M12.049 ICD-10-CM Code: Chronic postrheumatic arthropathy [Jaccoud], unspecified hand
M12.049 maps to CMS-HCC V28 94. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Inflammatory polyarthropathies (M05-M14)
M12.049
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceChronic postrheumatic arthropathy [Jaccoud], unspecified hand
A chronic joint condition affecting the hand (side not specified) that develops after rheumatic fever, characterized by reversible joint deformities without permanent damage to the joint structures.
Buddy Insight
Chronic postrheumatic arthropathy of unspecified hand indicates Jaccoud's arthropathy as a complication of previous rheumatic fever, potentially causing significant functional impairment in hand activities and fine motor skills.
CMS-HCC V28
MappedHCC 94
Code-level coefficient reference
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 057
Code-level coefficient reference
ESRD/PACE
MappedHCC 40
Code-level coefficient reference
RXHCC
MappedHCC 83
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for M12.049. Check the code and parent instructions in the Code Book.
Excludes 2
Official- arthropathic psoriasis (L40.5-)Inherited from M00-M99
- certain conditions originating in the perinatal period (P04-P96)Inherited from M00-M99
- certain infectious and parasitic diseases (A00-B99)Inherited from M00-M99
- compartment syndrome (traumatic) (T79.A-)Inherited from M00-M99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from M00-M99
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from M00-M99
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from M00-M99
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from M00-M99
- neoplasms (C00-D49)Inherited from M00-M99
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from M00-M99
Related Codes
Includes
OfficialNo Includes notes are included in this display for M12.049. Check the code and parent instructions in the Code Book.
Excludes 1
Official- arthrosis (M15-M19)Inherited from M12
- cricoarytenoid arthropathy (J38.7)Inherited from M12
Code First
OfficialNo Code First sequencing instructions are included in this display for M12.049. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for M12.049. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for M12.049. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is M12.049 an HCC code?
Yes. M12.049 (Chronic postrheumatic arthropathy [Jaccoud], unspecified hand) maps to HCC 94, Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.268. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: M12.049 is billable and maps to V28 HCC 94, Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- M12.049
- Description
- Chronic postrheumatic arthropathy [Jaccoud], unspecified hand
- HCC (V28)
- HCC 94 — Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders
- RAF reference coefficient
- 0.268
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work M12.049 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for M12.049
For M12.049, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
M12.049 is the ICD-10-CM diagnosis code for chronic postrheumatic arthropathy [jaccoud], unspecified hand. A chronic joint condition affecting the hand (side not specified) that develops after rheumatic fever, characterized by reversible joint deformities without permanent damage to the joint structures. M12.049 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).
Under the CMS-HCC V28 risk adjustment model, M12.049 maps to Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders (HCC 94) with a source-labeled community, non-dual, aged reference coefficient of 0.268. No V24 mapping is shown for M12.049; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Use this code only when laterality cannot be determined from documentation. For M12.049, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for M12.049 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when laterality cannot be determined from documentation
- •Query provider if documentation indicates bilateral involvement, as separate codes for each side may be more appropriate
Clinical Significance
Chronic postrheumatic arthropathy of unspecified hand indicates Jaccoud's arthropathy as a complication of previous rheumatic fever, potentially causing significant functional impairment in hand activities and fine motor skills. This condition requires ongoing management while monitoring for cardiac complications associated with rheumatic heart disease.
Documentation Requirements
- ✓Established history of rheumatic fever
- ✓Hand involvement without laterality specification
- ✓Evidence of chronic, reversible joint deformity
- ✓Clinical signs consistent with postrheumatic arthropathy
- ✓Absence of erosive changes on joint imaging
- ✓Assessment of hand function and fine motor skills
- ✓Current cardiac status evaluation
- ✓Treatment response and functional outcomes