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ICD-10-CM 2027

ICD-10 code for knee ankylosis

M24.66

Ankylosis, knee

Header — needs a more specific code

From the official ICD-10-CM alphabetic index entry “Ankylosis (fibrous) (osseous) (joint) › knee”. Page updated September 29, 2026.

About coding knee ankylosis

The ICD-10-CM code for knee ankylosis is M24.66 (Ankylosis, knee).

Within M24.6 (ankylosis of joint), M24.66 is specifically for ankylosis, knee. Related codes cover unspecified joint (M24.60), shoulder (M24.61), elbow (M24.62), wrist (M24.63), hand (M24.64), hip (M24.65), ankle and foot (M24.67) and other specified joint (M24.69).

To report this condition, pick the subcode that matches the documentation: M24.661 (knee), M24.662 (knee) and M24.669 (knee).

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 ankylosis ICD-10 codes

What is the ICD-10 code for knee ankylosis?

M24.66 — Ankylosis, knee (a header code; report a more specific subcode).

Is M24.66 billable?

No. M24.66 is a header code. Report one of its more specific subcodes instead.