M25.661 (Stiffness of right knee, not elsewhere classified) compared with M25.662 (Stiffness of left knee, not elsewhere classified), from the official CMS tabular data. M25.661 and M25.662 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. M25.661 and M25.662 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.
| M25.661Stiffness of right knee, not elsewhere classified | M25.662Stiffness of left knee, not elsewhere classified | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the musculoskeletal system and connective tissue | M00-M99 — Diseases of the musculoskeletal system and connective tissue |
| Definition | Stiffness of right knee, not elsewhere classified is a billable ICD-10-CM diagnosis code (M25.661). | Stiffness of left knee, not elsewhere classified is a billable ICD-10-CM diagnosis code (M25.662). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources