What is the treatment for knee effusion?

Treatment of Knee Effusion

Intra-articular corticosteroid injection is the most effective first-line treatment for knee effusion, particularly for acute exacerbations of knee pain accompanied by effusion, providing rapid relief of inflammatory symptoms. 1

Initial Management Approach

Non-Pharmacological Interventions

• Rest and activity modification to avoid aggravating movements 1
• Cold compresses applied locally 2 times daily can provide partial improvement (28% complete improvement rate) 2
• Elevation of the affected limb to reduce swelling

Pharmacological Management

1. First-line treatment for effusion:

   • Intra-articular corticosteroid injection - provides rapid relief of inflammatory symptoms, particularly effective for pain with effusion 1
   • Randomized controlled trials have shown steroids to be more effective than placebo for pain relief (Effect Size 1.27) 3
   • Benefits are typically short-term (1-3 weeks) 1

2. Oral medications:

   • Acetaminophen (up to 4g daily) - first-line oral analgesic for mild to moderate pain 1
   • NSAIDs (oral) - consider in patients unresponsive to acetaminophen, particularly with clinical signs of inflammation 3
     • Multiple studies show oral NSAIDs are better than placebo (Effect Size median 0.49) 3
   • Topical NSAIDs - apply 3-4 times daily for localized knee pain with minimal systemic absorption 1
     • Randomized controlled trial of topical diclofenac showed positive effect (ES 0.91) compared to placebo 3

3. Novel treatment option:

   • Low-dose spironolactone (25 mg daily for 2 weeks) has shown promising results for OA-related knee effusion
   • Studies show 66% complete improvement rate compared to 24% with ibuprofen 2

Aspiration Considerations

• Joint aspiration (arthrocentesis) should be performed for:

  • Diagnostic purposes when the cause of effusion is unknown 4
  • Immediate symptomatic relief 4
  • Before administering intra-articular corticosteroids

• Note that aspiration alone provides only temporary improvement in clinical parameters, with early re-accumulation of fluid typically occurring within a week 4

Treatment Algorithm Based on Effusion Etiology

For Osteoarthritis-Related Effusion

1. Intra-articular corticosteroid injection
2. Oral analgesics (acetaminophen or NSAIDs)
3. Consider spironolactone 25mg daily for 2 weeks 2
4. Physical therapy focusing on quadriceps strengthening exercises 1

For Traumatic Effusion

1. RICE protocol (Rest, Ice, Compression, Elevation)
2. Aspiration for diagnostic purposes and immediate relief 4
3. NSAIDs for pain and inflammation
4. Referral to orthopedic specialist if not improving after 6-8 weeks 1

Monitoring and Follow-up

• Reassess pain, range of motion, and effusion 1-2 weeks after treatment
• Regular monitoring of renal and hepatic function with prolonged NSAID use 1
• Consider referral to orthopedic specialist if:
  • No response to conservative treatment after 6-8 weeks
  • Recurrent effusions despite appropriate management
  • Mechanical symptoms suggesting internal derangement

Cautions and Pitfalls

• Avoid multiple repeated corticosteroid injections (limit to 3-4 per year) due to potential cartilage damage
• Always rule out infection before administering corticosteroids
• NSAIDs should be used with caution in patients with cardiovascular, renal, or gastrointestinal risk factors
• Aspiration alone without additional treatment will likely result in recurrence of effusion 4