What is the treatment for knee effusion?

Treatment of Knee Effusion

Intra-articular corticosteroid injection is the first-line treatment for knee effusion, particularly when accompanied by pain or inflammatory signs, providing significant relief within 1-2 weeks. 1, 2

Initial Pharmacological Management

Corticosteroid Injection (First-Line)

• Intra-articular long-acting corticosteroid is most effective when effusion is present, demonstrating superior outcomes compared to placebo with significant pain relief at 1 and 4 weeks 3, 1, 2
• Benefits typically last 1-12 weeks, though effects may diminish by 12-24 weeks 3, 2
• One study showed better outcomes specifically in patients with effusion present at baseline 3
• Avoid overuse of the injected joint for 24 hours following injection 1
• In diabetic patients, monitor glucose levels for 1-3 days post-injection due to transient hyperglycemia risk 1

Oral Analgesics (Concurrent or Alternative)

• Start with paracetamol (acetaminophen) up to 4g/day for mild to moderate effusion with pain—safe for long-term use with minimal side effects 1, 2
• Escalate to NSAIDs (oral or topical) if unresponsive to paracetamol, especially with persistent effusion (effect size median 0.49) 1, 2

Non-Pharmacological Management (Concurrent with Medications)

• Implement quadriceps strengthening exercises as the primary exercise intervention 1, 2
• Recommend weight reduction if patient is overweight 1, 2
• Provide regular patient education about the condition and management 1, 2
• Consider physical supports: walking sticks, insoles, or knee bracing 1, 2

Role of Aspiration

Aspiration provides only temporary improvement (lasting approximately 1 week) due to early re-accumulation of fluid and should be reserved for specific indications rather than routine treatment. 4

When to Aspirate:

• Effusions of unknown origin to establish diagnosis (particularly non-traumatic cases) 4
• For immediate clinical relief when symptoms are severe 4
• Exercise caution in traumatic effusions as benefit is minimal and short-lived 4

Management of Refractory Cases

Second-Line Options:

• Repeat intra-articular corticosteroid injection if previous injection provided relief 1
• Consider hyaluronic acid injections, though effect size is relatively small (0.04-0.9 over 60 days to one year) 3, 1, 2
• Hyaluronic acid requires 3-5 weekly injections with slower onset of action compared to corticosteroids 3
• Avoid both corticosteroid and hyaluronic acid injections within 3 months prior to knee replacement surgery due to increased infection risk 1

Surgical Intervention:

• Consider joint replacement for patients with refractory pain, disability, and radiographic deterioration despite conservative measures 1, 2

Treatment Tailoring

Adjust treatment intensity based on:

• Level of pain intensity and disability 1
• Signs of inflammation (warmth, redness, tenderness) 1
• Location and degree of structural damage on imaging 1
• Presence of risk factors for progression 1

Common Pitfalls to Avoid

• Do not rely on aspiration alone as definitive treatment—it provides only temporary relief lasting approximately one week 4
• Do not withhold corticosteroid injection in absence of visible effusion—one study found no clinical predictors of response, suggesting benefit extends beyond effusion alone 3
• Patients with effusion at baseline may have worse response to hyaluronic acid 3
• Do not perform injections close to planned surgical intervention (3-month window) 1