**3. Comparative regional anaesthesia options**

Several pain management methods are used after TKR and THR such as PCA, narcotics, epidural analgesia, and peripheral nerve block. However, those methods are associated with complications; continuous epidural infiltration and femoral and/or sciatic nerve block improve postoperative pain control and reduce consumption of narcotics but at the expense of other potential problems such as epidural bleeding (with prophylactic anticoagulation therapy), infection, urinary retention, diminished muscle control and nerve damage [26–31]. PCA administration of opioids is often associated with nausea and vomiting, respiratory depression, drowsiness, pruritus, reduced gut motility, and urinary retention. Continuous intra-articular infusion of analgesics is associated with large effusion of surgical wound [15, 26]. Even though those pain management methods have reduced the acute phase of postoperative pain to some extent, they do not address the major concerns of venous thromboembolism (VTE) and hospital-acquired infections.
