Development And Validation Of A Nomogram To Predict The Risk Of Nontraumatic Osteonecrosis Of The Femoral Head

Background:Although corticosteroids and alcohol are the two major risk factors for nontraumatic osteonecrosis of the femoral head(NONFH),the effects of other factors have rarely been studied,which has made early diagnosis and treatment difficult.This study aimed to develop and validate a nomogram to estimate the probability of NONFH,not considering corticosteroids and alcohol.Materials and methods:A training cohort of 790 patients(n=434,NONFH;n=356,femoral neck fractures [non-NONFH])diagnosed in our hospital from January 2011 to December2016 was used for model development.Univariate and multivariate logistic regression analyses were applied to develop the predictive model.Performance characterisation of the resulting nomogram included calibration,discriminatory ability,and clinical usefulness.After internal validation,the nomogram was further evaluated in a different cohorts of 300 consecutive patients included between January 2017 and December 2018.Results:The simple prediction nomogram included five predictors from univariate and multivariate analyses,including gender,total cholesterol,triglyceride,white blood cell count,and platelet count.Internal validation showed that the model had good discrimination(AUC=0.80)and good calibration.In the validation cohort,the nomogram still showed good discrimination(AUC=0.81)and good calibration.Decision curve analysis showed that the predictive nomogram was clinically useful.Conclusion:The simple diagnostic nomogram which combines demographic data and laboratory blood test results,could be used to quantify the probability of NONFH for early screening and diagnosis.