Excludes1 pair
M20.1- vs M71-
M20.1 and M71 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on M71
bunion (M20.1)
M20.1
Hallux valgus (acquired)
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M20-M25
Indexed under
- Hallux › valgus (acquired)
- Deformity › toe › hallux valgus
M71
Other bursopathies
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M70-M79
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027