Oth unil sec osteoarth of first carpometacarp joint, r hand

This code signifies degenerative joint disease affecting the first carpometacarpal (CMC) joint of the right hand, which is secondary to another underlying condition. This osteoarthritis is unilateral, meaning it affects only the right thumb base, and is not classified as post-traumatic or primary.

Apply this code when documentation specifies secondary osteoarthritis of the right first CMC joint, without a history of trauma to that specific joint. This diagnosis is typically supported by imaging reports (e.g., X-ray) showing degenerative changes and physician notes indicating a secondary cause, such as inflammatory arthritis or metabolic disorders.

• Ensure the documentation clearly states "secondary" osteoarthritis and specifies the right hand.
• Do not use this code if the osteoarthritis is primary (M18.11) or post-traumatic (M18.31).
• Code the underlying secondary condition first, if applicable, followed by this code.