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ICD-10-CM 2027

ICD-10 code for knee stiffness

M25.66

Stiffness of knee, not elsewhere classified

Header — needs a more specific code

From the official ICD-10-CM alphabetic index entry “Stiffness, joint NEC › knee”. Page updated September 29, 2026.

About coding knee stiffness

The ICD-10-CM code for knee stiffness is M25.66 (Stiffness of knee, not elsewhere classified).

Within M25.6 (Stiffness of joint, not elsewhere classified), M25.66 is specifically for Stiffness of knee, not elsewhere classified. Related codes cover unspecified joint, not elsewhere classified (M25.60), shoulder, not elsewhere classified (M25.61), elbow, not elsewhere classified (M25.62), wrist, not elsewhere classified (M25.63), hand, not elsewhere classified (M25.64), hip, not elsewhere classified (M25.65), ankle and foot, not elsewhere classified (M25.67) and other specified joint, not elsewhere classified (M25.69).

To report this condition, pick the subcode that matches the documentation: M25.661 (classified), M25.662 (classified) and M25.669 (classified).

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

Common questions about knee stiffness ICD-10 codes

What is the ICD-10 code for knee stiffness?

M25.66 — Stiffness of knee, not elsewhere classified (a header code; report a more specific subcode).

Is M25.66 billable?

No. M25.66 is a header code. Report one of its more specific subcodes instead.