ObjectiveTo explore the feasibility of establishment of a artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation.MethodsTwenty-four 8-week-old male severe combined immunodeficient (SCID) mice were divided into experimental group (n=12) and control group (n=12). The titanium nail was inserted into the tibial medullary cavity of mouse in the two groups to simulate artificial joint prosthesis replacement. And the cobalt-chromium particles were injected into the tibial medullary cavity of mouse in experimental group. The survival of the mouse was observed after operation; the position of the titanium nail and the bone mineral density of proximal femur were observed by X-ray film, CT, and Micro-CT bone scanning; and the degree of dissolution of the bone tissue around the tibia was detected by biomechanical test and histological staining.ResultsTwo mice in experimental group died, and the rest of the mice survived until the experiment was completed. Postoperative imaging examination showed that there was no obvious displacement of titanium nails in control group, and there were new callus around the titanium nails. In experimental group, there was obvious osteolysis around the titanium nails. The bone mineral density of the proximal tibia was 91.25%±0.67%, and the maximum shear force at the tibial nail-bone interface was (5.93±0.85) N in experimental group, which were significantly lower than those in control group [102.07%±1.87% and (16.76±3.09) N] (t=5.462, P=0.041; t=3.760, P=0.046). Histological observation showed that a large number of inflammatory cells could be seen around the titanium nails in experimental group, while there was no inflammatory cells, and obvious bone tissue formation was observed in control group.ConclusionThe artificial joint aseptic loosening mouse model can be successfully established by cobalt-chromium particles stimulation.
ObjectiveTo investigate the effectiveness and advantages of skeletal tractor in closed reduction and proximal femoral nail antirotation (PFNA) internal fixation of intertrochanteric fracture compared with traction table.MethodsThe clinical data of 86 patients with intertrochanteric fractures, who were treated with closed reduction and PFNA internal fixation between October 2016 and March 2018 and met the selection criteria, was retrospectively analysed. Among them, 44 cases were treated with skeletal tractor (trial group) and 42 cases were treated with traction table (control group). There was no significant difference between the two groups in gender, age, cause of injury, fracture side, AO classification, and degree of osteoporosis (P>0.05). The preoperative position time, operation time, intraoperative fluoroscopy times, intraoperative blood loss, fracture healing time, intraoperative and postoperative complications, and postoperative Harris score were compared between the two groups.ResultsThe operation was successfully completed in both groups. Compared with the control group, the patients in the trial group had shorter preoperative position time and operation time, fewer intraoperative fluoroscopy times, and less intraoperative blood loss (P<0.05). The patients were followed up 12-21 months in trial group (mean, 14.2 months) and 12-22 months in control group (mean, 14.3 months). Venous thrombosis of lower extremity occurred in 8 patients (3 cases of trial group and 5 cases of control group) after operation. Internal fixation failure occurred in 5 patients (2 cases of trial group and 3 cases of control group) during 1 year after operation. All fractures healed except for those with internal fixation failure, the fracture healing time was (11.6±2.9) weeks in trial group and (12.4±3.6) weeks in control group; and there was no significant difference between the two groups (t=1.250, P=0.214). At 1 year after operation, Harris score of the trial group was 86.2±5.9 and that of the control group was 84.1±6.1. There was no significant difference between the two groups (t=1.768, P=0.080).ConclusionCompared with traction table, skeletal tractor in closed reduction and PFNA internal fixation of intertrochanteric fracture can significantly shorten the preoperative position time and operation time, reduce the intraoperative fluoroscopy times, improve the operation efficiency, and have similar effectiveness.