BACKGROUND In recent years,there has been an increase in the number of total hip arthroplasty procedures in the younger patient population.This active group has higher expectations of their prosthesis in comparison to...BACKGROUND In recent years,there has been an increase in the number of total hip arthroplasty procedures in the younger patient population.This active group has higher expectations of their prosthesis in comparison to the older population,and there is a greater physical demand for the prosthesis.Short femoral stems were in-troduced to retain proximal bone stock and joint biomechanics and became more common to implant in this specific population.Currently,the long-term survival and functional outcomes of various short stems are still being investigated in different clinics.AIM To determine the 5-year survival of the Optimys hip stem.METHODS This was a prospective multicenter cohort study of 500 patients conducted in two hospitals in the Netherlands.All patients received the Optimys short stem(Mathys Ltd,Bettlach,Switzerland).The primary outcome measure was survival of the hip stem,with revision as the endpoint.The secondary outcome measurements included patient-reported outcome measures(PROMs).Kaplan-Meier analysis was used to calculate the 5-year survival rate.Log-minus-log transformation was performed to calculate the 95%confidence interval(95%CI).Mixed model analyses were performed to assess the course of the PROMs during the 1st 2 years after surgery.Analyses were modeled separately for the 1st and 2nd years to calculate the yearly change in PROMs during both follow-up periods with accompanying 95%CIs.RESULTS The mean age of the total 500 patients was 62.3 years(standard deviation:10.6)and 202 were male(40%).At a median follow-up of 5.5 years(interquartile range:4.5-6.7),7 patients were deceased and 6 revisions were registered,for infection(n=3),subsidence(n=2)and malposition(n=1).This resulted in an overall 5-year survival of 98.8%(95%CI:97.3-99.5).If infection was left out as reason for revision,a stem survival of 99.4%(95%CI:98.1-99.8)was seen.Baseline questionnaires were completed by 471 patients(94%),317 patients(63%)completed the 1-year follow-up questionnaires and 233 patients(47%)completed the 2-year follow-up.Both outcome measures significantly improved across all domains in the 1st year after the operation(P<0.03 for all domains).In the 2nd year after surgery,no significant changes were observed in any domain in comparison to the 1-year follow-up.CONCLUSION The Optimys stem has a 5-year survival of 98.8%.Patient-reported outcome measures increased significantly in the 1st postoperative year with stabilization at the 2-year follow-up.展开更多
AIM To evaluate the clinical and radiological outcome nineand ten years after short-stemmed,bone preserving and anatomical hip arthroplasty with the MiniHip^(TM)system.METHODS In a prospective study,186 patients under...AIM To evaluate the clinical and radiological outcome nineand ten years after short-stemmed,bone preserving and anatomical hip arthroplasty with the MiniHip^(TM)system.METHODS In a prospective study,186 patients underwent hip arthroplasty with a partial neck preserving short stem(MiniHip^(TM),Corin).Elderly patients were not excluded from this study,thus the mean age at the time of surgery was 59.3 years(range 32 to 82 years).Surgery and the follow-up assessments were performed at two Centers.Up until now,the mean follow-up was 112.5±8.2 mo.The Oxford Hip Score(OHS)and the Hip Dysfunction Osteoarthritis and Outcome Score(HOOS)was assessed pre-and each year after surgery.The clinical follow-up was accompanied by standardized a.p.and axial radiological examinations.Periprosthetic lucencies,hypertrophies within the Gruen zones one to fourteen were assessed.A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.RESULTS The OHS and HOOS improved from 18±3.3 to 46±2.0 and from 30±8.3 to 95±4.6 points,P<0.001 respectively.There were no differences regarding age,etiology,friction pairings,etc.,(P>0.05).Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively.Thus,the survivorship for aseptic loosening at nine to ten years was 98.66%.Including one stem revision due to a symptomatic exostosis,bursitis and thigh pain as well as one revision because of a septic stem loosening,the overall survival for the stem with revision for any reason was 97.32%.Besides one asymptomatic patient,radiological signs of a proximal stress-shielding,such as bone resorptions within the proximal Gruen zones,were not noticed.Findings suggesting a distal loading,e.g.,bony hypertrophies or bone appositions of more than 2 mm,were also not detected.CONCLUSION Regarding these first long-term results on the MiniHip^(TM),the implant performed exceedingly well with a high rate of survivorship for aseptic loosening.Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal,more physiological load transfer.This might minimize or exclude a stress shielding which might be associated with thigh pain,proximal bone loss and an increased risk of aseptic loosening.The MiniHip^(TM)is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.展开更多
The fatigue properties of titanium alloy short-stems with four different lengths,manufactured by electron beam melting(EBM)technology,were investigated by in vitro test and finite element(FE)analysis.FE simulation res...The fatigue properties of titanium alloy short-stems with four different lengths,manufactured by electron beam melting(EBM)technology,were investigated by in vitro test and finite element(FE)analysis.FE simulation results indicate that the maximum tensile stress concentrates at the lateral side of the stem body.The magnitude of the concentrated tensile stress increases and the corresponding area of the axial section decreases with increasing of stem length.Results from fatigue tests demonstrate that fatigue cracks mainly initiate from the rough surface of the stem where the maximum tensile stress concentrates.The fatigue strength decreases with the increase of stem length,which is attributed to the higher stress concentration on the longer stem surface.In addition,it is found that post EBM treatment via hot isostatic processing(HIP)is able to enhance the fatigue properties of the stems,since the pores generated during EBM are mostly closed during HIP.Our work also demonstrates that the stress concentration on the stem surface can be effectively mitigated and the corresponding fatigue properties of the EBM-fabricated titanium alloy short stem can be considerably improved by optimizing the design in the stem length.展开更多
BACKGROUND Subsidence is one of the concerning early complications in cementless femoral stem.Few publications have studied the influencing factors for subsidence in short cementless stems,due to their metaphyseal anc...BACKGROUND Subsidence is one of the concerning early complications in cementless femoral stem.Few publications have studied the influencing factors for subsidence in short cementless stems,due to their metaphyseal anchoring without diaphyseal invasion,they might demonstrate different subsidence patterns than with the conventional stems.AIM To analyze the factors associated with significant subsidence in short stems,including any radiographic parameters.METHODS The digitized radiographs of 274 consecutive short stem total hip arthroplasties were retrospectively reviewed.Subsidence,neck-filling ratio(NFR),seating height and lateral stem contact were evaluated after a minimum of two years follow-up.A threshold of subsidence>3 mm was considered a clinically significant migration.RESULTS For the entire cohort,subsidence occurred in 75 cases(27.4%)with the mean stem subsidence of 0.5 mm.(0-12.7,1.68).Twelve hips(4.4%)had significant subsidence(>3 mm).The univariate regression analysis demonstrated that age,diagnosis,BMI,Dorr’s type B,NFR,and seating height had no significant influence on significant subsidence,whereas insufficient lateral stem contact(≥1 mm)did have a statistically significant influence[Odds ratio(OR)=5.02;95%CI:1.3-18.9;P=0.017].The multivariate regression analysis also demonstrated that insufficient lateral stem contact was a statistically significant influencing factor(OR=5.5;95%CI:1.4-21.4;P=0.014).There was no femoral stem revision for aseptic loosening in our cohort.CONCLUSION This study demonstrated that insufficient lateral stem contact was a statistically significant influencing factor on significant subsidence.Therefore,it is a particularly important step to create proper lateral cortical contact when performing the short stem total hip arthroplasty.展开更多
BACKGROUND Short stems are usually uncemented prosthetics and are recommended in the treatment of traumatic or degenerative diseases of hip.In revision procedures for elderly patients with serious comorbidity,applying...BACKGROUND Short stems are usually uncemented prosthetics and are recommended in the treatment of traumatic or degenerative diseases of hip.In revision procedures for elderly patients with serious comorbidity,applying a short stem could reduce peri-and post-operative secondary surgical risks to femoral osteotomy,which are necessary for the removal of parts of the implant or acrylic cement from the medullary canal.There are no cases in the literature that apply a short stem for prosthetic revision by acrylic cement anchorage.CASE SUMMARY A male patient had a left hip replacement in 1995 due to coxarthrosis.At the age of eighty the patient reported an accidental trauma and walked with pain in the left thigh.The X-ray highlighted the stem breakage in the distal section without fracturing the femoral cortex.The patient had various comorbidities(diabetes,anaemia,heart deficiency,and arrhythmia)presenting a high operation risk(ASA 4).During the revision procedure,the distal apex of the stem could not be removed from the femoral cortex.Because of the poor general health of the patient,the surgeon decided not to perform a Wagner femoral osteotomy to remove the distal section of the stem and decided to implant a short stem to avoid removing the stem section of the previous implant.The patient had his left femur X-rayed 15 d post-trauma.CONCLUSION A field of application of short stem may be the development of a cemented short stem to reduce the complexity of the revision procedure.展开更多
Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution betw...Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long展开更多
BACKGROUND Failure in restoring individual anatomy could be a reason for persistent functional limitations post total hip arthroplasty.Femoroacetabular offset(FAO)plays an important role in anatomic restoration,as los...BACKGROUND Failure in restoring individual anatomy could be a reason for persistent functional limitations post total hip arthroplasty.Femoroacetabular offset(FAO)plays an important role in anatomic restoration,as loss of offset≥5 mm is associated with altered gait and decreased functional outcome.Preoperative assessment by use of digital templating has shown to be a reliable method for sizing the components in total hip arthroplasty,and can show if anatomic restoration is achieved.In recent years,short stems are growing in popularity as it could allow better restoration due to more variety in placement.AIM To assess whether restoration of the FAO differs between a short or a conventional stem by use of digital templating.Additionally,association of the preoperative offset and caput-colllum-diaphyseal angle(CCD-angle)within restoration of both stems was investigated,and the reliability of measurements was assessed.METHODS A total of 100 standardized hip radiographs were used for digital templating.Restoration of FAO was classified into“restored”or“not restored”,when a<5 mm or≥5 mm difference from baseline value presented,respectively.Differences between the two stems concerning proportions of correct restoration of the FAO were analyzed by use of McNemar tests.To assess association between CCDangle and preoperative FAO with absolute FAO restoration,multi-level analysis was performed by use of a linear mixed model to account for paired measurements.Through determination of the optimal point under the curve in operating curve-analysis,bootstrapping of thousand sets was performed to determine the optimal cutoff point of the preoperative FAO for restoration within the limits of 5 mm.Three observers participated for inter-observer reliability,with two observers measuring the radiographs twice for intra-observer reliability.RESULTS The mean preoperative FAO was 79.7 mm(range 62.5-113 mm),with a mean CCD-angle of 128.6°(range 114.5°-145°).The conventional stem could only restore the FAO in 72 of the cases,whereas the short stem restored the FAO in all cases.CCD-angle was not a predictor,but the preoperative FAO was.A cut-off point of 81.25 mm(95%confidence interval of 80.75-84.75 mm)in preoperative FAO was found where the conventional stem was unable to restore the FAO.Reliability of measurements was excellent,with an intra-observer reliability of 0.99 and inter-observer reliability in baseline measurements higher than 0.9 between the three observers.CONCLUSION In preoperative planning of FAO restoration in total hip arthroplasty,digital templating shows that short stems with a curve following the medial calcar are potentially better at restoring the FAO compared to conventional stems if the preoperative offset is≥80.0 mm.展开更多
BACKGROUND Total hip arthroplasty(THA)has increased along with an increasing demand for improved quality of life.Combined with prolonged life expectancy,the number of revision surgeries is expected to increase.Stress ...BACKGROUND Total hip arthroplasty(THA)has increased along with an increasing demand for improved quality of life.Combined with prolonged life expectancy,the number of revision surgeries is expected to increase.Stress shielding is a significant issue with traditional femoral stems used in THA,making revision surgeries particularly challenging in younger patients.This has sparked renewed interest in studying safety and functional outcomes of short metaphyseal femoral stems,which have the potential to alleviate these challenges and simplify revision surgeries.AIM To evaluate the long-term outcomes of short-stem THA.METHODS A total of 124 hips that underwent THA using the short femoral stem(TRILOCK®Depuy)between May 2006 and November 2008 were included in this study.Patients were followed for a period of 15 years.Outcomes were assessed in terms of pain relief,hip joint range of motion,improvement in mobility,and functional outcomes using the modified Harris Hip Score,Oxford hip score,and Western Ontario and McMaster Universities Osteoarthritis index score.RESULTS A total of 124 hips in 98 patients were evaluated.Significant improvements in functional outcomes were observed over the 15-year follow-up period,with no cases of subsidence,implant loosening,or complications necessitating revision surgery.The only complication reported was heterotopic ossification in 1 patient.CONCLUSION Short metaphyseal stems provide better functional outcomes with early mobilization,and its long-term follow-up without subsidence,implant loosening,or proximal femoral bone loss simplifies revision surgery in younger patients.展开更多
Short stems in total hip arthroplasty(THA)are becoming increasingly popular.In Germany,already 10.4%of all primary THAs are performed using a cementless short stem.The concept of modern,calcar-guided,short stems aims ...Short stems in total hip arthroplasty(THA)are becoming increasingly popular.In Germany,already 10.4%of all primary THAs are performed using a cementless short stem.The concept of modern,calcar-guided,short stems aims for an individualized reconstruction of the hip anatomy by following the calcar of the femoral neck,a bone-and soft-tissue-sparing implantation technique,and physiological loading.The stem design uses either metaphyseal fixation alone or additional diaphyseal anchoring,depending on the stem alignment and indication.These individualized anchorage types increase the potential indications for the safe use of a short stem.The design features may account for potential advantages of current short stem implants compared with earlier shortstem designs,particularly in cases of reduced bone quality or osteonecrosis of the femoral head and femoral neck fractures.The implantation technique,however,requires distinct knowledge regarding the characteristics of varus and valgus positioning,with the potential for clinical consequences.A learning curve for surgeons new to this technique must be taken into account.Cortical contact with the distal lateral cortex appears to be crucial to provide sufficient primary stability,and the use of intraoperative imaging to identify“undersizing”is highly recommended.Current results of several national registries indicate that calcarguided short stems are among the most successful implants in terms of mid-term survivorship.However,long-term data remain scarce.This review introduces the characteristics of calcar-guided short-stem THA and summarizes the current evidence.展开更多
Background: There have been a few reports of SMFTM stem for dysplastic hips. The aim of this study is to evaluate the influence of stem alignment in dysplastic femurs on the stability of the implants and on the bone r...Background: There have been a few reports of SMFTM stem for dysplastic hips. The aim of this study is to evaluate the influence of stem alignment in dysplastic femurs on the stability of the implants and on the bone reaction by means of consecutive radiographical analysis. Methods: The preoperative diagnosis is dysplastic osteoarthritis in all patients. Twenty-nine hips in 28 patients after MIS-THA were followed up for two or more years (3.5 years in average). The average age at the surgery was 60. Those who belonged to Crowe’s classification I were 19 and those of II were 10 hips. The shape of the femur was classified as Dorr’s Type A in 5, B in 21, and C in 3 hips. Results: The varus alignment of the stem was 21 hips and non-varus was 8 hips. Crowe’s Grade did not have influence on the stem alignment. The ratio of non-varus alignment was more with Dorr’s Type C than with others. Achieving rate of mediolateral fixation was significantly higher in the varus alignment than in non-varus. The significant subsidence occurred in 3 hips (10.3%) although all stems became stable within 6 months. No revision was necessary. Conclusion: The varus insertion of the stem seemed more secure also in dysplastic femurs, but even non-varus ones seemed acceptable as they brought about no severe problem. Comprehensively evaluating the result, careful selection of the patient is essential to take the advantage of and to overcome the disadvantage of this short stem for dysplastic hips.展开更多
Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many stud...Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many studies have focused on two of the most representative PFASs, PFOS and PFOA, the potential toxicity of short-chain PFASs has not yet been given sufficient attention.We used a battery of assays to evaluate the toxicity of several four-carbon and six-carbon perfluorinated sulfonates and carboxyl acids(PFBS,PFHxS, PFBA and PFHxA), with a human mesenchymal stem cell(hMSC) system.Our results demonstrate significant cyto-and potential developmental toxicity for all the compounds analyzed, with shared but also distinct mechanisms of toxicity.Moreover, the effects of PFBS and PFHxS were stronger than those of PFBA and PFHxA, but occurred at higher doses compared to PFOS or PFOA.展开更多
The cotton direct seeding after wheat(rape) harvested is under trial and would be the future direction at the Yangtze River Valley region of China.The objective of this study was to quantify the effects of branch and ...The cotton direct seeding after wheat(rape) harvested is under trial and would be the future direction at the Yangtze River Valley region of China.The objective of this study was to quantify the effects of branch and stem architecture on cotton yield and identify the optimal cotton architecture to compensate the yield loss due to the reduction of individual production capacity under high planting density in the direst seeding after wheat harvested cropping system.The characteristics of the stem and branch architecture and the relationships between architecture of the stem and branch with yield formation were studied on eight short season cotton cultivars during 2015 and 2016 cotton growth seasons.Based on the two years results,three cultivars with different architectures of stem and branch were selected to investigate the effect of mepiquat chloride(MC) application on the architecture of the stem and branch,boll retention,and the yield in 2017.Significant differences were observed on plant height,all fruiting nodes to branches ratio(NBR) in the cotton plant,and the curvature of the fruiting branch(CFB) among the studied cultivars.There were three types of stem and fruiting branch structures: Zhong425 with stable and suitable plant height and NBR(about 90 cm and 2.5,respectively),high CFB(more than 10.0),and high boll retention speed and seed cotton yield;Siyang 822 with excessive plant height and NBR,low CFB,and low boll retention speed and seed cotton yield;and other studied cultivars with unstable structure of stem and branch,boll retention speed,and seed cotton yield across years.And MC application could promote the appropriate plant height and NBR and high CFB and thus resulted in high boll retention speed and the yield.The results suggested that the suitable plant height and NBR(about 90 cm and 2.5 respectively),and high CFB(more than 10.0),which was related to both genotype and cultural practice,could promote the higher boll retention speed and seed cotton yield.展开更多
We established a QT interval assessment system that uses human embryonic stem cell-derived cardiomyocyte clusters (hES-CMCs) in which the field potential duration (FPD) or corrected FPD (FPDc) was measured as an indic...We established a QT interval assessment system that uses human embryonic stem cell-derived cardiomyocyte clusters (hES-CMCs) in which the field potential duration (FPD) or corrected FPD (FPDc) was measured as an indicator of drug-induced QT interval prolongation. To investigate the applicability of the hES-CMC system to drug safety assessment, we investigated short-term variability in FPDc (STVFPDc) (beat rate rhythmicity) as a marker of torsadogenic risk. We investigated the FPDc and STVFPDc of hES-CMCs treated with hERG channel blockers (E-4031 or cisapride) or with our proprietary compounds X, Y, and Z. We also evaluated the electrocardiograms and hemodynamics of dogs treated with compound X, Y, or Z. The torsadogenic hERG channel blockers increased STVFPDc and prolonged FPDc. Compounds X, Y, and Z had hERG inhibitory activity. Compound X prolonged FPDc with increased STVFPDc, whereas compounds Y and Z tended to shorten FPDc in the hES-CMC system. In the in vivo canine study, compound X prolonged corrected QT (QTc), and compounds Y and Z tended to shorten QTc, showing a good correlation with the results in hES-CMCs. These findings suggest that combined assessment of FPDc and STVFPDc in the hES-CMC system increases the predictability of torsadogenic risk.展开更多
文摘BACKGROUND In recent years,there has been an increase in the number of total hip arthroplasty procedures in the younger patient population.This active group has higher expectations of their prosthesis in comparison to the older population,and there is a greater physical demand for the prosthesis.Short femoral stems were in-troduced to retain proximal bone stock and joint biomechanics and became more common to implant in this specific population.Currently,the long-term survival and functional outcomes of various short stems are still being investigated in different clinics.AIM To determine the 5-year survival of the Optimys hip stem.METHODS This was a prospective multicenter cohort study of 500 patients conducted in two hospitals in the Netherlands.All patients received the Optimys short stem(Mathys Ltd,Bettlach,Switzerland).The primary outcome measure was survival of the hip stem,with revision as the endpoint.The secondary outcome measurements included patient-reported outcome measures(PROMs).Kaplan-Meier analysis was used to calculate the 5-year survival rate.Log-minus-log transformation was performed to calculate the 95%confidence interval(95%CI).Mixed model analyses were performed to assess the course of the PROMs during the 1st 2 years after surgery.Analyses were modeled separately for the 1st and 2nd years to calculate the yearly change in PROMs during both follow-up periods with accompanying 95%CIs.RESULTS The mean age of the total 500 patients was 62.3 years(standard deviation:10.6)and 202 were male(40%).At a median follow-up of 5.5 years(interquartile range:4.5-6.7),7 patients were deceased and 6 revisions were registered,for infection(n=3),subsidence(n=2)and malposition(n=1).This resulted in an overall 5-year survival of 98.8%(95%CI:97.3-99.5).If infection was left out as reason for revision,a stem survival of 99.4%(95%CI:98.1-99.8)was seen.Baseline questionnaires were completed by 471 patients(94%),317 patients(63%)completed the 1-year follow-up questionnaires and 233 patients(47%)completed the 2-year follow-up.Both outcome measures significantly improved across all domains in the 1st year after the operation(P<0.03 for all domains).In the 2nd year after surgery,no significant changes were observed in any domain in comparison to the 1-year follow-up.CONCLUSION The Optimys stem has a 5-year survival of 98.8%.Patient-reported outcome measures increased significantly in the 1st postoperative year with stabilization at the 2-year follow-up.
基金Supported by A sponsorship from Corin(Corin Group,Cirencest,United Kingdom)
文摘AIM To evaluate the clinical and radiological outcome nineand ten years after short-stemmed,bone preserving and anatomical hip arthroplasty with the MiniHip^(TM)system.METHODS In a prospective study,186 patients underwent hip arthroplasty with a partial neck preserving short stem(MiniHip^(TM),Corin).Elderly patients were not excluded from this study,thus the mean age at the time of surgery was 59.3 years(range 32 to 82 years).Surgery and the follow-up assessments were performed at two Centers.Up until now,the mean follow-up was 112.5±8.2 mo.The Oxford Hip Score(OHS)and the Hip Dysfunction Osteoarthritis and Outcome Score(HOOS)was assessed pre-and each year after surgery.The clinical follow-up was accompanied by standardized a.p.and axial radiological examinations.Periprosthetic lucencies,hypertrophies within the Gruen zones one to fourteen were assessed.A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.RESULTS The OHS and HOOS improved from 18±3.3 to 46±2.0 and from 30±8.3 to 95±4.6 points,P<0.001 respectively.There were no differences regarding age,etiology,friction pairings,etc.,(P>0.05).Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively.Thus,the survivorship for aseptic loosening at nine to ten years was 98.66%.Including one stem revision due to a symptomatic exostosis,bursitis and thigh pain as well as one revision because of a septic stem loosening,the overall survival for the stem with revision for any reason was 97.32%.Besides one asymptomatic patient,radiological signs of a proximal stress-shielding,such as bone resorptions within the proximal Gruen zones,were not noticed.Findings suggesting a distal loading,e.g.,bony hypertrophies or bone appositions of more than 2 mm,were also not detected.CONCLUSION Regarding these first long-term results on the MiniHip^(TM),the implant performed exceedingly well with a high rate of survivorship for aseptic loosening.Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal,more physiological load transfer.This might minimize or exclude a stress shielding which might be associated with thigh pain,proximal bone loss and an increased risk of aseptic loosening.The MiniHip^(TM)is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.
基金supported partially by the Chinese MoST(No.2017YFC1104903)the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-JSC031-02)+2 种基金the National Natural Science Foundation of China(Nos.81772425,51631007 and 51871220)the Science and Technology Commission of Shanghai Municipality(No.16441908700)the Shanghai Jiao Tong University(No.YG2016MS11)。
文摘The fatigue properties of titanium alloy short-stems with four different lengths,manufactured by electron beam melting(EBM)technology,were investigated by in vitro test and finite element(FE)analysis.FE simulation results indicate that the maximum tensile stress concentrates at the lateral side of the stem body.The magnitude of the concentrated tensile stress increases and the corresponding area of the axial section decreases with increasing of stem length.Results from fatigue tests demonstrate that fatigue cracks mainly initiate from the rough surface of the stem where the maximum tensile stress concentrates.The fatigue strength decreases with the increase of stem length,which is attributed to the higher stress concentration on the longer stem surface.In addition,it is found that post EBM treatment via hot isostatic processing(HIP)is able to enhance the fatigue properties of the stems,since the pores generated during EBM are mostly closed during HIP.Our work also demonstrates that the stress concentration on the stem surface can be effectively mitigated and the corresponding fatigue properties of the EBM-fabricated titanium alloy short stem can be considerably improved by optimizing the design in the stem length.
文摘BACKGROUND Subsidence is one of the concerning early complications in cementless femoral stem.Few publications have studied the influencing factors for subsidence in short cementless stems,due to their metaphyseal anchoring without diaphyseal invasion,they might demonstrate different subsidence patterns than with the conventional stems.AIM To analyze the factors associated with significant subsidence in short stems,including any radiographic parameters.METHODS The digitized radiographs of 274 consecutive short stem total hip arthroplasties were retrospectively reviewed.Subsidence,neck-filling ratio(NFR),seating height and lateral stem contact were evaluated after a minimum of two years follow-up.A threshold of subsidence>3 mm was considered a clinically significant migration.RESULTS For the entire cohort,subsidence occurred in 75 cases(27.4%)with the mean stem subsidence of 0.5 mm.(0-12.7,1.68).Twelve hips(4.4%)had significant subsidence(>3 mm).The univariate regression analysis demonstrated that age,diagnosis,BMI,Dorr’s type B,NFR,and seating height had no significant influence on significant subsidence,whereas insufficient lateral stem contact(≥1 mm)did have a statistically significant influence[Odds ratio(OR)=5.02;95%CI:1.3-18.9;P=0.017].The multivariate regression analysis also demonstrated that insufficient lateral stem contact was a statistically significant influencing factor(OR=5.5;95%CI:1.4-21.4;P=0.014).There was no femoral stem revision for aseptic loosening in our cohort.CONCLUSION This study demonstrated that insufficient lateral stem contact was a statistically significant influencing factor on significant subsidence.Therefore,it is a particularly important step to create proper lateral cortical contact when performing the short stem total hip arthroplasty.
文摘BACKGROUND Short stems are usually uncemented prosthetics and are recommended in the treatment of traumatic or degenerative diseases of hip.In revision procedures for elderly patients with serious comorbidity,applying a short stem could reduce peri-and post-operative secondary surgical risks to femoral osteotomy,which are necessary for the removal of parts of the implant or acrylic cement from the medullary canal.There are no cases in the literature that apply a short stem for prosthetic revision by acrylic cement anchorage.CASE SUMMARY A male patient had a left hip replacement in 1995 due to coxarthrosis.At the age of eighty the patient reported an accidental trauma and walked with pain in the left thigh.The X-ray highlighted the stem breakage in the distal section without fracturing the femoral cortex.The patient had various comorbidities(diabetes,anaemia,heart deficiency,and arrhythmia)presenting a high operation risk(ASA 4).During the revision procedure,the distal apex of the stem could not be removed from the femoral cortex.Because of the poor general health of the patient,the surgeon decided not to perform a Wagner femoral osteotomy to remove the distal section of the stem and decided to implant a short stem to avoid removing the stem section of the previous implant.The patient had his left femur X-rayed 15 d post-trauma.CONCLUSION A field of application of short stem may be the development of a cemented short stem to reduce the complexity of the revision procedure.
文摘Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long
文摘BACKGROUND Failure in restoring individual anatomy could be a reason for persistent functional limitations post total hip arthroplasty.Femoroacetabular offset(FAO)plays an important role in anatomic restoration,as loss of offset≥5 mm is associated with altered gait and decreased functional outcome.Preoperative assessment by use of digital templating has shown to be a reliable method for sizing the components in total hip arthroplasty,and can show if anatomic restoration is achieved.In recent years,short stems are growing in popularity as it could allow better restoration due to more variety in placement.AIM To assess whether restoration of the FAO differs between a short or a conventional stem by use of digital templating.Additionally,association of the preoperative offset and caput-colllum-diaphyseal angle(CCD-angle)within restoration of both stems was investigated,and the reliability of measurements was assessed.METHODS A total of 100 standardized hip radiographs were used for digital templating.Restoration of FAO was classified into“restored”or“not restored”,when a<5 mm or≥5 mm difference from baseline value presented,respectively.Differences between the two stems concerning proportions of correct restoration of the FAO were analyzed by use of McNemar tests.To assess association between CCDangle and preoperative FAO with absolute FAO restoration,multi-level analysis was performed by use of a linear mixed model to account for paired measurements.Through determination of the optimal point under the curve in operating curve-analysis,bootstrapping of thousand sets was performed to determine the optimal cutoff point of the preoperative FAO for restoration within the limits of 5 mm.Three observers participated for inter-observer reliability,with two observers measuring the radiographs twice for intra-observer reliability.RESULTS The mean preoperative FAO was 79.7 mm(range 62.5-113 mm),with a mean CCD-angle of 128.6°(range 114.5°-145°).The conventional stem could only restore the FAO in 72 of the cases,whereas the short stem restored the FAO in all cases.CCD-angle was not a predictor,but the preoperative FAO was.A cut-off point of 81.25 mm(95%confidence interval of 80.75-84.75 mm)in preoperative FAO was found where the conventional stem was unable to restore the FAO.Reliability of measurements was excellent,with an intra-observer reliability of 0.99 and inter-observer reliability in baseline measurements higher than 0.9 between the three observers.CONCLUSION In preoperative planning of FAO restoration in total hip arthroplasty,digital templating shows that short stems with a curve following the medial calcar are potentially better at restoring the FAO compared to conventional stems if the preoperative offset is≥80.0 mm.
文摘BACKGROUND Total hip arthroplasty(THA)has increased along with an increasing demand for improved quality of life.Combined with prolonged life expectancy,the number of revision surgeries is expected to increase.Stress shielding is a significant issue with traditional femoral stems used in THA,making revision surgeries particularly challenging in younger patients.This has sparked renewed interest in studying safety and functional outcomes of short metaphyseal femoral stems,which have the potential to alleviate these challenges and simplify revision surgeries.AIM To evaluate the long-term outcomes of short-stem THA.METHODS A total of 124 hips that underwent THA using the short femoral stem(TRILOCK®Depuy)between May 2006 and November 2008 were included in this study.Patients were followed for a period of 15 years.Outcomes were assessed in terms of pain relief,hip joint range of motion,improvement in mobility,and functional outcomes using the modified Harris Hip Score,Oxford hip score,and Western Ontario and McMaster Universities Osteoarthritis index score.RESULTS A total of 124 hips in 98 patients were evaluated.Significant improvements in functional outcomes were observed over the 15-year follow-up period,with no cases of subsidence,implant loosening,or complications necessitating revision surgery.The only complication reported was heterotopic ossification in 1 patient.CONCLUSION Short metaphyseal stems provide better functional outcomes with early mobilization,and its long-term follow-up without subsidence,implant loosening,or proximal femoral bone loss simplifies revision surgery in younger patients.
文摘Short stems in total hip arthroplasty(THA)are becoming increasingly popular.In Germany,already 10.4%of all primary THAs are performed using a cementless short stem.The concept of modern,calcar-guided,short stems aims for an individualized reconstruction of the hip anatomy by following the calcar of the femoral neck,a bone-and soft-tissue-sparing implantation technique,and physiological loading.The stem design uses either metaphyseal fixation alone or additional diaphyseal anchoring,depending on the stem alignment and indication.These individualized anchorage types increase the potential indications for the safe use of a short stem.The design features may account for potential advantages of current short stem implants compared with earlier shortstem designs,particularly in cases of reduced bone quality or osteonecrosis of the femoral head and femoral neck fractures.The implantation technique,however,requires distinct knowledge regarding the characteristics of varus and valgus positioning,with the potential for clinical consequences.A learning curve for surgeons new to this technique must be taken into account.Cortical contact with the distal lateral cortex appears to be crucial to provide sufficient primary stability,and the use of intraoperative imaging to identify“undersizing”is highly recommended.Current results of several national registries indicate that calcarguided short stems are among the most successful implants in terms of mid-term survivorship.However,long-term data remain scarce.This review introduces the characteristics of calcar-guided short-stem THA and summarizes the current evidence.
文摘Background: There have been a few reports of SMFTM stem for dysplastic hips. The aim of this study is to evaluate the influence of stem alignment in dysplastic femurs on the stability of the implants and on the bone reaction by means of consecutive radiographical analysis. Methods: The preoperative diagnosis is dysplastic osteoarthritis in all patients. Twenty-nine hips in 28 patients after MIS-THA were followed up for two or more years (3.5 years in average). The average age at the surgery was 60. Those who belonged to Crowe’s classification I were 19 and those of II were 10 hips. The shape of the femur was classified as Dorr’s Type A in 5, B in 21, and C in 3 hips. Results: The varus alignment of the stem was 21 hips and non-varus was 8 hips. Crowe’s Grade did not have influence on the stem alignment. The ratio of non-varus alignment was more with Dorr’s Type C than with others. Achieving rate of mediolateral fixation was significantly higher in the varus alignment than in non-varus. The significant subsidence occurred in 3 hips (10.3%) although all stems became stable within 6 months. No revision was necessary. Conclusion: The varus insertion of the stem seemed more secure also in dysplastic femurs, but even non-varus ones seemed acceptable as they brought about no severe problem. Comprehensively evaluating the result, careful selection of the patient is essential to take the advantage of and to overcome the disadvantage of this short stem for dysplastic hips.
基金supported by the National Natural Science Foundation of China (Nos.21876197, 21577166, 21707160)the Chinese Academy of Sciences (Nos.XDB14040301, 29[2015]30, QYZDJ-SSW-DQC017)the K.C.Wong Education Foundation.
文摘Per-and polyfluorinated alkyl substances(PFASs) are commonly used in industrial processes and daily life products.Because they are persistent, they accumulate in the environment, wildlife and humans.Although many studies have focused on two of the most representative PFASs, PFOS and PFOA, the potential toxicity of short-chain PFASs has not yet been given sufficient attention.We used a battery of assays to evaluate the toxicity of several four-carbon and six-carbon perfluorinated sulfonates and carboxyl acids(PFBS,PFHxS, PFBA and PFHxA), with a human mesenchymal stem cell(hMSC) system.Our results demonstrate significant cyto-and potential developmental toxicity for all the compounds analyzed, with shared but also distinct mechanisms of toxicity.Moreover, the effects of PFBS and PFHxS were stronger than those of PFBA and PFHxA, but occurred at higher doses compared to PFOS or PFOA.
基金funded by the National Key Research and Development Program of China(2018YFD0100400 and 2017YFD0201300)the Engineering Science and Technology Innovation Fund of Chinese Academy of Agricultural Sciences(2016PCTS-1)+1 种基金the National Natural Science Foundation of China(31671613)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)
文摘The cotton direct seeding after wheat(rape) harvested is under trial and would be the future direction at the Yangtze River Valley region of China.The objective of this study was to quantify the effects of branch and stem architecture on cotton yield and identify the optimal cotton architecture to compensate the yield loss due to the reduction of individual production capacity under high planting density in the direst seeding after wheat harvested cropping system.The characteristics of the stem and branch architecture and the relationships between architecture of the stem and branch with yield formation were studied on eight short season cotton cultivars during 2015 and 2016 cotton growth seasons.Based on the two years results,three cultivars with different architectures of stem and branch were selected to investigate the effect of mepiquat chloride(MC) application on the architecture of the stem and branch,boll retention,and the yield in 2017.Significant differences were observed on plant height,all fruiting nodes to branches ratio(NBR) in the cotton plant,and the curvature of the fruiting branch(CFB) among the studied cultivars.There were three types of stem and fruiting branch structures: Zhong425 with stable and suitable plant height and NBR(about 90 cm and 2.5,respectively),high CFB(more than 10.0),and high boll retention speed and seed cotton yield;Siyang 822 with excessive plant height and NBR,low CFB,and low boll retention speed and seed cotton yield;and other studied cultivars with unstable structure of stem and branch,boll retention speed,and seed cotton yield across years.And MC application could promote the appropriate plant height and NBR and high CFB and thus resulted in high boll retention speed and the yield.The results suggested that the suitable plant height and NBR(about 90 cm and 2.5 respectively),and high CFB(more than 10.0),which was related to both genotype and cultural practice,could promote the higher boll retention speed and seed cotton yield.
文摘We established a QT interval assessment system that uses human embryonic stem cell-derived cardiomyocyte clusters (hES-CMCs) in which the field potential duration (FPD) or corrected FPD (FPDc) was measured as an indicator of drug-induced QT interval prolongation. To investigate the applicability of the hES-CMC system to drug safety assessment, we investigated short-term variability in FPDc (STVFPDc) (beat rate rhythmicity) as a marker of torsadogenic risk. We investigated the FPDc and STVFPDc of hES-CMCs treated with hERG channel blockers (E-4031 or cisapride) or with our proprietary compounds X, Y, and Z. We also evaluated the electrocardiograms and hemodynamics of dogs treated with compound X, Y, or Z. The torsadogenic hERG channel blockers increased STVFPDc and prolonged FPDc. Compounds X, Y, and Z had hERG inhibitory activity. Compound X prolonged FPDc with increased STVFPDc, whereas compounds Y and Z tended to shorten FPDc in the hES-CMC system. In the in vivo canine study, compound X prolonged corrected QT (QTc), and compounds Y and Z tended to shorten QTc, showing a good correlation with the results in hES-CMCs. These findings suggest that combined assessment of FPDc and STVFPDc in the hES-CMC system increases the predictability of torsadogenic risk.
