圧潰を生じた特発性脛骨内顆骨壊死の1例

Spontaneous Osteonecrosis of the Medial Tibial Plateau with Collapse. Case Report

　73歳女性の圧潰を生じた特発性脛骨骨壊死(SONTP)の1例を経験した．SONTPは特発性膝関節骨壊死の中でも比較的稀であり，さらに圧潰を生じた報告例は少ない．本症例ではMRIでLonner分類Type Dと診断し，早期に人工膝関節置換術(TKA)を行った．術後1年の時点で良好な結果を得たので報告する．

　We report a case of spontaneous osteonecrosis of the tibial plateau (SONTP) complicated by collapse of the plateau in an otherwise healthy 73-year-old woman.　SONTP is a relatively rare form of osteonecrosis of the knee, and complication by collapse is even rarer.　We diagnosed this case as type D in the Lonner classification based on the MRI findings and performed total knee arthroplasty (TKA).　Excellent results have been obtained as of 1 year after surgery.