title: A nomogram for predicting the need for sciatic nerve block after total knee arthroplasty.
abstract: Sciatic nerve block (SNB) is commonly performed in combination with femoral nerve block (FNB) for postoperative analgesia following total knee arthroplasty (TKA). Despite the fact that 10-20 % of TKA patients require SNB for postoperative posterior knee pain, there are no existing studies that suggest a model to predict the need for SNB. The aim of our study was to develop a prediction tool to measure the likelihood of patients undergoing TKA surgery requiring a postoperative SNB.
  
  
  
  With institutional review board approval, we obtained data from the electronic medical record of patients who underwent TKA at the Cleveland Clinic. A multivariable logistic regression was used to estimate the probability of requiring a postoperative SNB. Clinicians selected potential predictors to create a model, and the potential nonlinear association between continuous predictors and SNB was assessed using the restricted cubic spline model.
  
  
  
  In total 6279 TKA cases involving 2329 patients with complete datasets were used for building the prediction model, including 276 (12 %) patients who received a postoperative SNB and 2053 (88 %) patients who did not. The estimated C statistic of the prediction model was 0.64. The nomogram is used by first locating the patient position on each predictor variable scale, which has corresponding prognostic points. The cut-off of 11.6 % jointly maximizes the sensitivity and specificity.
  
  
  
  This is the first study to be published on SNB prediction after TKA. Our nomogram may prove to be a useful tool for guiding physicians in terms of their decisions regarding SNB.
authors: Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA.|Outcomes Research Consortium, Cleveland, OH, USA.
authors: Rovnat
authors: R
authors: Babazade
authors: Outcomes Research Consortium, Cleveland, OH, USA.|Department of Anesthesiology, Saint Louis University Hospital, Saint Louis, MO, USA.
authors: Thilak
authors: T
authors: Sreenivasalu
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.
authors: Pankaj
authors: P
authors: Jain
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.
authors: Matthew T
authors: MT
authors: Hutcherson
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.
authors: Amanda J
authors: AJ
authors: Naylor
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.|Department of Quantitative Health Sciences,, Cleveland Clinic, Cleveland, OH, USA.
authors: Jing
authors: J
authors: You
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.|Anesthesiology, Cleveland Clinic, Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, USA.
authors: Hesham
authors: H
authors: Elsharkawy
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA.|Anesthesiology, Cleveland Clinic, Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, USA.
authors: Ali Sakr Esa
authors: AS
authors: Wael
authors: Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA. alparslanturan@yahoo.com.
authors: Alparslan
authors: A
authors: Turan
mesh_terms: D000368:Aged; D000465:Algorithms; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D049451:Nomograms; D010149:Postoperative Pain / Q000453:epidemiology / Q000517:prevention & control; D011237:Predictive Value of Tests; D012584:Sciatic Nerve; D012680:Sensitivity and Specificity
keywords: Nomogram; Postoperative pain; Sciatic nerve block; Total knee arthroplasty