M18.3Unilateral post-traumatic osteoarthritis of first carpometacarpal joint

M18.3 is the ICD-10-CM diagnosis code for unilateral post-traumatic osteoarthritis of first carpometacarpal joint. It belongs to category M18 (osteoarthritis of first carpometacarpal joint), block M15-M19 (osteoarthritis) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within M18 (osteoarthritis of first carpometacarpal joint), M18.3 is specifically for unilateral post-traumatic osteoarthritis of first carpometacarpal joint. Related codes cover bilateral primary osteoarthritis of first carpometacarpal joints (M18.0), unilateral primary osteoarthritis of first carpometacarpal joint (M18.1), bilateral post-traumatic osteoarthritis of first carpometacarpal joints (M18.2), other bilateral secondary osteoarthritis of first carpometacarpal joints (M18.4), other unilateral secondary osteoarthritis of first carpometacarpal joint (M18.5) and unspecified (M18.9).

To report this condition, pick the subcode that matches the documentation: M18.30 (unspecified hand), M18.31 (right hand) and M18.32 (left hand).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.