Reply to the Letter to the Editor: Low Albumin Levels, More Than Morbid Obesity, Are Associated With Complications After TKA.

Abstract

W e thank Xue and colleagues for their comments regarding our study. They highlighted several potentially important factors on complications after TKA. As addressed in our manuscript, our study is a retrospective outcomes study. It is our best intention to study many interesting risk factors while maintaining our focus. Therefore, we limited the number of risk factors in our analysis to the most interesting ones to us and other physicians in general, as we believe they are the mostrepresentative and thought-provoking risk factors to consider. Still, we conducted further analysis with additional variables, including anemia, duration of surgery, and type of anesthesia (Fig. 1). We hope this can provide a basis for future research. Regarding the questions posed by Xue and colleagues: First, anemia is a perioperative risk factor for total joint arthroplasty. The definition of anemia varies significantly, ranging from 10 g/dL to 13 g/dL. National Surgical Quality Improvement Program (NSQIP) data does include one preoperative value of the hematocrit without details related to the surgical date, and there is no information on the postoperative hematocrit withinNSQIPdataset.We adopted the definition of less than 10g/dL as anemia, and conducted a multivariable regression analysis. Perioperative medication is an interesting topic. However, there is no data reported in the NSQIP dataset, nor did NSQIP report information on perioperative glucose control. Second, our study excluded bilateral surgery and emergency surgery from the analysis. Our initial analysis did include revision surgery (3874 out of 56,260 subjects [6.9%]), which might be a limitation of our analysis. As we move forward, our future studies will focus on the risk factors associated with complications after primary TKA. We believe that increased surgical duration is likely associated with postoperative complications. However, there are many confounding factors that might contribute to prolonged surgical time, including surgeon experience and skill, (RE: Nelson CL, Elkassabany NM, Kamath AF, Liu J. Low Albumin Levels, More Than Morbid Obesity, Are Associated With Complications After TKA. Clin Orthop Relat Res. 2015;473:3163–172). The authors certify that they, or any members of their immediate families, have no commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. J. Liu MD, PhD, N. M. Elkassabany MD, MSCE Department of Anesthesiology & Critical Care, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA