Osteonecrosis (ON) of the knee is a progressive disease that can lead to subchondral collapse and end-stage osteoarthritis
of the knee. Originally described as a single disease, it includes three different pathologic entities: spontaneous osteonecrosis
of the knee (SONK), secondary osteonecrosis of the knee, and post-arthroscopic osteonecrosis of the knee.
This article reviews the current literature of these three different conditions by describing their epidemiology, etiology and
pathogenesis, clinical presentations and radiographic findings. Various treatment option (e.g., core decompression, bone
grafting, stem cells implantation, tibial osteotomy and arthroplasty), available for each entities are reviewed.
