M23.321 (Other meniscus derangements, posterior horn of medial meniscus, right knee) compared with M23.322 (Other meniscus derangements, posterior horn of medial meniscus, left knee), from the official CMS tabular data. M23.321 and M23.322 code the same condition on opposite sides.
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. M23.321 and M23.322 name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| M23.321Other meniscus derangements, posterior horn of medial meniscus, right knee | M23.322Other meniscus derangements, posterior horn of medial meniscus, left knee | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Other meniscus derangements, posterior horn of medial meniscus, right knee is a billable ICD-10-CM diagnosis code (M23.321). | Other meniscus derangements, posterior horn of medial meniscus, left knee is a billable ICD-10-CM diagnosis code (M23.322). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources