Osteonecrosis in diseases classified elsewhere, ankle and foot

• underlying disease, such as:
• caisson disease (T70.3)
• hemoglobinopathy (D50-D64)

• arthropathic psoriasis (L40.5-)
• certain conditions originating in the perinatal period (P04-P96)
• certain infectious and parasitic diseases (A00-B99)
• compartment syndrome (traumatic) (T79.A-)
• complications of pregnancy, childbirth and the puerperium (O00-O9A)
• congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
• endocrine, nutritional and metabolic diseases (E00-E88)
• injury, poisoning and certain other consequences of external causes (S00-T88)
• neoplasms (C00-D49)
• symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition

postprocedural osteopathies (M96.-)

• osteochondritis, osteomyelitis, and osteopathy (in):
• cryptococcosis (B45.3)
• diabetes mellitus (E08-E13 with .69-)
• gonococcal (A54.43)
• neurogenic syphilis (A52.11)
• renal osteodystrophy (N25.0)
• salmonellosis (A02.24)
• secondary syphilis (A51.46)
• syphilis (late) (A52.77)