M19.91 Primary osteoarthritis, unspecified site

Billable ICD-10-CM code, FY2026.

Applicable to

• Primary osteoarthritis NOS

Applies from M19 Other and unspecified osteoarthritis

Excludes1 (never code together)

• polyarthritis (M15.-)

Excludes2 (not included here)

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

MS-DRG index

Defines the logic of DRG(s) 553-554 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 715.10 Osteoarthrosis, localized, primary, site unspecified (approximate)

Code annotations containing back-references to M19.91

Back-references to M19

• Type 1 Excludes: M12 Other and unspecified arthropathy ("arthrosis (M15-M19)")
• Type 1 Excludes: M13 Other arthritis ("arthrosis (M15-M19)")
• Type 1 Excludes: M13 Other arthritis ("osteoarthritis (M15-M19)")
• Type 1 Excludes: M13.8 Other specified arthritis ("osteoarthritis (M15-M19)")
• Type 1 Excludes: M15 Polyosteoarthritis ("bilateral involvement of single joint (M16-M19)")

Diagnosis Index entries for M19.91

• Osteoarthritis › primary

Nearby codes

• M19.272 Secondary osteoarthritis, left ankle and foot
• M19.279 Secondary osteoarthritis, unspecified ankle and foot
• M19.29 Secondary osteoarthritis, other specified site
• M19.9 Osteoarthritis, unspecified site
• M19.90 Unspecified osteoarthritis, unspecified site
• M19.91 Primary osteoarthritis, unspecified site (this code)
• M19.92 Post-traumatic osteoarthritis, unspecified site
• M19.93 Secondary osteoarthritis, unspecified site