ICD-10 code for knee mouse

The ICD-10-CM code for knee mouse is M23.4 (Loose body in knee).

Within M23 (internal derangement of knee), M23.4 is specifically for Loose body in knee. Related codes cover cystic meniscus (M23.0), derangement of meniscus due to old tear or injury (M23.2), other meniscus derangements (M23.3), chronic instability of knee (M23.5), other spontaneous disruption of ligament(s) of knee (M23.6), other internal derangements of knee (M23.8) and unspecified internal derangement of knee (M23.9).

To report this condition, pick the subcode that matches the documentation: M23.40 (unspecified knee), M23.41 (right knee) and M23.42 (left knee).

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