Objective:To explore the mechanical behavior of acetabulum loaded by static stress and provide the mechanical basis for clinical analysis and judgement on acetabular mechanical distribution and effect of static stress...Objective:To explore the mechanical behavior of acetabulum loaded by static stress and provide the mechanical basis for clinical analysis and judgement on acetabular mechanical distribution and effect of static stress.Methods:By means of computer simulation, acetabular three dimensional model was input into three dimensional finite element analysis software ANSYS7.0. The acetabular mechanical behavior was calculated and the main stress value, stress distribution and acetabular unit displacement in the direction of main stress were analyzed when anterior wall of acetabulum and acetabular crest were loaded by 1 000 N static stress. Results:When acetabular anterior wall loaded by X direction and Z direction composition force, the stress passed along 4 directions: (1)from acetabular anterior wall to pubic symphysis along superior branch of pubis firstly, (2)from acetabular anterior wall to cacroiliac joint along pelvic ring,(3)in the acetabulum,(4)from the suffered point to ischium. When acetabular crest loaded by X direction and Y direction composition force, the stress transmitted to 4 directions: (1)from acetabular crest to ilium firstly, (2)from suffered point to cacroiliac joint along pelvic ring,(3) in the acetabulum ,(4)along the pubic branch,but no stress transmitted to the ischium branch.Conclusion:Analyzing the stress distribution of acetabulum and units displacement when static stress loaded can provide internal fixation point for acetabular fracture treatment and help understand the stress distribution of acetabulum.展开更多
Objective： The effect of tranexamic acid （TA） on patients receiving total knee arthroplasty （TKA） has been reported in many small clinical trials. But single trials are not sufficient enough to clarify the effect...Objective： The effect of tranexamic acid （TA） on patients receiving total knee arthroplasty （TKA） has been reported in many small clinical trials. But single trials are not sufficient enough to clarify the effectiveness and safety of TA. So, we carried out a meta-analysis of randomized controlled trials to investigate the efficacy and safety of the intravenous use of TA in TKA. Methods： Literatures were retrieved in Cochrane Library, OVID, PubMed, EMBASE, CNKI and Wanfang Data. All the related literatures were checked by two independent investigators and only the high quality randomized con- trolled trials were enrolled. Relevant data were analyzed using RevMan 5.1 to compare the difference of blood loss, transfusion and complications between TA group and con- trol group. Results： There were 353 related literatures and only 22 randomized controlled trials met the inclusion criteria. The use of TA in TKA significantly reduced total blood loss by a mean of 435.41 ml （95% C1300.62-570.21, P〈0.01）, post- operative blood loss by a mean of 406.69 ml （95% C1333.16- 480.22, P〈0.01）. TA also significantly lowered the transfu- sion rate （risk difference 0.30, 95% CI0.21-0.39, P〈0.01） and transfusion volume （mean difference 0.95 unit, 95% CI0.53- 1.37, P〈0.01）. The risks between TA group and control group in developing deep vein thrombosis and pulmonary embo- lism were not statistically significant. Conclusion： TA is beneficial for patients undergoing TKA, which can significantly reduce total blood loss, post- operative blood loss, transfusion rate, and transfusion volume. Meanwhile TA is recommended to reduce deep vein thrombosis and pulmonary embolism following TKA.展开更多
Objective： To evaluate the clinical application of the medial approach for repairing popliteal artery injuries. Methods： From 2002 to 2008, 11 cases ofpopliteal artery injuries had been repaired via the medial appr...Objective： To evaluate the clinical application of the medial approach for repairing popliteal artery injuries. Methods： From 2002 to 2008, 11 cases ofpopliteal artery injuries had been repaired via the medial approach. Of these cases, 8 had limb fractures, 1 had knee dislocation, and 2 had visceral injuries. Ten popliteal arteries were anastomosed directly while one was repaired with a great saphenous vein graft. Results： The operation time ranged from 3 to 4 hours （averaging 3.6 hours）. All the injured limbs survived. At the follow up, 8 legs recovered the full function, 2 had minor contracture, and 1 serious Volkmann＇s contracture without amputation. Conclusion： The medial approach for repair of the popliteal artery is effective, applicable, and more advantageous to the management of multi-injures.展开更多
Life-threatening in the short term and leading to a high level of morbidity in the long term, venous thromboembolism （VTE） is the most fearful complication following lower limb arthroplasty. With advances in surgica...Life-threatening in the short term and leading to a high level of morbidity in the long term, venous thromboembolism （VTE） is the most fearful complication following lower limb arthroplasty. With advances in surgical procedure, anesthetic management and postoperative convalescence have altered the risks of venous thromboembolism after total joint arthroplasty in the lower extremity.The pathogenesis of VTE is multifactorial and includes the well-known Virchow＇s triad of hypercoagulability, venous stasis and endothelial damage. Therefore, it is appropriate to use a multimodal approach to thromboprophylaxis. Despite extensive research, the ideal multimodal prophylaxis against venous thrombolism has not been identified. So this article reviews the recent developments in multimodal prophylaxis for thromboembolism after total joint arthroplasty.展开更多
Multibody musculoskeletal modeling of human gait has been proved helpful in investigating the pathology of musculoskeletal disorders.However,conventional inverse dynamics methods rely on external force sensors and can...Multibody musculoskeletal modeling of human gait has been proved helpful in investigating the pathology of musculoskeletal disorders.However,conventional inverse dynamics methods rely on external force sensors and cannot capture the nonlinear muscle behaviors.Meanwhile,the forward dynamics approach is computationally demanding and only suited for relatively simple tasks.This study proposed an integrated simulation methodology to fulfill the requirements of estimating foot-ground reaction force,tendon elasticity,and muscle recruitment optimization.A hybrid motion capture system,which combines the marker-based infrared device and markerless tracking through deep convolutional neural networks,was developed to track lower limb movements.The foot-ground reaction forces were determined by a contact model for soft materials,and its parameters were estimated using a two-step optimization method.The muscle recruitment problem was first resolved via a static optimization algorithm,and the obtained muscle activations were used as initial values for further simulation.A torque tracking procedure was then performed by minimizing the errors of joint torques calculated by musculotendon equilibrium equations and inverse dynamics.The proposed approach was validated against the electromyography measurements of a healthy subject during gait.The simulation framework provides a robust way of predicting joint torques,musculotendon forces,and muscle activations,which can be beneficial for understanding the biomechanics of normal and pathological gait.展开更多
文摘Objective:To explore the mechanical behavior of acetabulum loaded by static stress and provide the mechanical basis for clinical analysis and judgement on acetabular mechanical distribution and effect of static stress.Methods:By means of computer simulation, acetabular three dimensional model was input into three dimensional finite element analysis software ANSYS7.0. The acetabular mechanical behavior was calculated and the main stress value, stress distribution and acetabular unit displacement in the direction of main stress were analyzed when anterior wall of acetabulum and acetabular crest were loaded by 1 000 N static stress. Results:When acetabular anterior wall loaded by X direction and Z direction composition force, the stress passed along 4 directions: (1)from acetabular anterior wall to pubic symphysis along superior branch of pubis firstly, (2)from acetabular anterior wall to cacroiliac joint along pelvic ring,(3)in the acetabulum,(4)from the suffered point to ischium. When acetabular crest loaded by X direction and Y direction composition force, the stress transmitted to 4 directions: (1)from acetabular crest to ilium firstly, (2)from suffered point to cacroiliac joint along pelvic ring,(3) in the acetabulum ,(4)along the pubic branch,but no stress transmitted to the ischium branch.Conclusion:Analyzing the stress distribution of acetabulum and units displacement when static stress loaded can provide internal fixation point for acetabular fracture treatment and help understand the stress distribution of acetabulum.
文摘Objective： The effect of tranexamic acid （TA） on patients receiving total knee arthroplasty （TKA） has been reported in many small clinical trials. But single trials are not sufficient enough to clarify the effectiveness and safety of TA. So, we carried out a meta-analysis of randomized controlled trials to investigate the efficacy and safety of the intravenous use of TA in TKA. Methods： Literatures were retrieved in Cochrane Library, OVID, PubMed, EMBASE, CNKI and Wanfang Data. All the related literatures were checked by two independent investigators and only the high quality randomized con- trolled trials were enrolled. Relevant data were analyzed using RevMan 5.1 to compare the difference of blood loss, transfusion and complications between TA group and con- trol group. Results： There were 353 related literatures and only 22 randomized controlled trials met the inclusion criteria. The use of TA in TKA significantly reduced total blood loss by a mean of 435.41 ml （95% C1300.62-570.21, P〈0.01）, post- operative blood loss by a mean of 406.69 ml （95% C1333.16- 480.22, P〈0.01）. TA also significantly lowered the transfu- sion rate （risk difference 0.30, 95% CI0.21-0.39, P〈0.01） and transfusion volume （mean difference 0.95 unit, 95% CI0.53- 1.37, P〈0.01）. The risks between TA group and control group in developing deep vein thrombosis and pulmonary embo- lism were not statistically significant. Conclusion： TA is beneficial for patients undergoing TKA, which can significantly reduce total blood loss, post- operative blood loss, transfusion rate, and transfusion volume. Meanwhile TA is recommended to reduce deep vein thrombosis and pulmonary embolism following TKA.
文摘Objective： To evaluate the clinical application of the medial approach for repairing popliteal artery injuries. Methods： From 2002 to 2008, 11 cases ofpopliteal artery injuries had been repaired via the medial approach. Of these cases, 8 had limb fractures, 1 had knee dislocation, and 2 had visceral injuries. Ten popliteal arteries were anastomosed directly while one was repaired with a great saphenous vein graft. Results： The operation time ranged from 3 to 4 hours （averaging 3.6 hours）. All the injured limbs survived. At the follow up, 8 legs recovered the full function, 2 had minor contracture, and 1 serious Volkmann＇s contracture without amputation. Conclusion： The medial approach for repair of the popliteal artery is effective, applicable, and more advantageous to the management of multi-injures.
文摘Life-threatening in the short term and leading to a high level of morbidity in the long term, venous thromboembolism （VTE） is the most fearful complication following lower limb arthroplasty. With advances in surgical procedure, anesthetic management and postoperative convalescence have altered the risks of venous thromboembolism after total joint arthroplasty in the lower extremity.The pathogenesis of VTE is multifactorial and includes the well-known Virchow＇s triad of hypercoagulability, venous stasis and endothelial damage. Therefore, it is appropriate to use a multimodal approach to thromboprophylaxis. Despite extensive research, the ideal multimodal prophylaxis against venous thrombolism has not been identified. So this article reviews the recent developments in multimodal prophylaxis for thromboembolism after total joint arthroplasty.
基金the National Natural Science Foundations of China(Grant Nos.12102035 and 12125201)the China Postdoctoral Science Foundation(Grant No.2020TQ0042)the Beijing Natural Science Foundation(Grant No.L212008).
文摘Multibody musculoskeletal modeling of human gait has been proved helpful in investigating the pathology of musculoskeletal disorders.However,conventional inverse dynamics methods rely on external force sensors and cannot capture the nonlinear muscle behaviors.Meanwhile,the forward dynamics approach is computationally demanding and only suited for relatively simple tasks.This study proposed an integrated simulation methodology to fulfill the requirements of estimating foot-ground reaction force,tendon elasticity,and muscle recruitment optimization.A hybrid motion capture system,which combines the marker-based infrared device and markerless tracking through deep convolutional neural networks,was developed to track lower limb movements.The foot-ground reaction forces were determined by a contact model for soft materials,and its parameters were estimated using a two-step optimization method.The muscle recruitment problem was first resolved via a static optimization algorithm,and the obtained muscle activations were used as initial values for further simulation.A torque tracking procedure was then performed by minimizing the errors of joint torques calculated by musculotendon equilibrium equations and inverse dynamics.The proposed approach was validated against the electromyography measurements of a healthy subject during gait.The simulation framework provides a robust way of predicting joint torques,musculotendon forces,and muscle activations,which can be beneficial for understanding the biomechanics of normal and pathological gait.
