Optimal Age Group Selection and Development of a Nomogram To Predict Complications in Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty

Abstract Purpose By comparing the occurrence of complications at 30 days after Simultaneous bilateral total knee arthroplasty (SBTKA) for each age group, the optimal age range of patients receiving SBTKA was determined.An individualized histogram model was established to predict complications within 30 days after SBTKA. Methods The general data of 861 patients who received SBTKA in our hospital on January 1, 2012 and March 31, 2017 were retrospectively analyzed. According to the age of the patients, they were divided into four ages: less than 60 years old, 60 to 64 years old, 65 to 69 years old and over 70 years old. The incidence of complications in different ages was studied.According to the occurrence of complications, 96 cases were included in the complication group and 765 cases in the non-complication group. Univariate and multivariate Logistic regression analysis was conducted to determine and screen out the independent risk factors for complications after SBTKA, and then R software was used to construct the prediction model of the nomogram.The area under the curve (AUC), calibration curve, and decision curve analysis (DCA) were selected to evaluate the nomogram. Results Patients aged 60 to 64 years had the lowest overall postoperative complication rate (7.17%).Five independent predictors were identified by multivariate analysis and were used to establish the nomogram.The AUC of the nomogram was 0.851(95%CI:0.819–0.883).The calibration curve showed that the prediction of nomogram was highly consistent with the actual observation, and DCA showed that nomogram had good clinical usefulness. Conclusion The optimal age group for SBTKA is between 60 and 64 years of age, where the incidence of complications is lowest.Older age, lower preoperative hemoglobin levels, higher preoperative blood urea nitrogen(BUN) levels, longer operation time, and ASA grade ≥ III were identified as independent predictors of complications within 30 days after SBTKA.A nomogram containing the above five predictors could accurately predict the risk of complications within 30 days after SBTKA.