M71.21 Synovial cyst of popliteal space [Baker], right knee

Billable ICD-10-CM code, FY2026.

Applies from M71 Other bursopathies

Excludes1 (never code together)

• bunion (M20.1)
• bursitis related to use, overuse or pressure (M70.-)
• enthesopathies (M76-M77)

Applies from M71.2 Synovial cyst of popliteal space [Baker]

Excludes1 (never code together)

• synovial cyst of popliteal space with rupture (M66.0)

MS-DRG index

Defines the logic of DRG(s) 557-558 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 727.51 Synovial cyst of popliteal space (approximate)

Code annotations containing back-references to M71.21

Back-references to M71.2

• Type 2 Excludes: M67.4 Ganglion ("cyst of bursa (M71.2-M71.3)")
• Type 2 Excludes: M67.4 Ganglion ("cyst of synovium (M71.2-M71.3)")

Nearby codes

• M71.179 Other infective bursitis, unspecified ankle and foot
• M71.18 Other infective bursitis, other site
• M71.19 Other infective bursitis, multiple sites
• M71.2 Synovial cyst of popliteal space [Baker]
• M71.20 Synovial cyst of popliteal space [Baker], unspecified knee
• M71.21 Synovial cyst of popliteal space [Baker], right knee (this code)
• M71.22 Synovial cyst of popliteal space [Baker], left knee
• M71.3 Other bursal cyst
• M71.30 Other bursal cyst, unspecified site
• M71.31 Other bursal cyst, shoulder
• M71.311 Other bursal cyst, right shoulder