How should a Baker's cyst be managed, including conservative measures, NSAIDs, possible corticosteroid injection or aspiration, treatment of underlying knee pathology, weight loss, physiotherapy, and criteria for orthopedic referral?

Baker's Cyst Treatment

Conservative management is the first-line treatment for Baker's cysts, focusing on addressing underlying knee pathology through exercise therapy, NSAIDs for pain control, and weight loss if indicated, with corticosteroid injection or aspiration reserved for large symptomatic cysts that fail initial measures. 1, 2

Initial Conservative Approach

The foundation of Baker's cyst management centers on treating the underlying intra-articular knee pathology, as the cyst represents synovial fluid herniation secondary to knee joint disease 3, 2:

• Initiate structured exercise programs including quadriceps strengthening and low-impact aerobic exercise, which reduce pain and improve function in knee osteoarthritis (the most common underlying cause) 4, 1
• Recommend weight loss for patients with BMI ≥25 kg/m², as this addresses a primary risk factor for knee pathology 4, 1
• Prescribe oral or topical NSAIDs for short-term pain relief, though these do not alter long-term outcomes 4
• Avoid glucosamine, chondroitin, and acupuncture, as these lack evidence of clinical benefit 4

The evidence strongly supports exercise therapy, with effect sizes of 0.78-1.05 for pain reduction in knee osteoarthritis 4. This is critical because isolated treatment of the cyst without addressing knee pathology results in high recurrence rates 3.

Pharmacologic Management

NSAIDs are recommended for symptomatic relief but should be used judiciously 4:

• Topical NSAIDs provide effective pain relief with fewer systemic side effects 4
• Oral NSAIDs should be considered when topical agents or acetaminophen fail 4
• For patients with gastrointestinal risk, use selective COX-2 inhibitors or add gastroprotection 4
• NSAIDs provide short-term benefit only and do not prevent cyst recurrence 4

Interventional Procedures

Ultrasound-guided aspiration with corticosteroid injection is appropriate for large, symptomatic cysts causing significant pain or functional limitation 2:

• This procedure provides acute pain relief and may improve function temporarily 2
• Corticosteroid injection may be more effective than oral NSAIDs for acute-phase pain relief 4
• However, recurrence rates are high (up to 50-60%) with aspiration alone 3, 5
• The procedure is safe and can be performed at bedside with ultrasound guidance 2

Important caveat: Isolated cyst treatment without addressing underlying knee pathology leads to recurrence 3. The cyst communicates with the knee joint in most cases, so intra-articular pathology must be managed concurrently 6.

When to Refer to Orthopedics

Refer for orthopedic evaluation in these specific scenarios:

• Failure of 3-6 months of conservative therapy including exercise, NSAIDs, and weight management 4
• Recurrent large symptomatic cysts despite aspiration and corticosteroid injection 3
• Suspected cyst rupture presenting with acute calf pain and swelling (mimics DVT) 7
• Refractory pain with disability and radiographic evidence of severe knee osteoarthritis, as these patients may benefit from arthroscopic treatment of underlying pathology or eventual joint replacement 4

Arthroscopic communication-enlargement surgery with cyst wall removal is the most effective surgical approach for recalcitrant cases 3. However, arthroscopic surgery should not be performed for degenerative knee disease alone, as it provides no benefit over conservative management 4.

Physiotherapy Protocol

Structured physiotherapy is essential and should include 4:

• Quadriceps strengthening exercises (demonstrated effect size of 1.05 for pain reduction) 4
• Low-impact aerobic conditioning 4
• Neuromuscular education and self-management programs 4
• Range of motion exercises to maintain knee mobility 4

These interventions address the underlying knee pathology driving cyst formation and have long-term benefits extending 6-18 months 4.

Common Pitfalls to Avoid

• Do not perform isolated cyst excision or aspiration without addressing underlying knee pathology—this leads to high recurrence rates 3
• Do not recommend hyaluronic acid injections—these are not supported by evidence for knee osteoarthritis 4
• Do not rush to arthroscopic surgery for degenerative knee disease, as it provides no benefit over conservative management 4
• Always rule out DVT when patients present with acute calf pain and swelling, as ruptured Baker's cysts can mimic thrombosis 7
• Recognize that cyst size reduction takes time—clinical improvement begins within 10 days of treatment but complete resolution may require 12 weeks 5, 7