M18.9 Osteoarthritis of first carpometacarpal joint, unspecified

Billable ICD-10-CM code, FY2026.

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 715.34 Osteoarthrosis, localized, not specified whether primary or secondary, hand (approximate)
• 715.94 Osteoarthrosis, unspecified whether generalized or localized, hand (approximate)

Code annotations containing back-references to M18.9

Back-references to M18

• 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 M18.9

• Osteoarthritis › hand joint › first carpometacarpal joint

Nearby codes

• M18.4 Other bilateral secondary osteoarthritis of first carpometacarpal joints
• M18.5 Other unilateral secondary osteoarthritis of first carpometacarpal joint
• M18.50 Other unilateral secondary osteoarthritis of first carpometacarpal joint, unspecified hand
• M18.51 Other unilateral secondary osteoarthritis of first carpometacarpal joint, right hand
• M18.52 Other unilateral secondary osteoarthritis of first carpometacarpal joint, left hand
• M18.9 Osteoarthritis of first carpometacarpal joint, unspecified (this code)