ICD-10-CM 2027
ICD-10 code for intermittent hydrarthrosis
From the official ICD-10-CM alphabetic index entry “Hydrarthrosis › intermittent”. Page updated September 29, 2026.
About coding intermittent hydrarthrosis
The ICD-10-CM code for intermittent hydrarthrosis is M12.40 (Intermittent hydrarthrosis, unspecified site). The official index lists 10 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M12.40.
Within M12.4, choose M12.40 (unspecified site) only when documentation doesn't support a more specific option: shoulder (M12.41), elbow (M12.42), wrist (M12.43), hand (M12.44), hip (M12.45), knee (M12.46), ankle and foot (M12.47), other site (M12.48) and 1 more.
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 intermittent hydrarthrosis codes (official index)
- ankle M12.47 — Intermittent hydrarthrosis, ankle and foot
- elbow M12.42 — Intermittent hydrarthrosis, elbow
- foot joint M12.47 — Intermittent hydrarthrosis, ankle and foot
- hand joint M12.44 — Intermittent hydrarthrosis, hand
- hip M12.45 — Intermittent hydrarthrosis, hip
- knee M12.46 — Intermittent hydrarthrosis, knee
- multiple site M12.49 — Intermittent hydrarthrosis, multiple sites
- shoulder M12.41 — Intermittent hydrarthrosis, shoulder
- specified joint NEC M12.48 — Intermittent hydrarthrosis, other site
- wrist M12.43 — Intermittent hydrarthrosis, wrist
Common questions about intermittent hydrarthrosis ICD-10 codes
What is the ICD-10 code for intermittent hydrarthrosis?
- M12.40 — Intermittent hydrarthrosis, unspecified site. More specific codes apply when the documentation supports them: M12.47, M12.42, M12.47, M12.44 and others below.
What is the ICD-10 code for ankle intermittent hydrarthrosis?
- M12.47 — Intermittent hydrarthrosis, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for elbow intermittent hydrarthrosis?
- M12.42 — Intermittent hydrarthrosis, elbow (header code; choose a more specific subcode).
What is the ICD-10 code for foot joint intermittent hydrarthrosis?
- M12.47 — Intermittent hydrarthrosis, ankle and foot (header code; choose a more specific subcode).
What is the ICD-10 code for hand joint intermittent hydrarthrosis?
- M12.44 — Intermittent hydrarthrosis, hand (header code; choose a more specific subcode).
What is the ICD-10 code for hip intermittent hydrarthrosis?
- M12.45 — Intermittent hydrarthrosis, hip (header code; choose a more specific subcode).
What is the ICD-10 code for knee intermittent hydrarthrosis?
- M12.46 — Intermittent hydrarthrosis, knee (header code; choose a more specific subcode).
Is M12.40 billable?
- Yes. M12.40 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M12.40 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M12.40 as a principal diagnosis.
Is M12.40 a CC or MCC?
- No. M12.40 is neither a CC nor an MCC under MS-DRG v44.0.