A nomogram model based on the combination of the systemic immune-inflammation index, body mass index, and neutrophil/lymphocyte ratio to predict the risk of preoperative deep venous thrombosis in elderly patients with intertrochanteric femoral fracture: a retrospective cohort study - Zeng, Guowei; Li, Xu; Li, Wencai; Wen, Zhijia; Wang, Shenjie; Zheng, Shaowei; Lin, Xia; Zhong, Haobo; Zheng, Jianping; Sun, Chunhan (Journal of Orthopaedic Surgery & Research, 2023)