Total hip arthroplasty(THA)is an effective treatment for elderly femoral neck fractures,mid-to late-stage femoral head necrosis,and end-stage hip osteoarthritis.However,serious complications such as aseptic loosening of the prosthesis,peripheral fractures,and dislocation of the prosthesis still exist following THA,which makes the selection of the appropriate hip prosthesis type and placement position before THA an important challenge for surgeons.Currently,the commonly used preoperative planning methods for THA mainly rely on static images from two-dimensional(2D)X-ray or three-dimensional(3D)computed tomography(CT),which fail to adequately consider the hip joint in weight-bearing as well as motion,lumbar-hip joint changes,and prosthetic impingement during motion.Recently,the dual fluoroscopic imaging system,as a new in-vivo,dynamic radiological imaging technology,provides comprehensive and accurate dynamic 3D data for THA preoperative planning.However,the technical process and expert consensus on preoperative 3D planning of THA using a dual fluoroscopic imaging system have not yet been established,which affects the promotion and application of this technology.In light of the above,national orthopaedic experts and related professional representatives discussed and proposed seven consensus issues,and the'expert recommendation rate'and'strong recommendation rate'were obtained through a questionnaire survey on the recommendations of the participating experts.This consensus aims to provide guidance and reference for the standardised application of preoperative 3D planning of THA using the dual fluoroscopic imaging system.

Total hip arthroplasty(THA)is an effective treatment for elderly femoral neck fractures,mid-to late-stage femoral head necrosis,and end-stage hip osteoarthritis.However,serious complications such as aseptic loosening of the prosthesis,peripheral fractures,and dislocation of the prosthesis still exist following THA,which makes the selection of the appropriate hip prosthesis type and placement position before THA an important challenge for surgeons.Currently,the commonly used preoperative planning methods for THA mainly rely on static images from two-dimensional(2D)X-ray or three-dimensional(3D)computed tomography(CT),which fail to adequately consider the hip joint in weight-bearing as well as motion,lumbar-hip joint changes,and prosthetic impingement during motion.Recently,the dual fluoroscopic imaging system,as a new in-vivo,dynamic radiological imaging technology,provides comprehensive and accurate dynamic 3D data for THA preoperative planning.However,the technical process and expert consensus on preoperative 3D planning of THA using a dual fluoroscopic imaging system have not yet been established,which affects the promotion and application of this technology.In light of the above,national orthopaedic experts and related professional representatives discussed and proposed seven consensus issues,and the'expert recommendation rate'and'strong recommendation rate'were obtained through a questionnaire survey on the recommendations of the participating experts.This consensus aims to provide guidance and reference for the standardised application of preoperative 3D planning of THA using the dual fluoroscopic imaging system.

BACKGROUND:Femoral neck fracture is mainly fixed by three inverted triangle cannulated screws. Scholars have proposed to add a cannulated screw to enhance the fixation strength of femoral neck fracture of Pauwels III type based on three cannulated screw fixation, but the stability is not verified. OBJECTIVE:To analyze the biomechanical stability and stress of the three and four cannulated screws for the treatment of the Pauwels III femoral neck fractures. METHODS:The CT imaging results of the fourth generation of artificial bone sawbones were imported into the Mimics software wherein a three-dimensional finite element model of the proximal femur was prepared and introduced in the 3-matic software. Models of middlesegment of femoral neck with Pauwels III fractures were established. Cannulated screw models were established with UG 8.0 software and introduced in the fractures models. Finally, finite element models of Pauwels III femoral neck fractures fixed with three and four screws were established. In the same condition, an axial load of 411 N was applied on the femoral head with Abaqus software. The displacement of two markers of the broken ends and internal fixation system Von Mises stress distribution were compared between the two models. RESULTS AND CONCLUSION:(1) The displacement was 0.42 mm in three screws model, and 0.17 mm in the four screws model. (2) Von Mises stress peak was 547 MPa and 27.8 MPa in both models. The peak value was lower in models of fourscrews than that of three screws. Stress concentration position was at the fracture site in both models. The stress range of models of four screws was more extensive and scattered. (3) Finite element analysis results demonstrated that four-screw implantation for Pauwels III femoral neck fractures had strong anti-shearing force and biomechanical stability. Clinical advantages need further clinical comparative study.

0.05).Conclusion CAP infiltration at trigeminal nerve infraorbital branch region in rats can produce stronger analgesic effect,it related to the dosage,concentration,using dosage, time and intermission.