Prospective Single-Blinded Randomized Controlled Trial Comparing Pericapsular Injection Versus Lumbar Plexus Peripheral Nerve Block for Hip Arthroscopy

Abstract

Background: Hip arthroscopy has become the standard for the operative treatment of symptomatic femoroacetabular impingement. Given the high levels of postoperative pain associated with hip arthroscopy, optimal analgesia is critical to ensure patient comfort and safety after discharge. Purpose/Hypothesis: Our purpose was to perform a single-blinded randomized controlled trial comparing the use of pericapsular injection versus lumbar plexus blockade for postoperative pain control after arthroscopic surgery on the hip. We hypothesized that pericapsular injection would provide equivalent pain relief to that of lumbar plexus blockade while minimizing adverse effects and alleviating the dependence on a qualified individual to administer. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 64 consecutive patients undergoing hip arthroscopy were prospectively assessed over a 6-month period between 2017 and 2018. Patients were randomly allocated to 1 of 2 groups: 32 patients received a lumbar plexus blockade by a single anesthesiologist, while 32 patients received a pericapsular injection of 30 mL of ropivacaine and 12 mg of morphine. Postoperative pain in the postanesthesia care unit (PACU) as measured using the numeric rating scale, time to discharge, PACU morphine equivalents, and adverse effects were collected by PACU staff. Postoperative day 1 and 2 narcotic use was obtained through a telephone call with the patient on postoperative day 3. Results: We found no statistically significant difference in PACU pain scores at all time points, although there was a trend toward lower pain for patients receiving a pericapsular injection. PACU and short-term narcotic demand did not vary across the 2 arms. Time to discharge from the PACU did not differ. There were no major adverse events reported for either intervention. Conclusion: Pericapsular injection provides equivalent analgesia when compared with lumbar plexus blockade. It is a safe intervention that allows for efficient postoperative analgesia for patients undergoing hip arthroscopy. Registration: ClinicalTrials.gov ID: NCT03244631.

The Interface of Surgical and Anesthesiological Postoperative Analgesic Regime: Pericapsular Injection Versus Lumbar Plexus Block: Letter to the Editor

“…We clearly acknowledge that patients in the study by Scanaliato et al 8 have been correctly allocated by the randomization. In this respect, we do not believe the study qualifies as an RCT, considering both the internal (interventional mismatch with multiple analgesic medications) and external (eg, low reproducibility) validity of this study are quite low.…”

“…9 The application of the data from hip arthroplasty and surgical fixation of hip fractures to arthroscopic hip surgery is extrapolative at best. 5,8 The population in whom an intervention for fracture fixation or joint arthroplasty differs markedly from patients undergoing arthroscopic surgery of the hip. Likewise, Dr Nielsen and colleagues' objection to early mobilization and differential rehabilitation protocols is irrelevant in arthroscopic hip surgery.…”

“…We read the study by Scanaliato et al 8 with great interest. It seems that surgical hip procedures are an ever-growing field, and the demand for efficient and long-lasting postoperative pain management is concurrently substantial.…”

“…In this respect, we would like to express a concern that the addition of morphine to the injectate in a PNB is controversial, 1,3 whereas the addition of dexamethasone to the injectate presumably acts to enhance the duration of the block effect. Both morphine and dexamethasone are acknowledged analgesic drugs by themselves, and despite a negative aspiration test (not described with regard to the pericapsular injections by Scanaliato et al 8 ), systemic absorption might have occurred, which may have obscured the results.…”

“…Please allow us to argue, that although with vague and unprecise anatomic descriptions regarding the needle tip target in the pericapsular area, the authors are to be credited for trying, presumably, to target the sensory branches of the femoral nerve—aiming to preserve motor function postoperatively. 8 This particular idea, in this very area, is not new; the USG iliopsoas plane block 5 was described in 2018, 3 months later followed by the (since) much-acclaimed USG pericapsular nerve group (PENG) block. 2 Both of these blocks are high-precision, predominantly motor-sparing, USG nerve blocks, but even in expert hands with numerous performed USG PNBs, some complications are seen (ie, motor paralysis).…”