What are the initial treatment recommendations for an adult patient with knee osteoarthritis (OA)?

Initial Treatment for Knee Osteoarthritis

All patients with knee osteoarthritis should immediately begin exercise therapy (land-based or aquatic) and weight loss counseling if overweight, as these are the only strongly recommended interventions that improve both pain and function. 1

Core Non-Pharmacological Treatments (Strongly Recommended)

These three interventions form the foundation and must be implemented for every patient:

• Cardiovascular (aerobic) and/or resistance land-based exercise – This improves pain, function, and reduces disability. The choice between aerobic conditioning or strengthening should be based on the patient's current fitness level. 1

• Aquatic exercise – Equally effective as land-based exercise. Particularly useful for aerobically deconditioned patients who should start aquatic and progress to land-based programs. 1

• Weight loss for overweight/obese patients – Reduces mechanical stress on weight-bearing joints and improves outcomes. 1

• Patient education – Provide both oral and written information to counter the misconception that osteoarthritis is inevitably progressive and untreatable. 1, 2

Initial Pharmacological Treatment (All Conditional Recommendations)

No strong recommendations exist for initial pharmacological management. The following options are conditionally recommended and can be selected based on patient factors: 1

First-Line Options:

• Acetaminophen – Up to 4,000 mg/day (consider ≤3,000 mg/day in elderly for enhanced safety). Counsel patients to avoid all other acetaminophen-containing products including OTC cold remedies and opioid combinations. 1, 3

• Topical NSAIDs – Preferred over oral NSAIDs for patients ≥75 years due to minimal systemic absorption and substantially lower complication risk. 1, 3, 2

• Oral NSAIDs – Use at the lowest effective dose for the shortest duration. Must be co-prescribed with a proton pump inhibitor. 1, 2

• Tramadol – Alternative analgesic option. 1

• Intraarticular corticosteroid injections – Provides temporary symptom relief. 1

Critical Age-Based Consideration:

For patients ≥75 years, strongly prefer topical NSAIDs over oral NSAIDs due to substantially higher risks of GI bleeding, renal insufficiency, and cardiovascular complications in elderly patients. 1, 2

Adjunct Non-Pharmacological Treatments (Conditionally Recommended)

These can be added to core treatments: 1

• Self-management programs
• Manual therapy combined with supervised exercise
• Thermal agents (local heat or cold applications/ice packs) 1, 3
• Walking aids as needed
• Tai chi programs
• Medially directed patellar taping
• Compartment-specific insoles (medially wedged for lateral compartment OA; laterally wedged subtalar strapped for medial compartment OA)

What NOT to Use

Avoid these interventions as they lack efficacy: 1, 4

• Glucosamine – Data with lowest risk of bias show no important benefits over placebo. 4
• Chondroitin sulfate – Not supported by current evidence. 1, 4
• Topical capsaicin – Conditionally recommended against. 1
• Electroacupuncture – Should not be used. 1

Treatment Algorithm for Inadequate Response

If acetaminophen alone provides inadequate relief: 1

1. Strongly recommend adding or switching to oral/topical NSAIDs or intraarticular corticosteroid injections
2. For patients ≥75 years: Strongly recommend topical NSAIDs over oral NSAIDs
3. Alternative options include tramadol, duloxetine, or intraarticular hyaluronan injections (conditional recommendations)

Critical Safety Considerations

Before prescribing oral NSAIDs, assess: 1, 2

• Cardiovascular risk factors (especially in patients >50 years)
• History of GI bleeding or ulcers
• Renal function
• Current anticoagulation or antiplatelet therapy

For patients with history of symptomatic/complicated upper GI ulcer (but no bleed in past year): Use either COX-2 selective inhibitor OR nonselective NSAID plus proton pump inhibitor. 1

Common Pitfalls to Avoid

• Do not allow adjunct therapies (ice packs, TENS) to substitute for core interventions – Exercise and weight loss address underlying disease burden while adjuncts only enhance comfort. 3
• Do not prescribe NSAIDs without gastroprotection – Always co-prescribe proton pump inhibitor. 1, 2
• Do not recommend glucosamine/chondroitin despite patient requests – Redirect to evidence-based treatments. 4
• Do not use oral NSAIDs as first-line in elderly patients – Topical formulations have substantially better safety profiles. 1, 2