osteonecrosis

noun
os·​teo·​ne·​cro·​sis | \ ˌäs-tē-ō-nə-ˈkrō-səs How to pronounce osteonecrosis (audio) \
plural osteonecroses\ -​ˌsēz How to pronounce osteonecroses (audio) \

Medical Definition of osteonecrosis

: necrosis of bone especially : avascular necrosis