What are the next steps for managing persistent knee pain with no clear injury for 2 weeks?

Management of Knee Pain for 2 Weeks Without Injury

For a patient presenting with 2 weeks of atraumatic knee pain, initiate conservative management with topical NSAIDs (for knee), oral acetaminophen or NSAIDs, and exercise therapy—imaging is not indicated at this stage unless red flags are present. 1, 2

Initial Clinical Assessment

Key History Elements to Obtain

• Age matters for differential diagnosis: Patients under 40 are more likely to have patellofemoral pain (25% lifetime prevalence), while those over 45 with activity-related pain and less than 30 minutes of morning stiffness likely have osteoarthritis (95% sensitivity, 69% specificity) 2
• Pain pattern: Anterior knee pain worsened by squatting suggests patellofemoral pain (91% sensitive, 50% specific) 2
• Mechanical symptoms: Clicking, locking, or catching may suggest meniscal pathology, though these symptoms alone do not mandate surgery 1
• Functional impact: Inability to bear weight or ambulate 4 steps would be concerning 1

Physical Examination Findings

• Joint line tenderness: 83% sensitive and 83% specific for meniscal tears 2
• McMurray test: Knee rotation with extension (61% sensitive, 84% specific for meniscal tears) 2
• Effusion: Presence of joint effusion may indicate inflammatory process 3
• Point tenderness over bony landmarks: Would raise concern for fracture 1

Imaging Decisions at 2 Weeks

Do not obtain imaging at this stage unless specific red flags are present. 1, 2

• Radiographs are NOT indicated for patients who can ambulate without point tenderness over malleoli, talus, or calcaneus 1
• MRI is NOT recommended for diagnosis of knee osteoarthritis 1
• Consider imaging only if: Persistent pain beyond 3 weeks with failed conservative management, or if there are red flags such as inability to bear weight, severe trauma history, or neurological symptoms 1, 4

First-Line Treatment Protocol

Pharmacological Management

Start with topical NSAIDs as first-line for knee pain:

• Topical diclofenac is strongly recommended for knee pain—equivalent efficacy to oral NSAIDs with markedly fewer gastrointestinal adverse events 1
• Oral acetaminophen up to 4g/day is safe for initial mild-to-moderate pain, though use the lowest effective dose due to hepatotoxicity concerns 1, 3, 5, 6
• Oral NSAIDs (ibuprofen 400mg every 4-6 hours, maximum 3200mg/day) if unresponsive to acetaminophen—demonstrated effect size of 0.49 1, 5

Important caveat: Avoid NSAIDs in patients with cardiovascular disease, chronic kidney disease (especially eGFR <30), or risk of gastrointestinal bleeding; consider adding PPI if GI risk factors present 1

Non-Pharmacological Management (Equally Important)

These interventions should be initiated concurrently, not sequentially:

• Exercise therapy: Particularly quadriceps strengthening exercises—this is as important as medication 1, 2
• Weight reduction if BMI >25: Critical component of management 1
• Patient education and self-management programs: Empowers patients to manage their condition 1, 2
• Physical therapy: Suggested as part of comprehensive plan, can be delivered via group visits, internet-based, or telephone without loss of effectiveness 1

When to Escalate Treatment (If No Improvement by 4-6 Weeks)

Second-Line Pharmacological Options

• Topical capsaicin 0.025-0.075%: Moderate effect (SMD 0.44) but requires 2-4 weeks of continuous use before therapeutic effect; causes initial burning sensation 1
• Duloxetine: Consider as alternative or adjunct if inadequate response to NSAIDs/acetaminophen 1

Intra-articular Injections (For Persistent Pain)

If pain persists despite oral/topical medications and exercise:

• Corticosteroid injection: First-line injectable treatment for persistent knee pain with effusion—provides relief within 1-2 weeks, though benefits are time-limited (1-24 weeks) 1, 3
• Hyaluronic acid (viscosupplementation): Consider only after inadequate response to core treatments—has relatively small effect size 1, 3

What NOT to Do

Avoid these interventions:

• Opioids (including tramadol): Strongly recommended against—limited benefit with high risk of adverse effects, withdrawal symptoms, and serious adverse events 1
• Arthroscopic surgery: Strongly recommended against for degenerative knee disease, even with meniscal tears or mechanical symptoms—no better than exercise therapy at 1 year 1

Red Flags Requiring Urgent Evaluation

• Inability to bear weight or ambulate 1
• Signs of infection (fever, warmth, severe swelling) 7
• Neurological involvement 4
• Acute joint swelling with hemarthrosis suggesting acute ligamentous rupture 7
• Severe trauma with suspected fracture 1

Timeline Expectations

• Conservative management trial: 4-6 weeks minimum before considering advanced imaging or interventions 1, 2
• MRI consideration: Only if symptoms persist beyond 6-8 weeks despite appropriate conservative management 4
• Surgical referral: Reserved for end-stage disease with minimal joint space and inability to cope with pain after exhausting all conservative options 3, 8