What is the best course of treatment for an elderly male with a 2-month history of bilateral posterior leg pain from the glutes to the knees, no paresthesia or weakness, morning stiffness lasting 1 hour, and a history of mild bilateral hip Osteoarthritis (OA) and Sacroiliac (SI) joint arthritis?

Treatment Recommendation for Bilateral Posterior Leg Pain with Hip and SI Joint Osteoarthritis

This clinical presentation strongly suggests inflammatory osteoarthritis of the hip and SI joints rather than radicular pain, and should be treated with a structured exercise program as the primary intervention, supplemented with regular-dose paracetamol and consideration of intra-articular corticosteroid injections for acute exacerbations. 1

Clinical Reasoning: Why This is NOT Radicular Pain

The absence of paresthesia or weakness, combined with bilateral distribution and prominent morning stiffness lasting 1 hour, points away from nerve root compression and toward inflammatory osteoarthritis. 1, 2 While SI joint disorders can cause posterior leg symptoms extending to the knee without following dermatomal patterns, the bilateral nature and prolonged morning stiffness are hallmark features of inflammatory OA rather than mechanical SI joint dysfunction. 2, 3

Core Treatment Algorithm

First-Line: Exercise Therapy (Mandatory Foundation)

Exercise provides equivalent pain relief to oral NSAIDs and paracetamol, with superior safety profile, and must be the cornerstone of treatment. 1

• Strengthening exercises: Target hip and gluteal muscles with progressive resistance training at 60-80% of one repetition maximum, 8-12 repetitions, at least 2 days per week. 1
• Aerobic exercise: Moderate-intensity activity for 30-60 minutes daily (walking, cycling, swimming). 1
• Flexibility exercises: Daily stretching of hip flexors, hamstrings, and gluteal muscles to address morning stiffness. 1
• Supervised sessions: At least 12 directly supervised physical therapy sessions provide significantly better outcomes (effect size 0.46 for pain vs 0.28 for fewer sessions, p=0.03). 1

Second-Line: Pharmacologic Management

Regular-dose paracetamol (not "as needed") should be initiated alongside exercise, with oral NSAIDs reserved only if paracetamol fails. 1, 4

• Paracetamol: 1000mg three to four times daily (maximum 4000mg/day, consider 3000mg limit in elderly) taken regularly throughout the day, not as needed. 1, 4
• Topical NSAIDs: Apply to accessible areas (lateral hip, SI region) 3-4 times daily before considering oral NSAIDs. 1, 5
• Oral NSAIDs: Only if paracetamol and topical NSAIDs fail; must be prescribed with proton pump inhibitor for gastroprotection, at lowest effective dose for shortest duration. 1, 4

Critical caveat: In elderly patients, assess renal function before any NSAID use, and avoid NSAIDs entirely if significant cardiovascular, renal, or gastrointestinal disease exists. 4, 1

Third-Line: Intra-Articular Corticosteroid Injections

For acute pain exacerbations or when oral medications are contraindicated, intra-articular corticosteroid injections into the hip and/or SI joints provide 2-4 weeks of relief without systemic side effects. 5, 1

• Particularly valuable when patient cannot tolerate oral NSAIDs due to comorbidities. 5
• Can be performed in both hip and SI joints under image guidance. 6, 7
• Monitor glucose in diabetic patients for 1-3 days post-injection. 5

Essential Non-Pharmacologic Adjuncts

• Weight loss: If overweight/obese, even 5-10% body weight reduction significantly reduces mechanical stress and pain. 1
• Shock-absorbing footwear: Reduces impact loading on hips and SI joints. 1
• Heat application: Particularly beneficial for morning stiffness; apply heat for 15-20 minutes before rising from bed. 1
• Assistive devices: Consider walking stick if gait is antalgic to reduce hip loading. 1

What NOT to Do

• Do not use hyaluronic acid injections for hip OA: Strong evidence against efficacy. 1
• Do not prescribe opioids: Consensus recommendation against opioid use for OA pain. 1
• Do not rely on imaging severity: Radiographic findings correlate poorly with functional outcomes and should not guide treatment intensity. 8
• Do not start oral NSAIDs without trying paracetamol first: This violates guideline-recommended treatment hierarchy. 1, 4

Re-evaluation Timeline

Reassess at 4 weeks for pain reduction and functional improvement. 1 If inadequate response despite adherence to exercise and medications, consider:

• Increasing supervised exercise sessions 1
• Adding intra-articular injections 5
• Referral to orthopedic surgery if pain substantially affects quality of life after 3-6 months of comprehensive conservative treatment 1, 9

Key Clinical Pitfall

The most common error is treating this as radicular pain with imaging and interventions targeting the lumbar spine. The bilateral distribution, absence of neurologic deficits, and prominent morning stiffness clearly indicate inflammatory OA of the hip and SI joints, not nerve root compression. 1, 2 Treatment must focus on the affected joints, not the spine.