Regional Anesthesia Associated With Decreased Inpatient and Outpatient Opioid Demand in Tibial Plateau Fracture Surgery

Daniel J. Cunningham, MD, MHSc; Micaela LaRose, BA; Gloria Zhang, BS; Preet Patel, BS; Ariana Paniagua, BA; Jeffrey Gadsden, MD; Mark J. Gage, MD

Disclosures

Anesth Analg. 2022;134(5):1072-1081. 

In This Article

Discussion

In this study of patients undergoing fixation of tibial plateau fractures, the use of RA was significantly associated with decreases in inpatient opioid consumption up to 48 hours postoperatively and outpatient opioid demand at 90 days postoperatively after adjusting for baseline patient characteristics.

Our results show a significant decrease in opioid demand for the first 48 hours postoperatively in patients with RA compared to those without. Given that our institution administers opioids as needed according to patient comfort, this reduction in opioid consumption during the early postoperative period likely reflects superior pain relief with RA. Cooke et al[23] previously conducted an RCT examining the efficacy of continuous femoral nerve blockade in reducing pain and narcotic intake after surgical management of tibial plateau fractures and found no difference in pain relief or narcotic use in patients with and without RA. The authors speculated that the femoral nerve blockade alone might not sufficiently relieve pain as the articular branch of the sciatic nerve also supplies the knee. Sciatic-popliteal blocks were more common in our study. However, it is also possible that their smaller sample size (n = 42) resulted in no significant differences.

While RA for tibial plateau fractures has not been well studied, there is an abundance of literature on its utility in patients undergoing total knee arthroplasty and other elective procedures. Various studies have found pain reduction and opioid-sparing benefits of RA in total knee arthroplasty using adductor canal or femoral nerve blockade.[24] In patients undergoing tibial osteotomy, Motamed et al[25] found preoperative continuous femoral nerve blockade decreased length of stay and duration of rescue morphine requirements. While the same blocks may be used for tibial plateau fractures, factors such as acuity of pain, soft tissue injury, and inflammation may lead to a greatly different experience of pain in the trauma patient, limiting the generalizability of these studies.

Previous studies have described a clinically significant acute increase in pain as the effects of RA diminish, termed rebound pain. This phenomenon, hypothesized to be caused by an unmasking of nociceptive input, has been associated with increased opioid consumption, which may negate the early opioid-sparing benefits of RA.[26] While the duration of RA varies among regional techniques and with the type of local anesthetic administered, the onset of rebound pain has been reported 12 to 24 hours after initiation of RA and lasting 3 to 6 hours in ankle and shoulder surgeries.[26–28] In this study, we did not find any increase in opioid consumption during this time period that would suggest the occurrence of rebound pain. Several factors may have led to these findings. Mitigation of rebound pain has previously been demonstrated using preoperative nerve blockade, continuous nerve catheter infusions, adjuvant medications, and preemptive analgesia.[29–31] The multimodal pain regimen used postoperatively at our institution includes scheduled acetaminophen, which may have prevented the onset or truncated the intensity of rebound pain. Furthermore, heterogeneity in RA techniques used in this study could have caused variations in incidence and severity of rebound pain, affecting the results of the RA.

To the best of our knowledge, this is the first study to date that examines RA and long-term postoperative opioid consumption in patients with tibial plateau fractures. Our results demonstrate significant reduction in outpatient opioid consumption at 2 weeks and 90 days postoperatively in patients with RA. We also found that RA was associated with a significant increase in 6-week to 90-day opioid filling. In other words, patients receiving RA consumed lower volumes of opioids at 2 weeks and 90 days but were more likely to refill their prescriptions between 6 weeks and 90 days. The reason for this is unclear. It is possible that the discharge prescription lasted longer for patients with RA compared to patients without RA, so these patients were more likely to refill their prescriptions at a later time. Manoli et al[32] previously found that patients receiving spinal anesthesia for operatively managed tibial plateau fractures reported decreased pain scores at 3 months postoperatively compared to patients receiving general anesthesia. Our results may reflect an increased likelihood of persistent postoperative opioid use in the RA cohort despite lower levels of pain. It is unclear why this paradoxical association was observed. However, we did not measure pain scores, and the retrospective nature of this study limits the conclusions that can be drawn from these data. Further prospective, randomized investigations are needed to clarify the long-term impacts of RA on opioid consumption in tibial plateau fractures.

Results from previous retrospective studies of other surgical procedures have indicated that RA may not confer long-term opioid-sparing benefits. In patients undergoing abdominal surgery, total knee arthroplasty, and shoulder arthroplasty, no association has been found between the use of RA and the risk of persistent postoperative opioid use.[33] While these findings may not be generalizable to tibial plateau fractures due to differences in pain profiles and trajectories, they are important to consider as they challenge the notion that perioperative regional blockade can prevent the development of chronic pain and opioid consumption. Contradicting data from recent systematic review found moderate and low-quality evidence that RA could diminish persistent postoperative pain after nonorthopedic surgeries.[34] However, the authors cautioned that their conclusions were limited by being based on a few small studies and the inability to extend inferences to other surgical interventions or RA techniques. Furthermore, opioid demand was not analyzed. Evidence supporting the long-term benefits of RA is overall weak at present.

Given the lack of evidence demonstrating long-term benefits of RA, it is important to consider potential drawbacks associated with its use. Acute compartment syndrome (ACS) is a potential complication of high-energy tibial plateau fractures, and the use of RA remains controversial in this setting due to concern it may mask the associated increase in pain.[31] While femoral nerve blockades spare sensation to the leg, delayed detection of ACS may be a concern in patients receiving combined femoral-sciatic blocks, EA or spinal anesthesia. There is currently no consensus in the literature regarding the use of RA in patients at risk for compartment syndrome, as evidence is based on mixed results from case reports.[35] Additional site-specific complications include quadriceps weakness in patients receiving femoral nerve blockade, which may limit early ambulation put patients at risk of falls.[36] Furthermore, nerve blockade often adds time to the perioperative experience for the patient, surgeon, and anesthesiologist, incurs additional cost to the health care system, and represents an additional procedure for the patient.

This study has several limitations, which are mainly related to its retrospective, observational nature. First, we could not evaluate nonopioid perioperative analgesia since much of it would have been nonprescription (ie, home acetaminophen usage). Pain was also not evaluated since it would have been collected at nonstandard time intervals. Since opioids are administered according to a pain scale, lower opioid consumption likely correlates to lower pain. Furthermore, we could only measure outpatient opioid prescribing and cannot provide information on outpatient opioid consumption since this study is retrospective. Additionally, we did not have access to a standardized measure of injury severity such as Injury Severity Score, so we used several measures as surrogates for this, such as injury mechanism, additional injuries, and the presence of additional surgery within 7 days after tibial plateau fracture surgery. Finally, we included data on patients receiving all forms of RA with a variety of techniques, so our results are not specific to 1 technique. There are likely differences between block types, and this simplification likely reduces our sensitivity toward block effect. While this heterogeneity might be a weakness, it also strengthens the generalizability of the study results.

In this retrospective observational study, the use of RA in tibial plateau fracture surgery was associated with decreased inpatient opioid consumption up to 48 hours postoperatively and cumulative outpatient opioid demand at 90 days postoperatively. When treating patients with these fracture patterns, it is reasonable to consider RA to potentially diminish opioid use in this high-risk patient population.

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