M25.4Effusion of joint

M25.4 is the ICD-10-CM diagnosis code for effusion of joint. It belongs to category M25 (other joint disorder, not elsewhere classified), block M20-M25 (other joint disorders) 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 9 subcodes must be used instead.

Within M25 (other joint disorder, not elsewhere classified), M25.4 is specifically for effusion of joint. Related codes cover Hemarthrosis (M25.0), fistula of joint (M25.1), Flail joint (M25.2), other instability of joint (M25.3), pain in joint (M25.5), Stiffness of joint, not elsewhere classified (M25.6), Osteophyte (M25.7), other specified joint disorders (M25.8) and 1 more.

To report this condition, pick the subcode that matches the documentation: M25.40 (joint), M25.41 (shoulder), M25.42 (elbow), M25.43 (wrist), M25.44 (hand), M25.45 (hip), M25.46 (knee), M25.47 (foot) and 1 more.

Don't report M25.4 together with the conditions in its Excludes1 note: hydrarthrosis in yaws (A66.6), intermittent hydrarthrosis (M12.4-) and other infective (teno)synovitis (M65.1-).

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