Alphabetic Index FY2027

M66.1

Rupture of synovium

FY2027Chapter 13: Diseases of the musculoskeletal system and connective tissue/M65–M67 Disorders of synovium and tendon

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

M66.1 is a non-billable ICD-10-CM code header for rupture of synovium. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are M66.10 Rupture of synovium, unspecified joint; M66.11 Rupture of synovium, shoulder; M66.12 Rupture of synovium, elbow; M66.13 Rupture of synovium, wrist and 4 more. Its coding notes include 13 Excludes2 entries.

Excludes2

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

This code
  • rupture of popliteal cyst (M66.0)
Inherited from 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
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)

Includes

Further defines or gives examples of the content of the category.

Inherited from M66 Spontaneous rupture of synovium and tendon
  • rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength

Inclusion terms

Conditions classified to this code.

This code
  • Rupture of synovial cyst

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

More specific codes under M66.1 8