synonyms: Bakers cyst, popliteal cyst, synovial cyst
Bakers Cyst ICD-10
Bakers Cyst ICD-9
- 727.51 (synovial cyst of popliteal space)
Bakers Cyst Etiology / Epidemiology / Natural History
- The most common cystic in the knee.
- Generally associated the additional intra-articular pathology (meniscal tears).
Bakers Cyst Anatomy
- Result from accumulation of synovial fluid within a bursa in the posteromedial aspect of the knee.
- The gastrocnemius-semimembranosus bursa, normally relieves friction between the medial head of the gastrocnemius and semimembranosus tendon and comminicates directly with the knee joint. This transverse opening in the posteromedial aspect of the joint capsule acts as a one way valve with unidirectional flow of synovial fluid from the joint space into the bursal sac which is increased with intra-articular synovitis and effusion.
- The popliteal bursa communicates with the knee joint and can become cystic with synovitis, arthritis, meniscal tears or trauma which increase the joint fluid in the knee.
Bakers Cyst Clinical Evaluation
- Swelling or fullness in the popliteal fossa . Often have posterior knee pain and tenderness. Inability to fully flex the knee.
- Cysts often change in size
- Large cysts may track into the calf. Acute rupture of large cysts may cause severe calf pain and swelling similar to a DVT.
- Document neurovascular exam, especially in large cysts which have potential to compress the neurovascular structures in the popliteal space.
Bakers Cyst Diagnositc Tests
- A/P and lateral views of the knee are generally normal or demonstrate arthritic changes. Evaluate for calcifications in the cyst.
- MRI: demonstrates increased signal on T1 and T2 weighted images.
Bakers Cyst Classification / Treatment
- Asymptomatic popliteal cysts or minimally symptomatic cysts can be observed.
- Symptomatic popliteal cysts generally respond well with treatment of underlying pathology such as arthroscopy for meniscal tear or TKA for arthritis. Consider ultrasound guided cyst aspiration and penetration of any cyst loculations with intracystic injection. If knee effusion is present perform knee aspiration and knee joint steroid injection prior to cyst treatment.
- Recurrent popliteal cyst: arthroscopy with the treatment of intra-articular pathology (partial menisectomy / chondroplasty/ etc) with establish a posteromedial portal while viewing from anterior through the intercondylar notch. Enlarge the
cyst valve with a basket and shaver through the posteromedial portal to decompress the cyst.
- Cyst excision rarely indicated.
- Ruptured Popliteal Cyst: NSAIDs, activity modifications, elevation
Bakers Cyst Associated InjuriesBakers Cyst / Differential Diagnosis
- Exertional compartment syndrome
- Gastrocnemius strain or tear
- Superficial phlebitis
- Ganglia of the cruciate ligaments: may limit flexion and extention. (Deutsh A, Arthroscopy 1994;10:219), (Brown MF, Arthroscopy 1990;6:322).
Bakers Cyst Complications
Bakers Cyst Follow-up Care
- As indicated for underlying pathology (meniscal tear, arthritis)
Bakers Cyst Review References
- Van Nest D, Popliteal Cysts: A Systematic Review of Nonoperative and Operative Treatment. JBJS Rev. 2020 Mar;8(3):e0139.