M66
Header — not billable
Spontaneous rupture of synovium and tendon
Spontaneous rupture of synovium and tendon
M66 is a header (parent) code in the ICD-10-CM hierarchy. It is not billable for claim submission. Use one of the billable child codes listed below.
Billable codes in this category
Each of the codes below is billable. Choose the one that most accurately describes the patient's diagnosis.
M66.0
Rupture of popliteal cyst
M66.9 M66.0 classifies spontaneous rupture of a popliteal (Baker's) cyst — the dissection or decompression of a synovial fluid-filled cyst in the posterior knee space that occurs when normal force is applied to already-weakened tissue.
Spontaneous rupture of unspecified tendon
Nontraumatic rupture of a tendon where neither the specific tendon nor the anatomical site has been identified in documentation — the catch-all when both tendon type and location are unknown.
Inclusion & exclusion notes
Excludes 2 (not included here, but may be coded together if both present)
- rotator cuff syndrome (M75.1-)
- rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region