In a patient with bilateral knee osteoarthritis, which knee should be treated first?

Treatment Priority in Bilateral Knee Osteoarthritis

Treat the more symptomatic knee first—the one causing greater pain, functional limitation, or instability—as treatment decisions should be driven by symptom severity and impact on quality of life rather than radiographic findings alone. 1

Clinical Decision Framework

Determine Which Knee to Prioritize

Assess symptom severity in each knee individually:

• Pain intensity and frequency during weight-bearing activities, rest, and night pain 1, 2
• Functional limitations including difficulty with stairs, walking distance, and activities of daily living 3, 2
• Joint instability or "giving way" that affects ambulation safety 1
• Presence of effusion indicating active inflammation requiring immediate intervention 4, 3

The knee with the highest symptom burden and greatest impact on mobility should be treated first. 2 Patient-reported outcomes and quality of life considerations take precedence over radiographic severity, as imaging findings often do not correlate with symptom severity. 5, 2

Initial Treatment Approach for the Priority Knee

Begin with core non-pharmacological interventions simultaneously:

• Exercise programs including strengthening (particularly quadriceps) and aerobic fitness training 1
• Weight loss if BMI >25, as even modest reduction significantly improves pain and function 1, 4
• Assistive devices including cane use for the more symptomatic side if ambulation, stability, or pain warrants support 1

Add pharmacological management in stepwise fashion:

• First-line: Topical NSAIDs for localized knee pain with fewer systemic effects 1, 4
• Second-line: Oral acetaminophen up to 3,000-4,000 mg/day if topical agents insufficient 1, 4
• Third-line: Oral NSAIDs or COX-2 inhibitors at lowest effective dose for shortest duration, with proton pump inhibitor gastroprotection 1, 4

Addressing the Contralateral Knee

Apply core treatments bilaterally from the outset:

• Exercise programs, weight loss interventions, and patient education benefit both knees simultaneously 1
• Self-management strategies should address both joints even when one is more symptomatic 1

Pharmacological interventions can be adjusted based on bilateral symptom burden:

• Topical NSAIDs can be applied to both knees if both are symptomatic 1
• Systemic medications (oral NSAIDs, acetaminophen) treat both knees simultaneously 1, 4

Advanced Interventions for Refractory Cases

For acute flares with effusion in the priority knee:

• Intra-articular corticosteroid injections provide relief for up to 3 months, limited to 3-4 injections per year 4, 3
• Monitor diabetic patients for glycemic control following corticosteroid injection 4

Avoid interventions with poor evidence:

• Do not use hyaluronic acid injections—moderate-strength evidence recommends against routine use 4
• Do not perform arthroscopic lavage or debridement unless clear mechanical locking is present (not for "giving way" or gelling) 1, 6
• Do not prescribe lateral heel wedges for medial compartment OA 1
• Avoid tramadol and routine opioids due to poor risk-benefit profile 4, 6

Bracing Considerations

For unicompartmental disease with malalignment:

• Tibiofemoral braces are strongly recommended when disease causes sufficient impact on ambulation, stability, or pain 1
• Requires expertise in fitting and coordination between providers and brace suppliers 1

For patellofemoral OA:

• Patellofemoral braces are conditionally recommended, though patient tolerance varies 1
• Patellar taping provides short-term pain relief and functional improvement 1

Common Pitfalls to Avoid

• Do not delay treatment of the more symptomatic knee waiting for the other to "catch up"—address the priority knee immediately 2
• Do not rely solely on radiographic severity—patient-reported symptoms and functional impact determine treatment urgency 5, 2
• Do not use arthroscopy for routine OA management without clear mechanical symptoms 1
• Do not prescribe hyaluronic acid given evidence against its use 4
• Do not overlook bilateral core treatments—exercise and weight loss benefit both knees regardless of which is more symptomatic 1

Surgical Referral Timing

Consider total knee arthroplasty when:

• Symptoms substantially affect quality of life despite maximal conservative management 1, 4
• Referral should occur before prolonged functional limitation and severe pain become established 1
• Age, sex, obesity, and comorbidities should not be barriers to referral 1
• Preoperative optimization of diabetes, hypertension, and other comorbidities is essential 4