Popliteal cyst N076

Current RMA Instruments

Changes from previous Instruments

ICD Coding

• ICD-9-CM Code: 727.51.
• ICD-10-AM Code: M71.2.

Brief description

A popliteal cyst is a cystic swelling behind the knee arising due to enlargement of the bursa between the gastrocnemius and semimembranosus muscles.  The bursa lies between these two muscles on the inside of the popliteal fossa, slightly below the skin crease at the back of the knee.  A popliteal cyst generally connects to the adjacent knee joint space.

Confirming the diagnosis

Clinical manifestations (symptoms or a palpable swelling/mass) need to be present in order for the SOP to apply.  

Cysts that are small, asymptomatic, not evident on physical examination, and detected only by imaging studies (CT, MRI) performed because of unrelated joint symptoms, are not covered by the SOP.

The relevant medical specialist is an orthopaedic surgeon.

Additional diagnoses that are covered by SOP

• Baker's cyst

Conditions that are excluded from SOP

• Popliteal/Baker's cyst found incidentally and without clincial manifesations - incidental finding, not a disease or injury.
• Ganglion of the knee*
• Synovial cyst of the knee^#

* another SOP applies

^# non-SOP condition

Clinical onset

Popliteal cysts tend to occur in adults from ages 35 to 70.  Many are asymptomatic. Symptoms include posterior knee pain, knee stiffness, and swelling or a mass behind the knee (especially with the knee extended).  There may be discomfort with prolonged standing. Symptoms and swelling may be worsened by activity.

Clinical worsening

Worsening may be evidenced by enlargement of the mass/swelling or an onging increase in symptoms.