Can a Patient Have More Than One Baker's Cyst?
Yes, patients can have multiple Baker's cysts, though this is less common than having a single cyst. The literature documents recurrent cysts in the same location and, while less frequently discussed, the presence of multiple cysts simultaneously is recognized in clinical practice.
Evidence for Multiple Baker's Cysts
Recurrent cysts are well-documented, with one surgical series showing recurrence in 63% of knees after excision, demonstrating that the anatomical and pathological conditions allowing cyst formation can persist or recur 1
The mechanism of formation supports multiplicity: Baker's cysts develop when synovial fluid from knee joint effusions fills the gastrocnemius-semimembranosus bursa through a communicating pathway 2. Since multiple bursal communications can theoretically exist, and given that the underlying joint pathology (osteoarthritis, meniscal tears, inflammatory arthritis) affects the entire joint, conditions favor formation of more than one cyst 3
Bilateral presentation is documented, with surgical series reporting bilateral Baker's cysts requiring operative intervention 1, confirming that patients can have cysts in both knees simultaneously
Clinical Context and Implications
Secondary cysts predominate in adults (61% of cases), always associated with intraarticular knee pathology 3. This underlying joint disease creates persistent effusions that can fill multiple bursal spaces if anatomical communications exist 2
The distinction between recurrent and multiple cysts matters clinically: A recurrent cyst represents reformation at the same site after treatment, while multiple cysts would represent separate bursal enlargements. The high recurrence rate (63%) suggests the anatomical predisposition persists even after surgical excision 1
Diagnostic Approach
Ultrasound and MRI readily identify multiple cystic structures in the popliteal fossa 4. These imaging modalities can distinguish between a single multiloculated cyst versus truly separate cystic lesions 4
Look for atypical locations: While classic Baker's cysts arise from the gastrocnemius-semimembranosus bursa, imaging may reveal "abnormally positioned bursa" representing additional cystic collections 4
Treatment Considerations
Address the underlying joint pathology first, as this is the root cause driving cyst formation 3, 2. Treating only the cyst without addressing intraarticular lesions leads to high recurrence rates 1
Arthroscopic evaluation is recommended for secondary cysts to identify and treat associated meniscal tears, cartilage damage, or synovitis that perpetuate effusions 3, 2
Multiple cysts would require comprehensive joint assessment rather than isolated cyst treatment, as they indicate significant underlying joint disease 2
Common Pitfalls
Don't assume a single cyst without complete imaging: Ultrasound or MRI should evaluate the entire popliteal space to identify all cystic collections 4
Recurrence after treatment is extremely common (63% in surgical series), so patients should be counseled that repeat cyst formation is likely if underlying joint disease persists 1
Distinguish Baker's cysts from other popliteal masses: The differential includes popliteal artery aneurysms, which require duplex ultrasonography to distinguish from synovial cysts, especially in patients with vascular disease history 5