🧬 ICD-10 CM M86.68 — Other Chronic Osteomyelitis, Other Site
Billable Code Confirmed
ICD-10 CM M86.68 is a fully specified, billable 6-character ICD-10-CM code for FY2026.⁴ The 6th character “8” designates “other site” — a bone or bone group not separately captured by the shoulder, humerus, radius/ulna, hand, thigh, tibia/fibula, or ankle/foot subcategories under M86.6-.
Non-Billable Parent Codes
M86 — Osteomyelitis (unspecified acuity/chronicity/site) requires additional characters and is never billable.⁵ M86.6 — Other chronic osteomyelitis (no site) is a 4-character category that requires a 5th–6th character for site and is not billable on its own.
Clinical Context
“Other site” is selected when documentation confirms chronic osteomyelitis but the affected bone doesn’t map to shoulder, humerus, radius/ulna, hand, femur/thigh, tibia/fibula, or ankle/foot — for example, ribs, clavicle, pelvis (outside vertebral exclusion), sternum, or skull/facial bones outside the orbit/petrous bone exclusions.
Code Classification
This is a diagnosis code (ICD-10-CM), not a procedure code. It does not itself capture debridement, sequestrectomy, or hardware removal — those require separate CPT reporting.
🔍 Code Description
Other chronic osteomyelitis represents a persistent, low-grade bone infection lasting beyond the acute/subacute phase, typically without an active draining sinus tract (which would instead point to M86.40-series codes). It’s frequently a sequela of an open fracture, prior surgical site infection, hardware-associated infection, or hematogenous seeding that failed to fully resolve, and pathology may show sequestrum formation, involucrum, or sclerotic bony changes on imaging.
ICD-10 CM M86.68 specifically applies when the infected bone doesn’t fall into one of the named anatomic subcategories under M86.6-. Common documentation triggers include osteomyelitis of the rib, clavicle, sternum, pelvis (non-vertebral), or craniofacial bones outside the orbital and petrous exclusions. Coders should confirm site specificity in the operative note or imaging report before defaulting to “other site,” since a more precise subcategory code may actually apply.
🌳 Code Tree / Hierarchy
M86 Osteomyelitis ❌ Non-billable
│
├── M86.0 Acute hematogenous osteomyelitis ❌ Non-billable (requires site)
├── M86.1 Other acute osteomyelitis ❌ Non-billable (requires site)
│
├── M86.6 Other chronic osteomyelitis ❌ Non-billable (requires site)
│ │
│ ├── M86.60 Other chronic osteomyelitis, unspecified site ✅ Billable
│ ├── M86.65 Other chronic osteomyelitis, thigh ❌ Non-billable (requires laterality)
│ ├── M86.67 Other chronic osteomyelitis, ankle and foot ❌ Non-billable (requires laterality)
│ ├── M86.68 Other chronic osteomyelitis, other site ◀ THIS CODE ✅ Billable
│ └── M86.69 Other chronic osteomyelitis, multiple sites ✅ Billable
│
└── M86.9 Osteomyelitis, unspecified ✅ BillableSite Specificity Matters
Payers scrutinize “other site” (M86.68) claims because it’s a catch-all — confirm the operative report doesn’t actually document a named bone (e.g., humerus, tibia) that would push you to a more specific subcategory code instead.
Tip
✅ Includes
Chronic bone infection at a site not separately classified elsewhere under M86.6- (e.g., rib, clavicle, sternum, pelvis excluding vertebra, craniofacial bone excluding orbit/petrous bone). Sequestrum of the affected “other” bone is included under this code per index cross-reference.
❌ Excludes
Excludes 1
- B67.2 — Osteomyelitis due to echinococcus (a distinct parasitic etiology, coded instead of, not with, M86.68)
- A54.43 — Gonococcal osteomyelitis (specific organism code supersedes M86.68)
- A02.24 — Salmonella osteomyelitis (specific organism code supersedes M86.68)
Danger
Excludes 2
- H05.0- — Osteomyelitis of orbit (may be coded alongside M86.68 if the patient has a separate, concurrent chronic osteomyelitis at another “other” site)
- H70.2- — Osteomyelitis of petrous bone (separately codeable if a distinct concurrent infection exists)
- M46.2- — Osteomyelitis of vertebra (separately codeable if a distinct concurrent infection exists)
📋 Clinical Overview
Chronic vs. Acute vs. Subacute Osteomyelitis
Chronicity is a documentation-driven distinction that changes both the code category and DRG assignment — always verify the provider has explicitly characterized the infection as chronic rather than assuming based on duration alone.
| Feature | M86.68 | Related M86.18 | Related M86.9 |
|---|---|---|---|
| Acuity | Chronic, persistent infection | Acute, other site | Unspecified acuity |
| Site specificity | Other/unspecified named subcategory | Other site (acute) | Site not documented |
| Typical clinical picture | Low-grade, indolent, sequestrum/sclerosis on imaging | Rapid onset, systemic signs, elevated inflammatory markers | Insufficient documentation to classify |
Important
CDI should query when documentation says “osteomyelitis” without acuity or site — defaulting to M86.9 loses both severity and HCC specificity that M86.68 (or a more precise site code) would capture.
Manifestations & Symptom Burden
- Localized bone pain, often worse with weight-bearing or palpation at the affected site
- Low-grade fever or malaise in chronic (vs. high fever in acute) presentations
- Non-healing wound overlying the infected bone, with or without visible sequestrum
- Elevated ESR/CRP that may persist despite antibiotic therapy
- Radiographic sclerosis, cortical thickening, or sequestrum/involucrum on imaging
Tip
Code each documented manifestation separately if it meets reporting criteria (e.g., a non-healing surgical wound may warrant an additional complication code) rather than assuming it’s bundled into M86.68.
💰 HCC Risk Adjustment
| Model | HCC | Label | Base RAF (Community, Non-Dual, Aged) |
|---|---|---|---|
| CMS-HCC V28 | HCC 92 | Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis | ≈0.479¹ |
| CMS-HCC V24 (legacy) | HCC 39 | Bone/Joint/Muscle Infections/Necrosis | ≈0.401¹ |
ICD-10 CM M86.68 is HCC-mapped, so annual capture matters for risk adjustment revenue. Because chronic osteomyelitis can smolder for years, payers expect fresh MEAT each calendar year — active wound care, repeat imaging, antibiotic suppression therapy, or surgical intervention — not simply a carried-forward problem list entry.
🏥 MS-DRG Assignment
| DRG | Title | FY2026 Relative Weight | GMLOS |
|---|---|---|---|
| 539 | Osteomyelitis with MCC | 1.9697³ | 6.20 days³ |
| 540 | Osteomyelitis with CC | — | — |
| 541 | Osteomyelitis without CC/MCC | — | — |
ICD-10 CM M86.68 as principal diagnosis groups to MDC 08 medical DRGs 539/540/541.² If an OR procedure is performed during the same stay (excisional debridement, sequestrectomy, bone excision, hardware removal), the encounter is redirected to a surgical DRG partition instead — sequencing and procedure coding must align, or the claim will group incorrectly. No NCD is published specifically for M86.68; verify Noridian JE/JF LCD/LCA coverage for adjunctive therapies (e.g., hyperbaric oxygen for refractory chronic osteomyelitis) before billing.
🔗 Related ICD-10-CM Codes
Same M86.6 subcategory (site-specific): M86.60, M86.61, M86.62, M86.63, M86.64, M86.65, M86.66, M86.671, M86.672, M86.69
Related osteomyelitis presentations: M86.18 (other acute osteomyelitis, other site), M86.9 (osteomyelitis, unspecified), M89.7- (major osseous defect — use additional code if applicable), M46.20 (osteomyelitis of vertebra, unspecified — Excludes2)
🛠️ Commonly Associated CPT Codes
- 11044 — Debridement, bone (includes overlying skin/subcutaneous tissue/muscle/fascia); first 20 sq cm — primary surgical treatment for exposed infected bone.⁶
- 11047 — Debridement, bone; each additional 20 sq cm (add-on to 11044, cannot stand alone).⁷
- 20005 — Incision and drainage of soft tissue abscess, subfascial — for deep abscess drainage overlying infected bone.
- 20999 — Unlisted procedure, musculoskeletal system, other site — used when no site-specific bone excision/sequestrectomy code applies.
- 20680 — Removal of deep implant (e.g., infected hardware contributing to chronic osteomyelitis); modifier -79 if unrelated to a recent global-period procedure.⁸
- 76880 — Ultrasound, complete joint, real-time — occasionally used for abscess localization pre-procedure.
- 77080 — DXA bone density study — not for osteomyelitis diagnosis itself, but sometimes ordered to assess bone integrity pre-surgical planning.
🏷️ Modifier Reference
| Modifier | Name | When to Apply |
|---|---|---|
| -50 | Bilateral | Apply if a bilaterally paired “other site” bone (e.g., bilateral ribs or bilateral clavicles) is debrided in the same session and the CPT code doesn’t already specify laterality. |
| -25 | Significant, Separately Identifiable E/M | Apply when a significant, separately identifiable E/M service is performed the same day as a minor debridement procedure. |
| -24 | Unrelated E/M During Postop Period | Apply when an E/M visit during a global period is unrelated to the original osteomyelitis procedure. |
| -51 | Multiple Procedures | Apply when multiple distinct procedures (e.g., debridement plus hardware removal) are performed in the same session, subject to payer bundling edits. |
| -59 | Distinct Procedural Service | Apply when two procedures that might otherwise bundle (e.g., debridement at two clearly separate “other” sites) are truly distinct and not part of the same operative field. |
| -52 | Reduced Services | Apply when a planned debridement is reduced in scope intraoperatively. |
| -53 | Discontinued Procedure | Apply when the procedure is started but discontinued due to patient risk. |
| -58 | Staged/Related Procedure | Apply for a planned, staged return to the OR for further debridement of the same chronic osteomyelitis. |
| -78 | Unplanned Return to OR | Apply for an unplanned return to the OR for a related complication during the global period. |
| -79 | Unrelated Procedure During Postop Period | Apply when hardware removal or a new procedure during a global period is unrelated to the prior surgery. |
NCCI Bundling Considerations
CPT 11044 and 11047 are frequently edited against concurrent I&D or excision codes at the same anatomic site — verify NCCI Procedure-to-Procedure edits before appending modifier -59, and confirm medical necessity documentation supports each reported code as distinct rather than incidental to the primary debridement.
🔬 ICD-10-PCS Crosswalk
PCS codes are 7 characters (Section–Body System–Root Operation–Body Part–Approach–Device–Qualifier), so there is no single generic “other site” PCS code — the body system character changes depending on which bone is documented, and coders must pull the exact body part value from the operative note.
- 0PB00ZZ — Excision of sternum, open approach, no device, no qualifier — body system P (Upper Bones) applies because sternum, ribs, and clavicle are classified under Upper Bones, not Lower Bones; use this root operation for sequestrectomy/partial bone excision without complete removal.⁹
- 0P500ZZ — Destruction of sternum, open approach — appropriate when infected bone is fulgurated/ablated rather than physically excised; body part character changes to 1 (Ribs, 1–2), 2 (Ribs, 3 or more), or 9/B (Clavicle, Right/Left) if the “other” site is a rib or clavicle instead of the sternum.⁹
- 0P900ZZ — Drainage of sternum, open approach, no device — for open drainage of an associated bone/subperiosteal abscess; swap the device character to 0 (Drainage Device) if a drain is left in place.⁹
- If the “other site” is the pelvis, the body system character changes to Q (Lower Bones) instead of P — e.g., excision of pelvic bone would use body system Q, not P, since Sternum/Ribs/Clavicle (Upper Bones) and Pelvic Bone (Lower Bones) fall under different PCS body systems despite both being non-M86.6-named “other” sites.
Body System Depends on the Bone
Skull/facial “other” sites (outside the orbit/petrous exclusions) fall under body system N (Head and Facial Bones), not P or Q — always confirm the exact bone before assigning the body system character, since choosing the wrong one produces an invalid or incorrect PCS code entirely.
💊 Coding Scenarios and Examples
Example 1
Clinical Scenario:
Patient admitted with chronic draining wound over the sternum, 8 months post-sternotomy, with imaging confirming chronic osteomyelitis of the sternum without an active sinus tract. Surgeon performs bedside debridement of a 12 sq cm area down to bone.
| Field | Code | Rationale |
|---|---|---|
| CPT | 11044 | Sternum is not a named M86.6- subcategory, so debridement extending to bone is captured here; area is under 20 sq cm, no add-on needed. |
| PDx | M86.68 | Sternum falls under “other site” since it’s not one of the M86.6- named subcategories. |
Tip
Example 2
Clinical Scenario:
Patient with chronic clavicular osteomyelitis after a prior open reduction internal fixation undergoes debridement of a 25 sq cm area plus removal of retained infected hardware in the same operative session.
| Field | Code | Rationale |
|---|---|---|
| CPT | 11044 | Initial 20 sq cm of bone debridement. |
| CPT 2 | 11047 | Add-on for the additional 5 sq cm of bone debridement beyond the first 20. |
| PDx | M86.68 | Clavicle is not separately named under M86.6, so “other site” applies. |
Tip
Hardware removal (CPT 20680) should be reported as a third line if performed — don’t let it get absorbed into the debridement codes; confirm operative documentation separately identifies the hardware removal.
Example 3
Clinical Scenario:
Patient with chronic rib osteomyelitis following a prior thoracotomy presents for surgical debridement; intraoperatively the surgeon discontinues the procedure early due to hemodynamic instability, having debrided less than the planned area.
| Field | Code | Rationale |
|---|---|---|
| CPT | 11044--53 | Discontinued procedure modifier applies since the planned scope wasn’t completed due to patient risk. |
| PDx | M86.68 | Rib is not a named M86.6 subcategory. |
Tip
Document clearly why the procedure was discontinued to support modifier -53; payers may request the operative note before reimbursing at the reduced/discontinued rate.
⚠️ Coding Pitfalls and Tips
- Pitfall 1: Defaulting to M86.68 without confirming the bone truly isn’t one of the named M86.6- subcategories (shoulder, humerus, radius/ulna, hand, thigh, tibia/fibula, ankle/foot); Tips: Always cross-check the operative or imaging report against the full M86.6 subcategory list first.
- Pitfall 2: Coding both M86.68 and an organism-specific code (A54.43, B67.2, A02.24) together; Tips: These are Excludes1 — report only the organism-specific code when culture results confirm gonococcus, echinococcus, or salmonella.
- Pitfall 3: Missing the “use additional code” instruction for major osseous defect (M89.7-) when a significant bone defect results from the chronic infection; Tips: Review the note for documented bone loss or defect requiring reconstruction.
- Pitfall 4: Confusing “other chronic osteomyelitis” (M86.6-) with “chronic osteomyelitis with draining sinus” (M86.4-); Tips: Confirm whether an active sinus tract is documented before finalizing the subcategory.
- Pitfall 5: Letting M86.68 group to a medical DRG (539/540/541) when an OR procedure was actually performed and should redirect the claim to a surgical DRG; Tips: Verify all procedure codes are captured and sequenced correctly before final DRG assignment.
- Pitfall 6: Failing to re-document MEAT annually for HCC capture on a chronic, indolent infection; Tips: Confirm the current encounter shows active monitoring, evaluation, assessment, or treatment — not just a carried-forward problem list entry.
📚 Sources
1. HCC Buddy. *CMS-HCC V28/V24 Risk Adjustment Mapping — M86.6x Series.* 2026. https://hccbuddy.com/icd10/M86.671 2. CMS. *ICD-10-CM/PCS MS-DRG Definitions Manual, Version 43.0 (FY2026).* Centers for Medicare & Medicaid Services; 2025-2026. 3. ICD List. *MS-DRG 539 — Osteomyelitis with MCC, Version 43.0.* 2025-2026. https://icdlist.com/icd-10/drg/539 4. ICD10Data.com. *2026 ICD-10-CM Diagnosis Code M86.68.* 2025-2026. https://www.icd10data.com/ICD10CM/Codes/M00-M99/M86-M90/M86-/M86.68 5. ICD10Data.com. *2026 ICD-10-CM Diagnosis Code M86.* 2025-2026. https://www.icd10data.com/ICD10CM/Codes/M00-M99/M86-M90/M86-/M86 6. StarsPMB. *What is CPT 11044? How to Bill for Debridement Correctly.* 2025. https://starspmb.com/cpt-code-11044/ 7. SummitRCM. *CPT 11047 Add-On Code Guide for Bone Debridement.* 2025. https://summitrcm.com/blog/cpt-11047-add-on-code-guide-for-bone-debridement 8. Transcure. *Podiatry CPT Codes 2026 Cheat Sheet.* 2026. https://transcure.net/medical-billing/podiatry-cpt-codes/ 9. CMS. *ICD-10-PCS Tables — Upper Bones (0P) and Lower Bones (0Q) Body Systems.* Centers for Medicare & Medicaid Services; 2024-2026.Sources listed above correspond to superscript citations throughout this note. Verify all Medicare payment figures against your current CMS PFS Lookup tool and applicable MAC LCD prior to claim submission. Please use the latest AAPC/AHIMA Coding Books to verify each code within this note.