ICD-10-CM 2027
ICD-10 code for monoarthritis
From the official ICD-10-CM alphabetic index entry “Monoarthritis”. Page updated September 29, 2026.
About coding monoarthritis
The ICD-10-CM code for monoarthritis is M13.10 (Monoarthritis, not elsewhere classified, unspecified site). The official index lists 8 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M13.10.
Within M13.1, choose M13.10 (unspecified site) only when documentation doesn't support a more specific option: shoulder (M13.11), elbow (M13.12), wrist (M13.13), hand (M13.14), hip (M13.15), knee (M13.16) and ankle and foot (M13.17).
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 monoarthritis codes (official index)
- ankle M13.17 — Monoarthritis, not elsewhere classified, ankle and foot
- elbow M13.12 — Monoarthritis, not elsewhere classified, elbow
- foot joint M13.17 — Monoarthritis, not elsewhere classified, ankle and foot
- hand joint M13.14 — Monoarthritis, not elsewhere classified, hand
- hip M13.15 — Monoarthritis, not elsewhere classified, hip
- knee M13.16 — Monoarthritis, not elsewhere classified, knee
- shoulder M13.11 — Monoarthritis, not elsewhere classified, shoulder
- wrist M13.13 — Monoarthritis, not elsewhere classified, wrist
Common questions about monoarthritis ICD-10 codes
What is the ICD-10 code for monoarthritis?
- M13.10 — Monoarthritis, not elsewhere classified, unspecified site. More specific codes apply when the documentation supports them: M13.17, M13.12, M13.17, M13.14 and others below.
What is the ICD-10 code for ankle monoarthritis?
- M13.17 — Monoarthritis, not elsewhere classified, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for elbow monoarthritis?
- M13.12 — Monoarthritis, not elsewhere classified, elbow (header code; choose a more specific subcode).
What is the ICD-10 code for foot joint monoarthritis?
- M13.17 — Monoarthritis, not elsewhere classified, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for hand joint monoarthritis?
- M13.14 — Monoarthritis, not elsewhere classified, hand (header code; choose a more specific subcode).
What is the ICD-10 code for hip monoarthritis?
- M13.15 — Monoarthritis, not elsewhere classified, hip (header code; choose a more specific subcode).
What is the ICD-10 code for knee monoarthritis?
- M13.16 — Monoarthritis, not elsewhere classified, knee (header code; choose a more specific subcode).
Is M13.10 billable?
- Yes. M13.10 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M13.10 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M13.10 as a principal diagnosis.
Is M13.10 a CC or MCC?
- No. M13.10 is neither a CC nor an MCC under MS-DRG v44.0.