**6. Postoperative pain treatment/management methods**


**2. Classification of pain**

94 Primary Total Knee Arthroplasty

**3. Pain pathways**

physiological processes:

electrical activity.

experiences.

**1.** Acute pain: it is a type of pain that starts suddenly, has a nociceptive nature, has tissue damage, shows a close relationship with the cause of the lesion in terms of location, time, and intensity, and gradually disappears as the healing progresses [1, 2]. The most common

**2.** Superficial (cutaneous) pain: it is type of a pain that occurs against nociceptive stimuli that

**3.** Deep somatic pain: it is a pain that is usually caused by muscle, tendon, joint receptors or

**4.** Visceral pain: it is a pain originated from the deterioration of functions of their tissue (pa-

**5.** Chronic pain: it is defined as acute pain that begins as acute pain and lasts for 1–6 months [4].

In order for a stimulus to be perceived as pain, it is necessary to go through four different

**a.** Transduction; at the end of the nerve is the stage where the stimulus is converted into

**d.** Perception; interaction with the individual's psychology and subjective emotional

Postoperative pain is caused by neuronal damage that occurs during the surgical procedure and the stimulation of the nociceptors. In postoperative period, total knee arthroplasty (TKA) is painful and pain management is quite difficult. The main purpose of postoperative pain relief is to reduce the pain of the patient, to contribute to the healing process, to shorten the

Techniques such as intravenous analgesia, epidural analgesia, and peripheral nerve blocks are used to prevent postoperative pain. In addition, oral and parenteral analgesics, patientcontrolled analgesia, nerve blocks, and periarticular injection methods are used as multimodal analgesia method. Systemic opioids, nonsteroidal anti-inflammatory drugs, and local

**b.** Transmission; it is the spread of electrical activity throughout the nervous system.

types of acute pain are posttraumatic, postoperative, and obstetric pain [3].

occur in skin, subcutaneous tissue, and mucous membranes.

bones, which is blunt and cannot be localized.

rietal pleura, pericardium, and peritoneum).

**c.** Modulation; changes in nociceptive transmission.

**4. Postoperative pain in total knee arthroplasty**

length of hospital stay, and to reduce hospital costs.

anesthetics are frequently used for postoperative analgesia.


#### **6.1. Regional analgesia techniques and multimodal analgesia**

Despite improvements in pain management, approximately half of TKA (total knee arthroplasty) patients develop severe pain in the early postoperative period. Excessive tissue damage and complex innervation in TKA make pain control difficult. Femoral nerve, sciatic nerve, and obturator nerve are involved in the innervation of the knee joint. In major surgeries, such as TKA, changes occur in the endocrine system and central, peripheral, and sympathetic nervous systems. If postoperative analgesia is not achieved adequately, systemic responses induced by the surgery increase and serious risks may occur to the patients.

of ultrasonography and no difference was found in VAS scores and opioid consumption [32]. The sciatic nerve block (SNB) is used in addition to FNB for complete analgesia after TKA. In a systematic review, SNB administered as a supplement to FNB has shown that it does not provide adequate analgesic activity [33]. Studies with larger patient groups showed a significant reduction in postoperative opioid consumption, less opioid-induced adverse effects, and significantly lower resting and dynamic pain scores [34–38]. Adductor channel block was also studied. In the meta-analysis study performed, there was no significant difference in pain control and morphine consumption between the adductor canal bloc (ACB) and the femoral nerve block (FNB) group. However, it was observed that ACB provided faster postoperative mobilization ability without reduction of analgesia in patients undergoing TKA [39]. Another study conducted after TKA to compare the efficacy of single-shot adductor canal block (SACB) and postoperative continuous adductor canal block (CACB) placement and showed that CACB was superior to SACB for analgesia control but ambulation ability, success rate, early functional recovery, and treatment-related side effects were similar [40]. Different studies have shown that ACB and FNB have similar motor function recovery, strength ratings, and quadri-

Pain Management

97

http://dx.doi.org/10.5772/intechopen.74296

TKA operation is one of the most painful orthopedic procedures [43]. For this reason, it is difficult to provide adequate analgesia with a single drug or method. Multimodal analgesia methods will be more appropriate to reduce side effects and provide pain control. Multimodal analgesia is defined as providing more effective pain control by the combined use of various analgesic drugs and techniques that may have additive or synergistic effects targeting differ-

In multimodal pain management, patient education, preemptive oral medications, regional anesthesia methods, peripheral nerve blocks, local infiltrations, and postoperative rehabilitation are included. Most of the side effects seen in analgesia treatment are due to the parenteral opioid. One of the main goals of multimodal analgesia is to reduce the need for opioids.

Tissue inflammation in TKA surgery triggers the production of PGs that play a role in acute postoperative pain. NSAIDs reduce central sensitization by inhibiting central and peripheral prostaglandin synthesis. It may be effective for 2 weeks when inflammation continues in the postoperative period. Ketorolac is a nonselective COX inhibitor and has oral, parenteral, ophthalmic, and nasal forms. It is used in moderate and severe postoperative pain management after major surgeries [45]. It reduces opioid consumption when used as a part of multimodal pain management [46]. The use of NSAIDs can cause gastritis or peptic ulcer formation and impair platelet aggregation, renal function, and wound healing. For this reason, there are concerns about their use in the perioperative period. Preemptive use of selective COX-2 (cyclooxygenase) inhibitors (celecoxib and rofecoxib) has been shown to reduce postoperative pain scores in the knee surgeries [47]. The use of selective COX2 inhibitors in TKA surgeries has been shown to reduce opioid consumption, provide early onset of physical rehabilitation, and reduce

ceps muscle strength at postoperative 24 and 48 h in TKA patients [41, 42].

ent pain mechanisms in the peripheral and/or central nervous system [44].

**6.2. Drug therapy**

*6.2.1. Nonsteroidal anti-inflammatory drugs*

Conventional methods such as parenteral opioids, epidural analgesia, and femur blocks have been widely used to remove the pain associated with TKA [12]. In addition, the fascia iliaca block has recently been used more frequently to reduce the pain associated with TKA [13]. Comparing general anesthesia with neuraxial anesthesia in the patients with TKA, the risk of perioperative complications was significantly reduced in patients undergoing neuraxial anesthesia [14]. In another study, the risk of short-term complications in patients with TKA was higher in patients receiving general anesthesia than in patients receiving neuraxial anesthesia [15]. Neuraxial anesthesia was associated with the reduction of major complications. A recent meta-analysis has shown that there is a significant decrease in the incidence of postoperative surgical site infection in neuraxial anesthesia when compared to general anesthesia and neuraxial anesthesia in the patients with TKA and total hip arthroplasty (THA) [16]. The use of peripheral nerve block (PNB) also reduced the need for postsurgical critical care services [17].

Multimodal analgesia techniques are often used in the "fast-track" recovery protocols to improve pain relief. Mixture of local anesthetics and anti-inflammatory and opioid analgesics for periarticular infiltration has been used in the multimodal protocols. It can improve the pain score, reduce the total perioperative opioid consumption, enhance the early mobilization, and increase the patient satisfaction [18]. Several multimodal analgesics have been developed in clinical practice [19, 20] and paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, ketamine [21], alpha-2 adrenergic agonists [22], and corticosteroids have been used [23].

Periarticular drug injection is an attempt to apply a low-concentration, high-volume local anesthetic solution to the joint capsule and periarticular surrounding tissues to provide postoperative analgesia [24]. When used as a part of a multimodal analgesic protocol in patients undergoing TKA, femoral nerve blockade has been shown to reduce narcotic consumption and improve postoperative pain scores [25]. However, periarticular infiltration is usually insufficient to provide adequate analgesia in the anterior direction of the knee [26]. Periarticular infiltration analgesic protocols that infiltrate anterior, posterior, and medial compartments of the knee are reported to only last between 6 and 12 h [27]. Prolonged motor blockade, quadriceps muscle weakness, difficulty ambulating, and postoperative falls limit the utility of femoral nerve block (FNB) in the "fast track" rehabilitation protocols [28, 29]. In a study, Fascia iliaca block effectively reduced the amount of morphine used after TKA in the first 24 h. This study shows that the fascia iliaca block provides the same level of analgesia with the use of less morphine compared with the periarticular injection [30]. However, the fascia iliaca block requires as much as 40–50 mL of volume to achieve an effective result [31]. In another study, the analgesic efficacy of the fascia iliaca block was compared to the femur nerve block in the guideline of ultrasonography and no difference was found in VAS scores and opioid consumption [32]. The sciatic nerve block (SNB) is used in addition to FNB for complete analgesia after TKA. In a systematic review, SNB administered as a supplement to FNB has shown that it does not provide adequate analgesic activity [33]. Studies with larger patient groups showed a significant reduction in postoperative opioid consumption, less opioid-induced adverse effects, and significantly lower resting and dynamic pain scores [34–38]. Adductor channel block was also studied. In the meta-analysis study performed, there was no significant difference in pain control and morphine consumption between the adductor canal bloc (ACB) and the femoral nerve block (FNB) group. However, it was observed that ACB provided faster postoperative mobilization ability without reduction of analgesia in patients undergoing TKA [39]. Another study conducted after TKA to compare the efficacy of single-shot adductor canal block (SACB) and postoperative continuous adductor canal block (CACB) placement and showed that CACB was superior to SACB for analgesia control but ambulation ability, success rate, early functional recovery, and treatment-related side effects were similar [40]. Different studies have shown that ACB and FNB have similar motor function recovery, strength ratings, and quadriceps muscle strength at postoperative 24 and 48 h in TKA patients [41, 42].
