BACKGROUND Leg length discrepancy(LLD)following total hip arthroplasty(THA)is a common complaint,leading to decreased patient satisfaction.However,the effect of LLD before THA on outcomes and complications is not well...BACKGROUND Leg length discrepancy(LLD)following total hip arthroplasty(THA)is a common complaint,leading to decreased patient satisfaction.However,the effect of LLD before THA on outcomes and complications is not well defined.AIM To assess the effect of prior LLD on rates of falls,implant-related complications,stay length,readmissions,and implant survival following THA.METHODS A retrospective review of a nationwide insurance database was conducted from 2010 to 2021.All cases of THA and those with a prior diagnosis of LLD were identified.THA patients with LLD were matched to control patients 1:5 based on demographic and comorbidity profiles.Two-year fall rates and implant complications,lengths of stay,90-day readmissions,and time to revision were compared between cohorts.RESULTS A total of 2038 patients with LLD were matched to 10165 control patients.The LLD group showed significantly greater rates of falls[odds ratio(OR)=1.58;95%confidence interval(95%CI):1.24-2.01],dislocation(OR=2.61;95%CI:2.10-3.24),mechanical loosening(OR=4.58;95%CI:3.28-6.29),and periprosthetic fracture(OR=2.70;95%CI:1.96-3.72)compared to the control group(all P<0.001).Mean length of stay(LOS)was also significantly higher in the LLD group(3.1 days vs 2.8 days,P=0.034).No significant difference in 90-day readmission rates(7.75%vs 7.02%,P=0.244)was observed between the groups(P=0.244).Time to revision was significantly less in the LLD group(225 days vs 544 days,P<0.001).CONCLUSION LLD in patients having THA is related with significantly higher fall risk,rates of implant-related complications,LOS,and quicker time to revision.Identifying patients with LLD before their THA may help in identifying risks,better patient counselling,and more effective preoperative planning.However,the study have important limitations:Its design lacks information on the degree and cause of LLD,the time between diagnosis and surgery,and which leg with the discrepancy underwent the operation.Future well-designed studies should confirm the findings of this study.展开更多
Objective To examine the relationship between upper leg length （ULL） and metabolic syndrome （MetS） in older adults.Methods Data was collected from National Health and Nutritional Examination Survey （NHANES, 2009-...Objective To examine the relationship between upper leg length （ULL） and metabolic syndrome （MetS） in older adults.Methods Data was collected from National Health and Nutritional Examination Survey （NHANES, 2009-2010）. 786 individuals （385 males and 401 females） who were 60 years of age or older were included in this analysis. MetS was defined as having at least three of following conditions, i.e., cen-tral obesity, dyslipidemia, insulin resistance, and hypertension based on National Cholesterol Education Program guidelines. ULL was grouped into gender-specific tertiles.Results328 （41.7%） of participants were categorized as having MetS （38.7% in men and 49.1% in women,P = 0.002）. Compared to individuals in the 1st tertile （T1） of ULL, those in the 3rd tertile （T3） had lower levels of triglycerides （120.8 vs. 153.1 mg/dL,P = 0.045）, waist circumference （100.7vs. 104.2 cm,P = 0.049）, and systolic blood pressure （126.7vs. 131.4 mmHg, P = 0.005）, but higher levels of high-density-lipoprotein cholesterol （58.1vs. 52.4 mg/dL,P = 0.024）. The odds ratios （95% CI） of MetS from multivariate logistic regression were 0.57 （0.32-1.03） for individuals in the T2 of ULL and 0.39 （0.24-0.64） for individuals in the T3 of ULL, respectively （P-value for the trend 0.022）.Conclusions ULL was negatively associated with MetS in older adults. Further research is needed to identify potential mechanisms.展开更多
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
BACKGROUND Certain implant combinations change leg length and offset in primary total hip arthroplasty(THA).Poor restoration of leg biomechanics is a frequently cited reason for patient dissatisfaction following prima...BACKGROUND Certain implant combinations change leg length and offset in primary total hip arthroplasty(THA).Poor restoration of leg biomechanics is a frequently cited reason for patient dissatisfaction following primary THA.A pure high-offset stem should provide direct lateralization without affecting femoral length when compared to a standard stem.However,clinical experience with preoperative planning software based on computed tomography-based three-dimensionalmodels reveals that using pure high-offset stems in THA may cause a difference between expected(no change in femoral length)and actual(small increase)in postoperative femoral length.AIM To elucidate the causes of these femoral length discrepancies using preoperative planning software.METHODS Preoperative templating for 43 robotic-assisted THAs,optimizing acetabular size and orientation,center of rotation,stem size and offset,and prosthetic head diameter were obtained.The preoperative planning software was used to calculate differences between preoperative and postoperative femoral length for standard and pure high-offset stems,unique to each patient.RESULTS Whilst the increase in femoral length between standard and high-offset stems was not significant(P=0.93),35 femurs(81.4%)experienced a 1-mm increase,and 3(7.0%)experienced a 2-mm increase in femoral length while using high-offset stem compared to the standard stem.The incidence of femoral length increase was lower for patients with shorter femurs(18/22;81.8%)compared to patients with longer femurs(20/21;95.2%).CONCLUSION When pure high-offset stems were used in preoperative planning software,we demonstrated an unexpected increase in leg length between 1-2-mm in 88.4%of patients.This unexpected increase in femoral length is due to a function of the preoperative planning software’s planned stem alignment with the anatomical axis,and not an inherent fault in the stem design.With expanding accessibility of robotic-assisted THA platforms,all potential sources of postoperative leg length discrepancy should be identified during preoperative templating and necessary alterations to the surgical plan should be made to accommodate this unexpected difference when using a pure high-offset stem.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
[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA...[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA(机器人组),另外24例采用经改良Harding入路常规徒手THA(徒手组)。比较两组患者围手术期、随访结果及影像评估资料。[结果]两组患者均顺利完成改良Harding入路THA,机器人组的手术时间[min,(102.6±15.7)vs(83.7±16.8),P<0.001]和术中出血量[mL,(279.7±35.1)vs(212.5±29.6),P<0.001]均显著大于徒手组,两组患者术后引流量、住院天数的差异无统计学意义(P>0.05)。术后平均随访(20.8±8.5)个月。随时间推移,两组患者VAS评分、Harris评分、最大伸髋和最大屈髋活动度(range of motion,ROM)、最大内收和最大外展ROM均显著改善(P<0.05)。术后1周机器人组的VAS评分[分,M(P25,P75),2.0(2.0,4.0)vs 3.5(3.0,5.0),P<0.001]、最大屈髋[°,(74.5±9.0)vs(66.5±10.4),P=0.006]、最大内收[°,(18.5±6.2)vs(7.0±1.6),P<0.001]显著优于徒手组;术后1周和术后3个月机器人组的Harris评分[分,(75.1±4.9)vs(68.3±5.1),P<0.001;(84.8±4.9)vs(78.3±4.5),P<0.001]、最大伸髋[°,(20.5±5.3)vs(12.5±5.6),P<0.001;(31.0±3.6)vs(24.1±4.5),P<0.001]、最大外展[°,(26.2±3.3)vs(21.5±4.8),P<0.001;(33.4±3.8)vs(27.8±4.3),P<0.001]显著优于徒手组,但是,末次随访时两组间上述指标的差异均已无统计学意义(P>0.05)。影像方面,机器人组的术后双下肢长度差异(leg length discrepancy,LLD)[mm,(4.9±1.0)vs(8.1±1.4),P<0.001]和双侧联合偏心距(combined offset,CO)差值(■CO)的绝对值[mm,(1.5±0.5)vs(3.5±0.6),P<0.001]、髋臼假体外展角[°,(40.3±1.7)vs(45.3±4.1),P<0.001]和前倾角[°,(15.9±1.2)vs(18.8±3.6),P<0.001]均显著小于徒手组。[结论]与常规徒手THA相比,Mako机器人辅助下改良Harding入路THA假体置放更精准,早期治疗效果更优,但机器人技术的手术时间较长且术中失血量更大。展开更多
[目的]比较“肩-肩”新型解剖标记定位法与人工智能辅助规划系统(AIHIP系统)规划的全髋关节置换(total hip arthroplasty, THA)中假体置入定位及预防双下肢不等长的准确性。[方法] 2020年8月-2022年12月就诊于本院行初次THA的94例患者,...[目的]比较“肩-肩”新型解剖标记定位法与人工智能辅助规划系统(AIHIP系统)规划的全髋关节置换(total hip arthroplasty, THA)中假体置入定位及预防双下肢不等长的准确性。[方法] 2020年8月-2022年12月就诊于本院行初次THA的94例患者,按照随机数字表法分为两组,47例采用“肩-肩”法(肩-肩组),另外47例采用AIHIP系统规划法(智能组),分别于术前进行规划,比较两组临床和影像结果。[结果]两组患者手术时间、总失血量、术后下地时间的差异均无统计学意义(P>0.05)。影像方面,两组髋臼假体匹配、股骨柄假体匹配、双下肢长度差、联合偏心距的差异均无统计学意义(P>0.05),肩-肩组的尖肩距[(15.9±3.0) mm vs(17.7±3.4) mm, P<0.001]、截骨距[(7.8±2.7) mm vs(9.2±4.1) mm, P=0.003]均显著小于智能组。[结论]“肩-肩”新型解剖标记定位法可以在THA术中准确置入股骨侧假体,并可预防术后双下肢不等长。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 Leg length discrepancy(LLD)following total hip arthroplasty(THA)is a common complaint,leading to decreased patient satisfaction.However,the effect of LLD before THA on outcomes and complications is not well defined.AIM To assess the effect of prior LLD on rates of falls,implant-related complications,stay length,readmissions,and implant survival following THA.METHODS A retrospective review of a nationwide insurance database was conducted from 2010 to 2021.All cases of THA and those with a prior diagnosis of LLD were identified.THA patients with LLD were matched to control patients 1:5 based on demographic and comorbidity profiles.Two-year fall rates and implant complications,lengths of stay,90-day readmissions,and time to revision were compared between cohorts.RESULTS A total of 2038 patients with LLD were matched to 10165 control patients.The LLD group showed significantly greater rates of falls[odds ratio(OR)=1.58;95%confidence interval(95%CI):1.24-2.01],dislocation(OR=2.61;95%CI:2.10-3.24),mechanical loosening(OR=4.58;95%CI:3.28-6.29),and periprosthetic fracture(OR=2.70;95%CI:1.96-3.72)compared to the control group(all P<0.001).Mean length of stay(LOS)was also significantly higher in the LLD group(3.1 days vs 2.8 days,P=0.034).No significant difference in 90-day readmission rates(7.75%vs 7.02%,P=0.244)was observed between the groups(P=0.244).Time to revision was significantly less in the LLD group(225 days vs 544 days,P<0.001).CONCLUSION LLD in patients having THA is related with significantly higher fall risk,rates of implant-related complications,LOS,and quicker time to revision.Identifying patients with LLD before their THA may help in identifying risks,better patient counselling,and more effective preoperative planning.However,the study have important limitations:Its design lacks information on the degree and cause of LLD,the time between diagnosis and surgery,and which leg with the discrepancy underwent the operation.Future well-designed studies should confirm the findings of this study.
文摘Objective To examine the relationship between upper leg length （ULL） and metabolic syndrome （MetS） in older adults.Methods Data was collected from National Health and Nutritional Examination Survey （NHANES, 2009-2010）. 786 individuals （385 males and 401 females） who were 60 years of age or older were included in this analysis. MetS was defined as having at least three of following conditions, i.e., cen-tral obesity, dyslipidemia, insulin resistance, and hypertension based on National Cholesterol Education Program guidelines. ULL was grouped into gender-specific tertiles.Results328 （41.7%） of participants were categorized as having MetS （38.7% in men and 49.1% in women,P = 0.002）. Compared to individuals in the 1st tertile （T1） of ULL, those in the 3rd tertile （T3） had lower levels of triglycerides （120.8 vs. 153.1 mg/dL,P = 0.045）, waist circumference （100.7vs. 104.2 cm,P = 0.049）, and systolic blood pressure （126.7vs. 131.4 mmHg, P = 0.005）, but higher levels of high-density-lipoprotein cholesterol （58.1vs. 52.4 mg/dL,P = 0.024）. The odds ratios （95% CI） of MetS from multivariate logistic regression were 0.57 （0.32-1.03） for individuals in the T2 of ULL and 0.39 （0.24-0.64） for individuals in the T3 of ULL, respectively （P-value for the trend 0.022）.Conclusions ULL was negatively associated with MetS in older adults. Further research is needed to identify potential mechanisms.
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BACKGROUND Certain implant combinations change leg length and offset in primary total hip arthroplasty(THA).Poor restoration of leg biomechanics is a frequently cited reason for patient dissatisfaction following primary THA.A pure high-offset stem should provide direct lateralization without affecting femoral length when compared to a standard stem.However,clinical experience with preoperative planning software based on computed tomography-based three-dimensionalmodels reveals that using pure high-offset stems in THA may cause a difference between expected(no change in femoral length)and actual(small increase)in postoperative femoral length.AIM To elucidate the causes of these femoral length discrepancies using preoperative planning software.METHODS Preoperative templating for 43 robotic-assisted THAs,optimizing acetabular size and orientation,center of rotation,stem size and offset,and prosthetic head diameter were obtained.The preoperative planning software was used to calculate differences between preoperative and postoperative femoral length for standard and pure high-offset stems,unique to each patient.RESULTS Whilst the increase in femoral length between standard and high-offset stems was not significant(P=0.93),35 femurs(81.4%)experienced a 1-mm increase,and 3(7.0%)experienced a 2-mm increase in femoral length while using high-offset stem compared to the standard stem.The incidence of femoral length increase was lower for patients with shorter femurs(18/22;81.8%)compared to patients with longer femurs(20/21;95.2%).CONCLUSION When pure high-offset stems were used in preoperative planning software,we demonstrated an unexpected increase in leg length between 1-2-mm in 88.4%of patients.This unexpected increase in femoral length is due to a function of the preoperative planning software’s planned stem alignment with the anatomical axis,and not an inherent fault in the stem design.With expanding accessibility of robotic-assisted THA platforms,all potential sources of postoperative leg length discrepancy should be identified during preoperative templating and necessary alterations to the surgical plan should be made to accommodate this unexpected difference when using a pure high-offset stem.
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[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA(机器人组),另外24例采用经改良Harding入路常规徒手THA(徒手组)。比较两组患者围手术期、随访结果及影像评估资料。[结果]两组患者均顺利完成改良Harding入路THA,机器人组的手术时间[min,(102.6±15.7)vs(83.7±16.8),P<0.001]和术中出血量[mL,(279.7±35.1)vs(212.5±29.6),P<0.001]均显著大于徒手组,两组患者术后引流量、住院天数的差异无统计学意义(P>0.05)。术后平均随访(20.8±8.5)个月。随时间推移,两组患者VAS评分、Harris评分、最大伸髋和最大屈髋活动度(range of motion,ROM)、最大内收和最大外展ROM均显著改善(P<0.05)。术后1周机器人组的VAS评分[分,M(P25,P75),2.0(2.0,4.0)vs 3.5(3.0,5.0),P<0.001]、最大屈髋[°,(74.5±9.0)vs(66.5±10.4),P=0.006]、最大内收[°,(18.5±6.2)vs(7.0±1.6),P<0.001]显著优于徒手组;术后1周和术后3个月机器人组的Harris评分[分,(75.1±4.9)vs(68.3±5.1),P<0.001;(84.8±4.9)vs(78.3±4.5),P<0.001]、最大伸髋[°,(20.5±5.3)vs(12.5±5.6),P<0.001;(31.0±3.6)vs(24.1±4.5),P<0.001]、最大外展[°,(26.2±3.3)vs(21.5±4.8),P<0.001;(33.4±3.8)vs(27.8±4.3),P<0.001]显著优于徒手组,但是,末次随访时两组间上述指标的差异均已无统计学意义(P>0.05)。影像方面,机器人组的术后双下肢长度差异(leg length discrepancy,LLD)[mm,(4.9±1.0)vs(8.1±1.4),P<0.001]和双侧联合偏心距(combined offset,CO)差值(■CO)的绝对值[mm,(1.5±0.5)vs(3.5±0.6),P<0.001]、髋臼假体外展角[°,(40.3±1.7)vs(45.3±4.1),P<0.001]和前倾角[°,(15.9±1.2)vs(18.8±3.6),P<0.001]均显著小于徒手组。[结论]与常规徒手THA相比,Mako机器人辅助下改良Harding入路THA假体置放更精准,早期治疗效果更优,但机器人技术的手术时间较长且术中失血量更大。
文摘[目的]比较“肩-肩”新型解剖标记定位法与人工智能辅助规划系统(AIHIP系统)规划的全髋关节置换(total hip arthroplasty, THA)中假体置入定位及预防双下肢不等长的准确性。[方法] 2020年8月-2022年12月就诊于本院行初次THA的94例患者,按照随机数字表法分为两组,47例采用“肩-肩”法(肩-肩组),另外47例采用AIHIP系统规划法(智能组),分别于术前进行规划,比较两组临床和影像结果。[结果]两组患者手术时间、总失血量、术后下地时间的差异均无统计学意义(P>0.05)。影像方面,两组髋臼假体匹配、股骨柄假体匹配、双下肢长度差、联合偏心距的差异均无统计学意义(P>0.05),肩-肩组的尖肩距[(15.9±3.0) mm vs(17.7±3.4) mm, P<0.001]、截骨距[(7.8±2.7) mm vs(9.2±4.1) mm, P=0.003]均显著小于智能组。[结论]“肩-肩”新型解剖标记定位法可以在THA术中准确置入股骨侧假体,并可预防术后双下肢不等长。
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>
