A Study on Early Diagnosis for Fracture Nonunion Prediction Using Deep Learning and Bone Morphometric Parameters

Hui Yu ¹ Qiyue Mu ² Zhi Wang ³ Yu Guo ¹ Jing Zhao ² Guangpu Wang ² Qingsong Wang ² Xianghong Meng ³ Xiaoman Dong ³ Shuo Wang ^2* Jinglai Sun ^4*

• ¹ State Key Laboratory of Advanced Medical Materials and Devices,Tianjin University School of Medicine, Tianjin, China
• ² Department of Biomedical Engineering, Tianjin University School of Medicine, Tianjin, China
• ³ Radiology Department, Tianjin University Tianjin Hospital, Tianjin, China
• ⁴ Haihe Laboratory of Brain-computer Interaction and Human-machine Integration, Tianjin University School of Medicine, Tianjin, China

Background: Early diagnosis of nonunion fractures is vital for treatment planning, yet studies using bone morphometric parameters for this purpose are scarce. This study aims to create a fracture micro-CT image dataset, design a deep learning algorithm for fracture segmentation, and develop an early diagnosis model for fracture nonunion.Methods: Using fracture animal models, micro-CT images from 12 rats at various healing stages (days 1, 7, 14, 21, 28, and 35) were analyzed. Fracture lesion frames were annotated to create a high-resolution dataset. We proposed the Vision Mamba Triplet Attention and Edge Feature Decoupling Module UNet (VM-TE-UNet) for fracture area segmentation. And we extracted bone morphometric parameters to establish an early diagnostic evaluation system for the nonunion of fractures.Results: A dataset comprising 2,448 micro-CT images of the rat fracture lesions with fracture Region of Interest (ROI), bone callus and healing characteristics was established and used to train and test the proposed VM-TE-UNet which achieved a Dice Similarity Coefficient of 0.809, an improvement over the baseline's 0.765, and reduced the 95th Hausdorff Distance to 13.1. Through ablation studies, comparative experiments, and result analysis, the algorithm's effectiveness and superiority were validated. Significant differences (p<0.05) were observed between the fracture and fracture nonunion groups during the inflammatory and repair phases. Key indices, such as the average CT values of hematoma and cartilage tissues, BS/TS and BS/TV of mineralized cartilage, BS/TV of osteogenic tissue, and BV/TV of osteogenic tissue, align with clinical methods for diagnosing fracture nonunion by assessing callus presence and local soft tissue swelling. On day 14, the early diagnosis model achieved an AUC of 0.995, demonstrating its ability to diagnose fracture nonunion during the soft-callus phase.Conclusion: This study proposed the VM-TE-UNet for fracture areas segmentation, extracted micro-CT indices, and established an early diagnostic model for fracture nonunion. We believe that the prediction model can effectively screen out samples of poor fracture rehabilitation caused by blood supply limitations in rats 14 days after fracture, rather than the widely accepted 35 or 40 days. This provides important reference for the clinical prediction of fracture nonunion and early intervention treatment.