The mechanical properties of the pelvic trabecular bone have been studied at the continuum level. However, nothing is known about the tissue-level damage in the trabecular bone of the healthy human acetabulum at appar...The mechanical properties of the pelvic trabecular bone have been studied at the continuum level. However, nothing is known about the tissue-level damage in the trabecular bone of the healthy human acetabulum at apparent small strains characteristic of habitual. By a DAWING 4000 A supercomputer, nonlinear micro-finite element (μFE) analysis was performed to quantify tissue-level damage accumulation in trabecular bone at small strains. The data indicate that damage in trabecular bone commence at 0.2% apparent strain. The findings imply that tissue yielding can initiate at very low strains in the trabecular bone of the healthy acetabulum and that this local failure has negative consequences on the apparent mechanical properties of trabecular bone.展开更多
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
Background: The management of traumatic acetabular injuries (TAI), which are often complex and diverse, is difficult and costly in the context of low-income African countries. Objective: To evaluate the treatment of t...Background: The management of traumatic acetabular injuries (TAI), which are often complex and diverse, is difficult and costly in the context of low-income African countries. Objective: To evaluate the treatment of traumatic acetabular lesions in the Orthopedics and Traumatology Department of the Yalgado Ouedraogo University Hospital, for their better management. Patients and Methods: This was a retrospective study, conducted in our department from January 2012 to December 2016. Sixty-three patients with TAI and complete records were selected. The mean age of patients with coxofemoral dislocations was 34.2 years and 36.4 years for acetabulum fractures with male predominance in both injury types. The injuries were mainly caused by a violent road traffic accident (RTA) (90.5%). Forty hip dislocations and 41 acetabular fractures were reported, with a prevalence of iliac dislocations (52.5%) and posterior wall fractures of the acetabulum (24.4%). Results: The average time to manage TAI was 15.9 hours (range 2 - 100). Medical treatment was performed in all patients. Thirty-eight coxofemoral dislocations and 34 acetabular fractures were treated by orthopedic methods. Seven complex acetabular fractures and two coxo-femoral dislocations were performed by surgical method. Two patients died (3.2%), one in a hemorrhagic shock table and the other in a septic shock table. Immediate and late complications were identified. Conclusion: Early and adequate management of our TAI, requires a modern technical platform and a sufficient number of qualified medical personnel to improve their functional outcomes.展开更多
Fractures of the acetabulum in elderly patients were often caused by low energy trauma.Fractures involving anterior column are more common and often associated with impaction and comminution.Osteoporosis further compl...Fractures of the acetabulum in elderly patients were often caused by low energy trauma.Fractures involving anterior column are more common and often associated with impaction and comminution.Osteoporosis further complicates the management.Percutaneous fracture fixation has low morbidity but it is a technically demanding procedure.Open reduction and fracture fixation is done with or without simultaneous total hip replacement.Delayed total hip replacement is considered in posttraumatic arthritis patients.Patients with minimal displaced fractures,associated both-column fractures with secondary congruence of joint and patients who are medically unfit for surgery can be managed non-operatively.Whatever be the method of management,these elderly patients should be mobilised as early as possible.展开更多
Background With advance of age, alterations in bone quality, quantity and microarchitecture render osteoporotic trabecular bone become more sensitive to local failure. The aims of the present study were to clarify the...Background With advance of age, alterations in bone quality, quantity and microarchitecture render osteoporotic trabecular bone become more sensitive to local failure. The aims of the present study were to clarify the extent to which the distribution of tissue-level stresses and strains was affected by structural changes and the extent to which osteoporotic acetabular trabecular bone was damaged at small strains. Methods Using a DAWING 4000A supercomputer, nonlinear micro-finite element （μFE） analyses were performed to calculate the tissue-level strains and stresses for each element in the trabecular bone of one osteoporotic acetabulum at small strains to quantify the tissue-level damage accumulation and mechanical properties. Results In contour plots of the tissue, maximum principal logarithmic strains, high tissue-level strains, both compressive and tensile, were observed in the osteoporotic trabecular bone at small apparent strains from 0.2% to 0.5% strain. The compressive apparent stress-strain curve showed typical nonlinear behavior and tangent modulus reduction with increasing strains. The microdamage curve suggested that microdamage began at 0.2% apparent strain in the osteoporotic trabecular bone and increased sharply, although very few microfractures occurred. The quartiles of the maximum principal logarithmic strains, minimum principal logarithmic strains and Von Mises stresses increased nonlinearly. For the inter-quartile range of the Von Mises stresses, a leap occurred at small strains ranging from 0.2% to 0.3% while microdamage commenced. Conclusions Extensive microdamage was primarily responsible for the large loss in apparent mechanical properties that occurred in the trabecular bone of the osteoporotic acetabulum at small strains. With increasing apparent strains, continuous nonlinear increments of tissue-level strains and stresses resulted in microdamage that propagated throughout the specimen with very few microfractures. Chin Med J 2009; 122（17）：2041-204 7展开更多
Objective： To explore the treatment methods and outcome of posterior wall fractures of the acetabulum. Methods： The data of 31 patients （25 males and 6 females, aged 19-59 years, mean： 40.5 years） with posterior ...Objective： To explore the treatment methods and outcome of posterior wall fractures of the acetabulum. Methods： The data of 31 patients （25 males and 6 females, aged 19-59 years, mean： 40.5 years） with posterior wall fractures of the acetabulum hospitalized in our department from 2002 to 2006 were analyzed retrospectively in this study. The types of fractures, number of fragments, combined dislocations, and sciatic nerve function were documented before admission. All the fractures were treated with open reduction and internal fixation. Based on the fracture type and site, either screws alone or reconstructive plates were used. The patients were immobilized for an average of 12 weeks before partial weight bearing was permitted. After follow-up for 12-70 months （43.6 months on average）, modified Merle d＇Aubigne score was adopted to evaluate the outcomes of the operations. Results： The percentages of the excellent, good, fair and poor results were 48.4%, 41.9%, 6.5%, and 3.3%, respectively, with a good to excellent rate of 90.2%. Idiopathic sciatic nerve injury occurred in only one case. Conclusions： The sciatic nerve should be routinely exposed and protected during the surgery. The type of fixation should be based on the fracture type and site. Prolonged immobilization may be helpful in improving the final outcomes.展开更多
目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋...目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋臼角度、重建骨盆模型并规划,术中依据髋臼卵圆窝、横切迹、横韧带等解剖标志按规划置入假体。对照组采用传统徒手目测法。比较两组手术指标(时间、透视次数、出血量)、术后髋臼假体角度(外展角、前倾角)偏差、髋关节Harris评分(HHS)、疼痛视觉模拟评分(VAS)及脱位率。结果两组年龄、性别等基线资料可比。观察组出血量高于对照组(P<0.001),手术时间、透视次数差异无统计学意义。术后影像学测量显示,观察组的髋臼假体外展角和前倾角偏差均显著小于对照组(P<0.001)。术后1个月,观察组HHS评分明显更高、VAS评分明显更低(P<0.05);术后3、6个月两组功能与疼痛评分差异无统计学意义。观察组无脱位,对照组脱位1例。结论髋臼卵圆窝三维定位法结合解剖标志与个体化术前规划,能量化髋臼假体置入角度并显著提高髋臼假体置入的精准性,利于患者术后早期功能恢复,临床疗效满意,具有应用价值。展开更多
BACKGROUND Total hip arthroplasty(THA)is a common procedure for end stage osteoarthritis.The learning curve for THA is complex and challenging.One of the most difficult skills to master is acetabular reaming.We wish t...BACKGROUND Total hip arthroplasty(THA)is a common procedure for end stage osteoarthritis.The learning curve for THA is complex and challenging.One of the most difficult skills to master is acetabular reaming.We wish to identify if experience in arthroplasty leads to preservation of more bone stock.AIM To investigate if increasing surgeon experience will predict an ever decreasing acetabular cup size.METHODS A retrospective case series of four attending orthopaedic surgeons was completed.All uncemented elective total hip arthroplasties since appointment were selected for inclusion.The size of acetabular cup used was noted and logistic regression was used to identify if a trend to smaller cups existed.RESULTS A total of 1614 subjects were included with a mean age of 64 years.Overall cups were on average 0.18mm smaller per year(95%confidence interval-0.25 to-0.11,P<0.001).Individual surgeon trends showed cup sizes to decrease 0.27 mm/year for surgeon A,0.02 mm/year for surgeon B,0.15 mm/year for surgeon C and 0.29 mm/year for surgeon D.Three of the four surgeons had a more pronounced trend to smaller cups for male subjects than their female counterparts.CONCLUSION We found increasing surgeon experience to be associated with an ever-decreasing acetabular cup size.Smaller acetabular cup size may act as a surrogate marker of surgical proficiency by virtue of decreased acetabular reaming.展开更多
基金the National High Technology Research and Development Program (863) of China(No. 2006AA02A137the Postgraduate Creativity Foundation of Shanghai Jiaotong University (No. BXJ0730)
文摘The mechanical properties of the pelvic trabecular bone have been studied at the continuum level. However, nothing is known about the tissue-level damage in the trabecular bone of the healthy human acetabulum at apparent small strains characteristic of habitual. By a DAWING 4000 A supercomputer, nonlinear micro-finite element (μFE) analysis was performed to quantify tissue-level damage accumulation in trabecular bone at small strains. The data indicate that damage in trabecular bone commence at 0.2% apparent strain. The findings imply that tissue yielding can initiate at very low strains in the trabecular bone of the healthy acetabulum and that this local failure has negative consequences on the apparent mechanical properties of trabecular bone.
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Background: The management of traumatic acetabular injuries (TAI), which are often complex and diverse, is difficult and costly in the context of low-income African countries. Objective: To evaluate the treatment of traumatic acetabular lesions in the Orthopedics and Traumatology Department of the Yalgado Ouedraogo University Hospital, for their better management. Patients and Methods: This was a retrospective study, conducted in our department from January 2012 to December 2016. Sixty-three patients with TAI and complete records were selected. The mean age of patients with coxofemoral dislocations was 34.2 years and 36.4 years for acetabulum fractures with male predominance in both injury types. The injuries were mainly caused by a violent road traffic accident (RTA) (90.5%). Forty hip dislocations and 41 acetabular fractures were reported, with a prevalence of iliac dislocations (52.5%) and posterior wall fractures of the acetabulum (24.4%). Results: The average time to manage TAI was 15.9 hours (range 2 - 100). Medical treatment was performed in all patients. Thirty-eight coxofemoral dislocations and 34 acetabular fractures were treated by orthopedic methods. Seven complex acetabular fractures and two coxo-femoral dislocations were performed by surgical method. Two patients died (3.2%), one in a hemorrhagic shock table and the other in a septic shock table. Immediate and late complications were identified. Conclusion: Early and adequate management of our TAI, requires a modern technical platform and a sufficient number of qualified medical personnel to improve their functional outcomes.
文摘Fractures of the acetabulum in elderly patients were often caused by low energy trauma.Fractures involving anterior column are more common and often associated with impaction and comminution.Osteoporosis further complicates the management.Percutaneous fracture fixation has low morbidity but it is a technically demanding procedure.Open reduction and fracture fixation is done with or without simultaneous total hip replacement.Delayed total hip replacement is considered in posttraumatic arthritis patients.Patients with minimal displaced fractures,associated both-column fractures with secondary congruence of joint and patients who are medically unfit for surgery can be managed non-operatively.Whatever be the method of management,these elderly patients should be mobilised as early as possible.
文摘Background With advance of age, alterations in bone quality, quantity and microarchitecture render osteoporotic trabecular bone become more sensitive to local failure. The aims of the present study were to clarify the extent to which the distribution of tissue-level stresses and strains was affected by structural changes and the extent to which osteoporotic acetabular trabecular bone was damaged at small strains. Methods Using a DAWING 4000A supercomputer, nonlinear micro-finite element （μFE） analyses were performed to calculate the tissue-level strains and stresses for each element in the trabecular bone of one osteoporotic acetabulum at small strains to quantify the tissue-level damage accumulation and mechanical properties. Results In contour plots of the tissue, maximum principal logarithmic strains, high tissue-level strains, both compressive and tensile, were observed in the osteoporotic trabecular bone at small apparent strains from 0.2% to 0.5% strain. The compressive apparent stress-strain curve showed typical nonlinear behavior and tangent modulus reduction with increasing strains. The microdamage curve suggested that microdamage began at 0.2% apparent strain in the osteoporotic trabecular bone and increased sharply, although very few microfractures occurred. The quartiles of the maximum principal logarithmic strains, minimum principal logarithmic strains and Von Mises stresses increased nonlinearly. For the inter-quartile range of the Von Mises stresses, a leap occurred at small strains ranging from 0.2% to 0.3% while microdamage commenced. Conclusions Extensive microdamage was primarily responsible for the large loss in apparent mechanical properties that occurred in the trabecular bone of the osteoporotic acetabulum at small strains. With increasing apparent strains, continuous nonlinear increments of tissue-level strains and stresses resulted in microdamage that propagated throughout the specimen with very few microfractures. Chin Med J 2009; 122（17）：2041-204 7
文摘Objective： To explore the treatment methods and outcome of posterior wall fractures of the acetabulum. Methods： The data of 31 patients （25 males and 6 females, aged 19-59 years, mean： 40.5 years） with posterior wall fractures of the acetabulum hospitalized in our department from 2002 to 2006 were analyzed retrospectively in this study. The types of fractures, number of fragments, combined dislocations, and sciatic nerve function were documented before admission. All the fractures were treated with open reduction and internal fixation. Based on the fracture type and site, either screws alone or reconstructive plates were used. The patients were immobilized for an average of 12 weeks before partial weight bearing was permitted. After follow-up for 12-70 months （43.6 months on average）, modified Merle d＇Aubigne score was adopted to evaluate the outcomes of the operations. Results： The percentages of the excellent, good, fair and poor results were 48.4%, 41.9%, 6.5%, and 3.3%, respectively, with a good to excellent rate of 90.2%. Idiopathic sciatic nerve injury occurred in only one case. Conclusions： The sciatic nerve should be routinely exposed and protected during the surgery. The type of fixation should be based on the fracture type and site. Prolonged immobilization may be helpful in improving the final outcomes.
文摘目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋臼角度、重建骨盆模型并规划,术中依据髋臼卵圆窝、横切迹、横韧带等解剖标志按规划置入假体。对照组采用传统徒手目测法。比较两组手术指标(时间、透视次数、出血量)、术后髋臼假体角度(外展角、前倾角)偏差、髋关节Harris评分(HHS)、疼痛视觉模拟评分(VAS)及脱位率。结果两组年龄、性别等基线资料可比。观察组出血量高于对照组(P<0.001),手术时间、透视次数差异无统计学意义。术后影像学测量显示,观察组的髋臼假体外展角和前倾角偏差均显著小于对照组(P<0.001)。术后1个月,观察组HHS评分明显更高、VAS评分明显更低(P<0.05);术后3、6个月两组功能与疼痛评分差异无统计学意义。观察组无脱位,对照组脱位1例。结论髋臼卵圆窝三维定位法结合解剖标志与个体化术前规划,能量化髋臼假体置入角度并显著提高髋臼假体置入的精准性,利于患者术后早期功能恢复,临床疗效满意,具有应用价值。
文摘BACKGROUND Total hip arthroplasty(THA)is a common procedure for end stage osteoarthritis.The learning curve for THA is complex and challenging.One of the most difficult skills to master is acetabular reaming.We wish to identify if experience in arthroplasty leads to preservation of more bone stock.AIM To investigate if increasing surgeon experience will predict an ever decreasing acetabular cup size.METHODS A retrospective case series of four attending orthopaedic surgeons was completed.All uncemented elective total hip arthroplasties since appointment were selected for inclusion.The size of acetabular cup used was noted and logistic regression was used to identify if a trend to smaller cups existed.RESULTS A total of 1614 subjects were included with a mean age of 64 years.Overall cups were on average 0.18mm smaller per year(95%confidence interval-0.25 to-0.11,P<0.001).Individual surgeon trends showed cup sizes to decrease 0.27 mm/year for surgeon A,0.02 mm/year for surgeon B,0.15 mm/year for surgeon C and 0.29 mm/year for surgeon D.Three of the four surgeons had a more pronounced trend to smaller cups for male subjects than their female counterparts.CONCLUSION We found increasing surgeon experience to be associated with an ever-decreasing acetabular cup size.Smaller acetabular cup size may act as a surrogate marker of surgical proficiency by virtue of decreased acetabular reaming.
