Treatment of Baker's Cyst in the Back of the Knee

Understanding Baker's Cysts

Baker's cysts are fluid accumulations in the bursa of the gastrocnemius or semimembranosus muscles, often communicating with the knee joint space 1

Ultrasound is the preferred diagnostic tool to confirm the presence of a Baker's cyst and assess its characteristics 1
A Baker's cyst appears as a comma-shaped extension that can be visualized sonographically in the posterior transverse scan between the medial head of gastrocnemius and semimembranosus tendon 1

The American Academy of Orthopaedic Surgeons recommends self-management education programs and activity modifications for osteoarthritis-related Baker's cysts 2
The American Academy of Orthopaedic Surgeons suggests weight management for overweight patients with osteoarthritis-related Baker's cysts 2
Physical therapy to strengthen surrounding muscles is recommended for osteoarthritis-related Baker's cysts 3

Ruptured cysts can mimic deep vein thrombosis clinically and should be differentiated with appropriate imaging 1
Potential complications to monitor include cyst rupture with dissemination into the calf and, rarely, infection 1

Simple cysts contain only fluid with thin walls, while complex cysts have both fluid and solid components, possibly with thick walls or septa, according to the National Comprehensive Cancer Network 4
Aspiration (draining the fluid) can be used for symptomatic relief of Baker's cysts, as recommended by the National Comprehensive Cancer Network 4

The American College of Rheumatology strongly recommends oral NSAIDs as the initial pharmacologic treatment of choice for knee osteoarthritis, using the lowest effective dose for the shortest duration possible, and monitoring for gastrointestinal, cardiovascular, and renal adverse effects 5, 6, 7
The American College of Rheumatology recommends topical NSAIDs as a preferable first-line pharmacologic therapy due to their superior safety profile, and they should be considered before oral NSAIDs 8
Intra-articular corticosteroid injection into the knee joint is strongly recommended, demonstrating short-term efficacy for knee osteoarthritis, and reducing both knee joint inflammation and Baker's cyst size 5, 6, 9, 10

The American College of Rheumatology strongly recommends against glucosamine for the underlying osteoarthritis, as studies with lowest risk of bias fail to show important benefit, and there are concerns about publication bias in industry-sponsored trials 7
Acetaminophen has very limited utility, with small effect sizes and few patients experiencing important benefit, and may be appropriate only for short-term use when NSAIDs are contraindicated, requiring monitoring for hepatotoxicity if used regularly 6, 9, 10

The American College of Physicians recommends that Baker cysts should be drained when patients have significant symptoms, such as pain, swelling, and limited mobility, that persist despite conservative management, particularly when imaging confirms a simple cyst geographically correlated with focal symptoms 11

Baker cysts that are simple and geographically correlated with focal pain, and have significant symptoms affecting activities of daily living, including pain, swelling, or limited mobility, should be considered for aspiration with or without corticosteroid injection 11

Simple aspiration without sclerotherapy or corticosteroid injection invariably results in cyst refilling and should not be considered definitive therapy, according to the European Association for the Study of the Liver 12