M66.9 Spontaneous rupture of unspecified tendon

Billable ICD-10-CM code, FY2026.

Applicable to

• Rupture at musculotendinous junction, nontraumatic

Applies from M66 Spontaneous rupture of synovium and tendon

Includes

• rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength

Excludes2 (not included here)

• rotator cuff syndrome (M75.1-)
• rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 727.60 Nontraumatic rupture of unspecified tendon (approximate)

Code annotations containing back-references to M66.9

Back-references to M66

• Type 2 Excludes: M62.1 Other rupture of muscle (nontraumatic) ("rupture of tendon (M66.-)")

Diagnosis Index entries for M66.9

• Rupture, ruptured › tendon (traumatic) › nontraumatic (spontaneous)

Nearby codes

• M66.871 Spontaneous rupture of other tendons, right ankle and foot
• M66.872 Spontaneous rupture of other tendons, left ankle and foot
• M66.879 Spontaneous rupture of other tendons, unspecified ankle and foot
• M66.88 Spontaneous rupture of other tendons, other sites
• M66.89 Spontaneous rupture of other tendons, multiple sites
• M66.9 Spontaneous rupture of unspecified tendon (this code)