ICD-10-CM 2027
ICD-10 code for deformans osteitis
From the official ICD-10-CM alphabetic index entry “Osteitis › deformans”. Page updated September 29, 2026.
About coding deformans osteitis
The ICD-10-CM code for deformans osteitis is M88.9 (Osteitis deformans of unspecified bone). The official index lists 25 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M88.9.
Within M88, choose M88.9 (unspecified bone) only when documentation doesn't support a more specific option: skull (M88.0), vertebrae (M88.1) and other bones (M88.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 553 (Bone Diseases and Arthropathies with MCC, relative weight 1.2494) and DRG 554 (Bone Diseases and Arthropathies without MCC, relative weight 0.8331), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific deformans osteitis codes (official index)
- in (due to)
- malignant neoplasm of bone (see also, Neoplasm, malignant, by site) C41.9 — Malignant neoplasm of bone and articular cartilage, unspecified
- neoplastic disease D49.9 — Neoplasm of unspecified behavior of unspecified site
- carpus D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- clavicle D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- femur D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- fibula D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- finger D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- humerus D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- ilium D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- ischium D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- metacarpus D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- metatarsus D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- multiple sites D49.89 — Neoplasm of unspecified behavior of other specified sites
- neck D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- pubic ramus
- radius D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- rib D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- scapula D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- skull D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- tarsus D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- tibia D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- toe D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- ulna D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- vertebra D49.2 — Neoplasm of unspecified behavior of bone, soft tissue, and skin
- skull M88.0 — Osteitis deformans of skull
- specified NEC
- vertebra M88.1 — Osteitis deformans of vertebrae
Common questions about deformans osteitis ICD-10 codes
What is the ICD-10 code for deformans osteitis?
- M88.9 — Osteitis deformans of unspecified bone. More specific codes apply when the documentation supports them: C41.9, D49.9, D49.2, D49.2 and others below.
What is the ICD-10 code for skull deformans osteitis?
- M88.0 — Osteitis deformans of skull.
What is the ICD-10 code for vertebra deformans osteitis?
- M88.1 — Osteitis deformans of vertebrae.
Is M88.9 billable?
- Yes. M88.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M88.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M88.9 as a principal diagnosis.
Is M88.9 a CC or MCC?
- No. M88.9 is neither a CC nor an MCC under MS-DRG v44.0.