What is the treatment for osteoarthritis (OA) knee pain?

Treatment of Osteoarthritis Knee Pain

Start with acetaminophen up to 4,000 mg/day combined with quadriceps strengthening exercises, then escalate to oral NSAIDs if inadequate relief after 2-4 weeks, reserving intra-articular corticosteroids for acute exacerbations with effusion. 1

First-Line Treatment: Non-Pharmacological + Acetaminophen

Non-Pharmacological Interventions (Mandatory Foundation)

• Quadriceps strengthening exercises are strongly recommended as they provide sustained pain relief and functional improvement for 2-6 months 1
• Patient education programs through structured self-management (e.g., Arthritis Foundation programs) significantly improve pain outcomes 1
• Weight loss is recommended for overweight/obese patients (moderate strength recommendation) to reduce mechanical joint stress 1
• Walking aids (canes) and shoe insoles may reduce joint loading, though evidence is mixed for lateral wedge insoles 1

First-Line Pharmacological Treatment

• Acetaminophen (up to 4,000 mg/day) is the preferred initial oral analgesic due to favorable safety profile and long-term tolerability 1, 2
• Use the full 4,000 mg/day dose for 2-4 weeks before deeming it ineffective 1
• Counsel patients to avoid other acetaminophen-containing products to prevent exceeding maximum daily dose 1

Second-Line Treatment: NSAIDs

When to Escalate

• Oral NSAIDs are strongly recommended when acetaminophen fails or for patients with moderate-to-severe pain unresponsive to first-line therapy 1, 2
• NSAIDs demonstrate superior efficacy compared to acetaminophen (effect size ~0.5) but carry increased gastrointestinal and cardiovascular risks 1, 3

NSAID Selection Strategy

• Topical NSAIDs are preferred for patients ≥75 years old due to superior safety profile with comparable efficacy 1
• For patients with GI risk factors, use COX-2 selective inhibitors or add proton-pump inhibitors with nonselective NSAIDs 1
• Ibuprofen is FDA-approved for osteoarthritis symptom relief 2

Third-Line Treatment: Intra-Articular Corticosteroids

• Intra-articular corticosteroid injections are indicated for acute pain exacerbations, especially when accompanied by knee effusion 1
• These provide effective short-term pain relief but are not appropriate for routine long-term management 1

Additional Treatment Options (Limited Evidence)

May Consider (Limited Strength Recommendations)

• Manual therapy added to exercise programs may improve pain and function 1
• Neuromuscular training (balance, agility, coordination) combined with exercise may improve performance-based function 1
• FDA-approved laser treatment may reduce pain 1
• Transcutaneous electrical nerve stimulation (TENS) may provide pain relief 1
• Massage in addition to usual care may improve symptoms 1

Insufficient Evidence (Cannot Recommend For or Against)

• Hyaluronic acid injections have insufficient evidence despite widespread use 1
• Acupuncture lacks sufficient evidence to recommend 1
• Glucosamine and chondroitin sulfate show no clinical benefit in high-quality studies and should not be prescribed 1

Critical Pitfalls to Avoid

• Do not prescribe glucosamine or chondroitin sulfate - multiple high-quality studies demonstrate no clinical benefit 1
• Do not use lateral heel wedges for medial compartment OA - strong recommendation against this intervention 1
• Do not perform arthroscopic lavage or débridement for routine OA - no demonstrated benefit 1
• Do not underdose acetaminophen - use full 4,000 mg/day before declaring treatment failure 1
• Do not use NSAIDs as monotherapy without addressing exercise and weight management 1

Treatment Algorithm Summary

1. Initiate immediately: Quadriceps exercises + patient education + acetaminophen 4,000 mg/day 1
2. Add if overweight: Structured weight loss program 1
3. After 2-4 weeks if inadequate: Switch to or add oral NSAIDs (topical if age ≥75) 1
4. For acute flares with effusion: Intra-articular corticosteroid injection 1
5. Refractory cases: Consider surgical consultation for joint replacement 1

The optimal approach combines non-pharmacological interventions (which must not be neglected) with a stepwise pharmacological escalation based on pain severity and treatment response. 1