Patient-specific Hip Arthroplasty Dislocation Risk Calculator: An Explainable Multimodal Machine Learning-based Approach.

Purpose: To develop a multimodal machine learning-based pipeline to predict patient-specific risk of dislocation following primary total hip arthroplasty (THA).
Materials and Methods: This study retrospectively evaluated 17 073 patients who underwent primary THA between 1998 and 2018. A test set of 1718 patients was held out. A hybrid network of EfficientNet-B4 and Swin-B transformer was developed to classify patients according to 5-year dislocation outcomes from preoperative anteroposterior pelvic radiographs and clinical characteristics (demographics, comorbidities, and surgical characteristics). The most informative imaging features, extracted by the mentioned model, were selected and concatenated with clinical features. A collection of these features was then used to train a multimodal survival XGBoost model to predict the individualized hazard of dislocation within 5 years. C index was used to evaluate the multimodal survival model on the test set and compare it with another clinical-only model trained only on clinical data. Shapley additive explanation values were used for model explanation.
Results: The study sample had a median age of 65 years (IQR: 18 years; 52.1% [8889] women) with a 5-year dislocation incidence of 2%. On the holdout test set, the clinical-only model achieved a C index of 0.64 (95% CI: 0.60, 0.68). The addition of imaging features boosted multimodal model performance to a C index of 0.74 (95% CI: 0.69, 0.78; P = .02).
Conclusion: Due to its discrimination ability and explainability, this risk calculator can be a potential powerful dislocation risk stratification and THA planning tool. Keywords: Conventional Radiography, Surgery, Skeletal-Appendicular, Hip, Outcomes Analysis, Supervised Learning, Convolutional Neural Network (CNN), Gradient Boosting Machines (GBM) Supplemental material is available for this article. © RSNA, 2022.
Competing Interests: Disclosures of conflicts of interest: B.K. No relevant relationships. P.R. No relevant relationships. H.M.K. National Institutes of Health (NIH) grants. D.R.L. No relevant relationships. Q.J.J. No relevant relationships. S.F. No relevant relationships. W.K.K. NIH funds for research paid to institution; author provides statistical analyses to Data Safety Monitoring Boards; mutual funds or similar. B.J.E. Chair of Research Committee for Society for Imaging Informatics in Medicine; consultant to the editor for Radiology: Artificial Intelligence. R.J.S. Royalties or licenses from Zimmer Biomet, OrthAlign, and Link Orthopedics; consulting fees from Think Surgical and OrthAlign; patent planned, issued, or pending with Zimmer Biomet; leadership or fiduciary role with the American Association of Hip and Knee Surgeons, Muller Foundation, and the Academic Network of Conservational Hip Outomes Research; receipt of equipment, materials, drugs, medical writing, gifts, or other services from Springer. M.J.T. No relevant relationships. C.C.W. No relevant relationships.
(© 2022 by the Radiological Society of North America, Inc.)