title: The pathogenesis of nontraumatic osteonecrosis.
abstract: Nontraumatic osteonecrosis continues to be a challenging problem causing debilitating major joint diseases. The etiology is multifactorial, but steroid- and alcohol-induced osteonecrosis contribute to more than two thirds of all cases with genetic risk factors playing an important role in many other cases, especially when they contribute to hypercoagulable states. While the exact mechanisms remain elusive, many new insights have emerged from research in the last decade that have given us a clearer picture of the pathogenesis of nontraumatic osteonecrosis of the femoral head. Progression to end stage osteonecrosis of the femoral head appears to be related to four main factors: interactions involving the differentiation pathway of osteoprogenitor cells that promote adipogenesis, decreased angiogenesis, direct suppression of osteogenic gene expression and proliferation of bone marrow stem cells, and genetic anomalies or other diseases that promote hypercoagulable states.
authors.affiliation: Department of Orthopaedic Surgery, University of Virginia School of Medicine, 400 Ray C. Hunt Drive, Box 800159, Charlottesville, VA 22908, USA.
authors.forename: Jesse
authors.initials: J
authors.lastname: Seamon
authors.forename: Thomas
authors.initials: T
authors.lastname: Keller
authors.forename: Jamal
authors.initials: J
authors.lastname: Saleh
authors.forename: Quanjun
authors.initials: Q
authors.lastname: Cui