M66.10 Rupture of synovium, unspecified joint

Billable ICD-10-CM code, FY2026.

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

Applies from M66.1 Rupture of synovium

Applicable to

• Rupture of synovial cyst

Excludes2 (not included here)

• rupture of popliteal cyst (M66.0)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 727.50 Rupture of synovium, unspecified

Code annotations containing back-references to M66.10

Back-references to M66.1

• Type 1 Excludes: M71.3 Other bursal cyst ("synovial cyst with rupture (M66.1-)")

Back-references to M66

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

Diagnosis Index entries for M66.10

• Rupture, ruptured › synovium (cyst)

Nearby codes

• M66 Spontaneous rupture of synovium and tendon
• M66.0 Rupture of popliteal cyst
• M66.1 Rupture of synovium
• M66.10 Rupture of synovium, unspecified joint (this code)
• M66.11 Rupture of synovium, shoulder
• M66.111 Rupture of synovium, right shoulder
• M66.112 Rupture of synovium, left shoulder
• M66.119 Rupture of synovium, unspecified shoulder
• M66.12 Rupture of synovium, elbow