Oth unil sec osteoarth of first carpometacarp joint, l hand

This code signifies a degenerative joint disease affecting the base of the thumb on the left hand, specifically the joint between the trapezium bone and the first metacarpal. It indicates that the osteoarthritis is secondary to another underlying condition or injury, rather than being primary (idiopathic), and affects only the left hand.

Use this code for patients diagnosed with osteoarthritis of the left first carpometacarpal joint where the etiology is identified as secondary (e.g., post-traumatic, inflammatory, or metabolic). Documentation should clearly specify the left hand, the first carpometacarpal joint, and the secondary nature of the osteoarthritis.

• Ensure documentation explicitly states "secondary" osteoarthritis and specifies the left hand.
• Do not confuse with primary osteoarthritis (M18.12) or osteoarthritis affecting other joints of the hand.
• Code any underlying condition causing the secondary osteoarthritis (e.g., fracture, inflammatory arthritis) as a primary diagnosis, if applicable, with this code as a secondary diagnosis.