Perioperative Management in Total Knee Arthroplasty
Perioperative Management in Total Knee Arthroplasty
The paramount concern of patients is pain control after TKA. Recovery is directly correlated with adequacy of pain control. Classically, patients received intravenous patient controlled analgesia in the immediate postoperative period. However, intravenous opioids cause significant side effects, including sedation, confusion, itching, nausea, vomiting, ileus, and constipation. These side effects delay mobilization and increase time to discharge from the hospital.
Preemptive multimodal pain control has emerged as an effective method of pain control that minimizes side effects. Combining medications like acetaminophen, nonsteroidal antiinflammatory medications, gabapentin or pregabalin, and tramadol with short-acting opioids for breakthrough pain decrease postoperative complications and facilitate mobilization and earlier dismissal from the hospital. Recent studies have shown that multimodal pain strategies improve postoperative pain control when compared with traditional intravenous opioid-based strategies. Opioid requirements decreased from 50–29mg at 24 hours postoperatively and 69–47mg at 48 hours postoperatively. Length-ofstay decreased by 1 day. Joint range of motion improved by 51. The addition of adjunctive pain control techniques, such as spinal-epidural anesthesia, peripheral nerve blockade, and periarticular injection, play an increasing role in immediate postoperative pain control and side effect mitigation as well as decreasing opioid utilization and time to discharge.
Regional blockade is an effective strategy for site-specific pain control and for avoiding opioid induced side effects. Spinal-epidural anesthesia and indwelling epidural catheters are the least targeted types of regional blockade. Spinalepidural anesthesia and indwelling epidural catheters are rapid onset and can be performed routinely by most anesthesiologists. Indwelling epidural catheters may affect mobilization by affecting both legs. Because of serious potential consequences of a spinal hematoma, indwelling epidural catheters should be avoided in patients taking low molecular weight heparin or Factor Xa inhibitors and must be used judiciously in patients on warfarin. If longacting morphine is utilized, there is a high incidence of narcotic-related side-effects and these side-effects are not reversible, resulting in at least 48 hr of effect. Spinalepidural anesthesia and indwelling epidural catheters have the added benefit of reducing the incidence of DVT when compared with general anesthesia.
Peripheral nerve blockade (i.e. femoral, sciatic, adductor canal) is targeted to the operative extremity and less limited by anticoagulation than neuraxial anesthesia. The main barrier to peripheral nerve blockade is the additional training required by the anesthesiologist and time required to perform the procedure. The effect of peripheral nerve blockade on pain scores is profound. Peripheral nerve blockade facilitates early mobilization, but most patients experience quadriceps weakness, sensory abnormalities, or foot drop in the operative extremity depending on the peripheral blockade chosen. While rare, cases of peripheral nerve injury are described. Performing blocks using ultrasound guidance decreases the time required for anesthetic onset (11min with ultrasound versus 16min with conventional techniques), decreases narcotic pain medication use (20mg morphine versus 40mg), increases block efficacy (decreased pain scores at 12, 24, and 48hr), and reduces needle manipulation during placement (58 sec under the skin versus 120sec).
Direct intraoperative periarticular injection also provides targeted and effective pain control. Periarticular injection is site-specific, simple to perform, and has minimal side effects, as long as one is careful not to inject anesthetic intravascularly or intraneurally. At this point there is no universally agreed upon cocktail for an intraoperative periarticular injection. In recent years, off-label liposomal bupivacaine has gained favor among orthopaedic surgeons because of its theoretical long-acting effect. However, these benefits were realized simultaneously with improvement in periarticular injection technique, and it is unclear at this time whether the much more expensive liposomal bupivacaine or improved technique is the explanation for this benefit. Direct intraoperative periarticular injection had similar pain scores and fewer peripheral nerve injuries (one periarticular injection; nine peripheral nerve blockades) than peripheral nerve blockade. Periarticular injection did result in the use of seven more morphine equivalents than peripheral nerve blockade (12mg periarticular injection; 5mg peripheral nerve blockade).
Pain Management
The paramount concern of patients is pain control after TKA. Recovery is directly correlated with adequacy of pain control. Classically, patients received intravenous patient controlled analgesia in the immediate postoperative period. However, intravenous opioids cause significant side effects, including sedation, confusion, itching, nausea, vomiting, ileus, and constipation. These side effects delay mobilization and increase time to discharge from the hospital.
Preemptive multimodal pain control has emerged as an effective method of pain control that minimizes side effects. Combining medications like acetaminophen, nonsteroidal antiinflammatory medications, gabapentin or pregabalin, and tramadol with short-acting opioids for breakthrough pain decrease postoperative complications and facilitate mobilization and earlier dismissal from the hospital. Recent studies have shown that multimodal pain strategies improve postoperative pain control when compared with traditional intravenous opioid-based strategies. Opioid requirements decreased from 50–29mg at 24 hours postoperatively and 69–47mg at 48 hours postoperatively. Length-ofstay decreased by 1 day. Joint range of motion improved by 51. The addition of adjunctive pain control techniques, such as spinal-epidural anesthesia, peripheral nerve blockade, and periarticular injection, play an increasing role in immediate postoperative pain control and side effect mitigation as well as decreasing opioid utilization and time to discharge.
Regional blockade is an effective strategy for site-specific pain control and for avoiding opioid induced side effects. Spinal-epidural anesthesia and indwelling epidural catheters are the least targeted types of regional blockade. Spinalepidural anesthesia and indwelling epidural catheters are rapid onset and can be performed routinely by most anesthesiologists. Indwelling epidural catheters may affect mobilization by affecting both legs. Because of serious potential consequences of a spinal hematoma, indwelling epidural catheters should be avoided in patients taking low molecular weight heparin or Factor Xa inhibitors and must be used judiciously in patients on warfarin. If longacting morphine is utilized, there is a high incidence of narcotic-related side-effects and these side-effects are not reversible, resulting in at least 48 hr of effect. Spinalepidural anesthesia and indwelling epidural catheters have the added benefit of reducing the incidence of DVT when compared with general anesthesia.
Peripheral nerve blockade (i.e. femoral, sciatic, adductor canal) is targeted to the operative extremity and less limited by anticoagulation than neuraxial anesthesia. The main barrier to peripheral nerve blockade is the additional training required by the anesthesiologist and time required to perform the procedure. The effect of peripheral nerve blockade on pain scores is profound. Peripheral nerve blockade facilitates early mobilization, but most patients experience quadriceps weakness, sensory abnormalities, or foot drop in the operative extremity depending on the peripheral blockade chosen. While rare, cases of peripheral nerve injury are described. Performing blocks using ultrasound guidance decreases the time required for anesthetic onset (11min with ultrasound versus 16min with conventional techniques), decreases narcotic pain medication use (20mg morphine versus 40mg), increases block efficacy (decreased pain scores at 12, 24, and 48hr), and reduces needle manipulation during placement (58 sec under the skin versus 120sec).
Direct intraoperative periarticular injection also provides targeted and effective pain control. Periarticular injection is site-specific, simple to perform, and has minimal side effects, as long as one is careful not to inject anesthetic intravascularly or intraneurally. At this point there is no universally agreed upon cocktail for an intraoperative periarticular injection. In recent years, off-label liposomal bupivacaine has gained favor among orthopaedic surgeons because of its theoretical long-acting effect. However, these benefits were realized simultaneously with improvement in periarticular injection technique, and it is unclear at this time whether the much more expensive liposomal bupivacaine or improved technique is the explanation for this benefit. Direct intraoperative periarticular injection had similar pain scores and fewer peripheral nerve injuries (one periarticular injection; nine peripheral nerve blockades) than peripheral nerve blockade. Periarticular injection did result in the use of seven more morphine equivalents than peripheral nerve blockade (12mg periarticular injection; 5mg peripheral nerve blockade).
