Unlike these measures, postoperative nausea, vomiting, and antiemetic use, as well as time to discharge, showed more mixed results. With regard to nausea/vomiting, 2 studies16,18 reported nonsignificantly increased rates in the PNB group, whereas others reported significant reductions in nausea/vomiting29 and in the proportion of patients receiving antiemetics.17 Similarly, mixed results were seen in terms of patient discharge time from the PACU. Two studies16,18 reported a nonsignificant increase in time to discharge for the PNB group, while another29 noted a significant reduction for the PNB group compared with those receiving intravenous morphine. These mixed results were surprising, as we expected reductions in opioid use to result in fewer instances of nausea/vomiting and a quicker time to discharge. The reasons underlying these findings are not clear, although it has been suggested that current discharge guidelines and clinical pathways limit the ability to take advantage of the accelerated timeline offered by regional anesthesia.16,30 As experience with PNB grows, our guidelines and pathways are likely to adapt to capitalize on these advantages, and future studies may show more reliable improvements in these measures.
While rare, the risk of bleeding requiring blood transfusion following hip arthroscopy is one of the most common complications of this procedure. Though the studies included in this review did not report on the need for transfusion, a recent study by Cvetanovich and colleagues10 used a national database and found that, of patients undergoing hip arthroscopy (n = 1338), 0.4% (n = 5) had bleeding requiring a transfusion, with 0.3% (n = 4) requiring return to the operating room, similar to an earlier study by Clarke and colleagues,31 who noted bleeding from the portal site in 0.4% of hip arthroscopy patients. In terms of risk factors, Cvetanovich and colleagues10 found that ASA class, older age, and prior cardiac surgery were significantly associated with minor and overall complications, whereas both regional anesthesia/monitored anesthesia care and alcohol consumption of >2 drinks a day were significantly associated with minor complications, including bleeding requiring transfusions. They noted, however, that these risk factors accounted for only 5% of the variance in complication rates, indicating that other unidentified variables better explained the variance in complication rates. These authors concluded that complications associated with hip arthroscopy are so rare that we may not be able to predict which risk factors or anesthesia types are more likely to cause them. Further characterization of bleeding following hip arthroscopy and its associated risk factors is a valuable area for future research.
LIMITATIONS
Our study contains a number of limitations. This review included studies whose level of evidence varied from I to IV; therefore, our study is limited by any bias or heterogeneity introduced in patient recruitment, selection, variability of technique, data collection, and analysis used in these studies. This heterogeneity is most apparent in the block types and comparator groups. Furthermore, several different outcome measures were reported across the 6 studies used in this review, which decreased the relevance of any one of these individual outcomes. Finally, given the limited data that currently exist for the use of PNB in hip arthroscopy, we are unable to note meaningful differences between various types of PNBs, such as differences in postoperative pain or other measures such as quadriceps weakness, which can accompany femoral nerve block.12 While it is important to read our work with these limitations in mind, this systematic review is, to our knowledge, the only comprehensive review to date of studies reporting on PNB in hip arthroscopy, providing clinicians and patients with a greater understanding of the associated outcomes across these studies.
CONCLUSION
This systematic review shows improved outcomes and few complications with PNB use in hip arthroscopy, with reductions in postoperative pain, analgesic use, and the rate of inpatient admissions. Although opioid use was reduced in these studies, we found similar rates of postoperative nausea/vomiting as well as similar time to discharge from the PACU, which may reflect our continued reliance on outdated discharge guidelines and clinical pathways. Current attempts to provide peripheral nerve blockade are quite varied, with studies targeting femoral nerve, fascia iliaca, L1/L2 paravertebral, and lumbar plexus blockade. Future research efforts with a large prospective trial investigating these techniques should focus on which of these PNBs presents the optimal risk-benefit profile for hip arthroscopy patients and thus appropriately address the clinical questions at hand.
This paper will be judged for the Resident Writer’s Award.