Regional anesthesia has always been a stalemate in hip and knee joint replacement management. Its benefits include, other than lessening or avoidance of opioid drugs in the postoperative, better pain control, reduction in chronic pain occurrence, faster recovery and discharge rates, and thus reduction of immobilization-related severe adverse effects, such as thromboembolic events.

Lumbar epidural analgesia has been popular over the last decades as there is evidence for lower postoperative thromboembolic complications and other protective effects. Nevertheless, there is today little evidence for a decrease in perioperative mortality and morbidity in a low- to medium-risk population in relation to the use of perioperative epidural analgesia. Moreover, the widespread implementation of anticoagulant regimens may not only overcome the benefits of epidural analgesia on thromboembolic complications but also make around 30 % of the patients ineligible for the technique (Rawal 2012). The failure rate of the technique may reach 28 % (Hermanides et al. 2012). A previous systematic review in TKA comparing lumbar epidural blockade with systemic opioid analgesia reported better dynamic pain scores (Fowler et al. 2008). As the magnitude of pain relief must be weighed against the frequency of adverse events, patients who received epidural analgesia had more hypotension, urinary retention, and pruritus whereas systemic opioids caused more sedation, but no difference was found for the postoperative respiratory depression and nausea or vomiting. Development and implementation of peripheral nerve blocks (PNBs) for THA and TKA anesthesia and analgesia evolved from an understanding of the sensory innervations to the hip and knee and progressively received greater attention along the development of nerve stimulation and ultrasound technique and technology. A working knowledge of the sensory distribution of the lower limb helps one understand how PNBs can be useful in managing pain after lower extremity procedures. Unfortunately, these blocks traditionally have been overlooked as anesthetic choices, as many anesthesiologists had no experience in using these techniques, and orthopedic surgeons lacked an understanding of the patient benefits they offered. However, a clear understanding of the anatomy of the pertinent nerve innervation of the lower limb, the technical and procedural aspects of block delivery, and the advantages and disadvantages of both PNBs and traditional methods of postoperative analgesia (e.g., spinal or epidural blocks) is of great importance. In recent years, however, single-injection and continuous PNBs have become part of the orthopedic postoperative analgesic approach, as they have been shown to optimize patient outcomes, satisfaction, and rehabilitation while minimizing complications and reducing costs and length of hospital stay (Hogan et al. 2009).

The lumbar plexus may be blocked with three distinct approaches. Block of the full lumbar plexus (femoral, lateral femoral cutaneous, and obturator) is accomplished with the psoas block. In comparison, the fascia iliaca and femoral approaches will reliably block the femoral but not the lateral femoral, cutaneous, and obturator nerves.

Selection of regional analgesic technique is dependent on the surgical site. For example, the psoas compartment approach to the lumbar plexus is preferable for surgery to the hip because it is the most proximal lumbar plexus technique and provides complete block of the lumbar plexus and the needle or catheter insertion site is distant from the surgical incision (allowing preoperative placement). However, for patients undergoing total knee replacement or for patients in whom a psoas approach may be contraindicated due to infection or existing coagulopathy, a more distal approach to the lumbar plexus (femoral or fascia iliaca blockade) is warranted (Horlocker 2011).

In total hip replacement surgery, continuous lumbar plexus block and continuous femoral nerve block with PCNB or continuous infusion protocols showed a higher extend of block and more successful analgesia in opposition to single shot techniques. Posterior lumbar plexus blocks (psoas sheath blocks) have a greater efficacy than distal lumbar plexus blocks (femoral nerve blocks) in total hip replacement and are recommended. However, they have a potential for more serious complications than the femoral block (plus supplementary obturator and lateral cutaneous nerve of thigh blocks). This recommendation must be balanced against risks of motor blockade and falls and the efficacy of systemic multimodal analgesia (Aguirre et al. 2012).

Each of the aforementioned nerve block techniques has complications. LPBs carry a risk for epidural or subarachnoid injection when the needle is introduced improperly. There is also the risk that the aorta and/or inferior vena cava will be pierced. Both occurrences can be prevented by performing frequent aspirations to ensure that no cerebrospinal fluid or blood is drawn during block administration. Each FNB and SNB combination has minimal complications. SNBs uncommonly cause self-limiting dysesthesias, and FNBs carry a very low risk of intravascular injection or hematoma formation. Adverse effects are shown to be minimized by ultrasound-guided technique when performing such blocks.

The true benefits of PNB emerge when these procedures are compared with traditional spinal or epidural anesthesia and PCA methods. PNB techniques reduce postoperative nausea and vomiting and are not associated with the urinary retention problems that often plague patients who receive neuraxial blocks and other standard analgesic techniques. Moreover, PNBs are associated with faster rehabilitation times and faster discharge rates. Although neuraxial anesthesia does decrease blood loss and transfusion needs in THA patients, it carries the well-known risk for life-threatening spinal hematoma formation and severe neurologic dysfunction. Lower extremity blocks can be safely used in patients who receive anticoagulation therapy, which is known to increase the risk for hematoma formation in patients undergoing spinal anesthesia. Unlike spinal, epidural, and patient-controlled analgesia, PNBs have not been reported to cause severe hypotension or respiratory depression.

Finally, the concept of multimodal pain control including local periarticular injection (LIA) has received increasing interest in the recent literature, and published results are promising in terms of improved perioperative pain control, reduced need for narcotic medications, and reduced associated side effects. Recent reports have used periarticular injections as a supplement to conventional pain control modalities including patient-controlled anesthesia (PCA) pumps and peripheral nerve blocks. In addition, most of the data reported have been on predischarge pain control and functional recovery. LIA technique is a promising, easy, and safe technique, which has proven its efficacy after TKA. The joint and surrounding tissues are infiltrated by the surgeon with a high volume of a local anesthetic solution mainly including ropivacaine, epinephrine, and some adjuvants like NSAIDs, clonidine, corticosteroid, or opioids. The placement of the injections is important, and the total volume should be divided into quarters, with one-quarter injected into the posterior capsule, one-quarter into the medial periosteum and medial capsule, one-quarter into the lateral periosteum and lateral capsule, and one-quarter into the soft tissues around the skin incision (Dalury et al. 2011). The results of several randomized clinical trials demonstrate excellent pain relief and functional recovery after THA and TKA in a multimodal protocol in conjunction with a minimally invasive approach (Figs. 9.3 and 9.4).