ICD-10-CM > M00-M99 > M20-M25 > M23 > M23.0 > M23.02 M23.02 Cystic meniscus, posterior horn of medial meniscus Non-Billable/Non-Specific Codes M23.021Cystic meniscus, posterior horn of medial meniscus, right kneeM23.022Cystic meniscus, posterior horn of medial meniscus, left kneeM23.029Cystic meniscus, posterior horn of medial meniscus, unspecified knee