What are the treatment options for knee pain?

Treatment Options for Knee Pain

Start with acetaminophen up to 4,000 mg/day as first-line oral analgesic combined with quadriceps strengthening exercises and weight reduction if overweight. 1, 2

First-Line Treatment Approach

Non-Pharmacological Interventions (Start Immediately)

• Quadriceps strengthening exercises are essential and should be initiated in all patients, with closed kinetic chain exercises being more effective than open kinetic chain exercises 2
• Both land-based and aquatic exercise programs are effective; choose based on patient ability and preference 2
• Weight reduction is critical for overweight patients to reduce knee joint pressure—even modest weight loss significantly improves symptoms 1, 2
• Patient education about self-management strategies should be provided at the initial visit 2

First-Line Pharmacological Treatment

• Acetaminophen (up to 4,000 mg/day) is the preferred initial oral analgesic due to its favorable safety profile 1, 2
• Counsel patients to avoid other acetaminophen-containing products to prevent exceeding maximum daily dose 2
• Complete a full dosage trial (2-4 weeks) before considering acetaminophen ineffective 2

Important caveat: While older guidelines strongly favor acetaminophen, one high-quality placebo-controlled trial found acetaminophen no better than placebo for knee osteoarthritis 3. However, current guidelines still recommend it first-line due to superior safety compared to NSAIDs 1.

Second-Line Treatment (If Inadequate Response After 2-4 Weeks)

Topical NSAIDs

• Topical NSAIDs (particularly diclofenac) are strongly recommended for knee pain, especially in patients ≥75 years old due to better safety profile than oral NSAIDs 1, 4, 2
• Topical capsaicin can be offered as an alternative topical agent 1

Oral NSAIDs

• Consider oral NSAIDs only in patients unresponsive to acetaminophen, using the lowest effective dose for the shortest duration 1, 4
• For patients with increased gastrointestinal risk requiring oral NSAIDs, use either COX-2 selective inhibitors OR non-selective NSAIDs with gastroprotective agents 1, 2
• Evidence shows ibuprofen (1,200-2,400 mg/day) provides similar efficacy to acetaminophen in many patients, though with greater GI risk 5, 6
• Diclofenac sodium 75 mg twice daily has demonstrated superior efficacy to acetaminophen in rigorous placebo-controlled trials 3

Adjunctive Measures

• Add supportive devices (walking sticks, insoles, knee bracing) to reduce pressure on affected knee 1, 4, 2
• Consider duloxetine as alternative or adjunctive therapy for patients with inadequate response or contraindications to acetaminophen/NSAIDs 1

Third-Line Treatment (For Persistent Symptoms or Acute Flares)

Intra-Articular Corticosteroid Injections

• Indicated for acute exacerbations of knee pain, especially when accompanied by effusion 1, 4, 2
• Provides effective short-term pain relief 4

Radiofrequency Ablation

• Radiofrequency (conventional and cooled) of genicular nerves has been shown effective when conservative treatment fails 7

What NOT to Do

Avoid These Interventions

• Strongly suggest against initiating opioids (including tramadol) for knee pain due to unfavorable risk-benefit profile 1
• Do not recommend glucosamine or chondroitin sulfate—insufficient evidence for efficacy despite older guidelines mentioning them 2, 7
• Platelet-rich plasma infiltrations lack sufficient evidence and should only be considered in research settings 7

Treatment Algorithm Summary

1. Week 0: Start acetaminophen (up to 4,000 mg/day) + quadriceps exercises + weight reduction if applicable 1, 2

2. Week 2-4: If inadequate response, add or switch to topical NSAIDs (especially if age ≥75) 1, 4

3. Week 4-6: If still inadequate, consider oral NSAIDs with gastroprotection if indicated 1, 4

4. For acute flares with effusion at any time: Use intra-articular corticosteroid injection 1, 4

5. If conservative measures fail: Consider radiofrequency ablation of genicular nerves or surgical consultation 7

Critical Pitfalls to Avoid

• Never rely solely on medications without implementing exercise therapy—this significantly reduces treatment effectiveness 2
• Do not exceed 4,000 mg/day of acetaminophen due to hepatotoxicity risk 2
• Avoid long-term oral NSAID use without gastroprotection in high-risk patients (increased GI, cardiovascular, and renal adverse effects) 1, 2
• Do not use MRI for diagnosis of knee osteoarthritis—clinical findings and plain radiographs are sufficient 1