Idiopathic osteonecrosis (avascular necrosis of bone) where no causative factor has been identified and the specific bone site is not documented or determinable.
Verified May 8, 2026 · 5 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 9
- Region
- General
Documentation tips
What should appear in the chart to support M87.00.
Source · Editorial brief grounded in 5 cited references ↓
- Specify the affected bone by name in every encounter note — 'osteonecrosis' alone without a site will force M87.00 and invite a specificity query from payers.
- Distinguish the etiology: document 'idiopathic' or 'no known cause' explicitly to support M87.0x versus drug-induced (M87.1x) or post-traumatic (M87.2x) subcategories.
- Record imaging findings that confirm AVN — MRI signal changes, plain film subchondral collapse, or CT evidence of sclerosis — to substantiate the diagnosis code and link it to procedure codes.
- If a major osseous defect is present (e.g., significant structural bone loss), document it separately so the additional code from M89.7– can be assigned per tabular instruction.
- For multi-bone involvement, list each affected bone by side and name so M87.09 (multiple sites) or individual lateralized codes can be applied instead of defaulting to M87.00.
Related CPT procedures
Procedure codes commonly billed with M87.00. Linking the right diagnosis to the right procedure is what establishes medical necessity.
Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis
Common coding pitfalls
The recurring mistakes coders make with M87.00 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Using M87.00 when a specific bone is documented — any identifiable site has a more specific code in the M87.01–M87.09 range; M87.00 should not be used when laterality and bone are known.
- Coding M87.00 for drug-induced or corticosteroid-related AVN — that presentation belongs under M87.1x (osteonecrosis due to drugs), not the idiopathic subcategory.
- Applying M87.00 to pediatric patients with juvenile osteonecrosis — the Excludes1 note at M87 prohibits this; juvenile osteonecrosis codes to M91–M92.
- Designating the site as the joint rather than the bone — per Chapter 13 guidelines, AVN is coded to the bone even when the necrosis is at the bone's joint-facing end.
- Omitting the supplemental M89.7– code when a major osseous defect coexists — the 'Use additional code' instruction at M87 is not optional when the condition is documented.
Clinical context
Source · Editorial summary grounded in 5 cited references ↓
M87.00 is the fallback code within the M87.0 subcategory when a provider documents idiopathic aseptic necrosis — also called avascular necrosis (AVN) or osteonecrosis — but has not specified which bone is affected. Because M87 includes avascular necrosis of bone by definition, you do not need a separate AVN code when using M87.00. The Excludes1 note at the M87 category level bars using this code for juvenile osteonecrosis (M91–M92) or osteochondropathies (M90–M93) — those are mutually exclusive.
In orthopedic practice, idiopathic AVN most commonly presents in the femoral head, humeral head, or knee. When the affected bone is documented, use the specific site code (e.g., M87.051 for right femur, M87.011 for right shoulder). M87.00 is only appropriate when the documentation genuinely fails to identify any bone — which should be rare after imaging. If AVN is drug-induced (e.g., corticosteroids), code instead to M87.1x; if post-traumatic, to M87.2x.
Per FY2026 ICD-10-CM guidelines (Chapter 13), site designation for AVN is the bone, not the adjacent joint — even when the necrosis occurs at a joint-adjacent end of the bone. If a major osseous defect is also present, add a code from M89.7– per the 'Use additional code' instruction at the M87 category level. For multi-site involvement without a documented single unspecified bone, consider M87.09 (multiple sites) rather than M87.00.
Sibling codes
Other billable codes under M87.0 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01When is M87.00 actually correct to use?
02Can I use M87.00 for AVN of the femoral head if the note says 'hip AVN'?
03Does M87.00 require a 7th-character extension?
04How do I code corticosteroid-induced AVN?
05Should I add a code for the imaging study when billing M87.00?
06What is the difference between M87.00 and M87.09?
07Is a major osseous defect code always required with M87.00?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026 (FY2026, effective Oct 1, 2025)
- 02cms.govhttps://www.cms.gov/files/document/fy-2026-icd-10-cm-coding-guidelines.pdf
- 03icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M86-M90/M87-/M87.00
- 04aapc.comhttps://www.aapc.com/codes/icd-10-codes/M87.00
- 05aapc.comhttps://www.aapc.com/codes/icd-10-codes/M87.0
Mira AI Scribe
Mira captures the affected bone name, laterality, etiology descriptor (idiopathic vs. drug-related vs. post-traumatic), imaging modality and findings (MRI signal, subchondral collapse, Ficat-Arlet or ARCO stage), and any osseous defect — preventing a drop to M87.00 when a specific site code exists and blocking an audit flag for unspecified-site AVN in a patient with available imaging.
See how Mira captures M87.00 documentation