Biomechanical comparison of the therapeutic effect of a novel proximal femoral bionic intramedullary nail and traditional inverted triangle hollow screw on femoral neck fracture.

OBJECTIVE: A novel Proximal Femoral Bionic Nail (PFBN) has been developed by a research team for the treatment of femoral neck fractures. This study aims to compare the biomechanical properties of the innovative PFBN with those of the conventional Inverted Triangular Cannulated Screw (ITCS) fixation method through biomechanical testing. METHODS: Sixteen male femoral specimens preserved in formalin were selected, with the donors' age at death averaging 56.1 ± 6.3 years (range 47-64 years), and a mean age of 51.4 years. The femurs showed no visible damage and were examined by X-rays to exclude diseases affecting bone quality such as tumors, severe osteoporosis, and deformities. The 16 femoral specimens were randomly divided into an experimental group (n = 8) and a control group (n = 8). All femurs were prepared with Pauwels type III femoral neck fractures, fixed with PFBN in the experimental group and ITCS in the control group. Displacement and stress limits of each specimen were measured through cyclic compression tests and failure experiments, and vertical displacement and strain values under a 600 N vertical load were measured in all specimens through vertical compression tests. RESULTS: In the vertical compression test, the average displacement at the anterior head region of the femur was 0.362 mm for the PFBN group, significantly less than the 0.480 mm for the ITCS group (p < 0.001). At the fracture line area, the average displacement for the PFBN group was also lower than that of the ITCS group (0.196 mm vs. 0.324 mm, p < 0.001). The difference in displacement in the shaft area was smaller, but the average displacement for the PFBN group (0.049 mm) was still significantly less than that for the ITCS group (0.062 mm, p = 0.016). The situation was similar on the posterior side of the femur. The average displacements in the head area, fracture line area, and shaft area for the PFBN group were 0.300 mm, 0.168 mm, and 0.081 mm, respectively, while those for the ITCS group were 0.558 mm, 0.274 mm, and 0.041 mm, with significant differences in all areas (p < 0.001). The average strain in the anterior head area for the PFBN group was 4947 µm/m, significantly less than the 1540 µm/m for the ITCS group (p < 0.001). Likewise, in the fracture line and shaft areas, the average strains for the PFBN group were significantly less than those for the ITCS group (p < 0.05). In the posterior head area, the average strain for the PFBN group was 4861 µm/m, significantly less than the 1442 µm/m for the ITCS group (p < 0.001). The strain conditions in the fracture line and shaft areas also showed the PFBN group was superior to the ITCS group (p < 0.001). In cyclic loading experiments, the PFBN fixation showed smaller maximum displacement (1.269 mm vs. 1.808 mm, p < 0.001), indicating better stability. In the failure experiments, the maximum failure load that the PFBN-fixated fracture block could withstand was significantly higher than that for the ITCS fixation (1817 N vs. 1116 N, p < 0.001). CONCLUSION: The PFBN can meet the biomechanical requirements for internal fixation of femoral neck fractures. PFBN is superior in biomechanical stability compared to ITCS, particularly showing less displacement and higher failure resistance in cyclic load and failure experiments. While there are differences in strain performance in different regions between the two fixation methods, overall, PFBN provides superior stability.

Effects of off-pump coronary artery bypass graft on the clinical efficacy, surgical indicators, and cardiac function of patients with coronary heart disease.

BACKGROUND: Coronary heart disease (CHD) is a common clinical cardiovascular disease. This study aimed to analyze the effects of off-pump coronary artery bypass graft on the clinical efficacy, surgical indicators, and cardiac function of patients with CHD. METHODS: We retrospectively analyzed the clinical data of 120 patients with CHD who were treated in our hospital from May 2017 to May 2020. And they were divided into the control group (extracorporeal coronary artery bypass graft) and the observation group (off-pump coronary artery bypass graft). The clinical efficacy, surgical indicators, cardiac function, myocardial injury, the degree of cardiac autonomic nerve imbalance, incidence of complications and quality of life one year after the operation in the 2 groups were compared. RESULTS: The total effective rate of the observation group was significantly higher than that of the control group. Intraoperative blood loss, operation time, intraoperative blood transfusion, and hospital stay in the observation group were significantly better than those in the control group. After treatment, the levels of cardiac index (CI), ejection fraction (EF), stroke volume (SV), and cardiac output (CO) in the observation group and the control group were higher than those before treatment, especially in the observation group. Compared with those before operation, CK-MB and cTnI of the two groups significantly increased at all time points after surgery. After treatment, SDNN, LF, HF, and TP of patients in the two groups increased, which was significant in the observation group. The incidence of complications such as myocardial infarction, ischemic changes, respiratory insufficiency, and intraoperative ventricular fibrillation in the observation group was significantly lower than that in the control group. The score of quality of life in the observation group was significantly higher than the control group. CONCLUSIONS: In the treatment of patients with CHD, off-pump coronary artery bypass graft has good clinical effects, which can significantly improve the heart function, and cardiac autonomic nerve imbalance of patients, reduce myocardial damage, decrease the incidence of complications, and improve the quality of life. Therefore, off-pump coronary artery bypass graft is worthy of clinical application.