What is the recommended approach for total knee replacement?

Recommended Approach for Total Knee Replacement Pain Management

For total knee arthroplasty, use general anesthesia combined with a femoral nerve block (or adductor canal block) as the primary anesthetic technique, supplemented with scheduled paracetamol, NSAIDs or COX-2 inhibitors, cooling/compression techniques, and opioids titrated to pain intensity. 1, 2

Primary Anesthetic Technique

Choose one of two evidence-based approaches:

• General anesthesia + femoral nerve block (or adductor canal block) is the preferred primary technique for surgery and postoperative analgesia 1, 2
• Alternative: Spinal anesthesia with local anesthetic plus intrathecal morphine (0.1 mg) provides comparable analgesia 1, 2

Regional Block Optimization

• For extended analgesia beyond 24 hours, use continuous peripheral nerve block catheter rather than single-shot injection 2, 3
• Single-shot femoral nerve blocks significantly reduce pain during movement at 24h and 48h postoperatively 1
• Avoid bilateral blocks with full doses in elderly patients or those with significant comorbidities due to local anesthetic systemic toxicity risk 2, 3

Multimodal Analgesic Protocol

This layered approach addresses pain through multiple mechanisms while minimizing opioid-related adverse effects:

Baseline Non-Opioid Analgesia (Scheduled, Not PRN)

• Paracetamol (acetaminophen) administered on a scheduled basis as foundational analgesia 1, 2, 3
• Conventional NSAIDs or COX-2-selective inhibitors unless contraindicated 1, 2, 3
  • COX-2 inhibitors (e.g., celecoxib 200mg q12h for 5 days) reduce pain scores at 48-72h, decrease opioid consumption by ~40%, and improve early range of motion without increasing bleeding risk 4
  • NSAIDs provide superior pain relief and reduced supplemental analgesic use compared to placebo 1

Adjunctive Non-Pharmacological Techniques

• Cooling and compression techniques (cryotherapy) reduce local inflammation and pain 1, 2, 3
• Cryo/Cuff devices demonstrate superior pain control compared to standard dressings 1

Rescue Opioid Analgesia (Intensity-Based)

• For high-intensity breakthrough pain: intravenous strong opioids 1, 2, 3
• For moderate-to-low intensity pain: weak opioids 1, 2, 3
• Opioids should be reserved strictly as rescue analgesics, not scheduled 2

What NOT to Do: Critical Pitfalls

Avoid These Techniques Due to Insufficient Evidence or Harm

• Do NOT use epidural analgesia routinely - increased risk of serious adverse events without superior benefits compared to peripheral nerve blocks 2
• Do NOT combine femoral and sciatic nerve blocks - limited and inconsistent evidence with no proven benefit over adductor canal block alone 2
• Do NOT use intra-articular NSAIDs, neostigmine, clonidine, or corticosteroids - inconsistent transferable evidence 2
• Do NOT use spinal clonidine or spinal neostigmine - limited evidence and significant side effects 2
• Do NOT add alpha-2-adrenoceptor agonists (clonidine, epinephrine) to peripheral nerve blocks - lack of efficacy 2

Avoid These Rehabilitation Approaches

• Do NOT use continuous passive motion (CPM) routinely - provides no functional benefit and may cause harm 5
• Do NOT use postoperative functional knee bracing routinely - multiple guidelines advise against it 5

Postoperative Rehabilitation Framework

The evidence supports aggressive early mobilization to optimize functional outcomes:

Immediate Postoperative Period (Days 1-7)

• Begin immediate knee mobilization within the first week to increase range of motion and reduce pain 5
• Start isometric quadriceps exercises from postoperative day 1 if pain-free 5
• Progress to immediate full weight-bearing as tolerated - reduces anterior knee pain without affecting knee laxity 5
• Consider neuromuscular electrostimulation added to isometric strengthening for initial 6-8 weeks 5

Early Recovery Phase (Weeks 2-4)

• Progress to open and closed kinetic chain exercises as early as 4 weeks 5
• Prioritize closed kinetic chain exercises in the first postoperative month to mitigate patellofemoral pain risk 5

Extended Rehabilitation (Months 3-12)

• Continue structured rehabilitation for 9-12 months depending on functional goals 5
• Supervised outpatient physiotherapy provides best long-term outcomes, particularly for patients over 45 years 5
• Home-based rehabilitation with minimal supervision is acceptable for highly motivated patients living far from facilities 5

Clinical Outcomes and Expectations

• TKR effectively reduces pain and improves function in patients with end-stage osteoarthritis when less invasive treatments have failed 6
• Effect sizes across 19 studies demonstrate substantial improvements in pain reduction and functional improvement postoperatively 6
• Revision rates range from 0-13% in studies with ≥5 years follow-up 6
• Over 90% of patients achieve good or excellent outcomes according to validated knee scoring systems 7
• Younger, active patients (≤55 years) demonstrate 94% survival rate at 18 years with cemented posterior-stabilized prostheses 7