Anterior quadratus lumborum block for postoperative recovery after total hip arthroplasty: a study protocol for a single-center, double-blind, randomized controlled trial

BACKGROUND: Appropriate pain management is essential to improve the postoperative recovery after total hip arthroplasty (THA). Various case reports have indicated that anterior quadratus lumborum block (QLB) provides effective postoperative analgesia in lower limb surgeries. However, few randomized controlled trials have confirmed the efficacy of anterior QLB for lower limb surgeries. The aim of this single-center, double-blind, randomized controlled trial is to confirm the efficacy of anterior QLB for postoperative recovery after THA. METHODS: The participants will be randomly assigned to either the anterior QLB or placebo groups, using a set of random numbers for the allocation sequence. Only pharmacists will be aware of the allocations; other investigators will be blinded until study completion. After induction of general anesthesia, anterior QLB will be performed by using 0.25% levobupivacaine or normal saline. Fentanyl will be administered according to blood pressure change during the surgery. The primary outcome will be the quality of recovery 40 score (QoR-40). Secondary outcomes will include the visual analog scale score of pain intensity at rest and movement, intraoperative and postoperative doses of fentanyl, and incidence of postoperative nausea and vomiting. Statistical analysis will be performed by using the Student’s t test, Mann–Whitney U test, and Fisher’s exact test as appropriate. A P value of less than 0.05 will be considered statistically significant. DISCUSSION: The results of our study will reveal whether anterior QLB is effective for postoperative recovery after THA. TRIAL REGISTRATION: UMIN Clinical Trials Registry, UMIN000032255. Registered on 15 April 2018.