OBJECTIVE: In order to select the proper size of prosthesis ball head, the biomechanical changes of hip joint using different diameter prosthesis ball head was studied by three-dimensional finite element analysis. METHODS: The thin-layer CT data and related parameters of artificial femoral head prosthesis were used to establish the finite element model of hip joint after artificial femoral head replacement with different ball diameter of prosthesis(M0:preoperative model;M1:ball head diameter=original femoral head diameter;M2:ball head diameter=original femoral head diameter+1 mm;M3:Ball head diameter= Original femoral head diameter -1 mm;M4:ball head diameter =original femoral head diameter -2 mm). Loading the joint forces and related muscle loads were loaded, and the stress distribution and change of bone and cartilage around acetabulum were analyzed by simulating the standing state of one foot when walking slowly. RESULTS: (1) In M1 to M4, the stress concentration in pelvis was different. The peak value of Von Mises stress in the pelvis of M3 was 44.8 MPa, which was the closest to that before operation, with an increment of 13.4%. The displacement of the pelvis of M3 was the smallest in the four groups after operation, with an increment of 1.40 mm. The next was M1, with a peak value of 47.3 MPa, with an increment of 19.7%, and a pelvic displacement of 1.59 mm. (2) In acetabulum area, the peak value of Von Mises stress in M3 was 23.3 MPa, which was the closest to that before operation, with an increment of about 6.3%, followed by M1, with a peak value of 24.0 MPa and an increment of about 8.1%. (3) On the acetabulum cartilage, the stress distribution of M1 and M3 was similar to that before operation, and the peak value of Von Mises stress of M3 was 18.5 MPa, which was the closest to that before operation, followed by M1, which was 22.5 MPa. (4) M1 to M4 showed different degree of stress concentration in the outer upper quadrant of the artificial femoral head, but showed stress shielding under it;among them, the von Mises stress distribution of M3 was more uniform than that of other models, and its peak value (70.8 MPa) was the lowest in each group, followed by M1 (80.7 MPa). CONCLUSION When femoral head replacement is performed, it is suggested that the prosthesis ball head with the diameter less than 1 mm and the prosthesis ball head with the same diameter as the original femoral head should be used first, so as to obtain the closest natural mechanical characteristics of the hip joint before the replacement and reduce the risk of complications caused by size differences.
Femur Head ; Finite Element Analysis ; Hip Joint ; Hip Prosthesis ; Stress, Mechanical

Parathyroid hormone is one kind of osteoanabolic agents widely used in clinic for osteoporosis. However, parathyroid hormone needs to be further optimized in the treatment of osteoporosis due to its two way regulatory effect of bone formation with low-dose intermittent treatmentand bone resorption with high-dosecontinuous treatment. Hence, based on the molecular mechanism of parathyroid hormone regulating bone metabolism, we conclude that parathyroid hormone regulates bone metabolism mainly through the following signaling pathways: (1) Gs/cAMP/PKA signaling pathway, whichis the main mechanism of parathyroid hormone regulating bone metabolism to lead to bone formation or bone resorption. (2) G
Bone Resorption ; Humans ; Osteogenesis ; Osteoporosis ; Parathyroid Hormone ; Signal Transduction

OBJECTIVE: To investigate the feasibility of a drill template for the placement of guided template of middle and upper thoracic percutaneous vertebroplasty in thoracic pedicle approach on digital design and 3D printing technology. METHODS: The preoperative CT images of 20 patients with thoracic fracture were collected retrospectively. With the 3D soft tissue printing technology, the data was reconstructed by 3D imaging reconstruction software to produce 1∶1 three dimensional soft tissue model. The pedicle screw channel and the digital template were designed by the 3-matic module of Mimics15.0 software. After guide template was printed by 3D printer and three dimensional template was fixed on the model, 2.0 mm Kirschner was placed and the accuracy of a drill template was observed by CT scans, bone cement was injected through the puncture tube and verified with images. The time of nail guide design, guide template production and cost were recorded. RESULTS: The effectiveness of three dimensional thoracic model and digital guided template of middle and upper thoracic percutaneous vertebroplasty of thoracic fractures in thoracic pedicle approach was confirmed. Kirschner was placed and the accuracy of screw placement was confirmed with CT scanning. Template and the corresponding anatomical landmark fitted well, bone cement had showed good filling. The average printing time of upper thoracic spine model with soft tissue, the mean time of nail guide design, guide template production and cost were (719.00±3.03) min, (12.30±1.01) min, (55.50±10.30) min and RMB 3 150 yuan on average respectively. CONCLUSION By means of individual design and 3D soft tissue printingtechnology, accurate placement of guided template of middle and upper thoracic percutaneous vertebroplasty could be realized.
Humans ; Pedicle Screws ; Printing, Three-Dimensional ; Retrospective Studies ; Surgery, Computer-Assisted ; Vertebroplasty

OBJECTIVE: To explore biomechanical characteristics of minimally invasive different screw fixations in treating Sanders typeⅡcalcaneal fractures. METHODS: Dicom data of calcaneus by CT scan were input into Mimics 21.0 software and Ansys15.0 software to construct three-dimensional finite element digital model of calcaneus;this model was input into UG NX 10.0 software, and calcaneus was cut according to Sanders classification to establish Sanders typeⅡ calcaneus model with posterior articular surface collapse;then simulated minimally invasive screw internal fixation after calcaneal fracture:a screw from posterior articular surface was used to outside-in fix sustentaculum tali, other 4 screws were used to fix calcaneus by different methods through calcaneal tuberosity, and 4 different calcaneal models were obtained. Under the same conditions, 4 types of internal fixation models were loaded respectively, and nonlinear finite element analysis was performed to calculate the stress distribution of different internal fixation models. RESULTS: Under the same condition of loading, the model 3 had smaller displacement value, maximum calcaneus displacement value and maximum equivalent stress value of the screw than other three internal fixation models, and the stress was more dispersed. CONCLUSION In minimally invasive screw internal fixation of calcaneus fracture, after 1 sustentaculum tali screw fixation, 2 screws crossed fix posterior articular surface from calcaneal tuberosity, 2 screws fix parallelly calcaneocuboid joint from calcaneal tuberosity are more suitable for biomechanical requirements, and could provide basic theory for clinical treatment.
Bone Screws ; Calcaneus/surgery* ; Finite Element Analysis ; Fracture Fixation, Internal ; Fractures, Bone/surgery* ; Humans ; Treatment Outcome

There are still many unresolved problems in the treatment and prognosis of nondisplaced femoral neck fractures, such as nonunion and avascular necrosis of the caput femoris .In order to reduce the risk of various complications after non-displaced femoral neck fractures, the caput femoris posterior tilt of femoral neck fractures and its impact on prognosis have attracted more and more attention. A large number of scholars' studies have found that when the posterior tilt exceeds 20°, the risk of internal fixation failure increases significantly. Based on this concept, we can choose to use primary artificial joint replacement instead of three-screw internal fixation according to the different posterior tilt angles of patients to reduce the incidence of postoperative complications. At the same time, our analysis found that comminution of the posterior segment of the femoral neck would lead to an increase in the posterior inclination angles. The purpose of this review was to investigate the relationship between caput femoris posterior tilt of femoral neck fractures and surgical outcome, and to introduce a new method for measuring caput femoris posterior tilt of the femoral neck.
Humans ; Prognosis ; Postoperative Complications/epidemiology* ; Femoral Neck Fractures/complications* ; Femur Neck ; Reoperation ; Fracture Fixation, Internal/methods* ; Retrospective Studies

Objective:To investigate the relationship between adiponectin (ADIPOQ) gene polymorphism and postpartum type 2 diabetes mellitus (T2DM) in pregnant women with gestational diabetes mellitus (GDM).Methods:A retrospective study was conducted on 236 GDM postpartum women admitted to the Affiliated Hospital of Jining Medical College from June 2020 to June 2021 as observation subjects. They were divided into a T2DM group and a non T2DM group based on the occurrence of T2DM after delivery. The clinical data of the two groups were compared. The double deoxygenation end termination method was used to detect the single nucleotide polymorphism (SNP) of the ADIPOQ gene, and the four loci rs17366568, rs822395, rs1501299, and rs2241766 were classified. The relationship between ADIPOQ genotype polymorphism and postpartum T2DM was analyzed using a logistic regression model.Results:The G allele carrying the rs2241766 locus in ADIPOQ gene was negatively correlated with the occurrence of T2DM ( OR=0.71, 0.68, P<0.05). Compared with T2DM patients with TT genotype, the GT+ GG genotype at the rs2241766 locus had a lower risk of occurrence for gestational age ≥2 and HbA 1c>85%. Similarly, T2DM patients with pre pregnancy body mass index (BMI)>25 kg/m 2 were more likely to be carriers of the rs2241766 TT genotype ( P=0.026). The (GT+ TT) genotype carrying the T allele at the rs1501299 locus was a protective factor for gestational age and HbA 1c in T2DM patients. Conclusions:The rs2241766 and rs1501299 polymorphisms of the ADIPOQ gene are associated with susceptibility to postpartum T2DM in GDM women. Individuals with rs2241766 and rs1501299 mutant genotypes belong to the high-risk population for T2DM.