What are the treatment options for a patient with knee osteoarthritis (knee OA)?

Treatment of Knee Osteoarthritis

Start all patients with knee OA on a core triad of regular exercise (including quadriceps strengthening), weight loss if BMI ≥25 kg/m², and topical NSAIDs, adding oral acetaminophen as needed for pain control. 1

Initial Non-Pharmacological Management (First-Line for All Patients)

Exercise Therapy (Mandatory Foundation)

• Prescribe quadriceps strengthening exercises as they demonstrate significant improvements in both pain and function 2, 3, 4
• Implement 30-60 minutes of moderate-intensity, low-impact aerobic activity (walking, cycling, swimming) most days of the week, which shows substantial effect sizes of 0.52 for pain relief and 0.46 for disability reduction 3, 1, 4
• Add range-of-motion and flexibility exercises to address joint stiffness and limited motion 2, 4
• Utilize supervised exercise programs rather than self-directed programs, aiming for at least 12 supervised sessions for optimal results 4
• Exercise should be performed at least 3 times per week with gradual intensity increases over several months 4
• Pain during exercise should not prevent participation—clinical trials demonstrate improvements even in patients experiencing pain 4

Weight Management (Mandatory if BMI ≥25)

• Target a minimum 5% reduction in body weight, which significantly improves function 3, 1, 4
• Combine dietary modification with exercise for optimal results 3, 4

Patient Education and Self-Management

• Enroll patients in self-management educational programs that teach coping skills, activity modifications, goal-setting, and problem-solving strategies 3, 1

Assistive Devices

• Consider walking sticks, insoles (except lateral wedge insoles), and knee bracing for symptomatic relief 3
• Do not prescribe lateral heel wedges for medial compartmental knee OA—evidence suggests those who avoid them may experience fewer symptoms 2, 3
• Patellar taping may provide short-term relief of pain and improved function, particularly medial taping for immediate and 4-day relief 2

Pharmacological Treatment Algorithm

Step 1: Initial Pharmacotherapy

• Begin with topical NSAIDs applied to the knee combined with oral acetaminophen for mild-to-moderate pain 1, 5
• Acetaminophen shows substantial benefits in reducing pain in patients with mild-to-moderate symptoms 3, 1

Step 2: Escalation for Persistent Pain

• If pain persists despite acetaminophen, escalate to oral NSAIDs or COX-2 inhibitors, which demonstrate superiority over acetaminophen in moderate-to-severe OA pain 1, 5
• For patients with increased gastrointestinal risk, use either non-selective NSAIDs with gastroprotective agents or selective COX-2 inhibitors 3
• Topical capsaicin is an additional safe option with clinical efficacy 3

Step 3: Adjunctive Therapy for Inadequate Response

• Add duloxetine for patients with inadequate response to NSAIDs, as it achieves significant reductions in pain and statistically significant improvements in physical function 1

Step 4: Intra-Articular Injections

• Use intra-articular corticosteroid injections for acute flares of knee pain, especially when accompanied by effusion, providing short-term relief lasting 4-8 weeks 3, 1
• Hyaluronic acid injections may have symptomatic effects, though the American Academy of Orthopaedic Surgeons does not recommend them 3

Medications to Avoid

• Do not prescribe opioids, including tramadol, for osteoarthritis pain management—current evidence does not support their use and they carry significant adverse event risks 1
• This represents a divergence from older guidelines: while the 1995 American College of Rheumatology guidelines mentioned tramadol for moderate to severe pain 3, the most recent 2026 American Academy of Orthopaedic Surgeons guidelines explicitly recommend avoiding all opioids including tramadol 1

Reassessment and Surgical Referral

When to Escalate

• Consider combination pharmacotherapy using multiple agents from different classes if pain or functional limitation has not improved after initial treatment 1
• Refer for additional physical therapy if conservative measures are insufficient 1

Surgical Consultation Criteria

• Obtain weight-bearing plain radiographs before surgical referral 1
• Refer for surgical consultation when patients have radiographic evidence of knee OA with refractory pain and disability despite maximal conservative management 3, 1
• Joint replacement is the definitive surgical option for advanced disease 3, 6

Common Pitfalls to Avoid

• Do not skip the exercise and weight loss components—these are foundational and have the strongest evidence for long-term benefit 3, 1, 4
• Do not prescribe lateral wedge insoles for medial compartmental OA, as they may worsen symptoms 2, 3
• Do not use opioids as they lack supporting evidence and increase adverse event risk 1
• Do not delay surgical referral in patients with severe radiographic disease and refractory symptoms despite maximal conservative therapy 1