Is M91 a billable ICD-10-CM code?

No. M91 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does M91 sit in the tabular list?

Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Chondropathies (M91-M94).

What cannot be coded together with M91?

M91 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

M91

M91 — Juvenile osteochondrosis of hip and pelvis

Non-billable headerICD-10-CM

M91 is a non-billable header ICD-10-CM code for juvenile osteochondrosis of hip and pelvis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

slipped upper femoral epiphysis (nontraumatic) (M93.0-)

Other codes that can never be billed with M91

These codes carry an Excludes1 note pointing at M91. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading M91 alone.

M87Osteonecrosis

Risk adjustment

M91 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.

Code to one of these instead M91

7 child codes. Green means billable.

Questions about M91

Is M91 a billable ICD-10-CM code?: No. M91 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does M91 sit in the tabular list?: Diseases of the musculoskeletal system and connective tissue (M00-M99), in the block Chondropathies (M91-M94).
What cannot be coded together with M91?: M91 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.