Introduction
Osteonecrosis of the femoral head (ONFH) has been reported to be a common cause of acute hip pain in the early stage, following the progressive collapse of the femoral head with joint destruction. ONFH is also known as avascular necrosis or ischemic necrosis because of its pathological features, and it is thought to be caused by ischemia. Osteonecrosis caused by trauma (dislocation and/or fracture), decompression sickness, and radiation is defined as secondary osteonecrosis. Systemic steroid administration, habitual alcohol intake, and smoking are factors associated with ONFH, which have been addressed in this guideline; however, the mechanism of ONFH occurrence has not yet been elucidated, and its causes are still unknown.
To standardize the medical treatment for ONFH, it is necessary to develop new clinical practice guidelines, addressing the most relevant management and intervention strategies based on recent literature. In 2015, the working group for ONFH guidelines was organized mainly by the members of the Japanese Investigation Committee (JIC) for ONFH under the auspices of the Japanese Ministry of Health, Labour, and Welfare, and the Japanese Orthopaedic Association (JOA) established the development committee of clinical practice guidelines for ONFH in February 2018.