ICD-10-CM > M00-M99 > M86-M90 > M90 > M90.5 > M90.56 M90.56 Osteonecrosis in diseases classified elsewhere, lower leg Non-Billable/Non-Specific Codes M90.561Osteonecrosis in diseases classified elsewhere, right lower legM90.562Osteonecrosis in diseases classified elsewhere, left lower legM90.569Osteonecrosis in diseases classified elsewhere, unspecified lower leg