Is M66.861 a billable ICD-10-CM code?

Yes. M66.861 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does M66.861 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Disorders of synovium and tendon (M65-M67).

M66.861

M66.861 — Spontaneous rupture of other tendons, right lower leg

Billable / specific codeICD-10-CMright

M66.861 is a billable, specific ICD-10-CM code for spontaneous rupture of other tendons, right lower leg. It is valid for submission on a claim.

Excludes2 inherited from the categories above M66.861

Also inherited, and the opposite of Excludes1: these conditions are not part of M66.861, but a patient can have both, so you may code both.

Written on M66 — Spontaneous rupture of synovium and tendon

rotator cuff syndrome (M75.1-)
rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region

Risk adjustment

M66.861 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

M66.861 is named in 10 Medicare coverage policies — 3 listing it as supporting medical necessity, and 7 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A58865Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A58883Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A58893Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered
A59374Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Woundnot covered

Code history

M66.861 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share M66.86. If M66.861 is not quite right, the correct code is usually one of these.

Questions about M66.861

Is M66.861 a billable ICD-10-CM code?: Yes. M66.861 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does M66.861 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Disorders of synovium and tendon (M65-M67).