Objective:To compare the clinical efficacy between our first generation and second generation dynamic anterior plate-screw system for quadrilateral area (DAPSQ) in the treatment of T-shaped acetabular fractures.Methods:A retrospective study was conducted of the 28 patients with T-shaped acetabular fractures who had been treated at Department of Orthopaedics, General Hospital of Central Theater Command from January 2008 to December 2019. They were divided into 2 groups according to fixation methods. Group A [15 patients, 11 males and 4 females, an age of (43.5±9.1) years] were treated with the first generation DAPSQ while Group B [13 patients, 8 males and 5 females, an age of (42.5±7.0) years] with the second generation DAPSQ. Operation time, intraoperative bleeding, fracture reduction, function of the affected hip and postoperative complications were recorded and compared between the 2 groups.Results:The 2 groups were comparable because there was no significant difference between them in the preoperative general data ( P>0.05). The 28 patients were followed up for 12 to 60 months (average, 35.0 months). The operation time [(193.9±33.3) min] and intraoperative bleeding [(830.8±177.4) mL] for Group B were significantly less than those for Group A [(231.3±40.0) min and (1,043.3±190.7) mL] ( P<0.05). In Group A, according to the Matta scoring, the fracture reduction was rated as excellent in 8 cases, good in 5 and poor in 2; in Group B, the fracture reduction was rated as excellent in 8 cases, good in 4 and poor in one. According to the modified Merle d'Aubigné & Postel scoring at the final follow-up, the function of the affected hip was rated as excellent in 9 cases, as good in 3, as fair in 2 and as poor in one in Group A while as excellent in 9 cases, as good in 2 and as fair in 2 in Group B. There were no statistically significant differences between the 2 groups in reduction quality or in the function of the affected hip ( P>0.05). Follow-up observed hip traumatic arthritis in 2 cases in Group A and in one in Group B. Conclusion:In the treatment of T-shaped acetabular fractures, compared with the first generation DAPSQ, the second generation DAPSQ can shorten operation time and decrease intraoperative bleeding significantly, though both achieve comparable functional outcomes.

Objective:To analyze identification of copper death gene related subtypes,construction of prognosis model and influence of immune infiltration in osteosarcoma(OS)on basis of copper death gene.Methods:Survival and prognosis of OS associated copper death gene were analyzed combining by TARGET and GEO database.OS was divided into different subtypes of copper death by consistent clustering method.SSGSEA was used to analyze difference of immune cells in classification of copper death.Setting P value= 0.05 and q value=0.05,GO and KEGG enrichment analysis were performed on differential genes of copper death typing.Prognosis model was constructed according to results of Lasso regression analysis and cross validation,risk assessment analysis and ROC curve were used to evaluate accuracy of model prediction.Combined with clinical characteristics,nomograms were constructed to predict survival time of patients,and risk differences were analyzed.Immune cell infiltration and tumor microenvironment analysis were performed on OS samples."pRRophetic"package in R software was used to analyze drug sensitivity of OS samples.Results:FDX1,GLS,DLAT and PDHB as high-risk genes for OS prognosis were identified.According to copper death classification of OS samples,OS could be divided into two types:CRGclusterA and CRGclusterB.CRGclusterA was associated with Th2 cells,and CRGclusterB was associated with Th1 cells.Most OS copper death genes were highly expressed in CRGclusterA.Immune cell infiltration analysis results showed that γδ T cells,resting mast cells and resting dendritic cells were positively correlated with risk score,while CD8 T cells were negatively correlated with risk score.Drug sensitivity analysis showed that OS showed higher sensitivity to Elesclomol and GW.441756.Conclusion:Two subtypes of CRGclusterA and CRGclusterB are identified in this study.Four high-risk prognostic genes FDX1,GLS,DLAT and PDHB are identified,providing new insights into prognostic evaluation and immunotherapy target candidates for OS.

Objective:To introduce the standard screw implantation methods and to analyze the biomechanical stability of the second-generation dynamic anterior plate-screw system for quadrilateral area (DAPSQ).Methods:Six adult formalin-preserved corpses were selected to make a complete pelvic specimen. Further, the left high double-column fracture models were made and randomly fixed with second-generation DAPSQ or anterior reconstruction titanium plate and 1/3 tube buttress-plate (ARTPB). The specimens of intact pelvis (IP) group, DAPSQ group and ARTPB group were fixed on a Zwick Z100 material machine and loaded vertically with 200 N, 300 N, 400 N, 500 N, 600 N, 700 N, and 800 N in a simulated sitting position, respectively. The axial displacement and strain changes in the anterior and posterior columns were tested in the three groups. The stiffness was calculated accordingly.Results:The axial compression displacement in the three groups showed an increase trend as well with the vertical load increased from 200 N to 800 N ( F=68.581, P<0.001; F=91.795, P<0.001; F=33.819, P=0.002). The axial displacement in ARTPB group was significantly larger than that in DAPSQ group and IP group ( P<0.05), while the difference between DAPSQ and IP groups was not significant ( P>0.05). Under the vertical load of 600 N, the pelvic axial stiffness of IP group, DAPSQ group, and ARTPB group were 220.72±70.33 N/mm, 185.68±48.49 N/mm and 135.83±60.58 N/mm, respectively. The axial stiffness of ARTPB group was significantly lower than that in DAPSQ group and IP group ( t=5.345, P=0.003; t=6.443, P=0.001), while the difference between DAPSQ and IP groups was not significant ( t=2.138, P=0.086). There were no significant differences of the strain values in anterior column among the three groups during the load increasing from 200 N to 800 N ( P>0.05). With the load increasing from 500 N to 800 N, the strain values of the posterior column in ARTPB group were significantly greater than those of IP and DAPSQ groups ( P<0.05). However, the differences between IP and DAPSQ groups were not statistically significant in strain values of the posterior column ( P>0.05). Conclusion:Compared with anterior reconstruction titanium plate and 1/3 tube buttress-plate, acetabular double-column fracture model fixed with the second-generation DAPSQ has less axial compression displacement but with greater axial stiffness. The stress change in the posterior columns of the acetabulum is like in IP. Therefore, the second-generation DAPSQ has reliable biomechanical stability.