What is the treatment for knee effusion?

Treatment of Knee Effusion

For knee effusion with pain, start with oral paracetamol (acetaminophen) up to 4g/day, escalate to NSAIDs if ineffective, and use intra-articular corticosteroid injection for acute flares especially when effusion is present—this provides the most rapid and effective relief. 1, 2

Pharmacological Treatment Algorithm

First-Line: Oral Paracetamol

• Begin with paracetamol (acetaminophen) up to 4g/day for mild to moderate effusion with pain. 1, 2
• This agent is safe for long-term use with minimal side effects and comparable efficacy to ibuprofen in the short term. 3
• Continue if effective as an integral component of long-term pain control. 3

Second-Line: NSAIDs

• Escalate to NSAIDs (oral or topical) for patients unresponsive to paracetamol, particularly when effusion is present. 1, 2
• Oral NSAIDs demonstrate superior efficacy over placebo with median effect size of 0.49. 3, 1
• NSAIDs are generally more efficacious than paracetamol but carry increased gastrointestinal side effects. 3
• Topical NSAIDs (such as diclofenac) are useful alternatives for patients unwilling or unable to take oral NSAIDs, with effect sizes up to 0.91 compared to placebo. 3

Intra-Articular Corticosteroid Injection

• Use intra-articular long-acting corticosteroid for acute exacerbation of knee pain with effusion, especially when inflammatory signs are present. 1, 2
• This provides the most effective short-term relief with effect size of 1.27 over seven days. 3
• Benefits typically last 1-12 weeks, with significant pain relief and functional improvement at one and four weeks, though effects diminish by 12-24 weeks. 3, 1
• Corticosteroid injection is more effective when effusion is present, though some evidence suggests it should not be reserved exclusively for effusion cases. 3

Important caveat: Monitor glucose levels for 1-3 days after injection in diabetic patients due to potential transient hyperglycemia. 1

Non-Pharmacological Management (Concurrent with Medications)

• Implement patient education about the condition and its management. 1, 2
• Prescribe joint-specific exercises, especially quadriceps strengthening. 1, 2
• Recommend weight reduction if the patient is overweight. 1, 2
• Consider physical supports including walking sticks, insoles, or knee bracing. 1, 2

Management of Refractory Cases

Repeat Interventions

• For persistent effusion and pain despite conservative measures, consider repeat intra-articular corticosteroid injection if previous injection provided relief. 1
• Hyaluronic acid injections may be considered, though they have relatively small effect sizes and slower onset of action (requiring 3-5 weekly injections). 3, 1, 2
• Hyaluronic acid provides pain relief for several months rather than weeks, but this benefit is offset by logistical and cost issues. 3

Surgical Intervention

• Joint replacement should be considered for patients with refractory pain, disability, and radiographic evidence of deterioration when other treatment modalities have failed. 3, 1, 2

Role of Aspiration

• Aspiration provides only temporary improvement lasting approximately one week due to early re-accumulation of effusion. 4
• Aspiration is most useful for establishing diagnosis in effusions of unknown origin and for immediate clinical relief, but should be performed with consideration in traumatic cases. 4
• No long-term clinical benefit exists between aspirated and non-aspirated groups. 4

Treatment Tailoring

Tailor treatment according to:

• Knee-specific risk factors and general risk factors 1
• Level of pain intensity and disability 1
• Signs of inflammation (presence of effusion, warmth, erythema) 1
• Location and degree of structural damage 1

Critical Precautions

• Avoid overuse of the injected joint for 24 hours following intra-articular therapy. 1
• Avoid both corticosteroid and hyaluronic acid injections within 3 months prior to knee replacement surgery due to increased infection risk. 1