Femoral head collapse rate among Japanese patients with pre-collapse osteonecrosis of the femoral head

Ryuta Asada, Hiroyasu Abe, Hidetoshi Hamada, Yusuke Fujimoto, Hyonmin Choe, Daisuke Takahashi, Shusuke Ueda, Yutaka Kuroda, Takaki Miyagawa, Kazuki Yamada, Takeyuki Tanaka, Juji Ito, Satoshi Morita, Michiaki Takagi, Tomonori Tetsunaga, Ayumi Kaneuji, Yutaka Inaba, Sakae Tanaka, Shuichi Matsuda, Nobuhiko SuganoHaruhiko Akiyama

Research output: Contribution to journalArticlepeer-review


Objective: In this study, we aimed to elucidate the relationship between the duration from diagnosis to femoral head collapse and the collapse rate among patients with pre-collapse osteonecrosis of the femoral head (ONFH). Methods: In this retrospective, observational, multicenter study, we analyzed 268 patients diagnosed with ONFH and classified them using the Japanese Investigation Committee classification. The primary endpoint was duration from the time of diagnosis to femoral head collapse for each type of ONFH. Results: The 12-, 24-, and 36-month collapse rates among participants were 0%, 0%, and 0% for type A, respectively; 0%, 2.0%, and 10.8% for type B, respectively; 25.5%, 40.8%, and 48.5% for type C-1, respectively; and 57.4%, 70.3%, and 76.7% for type C-2 ONFH, respectively. A comparison of unilateral and bilateral ONFH, using Kaplan–Meier survival curves demonstrated similar collapse rates. Conclusions: The lowest collapse rate was observed for ONFH type A, followed by types B, C-1, and C-2. Additionally, a direct association was observed between the collapse rate and location of the osteonecrotic lesion on the weight-bearing surface.

Original languageEnglish
JournalJournal of International Medical Research
Issue number6
Publication statusPublished - 2021


  • femoral head collapse
  • Japan
  • Kaplan–Meier survival analysis
  • observational study
  • Osteonecrosis
  • osteonecrotic lesion

ASJC Scopus subject areas

  • Biochemistry
  • Biochemistry, medical
  • Cell Biology


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