Osteonecrosis is frequently located in more than one bone (multifocal). The three most common etiologies are local severe trauma, prolonged use of corticosteroids for serious medical conditions, and alcohol abuse. The diagnosis is one of high suspicion in a predisposed younger patient, usually less than 50, with persistent joint pain. Radiographs of the joint and magnetic resonance images confirm the diagnosis. Joint-saving procedures are first initiated if the joint is still anatomically preserved, and bone collapse has not occurred. In the later stages with collapse of bone and subsequent arthritis, the procedure of choice is joint arthroplasty. Earlier diagnosis and intervention, together with new surgical procedures and devices, may prolong the lifetime of the patient's natural joint.