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

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: ID: NCT03244631.

Keywords: hip arthroscopy; labral reconstruction; lumbar plexus blockade; pericapsular injection.