ICD-10/M19.91

M19.91 ICD 2026 Code: Primary osteoarthritis, unspecified site

M19.91 is the authoritative medical code for Primary osteoarthritis, unspecified site. This classification is used in medical billing and clinical recording to specify the clinical criteria for primary osteoarthritis, unspecified site (ICD-10-CM M19.91), ensuring healthcare documentation aligns with 2026 federal coding standards.

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Official Registry Overview & Definition

Primary osteoarthritis, unspecified site is a billable ICD-10-CM diagnosis code M19.91. Inclusion terms: Primary osteoarthritis NOS. Excludes1 (not coded here): polyarthritis M15.-. Excludes2 (not included here): arthrosis of spine M47.-; hallux rigidus M20.2; osteoarthritis of spine M47.-.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for M19.91 in the official ICD-10-CM tabular list.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Primary osteoarthritis NOS

Excludes1 — Not Coded Here

Conditions that can never be reported with this code; the two are mutually exclusive.

  • polyarthritis M15.-

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

  • arthrosis of spine M47.-
  • hallux rigidus M20.2
  • osteoarthritis of spine M47.-

Frequently Asked Questions (FAQ) & Clinical Guidance

What can't be coded together with M19.91?

Per official ICD-10-CM Excludes1 instructions, M19.91 must not be reported together with: polyarthritis (M15.-).

Can M19.91 be reported alongside related conditions?

Per official ICD-10-CM Excludes2 instructions, M19.91 and the following are not considered part of each other and may both be reported when both conditions are present: arthrosis of spine (M47.-); hallux rigidus (M20.2); osteoarthritis of spine (M47.-).

What conditions are included under M19.91?

Primary osteoarthritis, unspecified site includes: Primary osteoarthritis NOS.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M19.91 in its code family, with their registry titles.

  • M19 — Other and unspecified osteoarthritis
  • M19.0 — Primary osteoarthritis of other joints
  • M19.01 — Primary osteoarthritis, shoulder
  • M19.011 — Primary osteoarthritis, right shoulder
  • M19.012 — Primary osteoarthritis, left shoulder
  • M19.019 — Primary osteoarthritis, unspecified shoulder
  • M19.02 — Primary osteoarthritis, elbow
  • M19.021 — Primary osteoarthritis, right elbow
  • M19.022 — Primary osteoarthritis, left elbow
  • M19.029 — Primary osteoarthritis, unspecified elbow

View all 40 codes in the M19 family

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Osteoarthritis, primary