Anxiety Reduction

Data are conflicting regarding the efficacy of formal preoperative education for patients. The value of a multidisciplinary class experience lies more in reducing patients’ anxiety about their future procedure and recovery.⁷ A timeline for postoperative milestones can be introduced, and patients who are normally averse to taking medication can be reassured that temporary use of pain medication is important for successful rehabilitation. Evidence has not shown preoperative education sessions to decrease a patient’s postoperative pain experience; however, they can help with anxiety and setting expectations and can improve overall patient satisfaction.^7,18,26 Familiarity with equipment such as the continuous passive motion (CPM) machine and assistive walking aids can be developed. Patients who are normally averse to taking medication can be reassured that temporary utilization of pain medications is important and appropriate for successful rehabilitation. Subjects in total hip preoperative classes who also received a booklet had shorter lengths of stay by 3 days, substantially lowering costs.¹⁹ They also showed higher satisfaction levels and had more realistic expectations of surgery.

One critical part of standard preoperative counseling is identifying and planning for the management of complex patients with pain issues. As surgeons, we are limited in our ability to predict what an individual’s pain experience will be. There is no easily administered demographic or screening tool for preoperative TKA patients. A weak correlation suggests that bilateral knees or second knees may have lower pain scores.⁹ A careful history should be taken of the patient’s prior experiences with surgical pain. It is critical to know whether a patient has had problems with alcohol or drug dependence. A psychiatric history is important to elicit, because anxious or depressed patients who “catastrophize” are likely to experience more severe pain.²⁷ Patients who are already dependent on narcotics for pain control and patients with additional pain generators such as degenerative spine disease will need careful perioperative management. Preoperative planning with a pain specialist and/or psychiatrist is advised and can be useful when these red flags present themselves.

Preemptive Analgesia

Preoperative dosing of certain analgesics has broadened the practice of multimodal analgesia. The goal of preemptive pain control is sought by combining different classes of medications to affect the inflammatory response to surgical trauma, as well as neural pathways inherent in the perception of pain (Table 146-2).

Table 146-2 Preemptive Analgesia Options

Preemptive corticosteroids have the potential to safely downregulate the inflammatory response and help to control postoperative pain. The key to avoiding side effects is to use short-term low-dose regimens of agents such as dexamethasone.²⁸ Many protocols in use include a cyclooxygenase (COX)-2 inhibitor and a long-acting narcotic, along with various medications to control gastrointestinal side effects. Preemptive and continuous celecoxib has been shown to decrease postoperative narcotic use, while having no effect on bleeding.²¹ It does not appear to have any deleterious effect on component fixation.²⁰

Preemptive dosing of controlled-release oxycodone has been shown to reduce postoperative pain and patient-controlled analgesia (PCA) opiate use. One study of controlled-release oxycodone used in combination with celecoxib showed that patients used less parenteral opiate, had a decreased length of stay, and had three times less nausea. The two medications were administered preoperatively and then on a scheduled basis.⁸

Use of N-methyl-D-aspartate (NMDA) inhibitors such as gabapentin may provide similar relief. A double-blinded study showed that 300 mg of preemptively given gabapentin lowered narcotic use and visual analogue pain reports in the first 24 hours after lower extremity orthopedic surgery.²² Studies with preemptive pregabalin for postoperative pain have not shown such a difference.²³ A meta-analysis of the “gabapentinoid” class (gabapentin/pregabalin) concluded that these medications decreased postoperative pain, reduced opiate use, and decreased opiate-related side effects such as nausea and urinary retention in a variety of types of surgical settings. The gabapentinoid class was most commonly associated with sedation and dizziness as side effects in the meta-analysis.³¹

Most studies that begin with a regimen of preemptive COX-2, gabapentin, or OxyContin CR dosing continue these medications on a scheduled basis postoperatively with good results. This will be further discussed in the postoperative section. Several additional studies on preemptive COX-2 inhibitors and NMDA inhibitors were retracted in 2007 because it was discovered that fraudulent data were used.¹⁶ This setback necessitates that we proceed with caution in their use and look for further evidence of their efficacy.

Prophylaxis of gastrointestinal upset has a long-standing role in anesthesia. A more aggressive regimen is warranted with knee replacement patients, who are likely to receive nonsteroidal anti-inflammatory drugs (NSAIDs) and opiates at various points in their postoperative course. Proton pump inhibitors or antacids are useful for preventing and treating reflux symptoms. Scopolamine patches can be applied preoperatively to reduce nausea and vomiting. Additional antiemetics such as metoclopramide or ondansetron may be administered preoperatively or intraoperatively. If preemptive gastrointestinal prophylaxis is not currently in use at a given institution, collaboration with the anesthesia team is needed to determine the optimal timing and dosages of these medications. Usually one medication administered preemptively can be synergistic with an agent of a different mechanism if later postoperative nausea develops. Corticosteroids, in addition to analgesic effects, have been shown to help control postoperative nausea and vomiting in a wide range of surgical settings.²⁸

Regional Anesthesia and Blocks

Presently, arthroplasty surgeons are moving toward a consensus that regional anesthesia is the preferred method over general anesthesia for total knee replacement. Spinal anesthesia with local anesthetic was established as having shorter operative times, reduced need for transfusions, and decreased incidence of thromboembolic events in a 2009 meta-analysis.¹¹

Long-acting intrathecal narcotics are uncommonly used, given the requirement for a sustained monitoring period for respiratory depression. Additional regional blocks such as lumbar plexus, sciatic, and femoral with or without obturator give varying degrees and distributions of anesthesia. These blocks may be administered as one-shot preoperative or postoperative treatments, or they may be situated with a continuous infusion catheter. A protocol of femoral nerve catheter, one-shot sciatic block, and standing oral medication reduced length of stay and resulted in earlier ambulation in TKA patients.²⁴ The finer details of selecting medications and infusion rates are best left to the anesthesiologist, but surgeons should be aware of the risks and benefits of using these methods.

Epidural anesthesia provides the broadest distribution of pain relief but can have side effects such as hypotension, nausea, vomiting, urinary retention, pruritus, and dizziness. If anticoagulation is initiated in the first 24 hours postoperatively, care must be taken that the epidural is removed at the appropriate time. Lumbar plexus block is less commonly done but is a safer option if a catheter is to be left in place while anticoagulation is started. Femoral and obturator nerve catheters are less of a worry with regard to anticoagulation, but patients may still have significant posterior knee pain. The addition of a sciatic block could address the posterior pain distribution. These blocks usually require an anesthesiologist trained in regional anesthesia, as well as nerve stimulators or ultrasound guidance. In addition, these blocks have unpredictable motor components that may limit early ambulation and participation in physical therapy. Patients may be unable to mobilize well and in some cases are at risk for falls while still under the effects of femoral nerve block.¹² A decrease in the concentration of infused bupivacaine from 0.2% to 0.1% should enhance a patient’s ability to participate in therapy, with rescue opiates or NSAIDs readily available. Patients with indwelling catheters could be instructed to be partial weight bearing to avoid falls. Epidural, lumbar plexus, and sciatic blocks could mask a peroneal nerve injury; this should be considered especially in cases with associated preoperative deformity (valgus, flexion contracture). Anesthetic techniques for TKA will be covered in greater detail in a separate chapter.