What are the treatment options for a swollen knee with limited range of motion?

Treatment of Swollen Knee with Limited Range of Motion

For a swollen knee with loss of range of motion, initiate treatment with a combination of non-pharmacological interventions (rest, ice, compression, elevation, range-of-motion exercises) and acetaminophen/paracetamol as first-line analgesia, reserving NSAIDs for patients unresponsive to acetaminophen, while considering intra-articular corticosteroid injection if significant effusion is present. 1

Initial Assessment and Immediate Management

First, rule out serious pathology requiring urgent intervention:

• Assess for signs of infection (fever, warmth, severe pain) or acute trauma that may indicate fracture, ligament rupture, or knee dislocation—these require immediate evaluation and possible arthrocentesis or imaging 2, 3
• If significant trauma occurred, evaluate neurovascular status and consider urgent imaging to exclude fracture or dislocation 4, 3
• For atraumatic swelling with effusion, arthrocentesis with synovial fluid analysis is essential to differentiate infectious, crystal-induced, and inflammatory causes 5

Non-Pharmacological Treatment (Foundation of Care)

Non-pharmacological interventions should be implemented immediately and form the cornerstone of treatment:

• RICE protocol: Rest, ice, compression, and elevation until definitive treatment is established 3
• Range-of-motion/flexibility exercises: Despite limited evidence (Level V), these exercises are recommended to address joint stiffness and loss of motion, with low cost and minimal harm 1
• Low-impact aerobic exercises: Walking or cycling programs reduce pain (effect size 0.52) and disability (effect size 0.46) with Level I evidence 1
• Quadriceps strengthening: Level II evidence shows statistically significant and possibly clinically important effects on pain and function 1
• Weight reduction: If overweight, weight loss through dietary modification and exercise improves function (WOMAC function subscale effect size 0.69) with Level I evidence 1
• Patient education: Individualized education packages, phone calls, and coping skills training reduce pain and improve outcomes 1

Pharmacological Treatment Algorithm

Step 1: Acetaminophen/Paracetamol

• Paracetamol is the oral analgesic to try first and, if successful, the preferred long-term oral analgesic 1
• This recommendation prioritizes safety over potency, particularly important for long-term management

Step 2: NSAIDs (if acetaminophen fails)

• NSAIDs should be considered in patients unresponsive to paracetamol 1
• Ibuprofen 400-2400 mg daily has demonstrated efficacy in controlling pain and inflammation in knee conditions 6
• Critical caveat: NSAIDs carry risks of cardiovascular thrombotic events, GI bleeding/ulceration, and should be used at the lowest effective dose for the shortest duration 6
• In patients with increased GI risk, use non-selective NSAIDs with gastroprotective agents or selective COX-2 inhibitors 1
• Avoid NSAIDs in patients with recent heart attack, immediately before/after cardiac surgery, or with aspirin-sensitive asthma 6

Step 3: Topical NSAIDs

• Topical NSAID applications have clinical efficacy and are safer than oral NSAIDs, particularly for localized knee pain 1

Step 4: Intra-articular Corticosteroid Injection

• Intra-articular injection of long-acting corticosteroid is indicated for flare of knee pain, especially if accompanied by effusion 1
• This is particularly appropriate when swelling is prominent and other measures have been insufficient
• Critical warning: Only administer after infection has been definitively excluded through arthrocentesis 5

Physical Therapy Considerations

Referral to physical therapy is strongly recommended:

• Physical therapy addresses impairments including loss of motion, strength deficits, effusion, and altered movement patterns 1
• Quadriceps strengthening exercises show significant improvements in pain (effect size 1.05) when compared to control groups 1
• Both supervised and home-based exercise programs demonstrate efficacy, with long-term improvements reported at 6-18 months 1
• Fitness training appears equally efficacious to strengthening exercises over 18 months 1

Additional Treatment Options

For specific presentations:

• Patellar taping: Provides short-term relief of pain and improvement in function (Level II evidence, Grade B) 1
• Assistive devices: Walking sticks, insoles, and knee bracing may be beneficial, though evidence is limited 1
• Opioid analgesics: Useful alternatives in patients where NSAIDs are contraindicated, ineffective, or poorly tolerated 1

Red Flags Requiring Advanced Evaluation

Obtain radiographs (AP, lateral, sunrise/Merchant, tunnel views) if:

• Popping occurs with pain, swelling, locking, catching, or giving way 7
• Symptoms persist despite conservative management 7
• Concern for structural abnormality such as osteochondritis dissecans or meniscal tear 7

Consider MRI if:

• Radiographs reveal structural abnormality requiring further characterization 7
• Initial radiographs are normal but symptoms persist, to detect meniscal tears, articular cartilage damage, or bone marrow lesions 7

Common Pitfalls to Avoid

• Never administer intra-articular corticosteroids without first excluding infection through arthrocentesis 5
• Do not prescribe NSAIDs without assessing cardiovascular and GI risk factors 6
• Avoid prolonged NSAID use without attempting acetaminophen first 1
• Do not neglect non-pharmacological interventions—they have Level I evidence and should be implemented regardless of pharmacological choices 1
• Monitor patients on NSAIDs for signs of GI bleeding (melena, hematemesis), liver dysfunction, and cardiovascular events 6