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BACKGROUND: As a classic surgical method for the treatment of femoral head necrosis and femoral neck fracture, total hip arthroplasty has some problems, such as poor placement of prosthesis, postoperative dislocation and so on. OrthoPilot navigation assisted total hip arthroplasty can theoretically improve the accuracy and safety of prosthesis placement. At present, there are few studies on its application in total hip arthroplasty in China. OBJECTIVE: To explore the feasibility and short-term clinical effect of OrthoPilot navigation assisted total hip arthroplasty. METHODS: A retrospective analysis was performed in 23 patients who received OrthoPilot navigation assisted total hip arthroplasty in the Department of Joint surgery of the First Affiliated Hospital of Anhui Medical University from June 2019 to April 2022. A total of 23 patients with freehand total hip arthroplasty were matched at 1:1 according to sex, age, body mass index and preoperative Harris score. The anteversion and inclination angles during and after operation were measured and counted. The operation time, total blood loss, postoperative drainage, average hemoglobin loss and postoperative Harris scores were calculated. RESULTS AND CONCLUSION: (1) The operation time in the navigation group was (152.4±39.9) minutes and in the non-navigation group was (115.3±35.4) minutes, with statistically significant (P=0.02). (2) In terms of angle measurement, the anteversion angle of acetabular cup was (42.3±3.5)° during operation and (42.6±5.5)° after operation, with no significant difference (P=0.574) in the navigation group. The inclination angle of acetabular cup was (18.5±3.4)° during operation and (19.3±3.9)° after operation, with no significant difference (P=0.567) in the navigation group. (3) According to “Lewinnek safe zone”, 22 hips were in the safety zone and 1 hip outside the safety zone after operation in the navigation group, while 17 hips were in the safety zone and 6 hips outside the safety zone after operation in the non-navigation group, showing a significant difference (χ ² =4.212, P=0.04). (4) In terms of surgical treatment, there was no significant difference in total blood loss, postoperative drainage, average hemoglobin loss, Harris score, and the incidence of postoperative lower extremity deep venous thrombosis between the two groups. (5) The average follow-up was 3 months after operation, and there were no patients with early infection or dislocation in the two groups. (6) These results verify that OrthoPilot navigation assisted total hip arthroplasty can improve the accuracy and safety of acetabular cup placement, and its short-term clinical effect is not significantly different from that of freehand total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Rapeseed is mainly cultivated in hilly areas in China and the inclination angle is an important parameter for influencing the seeding quality of a seed-metering device. However, the relationship between seeding performance and inclination angle remains unclear. This study analyzes the influence of inclination angle (θ) on the characteristics of seed-filling and seeding performance in a centralized seed-metering system of rapeseed using DEM simulation and the bench test. The results revealed that the inclination angle (θ) had a significant effect on seed-filling performance. The missing seeds ratio and the deviation of seed layer height increased with an increase in a lateral inclination angle. The missing seeds ratio in the forward direction (−Y direction) and seed-filling angle, double seed-filling ratio, and seed layer height in the back direction (Y direction) increased with the increasing inclination angle. Under seed-cleaning treatment, the missing seeds ratio was significantly reduced in the −Y direction at a seed layer height of 25 mm, and the qualified ratio was more than 91.0% at a seed layer height of 20 mm in X direction. The phenomenon of seeds passing through the seed-metering wheel disappeared with a qualified ratio larger than 90.0% in Y direction by installing a seed-cleaning brush. The results contributed to improving the knowledge of seed-filling characteristics of the centralized seed-metering device at inclination conditions and should help to improve seeding performance by adjusting the seed layer height and installing a seed-cleaning brush. [ABSTRACT FROM AUTHOR]