Background: This is a rare case of piriformis syndrome. We discuss the patient’s symptoms, imaging study results, laboratory examination findings, and prescribed treatment in an attempt to determine the possible mech...Background: This is a rare case of piriformis syndrome. We discuss the patient’s symptoms, imaging study results, laboratory examination findings, and prescribed treatment in an attempt to determine the possible mechanisms or reasons for this patient’s development of piriformis syndrome. Methods: The patient is a 22-year-old female soldier who was admitted for lower back pain with soreness radiating to her right buttock and right lower extremity. We found that she had leg length discrepancy under X-ray finding. She was diagnosed piriformis syndrome by physical examination and Magenetic Resonance Image. Results: We performed scanography for lower extremities revealed a left femur length of 42.7 cm, a right femur length of 43.3 cm, a left tibia length of 33.2 cm, and a right tibia length of 33.6 cm;her left lower extremity was 1 cm shorter than her right. The MRI of sacrum also reveals hypertrophy of right piriformis muscle. Conclusions: Piriformis syndrome might be caused by short-term compensation in congenital leg length discrepancy. The patient with leg length discrepancy changed posture when standing, walking, and running. These compensation postures could lead to abnormality position of bones where there is insertion of the muscle.展开更多
The use of cementless total hip arthroplasty (THA) is on the increase. In order to achieve rotational and axial stability larger implants may be required than originally templated for. This could potentially result in...The use of cementless total hip arthroplasty (THA) is on the increase. In order to achieve rotational and axial stability larger implants may be required than originally templated for. This could potentially result in a lar-ger leg length inequality. Our objective was to determine whether there is greater inequality in leg length post-operatively in cementless THA as compared to cemented implants. 136 consecutive patients undergoing elective THA between June 2007 and May 2008 were included. Post-operative digital radiographs were ex-amined to determine leg length. Twenty seven patients (20%) underwent a cemented procedure and 109 (80%) a cementless procedure. In the cemented group the mean leg length discrepancy was 7.3 mm (range 19 mm short to 21 mm long). In the cementless group the mean measured leg length discrepancy was 6.3 mm (range 18 mm short to 23 mm long). There was no significant difference between the two groups (P = 0.443). This study shows that with accurate pre-operative templating, both cemented and cementless proce-dures produce comparable and acceptable leg length discrepancies.展开更多
Background：Total hip arthroplasty （THA） is one of the most effective treatments for phase Ⅲ and Ⅳ hip arthrosis.Lower limb length balancing is one of the determining factors of a successful surgery,particularly i...Background：Total hip arthroplasty （THA） is one of the most effective treatments for phase Ⅲ and Ⅳ hip arthrosis.Lower limb length balancing is one of the determining factors of a successful surgery,particularly in patients with developmental dysplasia of the hip （DDH）.The purpose of this study was to evaluate the postoperative change in intra-pelvic obliquity （intra-PO） angle in the coronal plane and its effects on leg length discrepancy （LLD） within 2 years.Methods：A total of 78 patients （70 females,8 males） were enrolled in this study.All patients were suffering from DDH with varying degrees of LLD.Pelvic plain radiographs were collected before and after the operation.The intra-PO angles were measured 0,0.5,1 and 2 years after THA.At the same time,postoperative LLD was measured with blocking test.Results：PO changed significantly in the first year after THA surgery （0 year vs.0.5 year,P 〈 0.01;0.5 year vs.1 year,P 〈 0.01）,and the changing value of intra-PO angle （△PO） slowed down substantially during the first 2 years after THA （0.5 year vs.0.5-1 year,P 〈 0.01;0.5-1 year vs.1-2 years,P 〈 0.01）.With the change in intra-PO angle,LLD also got narrow within the 1st year （0 year vs.0.5 year,P 〈 0.01;0.5 year vs.1 year,P 〈 0.01）.Elderly patients had a smaller intra-PO angle reduction （Group A vs.Group B,P =0.01;Group B vs.Group C,P〈 0.01）.Conclusions：Intra-PO angle and LLD gap narrowed with time after THA surgery.In particular,elderly patients had smaller change in intra-PO angle.展开更多
Objective To investigate the methods to maintain leg equalization for patients undergoing primary total hip joint replacement. Methods 40 patients,45 hips with various diseases were treated by total hip joint replacem...Objective To investigate the methods to maintain leg equalization for patients undergoing primary total hip joint replacement. Methods 40 patients,45 hips with various diseases were treated by total hip joint replacement from Jan 2000 to Sep 2001.Before operation, the perpendicular length from center of femoral head to the summit of great tuberosity and the tip of less tuberosity to the line of bilateral ischial tuberosity were measured; the length from anterior superior iliac spine to medial malleolus were measured at same time.Leg length was decided and corrected according to these lines. Results Before operation, shortening of limbs were presented in 39 hips, 1 to 4 cm, average 2.4 cm.After operation, discrepancy of both legs was 0～0.8 cm.Apparent limps were not observed in all patients. Conclusion This measurement is a useful method to maintain and recover leg length in total hip joint replacement.展开更多
目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD...目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD的关系。方法:回顾性分析2020年10月至2022年6月符合标准的40例行单侧THA的患者,其中男21例,女19例;年龄30~81(58.90±14.13)岁;身体质量指数(body mass index,BMI)为17.3~31.5(25.3±3.4)kg·m^(-2);左侧18例,右侧22例。诊断为股骨头坏死30例(FicatⅣ期),髋关节骨性关节炎2例(TünnisⅢ期),发育性髋关节脱位合并终末期骨关节炎2例(CroweⅢ期),股骨颈骨折6例(GardenⅣ期)。术前、术后拍摄骨盆CT三维重建,经Mimics软件处理后建立三维重建模型,在模型上对FO、RCH、LLD进行测量。结果:术后双侧FO差值与LLD呈正相关性(r=0.744,P<0.001);将FO重建组与偏心距未重建组进行卡方检验得出:FO重建组下肢等长率高于FO未重建组(χ^(2)=6.320,P=0.012)。术后双侧RCH差值与LLD呈负相关性(r=-0.877,P<0.001);双侧FO差值及双侧RCH差值与术后LLD之间存在线性关系,且满足线性回归方程:术后LLD=0.038x-0.099y+0.257(x为术后双侧FO差值;y为术后双侧RCH差值;单位为cm),F=77.993,R2=0.808,P=0.009。结论:THA术后LLD随着FO的增大而增大,随着RCH增大而减小;重建FO更易获得下肢等长效果。THA术后双侧FO差值及双侧RCH差值与LLD之间存在线性关系,回归方程可为判断LLD提供一种理论参考。展开更多
The equivalent mechanism of the system is often considered as one specific mechanism in most existing studies of multi-legged robots, however the equivalent mechanism is varying while the robot moves on the ground. Fo...The equivalent mechanism of the system is often considered as one specific mechanism in most existing studies of multi-legged robots, however the equivalent mechanism is varying while the robot moves on the ground. Four typical tripod period gaits of a radial symmetrical six-legged robot are analyzed. Similar to the metamorphic mechanism, the locomotion of multi-legged robot is considered as a series of varying hybrid serial-parallel mechanisms by assuming the constraints of the feet on the ground with hinges. One gait cycle is divided into several periods, and in different walking period there is a specific equivalent mechanism corresponding to it, and the walking process of multi-legged robot is composed by these series of equivalent mechanisms. Walking performance can be got by analyzing these series of equivalent mechanisms. Kinematics model of the equivalent mechanism is established, workspaces of equivalent mechanisms are illustrated by simulation and a concept of static stability workspace is proposed to evaluate the static stability of these four gaits. A new method to calculate the stride length of multi-legged robots is presented by analyzing the relationship between the workspace of two adjacent equivalent parallel mechanisms in one gait cycle. The stride lengths of four gaits are given by simulations. Comparison of stride length and static stability among these four typical tripod gaits are given. It has been proved that mixed gait and insect-wave gait II have better static stability than mammal kick-off gait and insect-wave gait I. Insect-wave gait II displays its advantage on stride length while the height of robot body lower than 87 mm, mammal kick-off gait has superiority on stride length while the height of robot body higher than 115 mm, and insect-wave gait I shows its shortcoming in stride length. The proposed method based on metamorphic theory and combining the footholds and body height of robot provides a new method to comprehensive analyze the performance of multi-legged robot.展开更多
<span style="font-family:Verdana;">The purpose of this paper is to review relevant literature concerning limb length inequalities in adults and to make recommendations for assessment and intervention b...<span style="font-family:Verdana;">The purpose of this paper is to review relevant literature concerning limb length inequalities in adults and to make recommendations for assessment and intervention based on the literature and our own clinical experience. The research was carr</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ied</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> out on PUB MED, Non-English articles and duplicates in the databases were not included. Limb length inequality and common classification criteria are defined and etiological factors are present. Common methods of detecting limb length inequality include model manual technics. </span><span style="font-family:Verdana;">This work has the purpose of describing a well standardized therapeutic in the form of practical guidance. The approach we describe provides standardized model evaluation for leg lower limb in order to be used in rehabilitation </span><span style="font-family:Verdana;">clinic.</span></span></span></span>展开更多
文摘Background: This is a rare case of piriformis syndrome. We discuss the patient’s symptoms, imaging study results, laboratory examination findings, and prescribed treatment in an attempt to determine the possible mechanisms or reasons for this patient’s development of piriformis syndrome. Methods: The patient is a 22-year-old female soldier who was admitted for lower back pain with soreness radiating to her right buttock and right lower extremity. We found that she had leg length discrepancy under X-ray finding. She was diagnosed piriformis syndrome by physical examination and Magenetic Resonance Image. Results: We performed scanography for lower extremities revealed a left femur length of 42.7 cm, a right femur length of 43.3 cm, a left tibia length of 33.2 cm, and a right tibia length of 33.6 cm;her left lower extremity was 1 cm shorter than her right. The MRI of sacrum also reveals hypertrophy of right piriformis muscle. Conclusions: Piriformis syndrome might be caused by short-term compensation in congenital leg length discrepancy. The patient with leg length discrepancy changed posture when standing, walking, and running. These compensation postures could lead to abnormality position of bones where there is insertion of the muscle.
文摘The use of cementless total hip arthroplasty (THA) is on the increase. In order to achieve rotational and axial stability larger implants may be required than originally templated for. This could potentially result in a lar-ger leg length inequality. Our objective was to determine whether there is greater inequality in leg length post-operatively in cementless THA as compared to cemented implants. 136 consecutive patients undergoing elective THA between June 2007 and May 2008 were included. Post-operative digital radiographs were ex-amined to determine leg length. Twenty seven patients (20%) underwent a cemented procedure and 109 (80%) a cementless procedure. In the cemented group the mean leg length discrepancy was 7.3 mm (range 19 mm short to 21 mm long). In the cementless group the mean measured leg length discrepancy was 6.3 mm (range 18 mm short to 23 mm long). There was no significant difference between the two groups (P = 0.443). This study shows that with accurate pre-operative templating, both cemented and cementless proce-dures produce comparable and acceptable leg length discrepancies.
文摘Background：Total hip arthroplasty （THA） is one of the most effective treatments for phase Ⅲ and Ⅳ hip arthrosis.Lower limb length balancing is one of the determining factors of a successful surgery,particularly in patients with developmental dysplasia of the hip （DDH）.The purpose of this study was to evaluate the postoperative change in intra-pelvic obliquity （intra-PO） angle in the coronal plane and its effects on leg length discrepancy （LLD） within 2 years.Methods：A total of 78 patients （70 females,8 males） were enrolled in this study.All patients were suffering from DDH with varying degrees of LLD.Pelvic plain radiographs were collected before and after the operation.The intra-PO angles were measured 0,0.5,1 and 2 years after THA.At the same time,postoperative LLD was measured with blocking test.Results：PO changed significantly in the first year after THA surgery （0 year vs.0.5 year,P 〈 0.01;0.5 year vs.1 year,P 〈 0.01）,and the changing value of intra-PO angle （△PO） slowed down substantially during the first 2 years after THA （0.5 year vs.0.5-1 year,P 〈 0.01;0.5-1 year vs.1-2 years,P 〈 0.01）.With the change in intra-PO angle,LLD also got narrow within the 1st year （0 year vs.0.5 year,P 〈 0.01;0.5 year vs.1 year,P 〈 0.01）.Elderly patients had a smaller intra-PO angle reduction （Group A vs.Group B,P =0.01;Group B vs.Group C,P〈 0.01）.Conclusions：Intra-PO angle and LLD gap narrowed with time after THA surgery.In particular,elderly patients had smaller change in intra-PO angle.
文摘Objective To investigate the methods to maintain leg equalization for patients undergoing primary total hip joint replacement. Methods 40 patients,45 hips with various diseases were treated by total hip joint replacement from Jan 2000 to Sep 2001.Before operation, the perpendicular length from center of femoral head to the summit of great tuberosity and the tip of less tuberosity to the line of bilateral ischial tuberosity were measured; the length from anterior superior iliac spine to medial malleolus were measured at same time.Leg length was decided and corrected according to these lines. Results Before operation, shortening of limbs were presented in 39 hips, 1 to 4 cm, average 2.4 cm.After operation, discrepancy of both legs was 0～0.8 cm.Apparent limps were not observed in all patients. Conclusion This measurement is a useful method to maintain and recover leg length in total hip joint replacement.
文摘目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD的关系。方法:回顾性分析2020年10月至2022年6月符合标准的40例行单侧THA的患者,其中男21例,女19例;年龄30~81(58.90±14.13)岁;身体质量指数(body mass index,BMI)为17.3~31.5(25.3±3.4)kg·m^(-2);左侧18例,右侧22例。诊断为股骨头坏死30例(FicatⅣ期),髋关节骨性关节炎2例(TünnisⅢ期),发育性髋关节脱位合并终末期骨关节炎2例(CroweⅢ期),股骨颈骨折6例(GardenⅣ期)。术前、术后拍摄骨盆CT三维重建,经Mimics软件处理后建立三维重建模型,在模型上对FO、RCH、LLD进行测量。结果:术后双侧FO差值与LLD呈正相关性(r=0.744,P<0.001);将FO重建组与偏心距未重建组进行卡方检验得出:FO重建组下肢等长率高于FO未重建组(χ^(2)=6.320,P=0.012)。术后双侧RCH差值与LLD呈负相关性(r=-0.877,P<0.001);双侧FO差值及双侧RCH差值与术后LLD之间存在线性关系,且满足线性回归方程:术后LLD=0.038x-0.099y+0.257(x为术后双侧FO差值;y为术后双侧RCH差值;单位为cm),F=77.993,R2=0.808,P=0.009。结论:THA术后LLD随着FO的增大而增大,随着RCH增大而减小;重建FO更易获得下肢等长效果。THA术后双侧FO差值及双侧RCH差值与LLD之间存在线性关系,回归方程可为判断LLD提供一种理论参考。
基金supported by National Science Foundation for Distinguished Young Scholoars, China (Grant No. 51125020)Program for New Century Excellent Talents in University, China
文摘The equivalent mechanism of the system is often considered as one specific mechanism in most existing studies of multi-legged robots, however the equivalent mechanism is varying while the robot moves on the ground. Four typical tripod period gaits of a radial symmetrical six-legged robot are analyzed. Similar to the metamorphic mechanism, the locomotion of multi-legged robot is considered as a series of varying hybrid serial-parallel mechanisms by assuming the constraints of the feet on the ground with hinges. One gait cycle is divided into several periods, and in different walking period there is a specific equivalent mechanism corresponding to it, and the walking process of multi-legged robot is composed by these series of equivalent mechanisms. Walking performance can be got by analyzing these series of equivalent mechanisms. Kinematics model of the equivalent mechanism is established, workspaces of equivalent mechanisms are illustrated by simulation and a concept of static stability workspace is proposed to evaluate the static stability of these four gaits. A new method to calculate the stride length of multi-legged robots is presented by analyzing the relationship between the workspace of two adjacent equivalent parallel mechanisms in one gait cycle. The stride lengths of four gaits are given by simulations. Comparison of stride length and static stability among these four typical tripod gaits are given. It has been proved that mixed gait and insect-wave gait II have better static stability than mammal kick-off gait and insect-wave gait I. Insect-wave gait II displays its advantage on stride length while the height of robot body lower than 87 mm, mammal kick-off gait has superiority on stride length while the height of robot body higher than 115 mm, and insect-wave gait I shows its shortcoming in stride length. The proposed method based on metamorphic theory and combining the footholds and body height of robot provides a new method to comprehensive analyze the performance of multi-legged robot.
文摘<span style="font-family:Verdana;">The purpose of this paper is to review relevant literature concerning limb length inequalities in adults and to make recommendations for assessment and intervention based on the literature and our own clinical experience. The research was carr</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ied</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> out on PUB MED, Non-English articles and duplicates in the databases were not included. Limb length inequality and common classification criteria are defined and etiological factors are present. Common methods of detecting limb length inequality include model manual technics. </span><span style="font-family:Verdana;">This work has the purpose of describing a well standardized therapeutic in the form of practical guidance. The approach we describe provides standardized model evaluation for leg lower limb in order to be used in rehabilitation </span><span style="font-family:Verdana;">clinic.</span></span></span></span>
