A rare case of spontaneous osteonecrosis of knee (SONK) treated with osteochondral autologous transfer system (OATS)

Abstract

A 34 years old male presented with spontaneous onset of progressive left knee pain since 4 weeks which aggravated on strenuous activities with no history of trauma, steroids or alcohol intake. Local tenderness was elicited over joint line with normal xrays and MRI revealed diffuse subchondral oedema with crescent sign hypointense on T1 and hyperintense on T2 weighted images. Diagnosis of spontaneous osteonecrosis of knee (SONK) was made. He was initially managed conservatively with analgesics and calcium supplements with no improvement. So osteochondral autologous transfer system (OATS) surgery was performed. Patient reported dramatic improvement.