Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 7 3 2022 03 05 85 94 Babak Siavashi Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammad Heshmati Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Golbakhsh Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Seyyed Hossein Shafiei Assistant Professor, Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Farhad Mahdavi Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammadreza Sadeghi Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Yegane Yousefifar Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Salar Baghbani Department of Orthopedics, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammadreza Bozorgmanesh Department of Orthopedics, Vali-e-Asr Hospital, School of Medicine, Arak University of Medical Sciences, Arak, Iran 2021 06 29 2021 08 31 Background: The aim of this study was to develop a prognostic model to identify a subgroup of high-risk patients for non-healing after femoral neck fracture fixation among young adults. The model was implemented by presenting graphically as a nomogram that could be easily used in every day clinical cases. Methods: Data on a total of 129 patients were included in the current study. The mean [standard deviation (SD)] age of the participants was 42 (13) years and 28% of the patients were women. Harrell’s C statistic was used as a measure of discrimination predictive power. We calculated the Nam-D’Agostino χ2 to examine calibration for prediction models. Results: Approximately, 83% of fractures united uneventfully, with avascular necrosis (AVN), fixation nonhealing, non-union, infection, arthroplasty, and death being observed. Body mass index (BMI) and head acetabular trabecular angle (HATA) were inversely associated with the risk of all-cause nonhealing. The final model showed excellent discriminatory power [Harrell’s C statistic: 0.820, 95% confidence interval (CI) (0.680-0.960)] and it was well-calibrated [Nam-D’Agostino χ2: 10.1, (P = 0.3456)]. A nomogram developed by incorporating significant predictors modelled without discretizing continuous variables. Conclusion: Using readily available clinical and radiological data, we developed a parsimonious, simple, accurate yardstick to measure the 5-year risk of nonhealing after femoral neck fractures among young adults. In order to add ease-of-use and to promote its integration into clinical practice, the prognostic model was demonstrated visually as a statistic nomogram. https://jost.tums.ac.ir/index.php/jost/article/view/295 https://jost.tums.ac.ir/index.php/jost/article/download/295/236