BACKGROUND With the modernization of society and transportation in the last decades in China,the incidence of high-energy trauma increased sharply in China,including that of acetabular fractures.AIM To establish diffe...BACKGROUND With the modernization of society and transportation in the last decades in China,the incidence of high-energy trauma increased sharply in China,including that of acetabular fractures.AIM To establish different finite element models for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.METHODS The three-dimensional models of the normal and fractured pelvis and the five internal fixations were established using the computed tomography data of the pelvis of a living volunteer.After the vertebral body model was inserted in the way of origin matching and all cancellous bones were copied using the duplicated cancellous bone model as the subtractive entity,the Boolean operation was performed on the pelvis model to obtain the model of the complete pelvis cortical and cancellous bones.RESULTS In the standing position,the maximum stress was 46.21 MPa.In the sitting position,the sacrum bore the simulated gravity load at the upper end.When comparing the five fixations,there were no significant differences in the stress mean values among groups(sitting:P=0.9794;standing:P=0.9741).In terms of displacement,the average displacement of the internal iliac plate group was smaller than that of the spring plate group(P=0.002),and no differences were observed between the other pairs of groups(all P>0.05).In the standing position,there were no significant differences in the mean value of displacement among the groups(P=0.2985).It can be seen from the stress nephogram of the internal fixations in different positions that the stress of the internal fixation was mainly concentrated in the fracture segment.CONCLUSION There were no significant differences among the fixations for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.展开更多
Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fra...Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fractures was done. Fixation was done with locking plate for femoral shaft fracture （3 patients）, supracondylar fracture of femur （gap nonunion）, fracture of clavicle, fracture of both forearm bones （radius and ulna） fracture of ulna, fracture of shaft of humerus, fracture of tibial diaphysis and supracondylar frac- ture of humerus （one patient each）. Five fractures had more than one previous failed internal fixation. One patient had infected nonunion which was managed by debridement with cast immobilization followed by fixation with locking plate at six weeks. Seven fractures were atrophic, two were oligotrophic, and one was hypertrophic. Fibular autograft was used in 2 cases and iliac crest cancellous bone graft used in all the patients. Results： Minimum follow-up was 6 months （range, 6 months to 2.5 years）. Average time for union was 3.4 months （range 2.5 to 6 months）. None of the patients had plate- related complications or postoperative wound infections. Conclusion： Along with achieving stability with locking compression plate, meticulous soft tissue dissection, acceptable reduction, good fixation technique and bone grafting can help achieve union in difficult nonunion cases. Though locking plate does not by itself ensure bony union, we have found it to be another useful addition to our armamentarium for treating difficult fracture nonunions.展开更多
Background Anterior cruciate ligament reconstruction （ACLR） has developed dramatically in the last century.Now,ACLR has become a reliable and productive procedure.Patients feel satisfied in 〉90% cases.The aim of th...Background Anterior cruciate ligament reconstruction （ACLR） has developed dramatically in the last century.Now,ACLR has become a reliable and productive procedure.Patients feel satisfied in 〉90% cases.The aim of this study was to evaluate the feasibility of allogenetic cortical bone cross-pin （ACBCP） used as a clinical fixation method in anterior cruciate ligament reconstruction on the femoral side based on biomechanical tests in vitro.Methods The specimens were provided by the bone banks of the First Affiliated Hospital of People＇s Liberation Army of General Hospital from September 2011 to June 2012.Fresh deep frozen human allogenetic cortical bone was machined into cross-pins which is 4.0 mm in diameter and 75.0 mm in length.Biomechanical parameters compared with Rigidfix were collected while cross-pins were tested in double-shear test.The load-to-failure test and cycling test were carried out in a goat model to reconstruct anterior cruciate ligament with Achilles tendon autograft on the femoral side fixed by human 4.0 mm ACBCP and 3.3 mm Rigidfix served as control.Maximum failure load,yield load,and stiffness of fixation in single load-to-failure test were compared between the two groups.Cycle-specific stiffness and displacement at cycles 1,30,200,400,and 1 000 were also compared in between.Results In double-shear test both maximum failed load and yield load of 4.0 mm humanACBCP were （1 236.998±201.940） N.Maximum failed load and yield load of Rigidfix were （807.929±110.511） N and （592.483±58.821） N.The differences of maximum failed load and yield load were significant between ACBCP and Rigidfix,P 〈0.05.The shear strength of ACBCP and Rigidfix were （49.243±8.039） MPa and （34.637±3.439） MPa,respectively,P 〈0.05.In the load-to-failure test ex vivo,yield load and maximum failed load of ACBCP fixation complexity （（867.104±132.856）N,（1 032.243±196.281） N） were higher than those of Rigidfix （（640.935±42.836） N,（800.568±64.890） N,P 〈0.05）.However,stiffness did not differ significantly between ACBCP group （（247.116±31.897）N/mm） and Rigidfix group （（220.413±51.332） N/mm,P 〉0.05）.In the cycling test,the cycle-specific stiffness and displacement at cycles 1,30,200,400,and 1 000 did not differ significantly between the ACBCP group and Rigidfix group,P 〉0.05.Conclusions Allogenetic cortical bone cross-pin possesses satisfactory biomechanical profile which is safe for ACLR and suitable for an aggressive rehabilitation program.Animal and clinical tests should be recommended before clinical use to secure the ACBCP could successfully substituted by host new bone in vivo.展开更多
基金National Natural Science Foundation of China,No.81272008.
文摘BACKGROUND With the modernization of society and transportation in the last decades in China,the incidence of high-energy trauma increased sharply in China,including that of acetabular fractures.AIM To establish different finite element models for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.METHODS The three-dimensional models of the normal and fractured pelvis and the five internal fixations were established using the computed tomography data of the pelvis of a living volunteer.After the vertebral body model was inserted in the way of origin matching and all cancellous bones were copied using the duplicated cancellous bone model as the subtractive entity,the Boolean operation was performed on the pelvis model to obtain the model of the complete pelvis cortical and cancellous bones.RESULTS In the standing position,the maximum stress was 46.21 MPa.In the sitting position,the sacrum bore the simulated gravity load at the upper end.When comparing the five fixations,there were no significant differences in the stress mean values among groups(sitting:P=0.9794;standing:P=0.9741).In terms of displacement,the average displacement of the internal iliac plate group was smaller than that of the spring plate group(P=0.002),and no differences were observed between the other pairs of groups(all P>0.05).In the standing position,there were no significant differences in the mean value of displacement among the groups(P=0.2985).It can be seen from the stress nephogram of the internal fixations in different positions that the stress of the internal fixation was mainly concentrated in the fracture segment.CONCLUSION There were no significant differences among the fixations for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.
文摘Objective： To present our experience in treatment of difficult ununited long bone fractures with locking plate. Methods： Retrospective evaluation of locking plate fixation in 10 difficult nonunions of long bone fractures was done. Fixation was done with locking plate for femoral shaft fracture （3 patients）, supracondylar fracture of femur （gap nonunion）, fracture of clavicle, fracture of both forearm bones （radius and ulna） fracture of ulna, fracture of shaft of humerus, fracture of tibial diaphysis and supracondylar frac- ture of humerus （one patient each）. Five fractures had more than one previous failed internal fixation. One patient had infected nonunion which was managed by debridement with cast immobilization followed by fixation with locking plate at six weeks. Seven fractures were atrophic, two were oligotrophic, and one was hypertrophic. Fibular autograft was used in 2 cases and iliac crest cancellous bone graft used in all the patients. Results： Minimum follow-up was 6 months （range, 6 months to 2.5 years）. Average time for union was 3.4 months （range 2.5 to 6 months）. None of the patients had plate- related complications or postoperative wound infections. Conclusion： Along with achieving stability with locking compression plate, meticulous soft tissue dissection, acceptable reduction, good fixation technique and bone grafting can help achieve union in difficult nonunion cases. Though locking plate does not by itself ensure bony union, we have found it to be another useful addition to our armamentarium for treating difficult fracture nonunions.
文摘Background Anterior cruciate ligament reconstruction （ACLR） has developed dramatically in the last century.Now,ACLR has become a reliable and productive procedure.Patients feel satisfied in 〉90% cases.The aim of this study was to evaluate the feasibility of allogenetic cortical bone cross-pin （ACBCP） used as a clinical fixation method in anterior cruciate ligament reconstruction on the femoral side based on biomechanical tests in vitro.Methods The specimens were provided by the bone banks of the First Affiliated Hospital of People＇s Liberation Army of General Hospital from September 2011 to June 2012.Fresh deep frozen human allogenetic cortical bone was machined into cross-pins which is 4.0 mm in diameter and 75.0 mm in length.Biomechanical parameters compared with Rigidfix were collected while cross-pins were tested in double-shear test.The load-to-failure test and cycling test were carried out in a goat model to reconstruct anterior cruciate ligament with Achilles tendon autograft on the femoral side fixed by human 4.0 mm ACBCP and 3.3 mm Rigidfix served as control.Maximum failure load,yield load,and stiffness of fixation in single load-to-failure test were compared between the two groups.Cycle-specific stiffness and displacement at cycles 1,30,200,400,and 1 000 were also compared in between.Results In double-shear test both maximum failed load and yield load of 4.0 mm humanACBCP were （1 236.998±201.940） N.Maximum failed load and yield load of Rigidfix were （807.929±110.511） N and （592.483±58.821） N.The differences of maximum failed load and yield load were significant between ACBCP and Rigidfix,P 〈0.05.The shear strength of ACBCP and Rigidfix were （49.243±8.039） MPa and （34.637±3.439） MPa,respectively,P 〈0.05.In the load-to-failure test ex vivo,yield load and maximum failed load of ACBCP fixation complexity （（867.104±132.856）N,（1 032.243±196.281） N） were higher than those of Rigidfix （（640.935±42.836） N,（800.568±64.890） N,P 〈0.05）.However,stiffness did not differ significantly between ACBCP group （（247.116±31.897）N/mm） and Rigidfix group （（220.413±51.332） N/mm,P 〉0.05）.In the cycling test,the cycle-specific stiffness and displacement at cycles 1,30,200,400,and 1 000 did not differ significantly between the ACBCP group and Rigidfix group,P 〉0.05.Conclusions Allogenetic cortical bone cross-pin possesses satisfactory biomechanical profile which is safe for ACLR and suitable for an aggressive rehabilitation program.Animal and clinical tests should be recommended before clinical use to secure the ACBCP could successfully substituted by host new bone in vivo.
