M02.861 Other reactive arthropathies, right knee

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from M02 Postinfective and reactive arthropathies

Excludes1 (never code together)

• Behçet's disease (M35.2)
• direct infections of joint in infectious and parasitic diseases classified elsewhere (M01.-)
• postmeningococcal arthritis (A39.84)
• mumps arthritis (B26.85)
• rubella arthritis (B06.82)
• syphilis arthritis (late) (A52.77)
• rheumatic fever (I00)
• tabetic arthropathy [Charcôt's] (A52.16)

Code first

• underlying disease, such as:
• congenital syphilis [Clutton's joints] (A50.5)
• enteritis due to Yersinia enterocolitica (A04.6)
• infective endocarditis (I33.0)
• viral hepatitis (B15-B19)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
• CMS-HCC V22: HCC 39 — Bone/Joint/Muscle Infections/Necrosis
• ESRD V24: HCC 39

MS-DRG index

Defines the logic of DRG(s) 548-550 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 711.46 Arthropathy associated with other bacterial diseases, lower leg (approximate)
• 711.56 Arthropathy associated with other viral diseases, lower leg (approximate)
• 711.86 Arthropathy associated with other infectious and parasitic diseases, lower leg (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Manifestation codes as principal diagnosis: Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and are not allowed as principal diagnosis.

Code annotations containing back-references to M02.861

Back-references to M02

• Type 1 Excludes: M01 Direct infections of joint in infectious and parasitic diseases classified elsewhere ("postinfective arthropathy (M02.-)")

Nearby codes

• M02.85 Other reactive arthropathies, hip
• M02.851 Other reactive arthropathies, right hip
• M02.852 Other reactive arthropathies, left hip
• M02.859 Other reactive arthropathies, unspecified hip
• M02.86 Other reactive arthropathies, knee
• M02.861 Other reactive arthropathies, right knee (this code)
• M02.862 Other reactive arthropathies, left knee
• M02.869 Other reactive arthropathies, unspecified knee
• M02.87 Other reactive arthropathies, ankle and foot
• M02.871 Other reactive arthropathies, right ankle and foot
• M02.872 Other reactive arthropathies, left ankle and foot