Pericollapse Stage of Osteonecrosis of the Femoral Head: A Last Chance for Joint Preservation

Zhang, Qing-Yu; Li, Zi-Rong; Gao, Fu-Qiang; Sun, Wei

I/II) and skillful techniques. [1] [2] [3] However, ARCO Stages I and II are also known as subclinical states because lesions at these stages are often insidious, and the symptoms and signs are minimal and nonspecific, which leads to the fact that those patients rarely make a first visit to an orthopedist. Meanwhile, surgical intervention of asymptomatic ONFH is controversial due to the observation of spontaneous repair of necrotic lesions, great variability of progression (with only 7% of small lesions and 80% of large lesions collapsing by the 8 th year after diagnosis) at the early stage, and limited evidence for treatment. [3, 9, 10] On the other hand, the "wait-and-watch" policy may miss the critical window of opportunity to prevent head depression. For children receiving chemotherapeutic treatment for malignancies, up to 72% of patients have already been at Stage IV by the time they are diagnosed. [11] Defining specific biomarkers in the development of ONFH is of great importance to guarantee both diagnostic accuracy and joint-preserving success rate.