BACKGROUND:Bipolar femoral head prosthesis has achieved the desired repair effect in patients with femoral neck fracture, but there is stil much controversy on the biomechanical properties of bipolar artificial femoral head prosthesis. OBJECTIVE:To compare biomechanical properties of the bipolar femoral head prosthesis replacement and internal fixation in the repair of femoral neck fracture in the elderly. METHODS:Twenty-three (46 sides) senile femoral neck fracture specimens were analyzed and randomized into internal fixation group(n=23)and bipolar femoral head prosthesis replacement group (n=23). Specimens in the internal fixation group underwent conventional metal implant fixation. Specimens in the bipolar femoral head prosthesis replacement group underwent bipolar femoral head prosthesis replacement. Mechanical properties of femoral prosthesis stem were tested on universal testing machine. Biomechanical properties after bipolar femoral head prosthesis replacement and internal fixation were compared. RESULTS AND CONCLUSION:(1) The maximum loadwassignificantly higher in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). The maximum load trend images showed that the maximum load was significantly higher in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). (2) The displacement in axial pul test was significantly shorter in the bipolar femoral head prosthesis replacement group than in theinternal fixation group (P< 0.05). The displacement trend images exhibited that the displacement in axial pul test was significantly shorter in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). (3) These findings suggest that compared with the implant, bipolar femoral head prosthesis replacement in the repair of femoral neck fracture in the elderly is more stable, has better repair effects, can elevate hip function and obtain good initial stability.

The liver is a highly proliferative organ. As the liver injured, the hepatocytes can quickly enter the cell cycle to restore the volume and function of liver. Liver regeneration involves complex processes that depend on the interaction of many different cell types. As limited by the average cell change level in tissues, traditional sequencing methods can only acquire the average genetic information reflecting dominant cell subpopulations, but ignore the secondary cell subpopu-lations, which leads to the loss of cellular heterogeneity information. Single-cell sequencing tech-nology can analyze the biological behavior of single cell, which helps to better understand the distri-bution, interaction and cell heterogeneity of different cells during liver regeneration. The authors review the application of single cell sequencing technology in liver regeneration.