What should I do for knee swelling and pain after falling onto my knee?

Management of Knee Swelling and Pain After Fall

You should obtain knee X-rays (anteroposterior and lateral views) immediately if you have focal tenderness, visible swelling/effusion, or cannot bear weight for four steps, as these Ottawa rule criteria indicate need for imaging to rule out fracture. 1

Immediate Assessment and Imaging Decision

Apply the Ottawa Knee Rules to determine if radiographs are needed. X-rays are indicated if ANY of the following are present: 1

• Age ≥55 years
• Isolated tenderness at the head of the fibula
• Isolated tenderness at the patella
• Inability to flex the knee to 90 degrees
• Inability to bear weight for 4 steps (both immediately after injury and in the emergency department/clinic)

The Ottawa rules have 99.7% sensitivity for detecting fractures, meaning they correctly rule out fracture without radiography in 299 out of 300 patients. 1

Do not apply clinical decision rules if you have: 1

• Gross deformity of the knee
• Penetrating injury
• Altered mental status (head injury, intoxication, dementia)
• Neuropathy (paraplegia, diabetes)
• Multiple injuries making examination unreliable

Initial Treatment Protocol

Begin functional treatment immediately rather than immobilization, as this leads to faster recovery and return to activities. 2

First 48-72 Hours - Protection Phase

• Apply ice (ice and water mixture surrounded by damp cloth) for 20-30 minutes, 3-4 times daily - never place ice directly on skin to avoid cold injury 1
• Apply a compression wrap or knee brace for comfort - ensure it doesn't compromise circulation 1, 2
• Elevate the knee above heart level when resting 2
• Avoid activities that cause pain, but do not completely immobilize the joint 1, 2

Pain Management

NSAIDs (ibuprofen, naproxen, celecoxib) are recommended to reduce pain and swelling and accelerate return to activity. 2 These medications have been shown to improve pain control, decrease swelling, and enable faster return to normal activities compared to placebo. 2

Acetaminophen is equally effective if NSAIDs are contraindicated. 2

Functional Support (Days 2-42)

Use a knee brace or lace-up support for 4-6 weeks, as this is superior to immobilization and leads to faster return to sports (4.6 days sooner) and work (7.1 days sooner). 2 Lace-up or semirigid supports are more effective than elastic bandages or tape. 2

Complete immobilization should be avoided - it shows no benefits and actually delays recovery without improving outcomes. 2

Exercise Therapy (Begin Within 48-72 Hours)

Start supervised exercise therapy within 48-72 hours of injury, even while using a brace. 2 This has Level 1 evidence for effectiveness and should include:

• Range of motion exercises - gentle knee flexion and extension
• Strengthening exercises - quadriceps and hamstring strengthening
• Proprioception training - balance exercises to prevent recurrent injury
• Coordination and functional exercises - sport-specific movements as tolerated

Supervised exercises are superior to home exercises alone. 2

When to Obtain Advanced Imaging

If X-rays are negative but you have persistent pain, inability to bear weight, or suspected ligament/meniscus injury, MRI without IV contrast is the next appropriate study. 1

MRI is highly accurate for detecting:

• Occult fractures not visible on X-rays 1
• Meniscal tears 1
• Ligament injuries (ACL, PCL, MCL, LCL) 1
• Bone marrow contusions 1

CT without contrast may be performed instead of MRI if radiographically occult fractures are suspected, particularly for tibial plateau fractures where CT shows 100% sensitivity compared to 83% for plain radiographs. 1

Red Flags Requiring Urgent Evaluation

Seek immediate medical attention if you develop: 1, 3

• Absent pulses, pallor, or cool extremity - suggests vascular injury requiring emergent intervention 3
• Gross deformity - may indicate dislocation or severe fracture 1
• Numbness or inability to move foot/ankle - suggests nerve injury 3
• Severe, uncontrolled pain despite treatment
• Signs of compartment syndrome (progressive pain, tense swelling, pain with passive stretch)

Follow-Up Timing

Re-examination in 3-5 days is critical for accurate diagnosis, as excessive swelling and pain can limit the initial examination up to 48 hours after injury. 1 This delayed examination helps distinguish partial ligament tears from complete ruptures. 1

Return to Activity Timeline

For mild knee sprains: Return to sedentary work at 2 weeks, full return to work and sports at 3-4 weeks depending on functional recovery. 2

For moderate to severe sprains: Return to sedentary work at 3-4 weeks, full return to work and sports at 6-8 weeks depending on rehabilitation progress. 2

Common Pitfalls to Avoid

• Do not rely on RICE protocol alone - there is no evidence it positively influences pain, swelling, or function as a standalone treatment 2
• Do not apply heat in the acute phase - this is not recommended for acute knee injuries 2
• Do not delay exercise therapy - early movement promotes better healing and functional outcomes 2
• Do not immobilize beyond initial pain control - prolonged immobilization leads to decreased range of motion, chronic pain, and joint instability 2
• Do not skip the 3-5 day follow-up examination - initial examination cannot reliably distinguish partial from complete ligament tears 1