Multimodal Analgesic for Knee Arthroplasty: Comment.

We read with great interest the article by Felipe Muñoz-Leyva et al.1 entitled “No Benefits of Adding Dexmedetomidine, Ketamine, Dexamethasone, and Nerve Blocks to an Established Multimodal Analgesic Regimen after Total Knee Arthroplasty” published in the July 2022 issue of Anesthesiology. We appreciate the authors’ great work. However, we also found two worthwhile issues that we would like to raise to the investigators.First, the dosages of some analgesics were not fixed in perioperative management. For example, all patients were administered 650 to 1,000 mg acetaminophen and 100 to 200 mg celecoxib in the perioperative period, and 5 to 10 mg immediate-release oral oxycodone or 1 to 2 mg hydromorphone was supplemented after surgery. What was the dosing rationale, and were the administered amounts different between groups?Second, the authors reported that the incidence of plantar flexion impairment on postoperative day 0 was 17.9% and 46.1% for control group and study group, respectively; and the incidence of dorsi flexion impairment on postoperative day 0 was 28.2% and 46.1%, respectively. According to previous studies,2 the interventions used in this study, including periarticular anesthetic infiltration, adductor canal block, and infiltration between popliteal artery and capsule of knee block, hardly block motor nerves and reduce lower limb muscle strength. Could the authors explain the potential reasons for the high incidence of ankle motor impairment in their study?This letter was supported by 1.3.5 Project of Sichuan University West China Hospital (Sichuan, China), grant No. ZYJC18040.The authors declare no competing interests.