In Reply

Abstract

We would like to thank the authors of the letter for their interest in our study and their concerns regarding our recent publication entitled “Local Infiltration Analgesia Versus Continuous Femoral Nerve Block in Pain Relief After Total Knee Arthroplasty: A Randomized Controlled Trial” [1Kurosaka K. Tsukada S. Seino D. et al.Local infiltration analgesia versus continuous femoral nerve block in pain relief after total knee arthroplasty: a randomized controlled trial.J Arthroplasty. 2015; (in press)Google Scholar]. The following are our answers to the 4 questions to the authors included in the letter.1.As the authors of the letter pointed out, preoperative psychologic comorbidities may affect the postoperative pain in elderly patients. It is difficult to quantitatively compare the psychologic comorbidities as the background of study patients between the groups. We believed that the strict random allocation—the most important strength of our study—would be the optimum solution to prevent the bias that arises from the preoperative psychologic comorbidities [2Torgerson D.J. Torgerson C.J. 4 What is special about randomisation?.in: Torgerson D.J. Torgerson C.J. editors. Designing randomised trials in health, education and the social sciences: an introduction. Palgrave Macmillan, New York2008: 22Crossref Scopus (252) Google Scholar]. Just for the record, there were no patients who had been diagnosed with psychological comorbidities nor had any been prescribed anticonvulsants, antidepressants, or opioids in the study population.2.All patients were managed under standardized general anesthesia during the study period. They were administered remifentanil hydrochloride (Ultiva; Janssen Pharmaceutical K.K, Tokyo, Japan) together with fentanyl citrate (Fentanyl; Janssen Pharmaceutical K.K) during surgery. Just before the completion of surgery, 10 mg/mL of flurbiprofen axetil (Ropion; Kaken, Tokyo, Japan; 5 mL) was intravenously administered. The total amounts of remifentanil hydrochloride and fentanyl citrate were not significantly different between the local infiltration analgesia (LIA) group and the continuous femoral nerve block (FNB) group (mean, 2.2 ± 0.9 mg vs 2.1 ± 0.9 mg; P = .80 and mean, 0.22 ± 0.09 mg vs 0.27 ± 0.09 mg; P = .07, respectively). We also noted the influence of anesthesia in the immediate postoperative period. Thus, the primary outcome was defined as pain at rest 1 day after surgery instead of an earlier postoperative time.3.We agree with the author of the letter that the patients’ satisfaction score and pain score during activity may be important in the comparison of the analgesic modalities for pain relief after total knee arthroplasty. However, we focused on the pain score at rest because the primary end point of the randomized controlled trial should ideally be a single outcome [3Pocock S.J. Geller N.L. Tsiatis A.A. The analysis of multiple endpoints in clinical trials.Biometrics. 1987; 43: 487Crossref PubMed Scopus (398) Google Scholar]. We believe that our results can provide important information for future studies to clarify the efficacy of LIA, including the patients’ satisfaction and rehabilitation.4.Before the surgery, patients were instructed to use patient controlled analgesia when they felt intolerable pain. The total volume of morphine per kilogram of body weight during the first 24-hour postoperative period was not significantly different between the groups (mean, 0.20 ± 0.08 mg/kg in the LIA group vs 0.25 ± 0.11 mg/kg in the continuous FNB group; P = .12). Although the significant difference in terms of morphine consumption was not detected by this calculation method, we can assure the clinical importance of our study because the postoperative visual analog scale score was lower in the LIA group compared with the continuous FNB group with a similar total volume of morphine consumption between the groups. Download .pdf (.63 MB) Help with pdf files Conflict of Interest Statement for Kurosaka Download .pdf (.11 MB) Help with pdf files Conflict of Interest Statement for Tsukada Download .pdf (.48 MB) Help with pdf files Conflict of Interest Statement for Seino Download .pdf (.5 MB) Help with pdf files Conflict of Interest Statement for Morooka Download .pdf (.65 MB) Help with pdf files Conflict of Interest Statement for Nakayama Download .pdf (.53 MB) Help with pdf files Conflict of Interest Statement for Yoshiya Comparing Local Infiltration and Continuous Femoral Nerve Block for Pain Relief After Total Knee ArthroplastyThe Journal of ArthroplastyVol. 31Issue 5PreviewThe recent article by Kurosaka et al [1] comparing efficacy of local infiltration analgesia and continuous femoral nerve block for pain relief after total knee arthroplasty (TKA) was of great interest. They showed that local infiltration was associated with an improved early postoperative pain relief during initial 24 hours after surgery. Many things of this study were well done. The authors used a prospective, 2-arm, parallel-group, randomized, controlled design. They chose a well-validated end point of postoperative pain assessment: visual analog scale (VAS) score. Full-Text PDF