M71.20

Synovial cyst of popliteal space [Baker], unspecified knee

FY2027Chapter 13: Diseases of the musculoskeletal system and connective tissue/M70–M79 Other soft tissue disorders

BillableComplete code, valid to report

M71.20 (also written M7120) is a billable ICD-10-CM diagnosis code for synovial cyst of popliteal space [Baker], unspecified knee. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 138 codes in category M71 (Other bursopathies). Its coding notes include 4 Excludes1 entries and 10 Excludes2 entries.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from M71.2 Synovial cyst of popliteal space [Baker]
  • synovial cyst of popliteal space with rupture (M66.0)
Inherited from M71 Other bursopathies
  • bunion (M20.1)
  • bursitis related to use, overuse or pressure (M70.-)
  • enthesopathies (M76-M77)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (10 notes)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • arthropathic psoriasis (L40.5-)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • compartment syndrome (traumatic) (T79.A-)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 13 Diseases of the musculoskeletal system and connective tissue
  • Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition