Anterior Quadratus Lumborum Block Does Not Provide Superior Pain Control After Hip Arthroscopy

A Double-Blinded Randomized Controlled Trial

Stephen C. Haskins, M.D.; Audrey Tseng, B.A.; Haoyan Zhong, M.P.A.; Marko Mamic, M.D.; Stephanie I. Cheng, M.D.; Jemiel A. Nejim, M.D.; Douglas S. Wetmore, M.D.; Struan H. Coleman, M.D.; Anil S. Ranawat, M.D.; Danyal H. Nawabi, M.D.; Bryan T. Kelly, M.D.; Stavros G. Memtsoudis, M.D., Ph.D., M.B.A.


Anesthesiology. 2021;135(3):433-441. 

In This Article

Abstract and Introduction


Background: Hip arthroscopy is associated with moderate to severe postoperative pain. This prospective, randomized, double-blinded study investigates the clinically analgesic effect of anterior quadratus lumborum block with multimodal analgesia compared to multimodal analgesia alone. The authors hypothesized that an anterior quadratus lumborum block with multimodal analgesia would be superior for pain control.

Methods: Ninety-six adult patients undergoing ambulatory hip arthroscopy were enrolled. Patients were randomized to either a single-shot anterior quadratus lumborum block (30 ml bupivacaine 0.5% with 2 mg preservative-free dexamethasone) or no block. All patients received neuraxial anesthesia, IV sedation, and multimodal analgesia (IV acetaminophen and ketorolac). The primary outcome was numerical rating scale pain scores at rest and movement at 30 min and 1, 2, 3, and 24 h.

Results: Ninety-six patients were enrolled and included in the analysis. Anterior quadratus lumborum block with multimodal analgesia (overall treatment effect, marginal mean [standard error]: 4.4 [0.3]) was not superior to multimodal analgesia alone (overall treatment effect, marginal mean [standard error]: 3.7 [0.3]) in pain scores over the study period (treatment differences between no block and anterior quadratus lumborum block, 0.7 [95% CI, −0.1 to 1.5]; P = 0.059). Postanesthesia care unit antiemetic use, patient satisfaction, and opioid consumption for 0 to 24 h were not significantly different. There was no difference in quadriceps strength on the operative side between groups (differences in means, 1.9 [95% CI, −1.5 to 5.3]; P = 0.268).

Conclusions: Anterior quadratus lumborum block may not add to the benefits provided by multimodal analgesia alone after hip arthroscopy. Anterior quadratus lumborum block did not cause a motor deficit. The lack of treatment effect in this study demonstrates a surgical procedure without benefit from this novel block.


Hip arthroscopy is associated with moderate to severe pain.[1] The lumbar plexus block for postoperative analgesia was previously studied by YaDeau et al., who found statistically significant reductions in postanesthesia care unit (PACU) resting pain, but no change in most secondary outcomes, including PACU analgesic usage, PACU pain with movement, and patient satisfaction.[2] Additionally, two inpatient falls without injury were attributed to quadriceps weakness.

The quadratus lumborum block is a well-studied block for supplemental analgesia after abdominal and pelvic surgery that has been lauded for its ease of performance, tolerability by patients, and absence of side effects such as hypotension, urinary retention, or the quadriceps weakness associated with lumbar plexus blockade—all of which promote early ambulation and discharge.[3] Additionally, the quadratus lumborum block type I (also known as lateral quadratus lumborum block) has been shown to have a clinical benefit as an alternative to lumbar plexus, fascia iliaca, or femoral nerve block in patients with hip fracture as a perioperative analgesic.[4] However, it has had mixed results for total hip arthroplasty.[5–7] Retrospective studies have shown mixed results when evaluating quadratus lumborum block as an analgesic block for hip arthroscopy.[8,9] However, there are no published prospective randomized controlled trials.

Depending on the approach (e.g., anterior, lateral, posterior, or intramuscular), the quadratus lumborum block can result in local anesthetic spread generating analgesia ranging from T6 to L4.[10] With the anterior approach to the quadratus lumborum block, also known as quadratus lumborum block 3 or the anterior quadratus lumborum block, the local anesthetic is injected between the psoas muscle and the quadratus lumborum muscle. Given that branches of the lumbar plexus travel between the psoas major muscle and the quadratus lumborum, the anterior quadratus lumborum block appears to be the preferred approach to providing analgesia to both the lower extremities and the trunk as it consistently provides a spread of local anesthesia to the L1 to L3 nerve roots.[11] Hip innervation is primarily derived from the lumbar plexus (L1 to L4); therefore, it is crucial to ensure coverage of the lumbar nerve roots to optimize analgesia[12] while avoiding quadriceps weakness.

In addition to the surgical pain caused by hip arthroscopy, intra-abdominal fluid extravasation is a well-established complication that can occur approximately 16% of the time and can be readily identified by point-of-care ultrasound.[13–15] Additionally, intra-abdominal fluid extravasation has been associated with increased pain scores in the postoperative period.[13–15] Given that intra-abdominal fluid extravasation can increase postoperative pain, it is worth investigating the incidence in the patient population when evaluating the clinically analgesic effect of specific pain interventions in the hip arthroscopy population.

The study objective was to investigate the impact of adding anterior quadratus lumborum block to a multimodal analgesia plan on pain scores over the first 24 h after surgery. We hypothesized that the addition of anterior quadratus lumborum block to multimodal analgesia would be associated with superior postoperative pain control, as well as a significant decrease in opioid use, postoperative nausea, and vomiting, and would not cause quadriceps weakness.