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


Ninety-six patients scheduled for a hip arthroscopy were randomized to receive either an anterior quadratus lumborum block or no block. All patients enrolled were included in the analysis (Figure 2). Baseline demographics, preoperative pain scores, and intraoperative variables between the two groups were similar (Table 1).

Figure 2.

Consolidated Standards of Reporting Trials patient flow diagram. Modified from Schulz KF, Altman DG, Moher D, for the CONSORT Group. CONSORT 2010 Statement: Updated guidelines for reporting parallel group randomised trials. BMJ 2010;340:c332.

For the primary outcome, quadratus lumborum block with multimodal analgesia was not superior to multimodal analgesia alone. There was no overall treatment difference in pain scores between the two groups over the study time. For secondary outcomes looking at numerical rating scale difference at each observed study time, the numerical rating scale at rest was only significantly lower in the anterior quadratus lumborum block group (3.3 ± 3.4) compared to the control group (4.4 ± 3.3; differences in means, 1.3 [95% CI, 0.2 to 2.4]; P = 0.023) at 30 min after PACU arrival. Of note, the correlation between delivery of intraoperative IV hydromorphone hydrochloride and numerical rating scale pain score at 30 min was weak (0.07 for numerical rating scale rest and 0.14 for numerical rating scale move). There was no significant difference between the anterior quadratus lumborum block versus no block groups for pain scores at rest or with movement at any other time point (Table 2).

Intra-abdominal fluid extravasation was present in both groups, 18.8% in the anterior quadratus lumborum block group and 22.9% in the no block group. There was no difference in subgroup numerical rating scale pain scores for patients with intra-abdominal fluid extravasation (Table 3).

Opioid consumption for 0 to 24 h, PACU antiemetic use, and PACU patient satisfaction were also not significantly different (Table 4). There was no difference between the opioid-related symptom distress scale and the Quality of Recovery 40 scores in the PACU and postoperative day 1. Regarding the anterior quadratus lumborum block mitigating side effects of hypotension and urinary retention, there was no statistical difference between the anterior quadratus lumborum block group and the no block group. There was no difference in the incidence of nausea and vomiting between the groups both in the PACU and on postoperative day 1 (Table 4). There was no difference in the change of quadriceps strength on the operative side between groups (Table 4; differences in means, 1.9 [95% CI, −1.5 to 5.3]; P = 0.268). At the 6-month follow-up, there was no difference in the self-administered Leeds assessment of neuropathic symptoms and signs of pain scale scores between the groups.