Objective:To explore the prevalence rate of knee joint osteoarthritis and its pathogenetic fea- tures among the middle-aged and old aged people in the urban and rural area of Xi'an.Methods:From May to October 2005...Objective:To explore the prevalence rate of knee joint osteoarthritis and its pathogenetic fea- tures among the middle-aged and old aged people in the urban and rural area of Xi'an.Methods:From May to October 2005,1538 Han nationality above 40 years in Xi'an were investigated according to strati- fied and cluster random sampling.The same questionnaire was delivered to subjects who had been given normotopia and lateral position radiographic examination in both knees.Excluded from etiological arthri- tis,some subjects with clinical symptoms and a radiographic grade (beyond Kellgren & Lawrence gradeⅡ) were finally diagnosed as spontaneous knee joint osteoarthritis.All analyses were performed with SPSS 13.0 and t test,U test.Single factor analysis and multiple logistic regression analysis were used to analyze dates.Results:The total prevalence of spontaneous knee joint osteoarthritis was 12.1% with 2.5% and 2.1% for right and left knees,respectively.The prevalence of knee joint osteoarthritis in wom- en was 2.5 times of that in men (17.2% vs 6.8%,P=0.000).the osteophyte prevalence in women was 2.3 times of that in men (26.5% vs 11.4%,P=0.000).The prevalence of knee joint osteoarthritis and osteophyte increased with the growth of age.So did the symptomatic knee,except for the age group of 56- 60 years and 66-70 years.The prevalence of symptomatic knee joint for urban area was significantly higher than that for rural area (56.3% vs 45.3%,P=0.003).In women,the prevalence of knee joint os- teoarthritis increased significantly with the increasing of body mass index,which had not been observed in men.Female and obesity are the risk factors for osteoarthritis,but bean and its products and meat could prevent the osteoarthritis.Conclusion:Old age,female and obesity serve as risk factors for knee joint os- teoarthritis.展开更多
Objective To investigate the influence of gender on osteoarthritic knee rehabilitation outcome of osteoarthritis patient undergoing total knee arthroplasty(TKA).Methods We prospectively studied thirty male and thirty ...Objective To investigate the influence of gender on osteoarthritic knee rehabilitation outcome of osteoarthritis patient undergoing total knee arthroplasty(TKA).Methods We prospectively studied thirty male and thirty female knee primary osteoarthritis patients receiving unilateral TKA with posterior stable-fixed plateau prosthesis at our hospital from March 2003 to March 2008.The age and body mass index of male and female patients were matched.The surgical and rehabilitation clinical factors were compared between two groups.Results There was no significant difference in postoperative hospitalization time,surgical tourniquet time,and wound drainage volume between two groups(P>0.05).The extension/flexion degrees of knee joint before operation,1-week,2-week and 1-year after operation for male patients were 6.0 ± 3.3 degrees/ 114.0 ± 10.0 degrees,2.0 ± 1.6 degrees/93.0 ± 7.4 degrees,0.6 ± 0.6 degrees/104.0 ± 9.9 degrees and 0.3 ± 0.5 degrees/125.0 ± 8.8 degrees,for female patients were 7.0 ± 3.4 degrees/112.0 ± 14.0 degrees,2.0 ± 1.3 degrees/89.0 ± 10.9 degrees,0.9 ± 0.8 degrees/101.0 ± 11.8 degrees,0.4 ± 0.5 degrees/124.0 ± 7.1 degrees.The range of motion before operation,1-week,2-week,and 1-year after operation for male patients was 108.0 ± 9.5 degrees,91.0 ± 7.1 degrees,103.0 ± 9.9 degrees,and 125.0 ± 8.9 degrees,for female patients was 105.0 ± 14.1 degrees,87.0 ± 11.4 degrees,100.0±11.9 degrees,and 124.0 ± 7.0 degrees.The preoperative and 1-year postoperative HSS scores were 55.8 ± 13.3 and 89.6 ± 6.7 for males and 54.5 ± 13.8 and 89.2 ± 4.1 for females.No significant statistical difference was observed between two gender groups in regards to degree of extension and flexion,range of motion and HSS score(P>0.05).Conclusions Gender does not influence postoperative knee function of osteoarthritis patients.TKA significantly improves knee joint function and relieve osteoarthritis-related pain.展开更多
ABSTRACT:Knee osteoarthritis(KOA),a complicated peripheral joint disorder,can be caused by non-modifiable and modifiable risk factors.At present,the treatment for osteoarthritis is mainly to manage symptoms and improv...ABSTRACT:Knee osteoarthritis(KOA),a complicated peripheral joint disorder,can be caused by non-modifiable and modifiable risk factors.At present,the treatment for osteoarthritis is mainly to manage symptoms and improve quality of life.Although some patients with osteoarthritis may choose pharmacological agents for pain relief,it has been confirmed that a variety of preparations and doses of pharmacological agents were ineffective.In recent years,Traditional Chinese medicine(TCM)has been shown unique superiorities in the treatment of osteoarthritis,including KOA.Therefore,this article primarily investigated the key points of common syndromes,TCM nursing methods and healthy guidance of KOA,aiming at maintaining and developing the strengths of TCM,improving its efficacy and standardizing its behavior.展开更多
Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of...Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of the knee joint.Non-invasive methods based on mechanical action are also used for the rehabilitation of a patient after arthroplasty.This paper presents numerical models of the knee joint with degenerative OA changes and arthroplasty.Using these models,a computational study was made of the influence of the intensity of shock-wave exposure on the conditioning for the regeneration of bone and cartilage tissues.Based on the modeling results,it was found that in the knee joint with degenerative OA changes,conditions for the regeneration of cartilage and meniscus tissues were fulfilled under medium and highintensity loading.Under high-intensity loading(up to 0.9 m J/mm^(2)),the stress level was significantly below the ultimate value required for fracture.At knee arthroplasty,the conditions for bone tissue regeneration around the tibia component are fulfilled only under high-intensity loading.展开更多
Objective To investigate the expression of miRNA-140 in chondrocytes and synovial fluid of osteoarthritis(OA) patients, and explore the relationship between the miRNA-140 expression and OA severity. Methods This study...Objective To investigate the expression of miRNA-140 in chondrocytes and synovial fluid of osteoarthritis(OA) patients, and explore the relationship between the miRNA-140 expression and OA severity. Methods This study enrolled 30 OA patients who underwent total knee arthroplasty for chondrocytes sampling and 30 OA patients who underwent intra-articular injection for synovial fluid sampling. All OA patients were grouped into mild [Kellgren and Lawrence(KL) grade 1-2], moderate(KL grade 3) and severe(KL grade 4), with 10 in each subgroups for each sampling purposes. 7 non-OA patients and 10 patients with knee injury were collected for cartilage and synovial fluid sampling respectively as control groups. Chondrocytes were isolated from the cartilage tissue and cultured in vitro. Quantitative real time PCR for miRNA-140 in chondrocytes and synovial fluid were performed, and the U6 sn RNA was used as internal control. The expression difference of miRNA-140 among groups and correlation between the expression and the KL grade of OA were analysed using one-way ANOVA and Spearman test respectively. Results The expression of miRNA-140 in chondrocytes of knees in OA patients was reduced than that in normal knees, and the between-group difference was statistically significant(F=305.464, P<0.001). miRNA-140 could be detected in synovial fluid of both normal knees and OA knees, its relative expression level was reduced in synovial fluid of OA group compared with normal group, and the between-group difference was statistically significant as well(F=314.245, P<0.001). The relative expression level of miRNA-140 in both chondrocytes and synovial fluid were negatively correlated with the KL grade of OA(r=-0.969, P<0.001; r=-0.970, P<0.001). Conclusion miRNA-140 could be detected in chondrocytes and synovial fluid of OA patients, and its expression was negatively correlated with the severity of OA.展开更多
Objective To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). Methods A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen fo...Objective To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). Methods A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen for this 17-week, randomized, double-dummy, diclofenac sodium-controlled trial, with diacerein dosage of 100 mg/d and diclofenac sodium of 75mg/d. Efficacy and safety of both drugs were evaluated. Results Totally 106 patients in the diacerein group and 107 patients in the diclofenac group were considered qualified for the evaluation. After 12 weeks of treatment, the total effective rates of patients/physicians’ overall assessment in diacerein and diclofenac groups were 65.4%/61.6% and 61.2%/61.2%, respectively (P>0.05). The primary efficacy parameter [visual analog scale (VAS) assessment of pain on 20 metres walking] and the secondary efficacy parameters [tenderness on palpation, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short-Form (SF-36) Health Survey] significantly improved compared with baseline in both groups (P<0.05). In the follow-up period, there were no obvious changes in above parameters in diacerein group. However, in diclofenac group, pain on 20 metres walking, tenderness on palpation, and WOMAC became aggravated after withdrawing the drug for 4 weeks (P<0.05). Moreover, the consumption of paracetamol was significantly lower in diacerein group than in diclofenac group during follow-up (P<0.001). The incidences of related adverse events were 35.7% in diacerein and 45.1% in diclofenac group, respectively. Mild-to-moderate gastrointestinal disorders were the most frequent adverse events. Conclusions Diacerein is as effective as diclofenac sodium in treating patients with knee OA. Furthermore, it has better extended effect and a good safety profile. It is generally well tolerated and has no severe adverse effect.展开更多
Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral pos...Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral postoperative joint alignment. However, contemporary approaches, such as kinematic alignments and hybrid techniques including adjusted mechanical, restricted kinematic, inverse kinematic, and functional alignments, are gaining attention for their ability to restore native joint kinematics and anatomical alignment, potentially leading to enhanced functional outcomes and greater patient satisfaction. The ongoing debate on optimal alignment strategies considers the following factors: long-term implant durability, functional improvement, and resolution of individual anatomical variations. Furthermore, advancements of computer-navigated and robotic-assisted surgery have augmented the precision in implant positioning and objective measurements of soft tissue balance. Despite ongoing debates on balancing implant longevity and functional outcomes, there is an increasing advocacy for personalized alignment strategies that are tailored to individual anatomical variations. This review evaluates the spectrum of various alignment techniques in TKA, including mechanical alignment, patient-specific kinematic approaches, and emerging hybrid methods. Each technique is scrutinized based on its fundamental principles, procedural techniques, inherent advantages, and potential limitations, while identifying significant clinical gaps that underscore the need for further investigation.展开更多
Osteoarthritis is the most prevalent chronic and debilitating joint disease,resulting in huge medical and socioeconomic burdens.Intra-articular administration of agents is clinically used for pain management.However,t...Osteoarthritis is the most prevalent chronic and debilitating joint disease,resulting in huge medical and socioeconomic burdens.Intra-articular administration of agents is clinically used for pain management.However,the effectiveness is inapparent caused by the rapid clearance of agents.To overcome this issue,nanoparticles as delivery systems hold considerable promise for local control of the pharmacokinetics of therapeutic agents.Given the therapeutic programs are inseparable from pathological progress of osteoarthritis,an ideal delivery system should allow the release of therapeutic agents upon specific features of disorders.In this review,we firstly introduce the pathological features of osteoarthritis and the design concept for accurate localization within cartilage for sustained drug release.Then,we review the interactions of nanoparticles with cartilage microenvironment and the rational design.Furthermore,we highlight advances in the therapeutic schemes according to the pathology signals.Finally,armed with an updated understanding of the pathological mechanisms,we place an emphasis on the development of“smart”bioresponsive and multiple modality nanoparticles on the near horizon to interact with the pathological signals.We anticipate that the exploration of nanoparticles by balancing the efficacy,safety,and complexity will lay down a solid foundation tangible for clinical translation.展开更多
Background:Postoperative care has been evolving since the concept of enhanced recovery after surgery(ERAS)was introduced in China.This study aimed to evaluate the effects of early ambulation within 24h after unilatera...Background:Postoperative care has been evolving since the concept of enhanced recovery after surgery(ERAS)was introduced in China.This study aimed to evaluate the effects of early ambulation within 24h after unilateral total knee arthroplasty(TKA)on postoperative rehabilitation and costs in a Chinese population.Methods:This cohort study of patients with knee osteoarthritis who had undergone TKA at 24 large teaching hospitals between January 2014 and November 2016 involved 2687 patients who began ambulating within 24h(Group A)and 3761 patients who began ambulating later than 24h(Group B).The outcome measurements,such as length of stay(LOS),total hospitalization costs,dynamic pain level,knee flexion range of motion(ROM),results of the 12-Item Short Form Survey(SF-12),incidence of thromboembolic events and other complications,were recorded and compared.Results:The early ambulation group(Group A)had a shorter LOS and lower hospitalization costs and pain levels than the late ambulation group(Group B).There was a favorable effect in enhancing ROM for patients in Group A compared with patients in Group B.In Group A,patients had significantly higher postoperative SF-12 scores than those in Group B.The incidence of deep venous thrombosis(DVT)and pulmonary infection was significantly lower in Group A than in Group B.The incidence of pulmonary embolism(PE)and other complications did not differ between the two groups.Conclusions:Early ambulation within 24h after TKA was associated with reduced LOS,improved knee function,lower hospitalization costs and lower incidence of DVT and pulmonary infection in the Chinese population.展开更多
Objective To assess the effects of suction drainage versus nondrainage on the post-operative rehabilitation of patients receiving primary bilateral total knee arthroplasties(TKA).Methods A prospective study including ...Objective To assess the effects of suction drainage versus nondrainage on the post-operative rehabilitation of patients receiving primary bilateral total knee arthroplasties(TKA).Methods A prospective study including 40 patients was conducted.These patients were diagnosed with osteoarthritis and underwent primary bilateral TKA between October 2007 and September 2009 with the same operation team.A suction drainage was placed by randomization in only one knee for each patient,while the other knee as self-control.Pain visual analogue scale score,extremity swelling,wound healing,range of motion and incidence of early post-operative complications between the drained and nondrained group were compared statistically.Results Each patient was followed up for 12 months.Placing drainage did not relieve the pain,extremity swelling,ecchymosis,or reduce the incidence of early complications(all P>0.05).Conclusions Suction drainage in TKA does not exhibit substantial advantages in promoting post-operative rehabilitation after unsophisticated TKA,compared with nondrainage.On the other hand,it might complicate the surgical operation,and increase the incidence of post-operative hemorrhage and retrograde infection.Thus we do not recommend suction drainage in unsophisticated TKA.展开更多
Osteoarthritis(OA)is the most common type of degenerative joint disease which affects 7%of the global population and more than 500 million people worldwide.One research frontier is the development of hydrogels for OA ...Osteoarthritis(OA)is the most common type of degenerative joint disease which affects 7%of the global population and more than 500 million people worldwide.One research frontier is the development of hydrogels for OA treatment,which operate either as functional scaffolds of tissue engineering or as delivery vehicles of functional additives.Both approaches address the big challenge:establishing stable integration of such delivery systems or implants.Adhesive hydrogels provide possible solutions to this challenge.However,few studies have described the current advances in using adhesive hydrogel for OA treatment.This review summarizes the commonly used hydrogels with their adhesion mechanisms and components.Additionally,recognizing that OA is a complex disease involving different biological mechanisms,the bioactive therapeutic strategies are also presented.By presenting the adhesive hydrogels in an interdisciplinary way,including both the fields of chemistry and biology,this review will attempt to provide a comprehensive insight for designing novel bioadhesive systems for OA therapy.展开更多
Objective Iodothyronine deiodinases(DIOs)are important selenoproteins that play a key role in the bone and joint diseases.Osteoarthritis(OA)is the most prevalent joint disease especially in elders.This bioinformatic a...Objective Iodothyronine deiodinases(DIOs)are important selenoproteins that play a key role in the bone and joint diseases.Osteoarthritis(OA)is the most prevalent joint disease especially in elders.This bioinformatic analysis was performed to explore the role of DIOs in OA pathogenesis.Methods The biological functions of selenoprotein DIOs were analyzed by bioinformatic techniques,mcluding GenCLip 3.0,Database for Annotation,Visualization and Integrated Discovery(DAVID),STRING,Cytoscape,and Network Analyst.The expression of DIOs in the healthy individuals and OA patients was determined by mining OA-related microarray data in the gene expression omnibus(GEO)database of National Center for Biotechnology Information and performing a Meta-analysis of the data with Review Manager 5.3.Results Cluster analysis revealed that the function of the DIOs was associated with thyroid hormone receptor and iodothyronine;GO analysis showed that DIOs were mainly involved in biological processes,such as ethanol metabolism and phenol-containing compound metabolism and primarily involved in the cytochrome P450 metabolism of exogenous organisms and thyroid hormone signaling;SULT1A1 was the core node of the PPI network;miRNAs and thyroid hormones had some iterations with DIO1 and DI02;Meta-analysis showed that DIO3 expression was significantly up-regulated in OA patients(SMD=0.31,95%CI:0.03,0.59,P=0.03).Conclusions The main biological functions of DIOs were closely associated with the regulation of thyroid hormone.And the up-regulated expression of DIO3 may have crucial impact on the occurrence of OA.展开更多
Objective: To examine the changes of mu-opioid receptors (MORs) expression in human chronic inflamed knee joint synovium tissue. Methods:Knee joint synovium tissues were taken from 21 patients with chronic arthritis (...Objective: To examine the changes of mu-opioid receptors (MORs) expression in human chronic inflamed knee joint synovium tissue. Methods:Knee joint synovium tissues were taken from 21 patients with chronic arthritis (inflamed group) and 6 fresh bodies with normal knee joints (control group). And the expression of MORs was detected by using immunohistochemistry. flow cytometry(FCM) and reverse-transcription polymerase chain reaction (RT-PCR). Results: The expression of MORs in the inflamed group was significantly higher than that in the normal group by using the 3 techniques(P<0. 05). Conclusion: Chronic inflammation enhances the up-regulation of MORs in human knee joint synovium tissue.展开更多
Background: The purpose of this study was to compare the frequency of femoroacetabular impingement(FAI) between matched groups of military veterans and civilian patients with end-stage hip osteoarthritis(OA).Methods: ...Background: The purpose of this study was to compare the frequency of femoroacetabular impingement(FAI) between matched groups of military veterans and civilian patients with end-stage hip osteoarthritis(OA).Methods: Patients who underwent a primary total hip arthroplasty(THA) between January 1, 2015 and December 31, 2015 at a single Veteran’s Affairs Hospital were identified. Veterans were then matched 1:2 with civilian patients from our prospective outcome registry. The alpha angle and lateral center-edge angle(LCEA) were measured by a single evaluator. Independent t-tests were used to compare joint angles, and Fisher exact tests were used to compare the prevalence of cam(alpha angle ≥60°), pincer(LCEA ≥40°), or mixed-type pathologies.Results: Twenty-one veterans were matched 1:2 with civilian patients. The mean alpha angle did not significantly differ between groups(P=0.33) nor did the prevalence of cam deformities(P=0.79). The LCEAs were significantly greater in veterans than in civilians(P=0.04), and veterans also demonstrated a significantly greater prevalence of pincer and mixed-type deformities than civilians(P=0.025 and P=0.004, respectively).Conclusions: These results suggest that FAI is perhaps a more common mechanism in the progression of OA in a veteran population than in a civilian population, as pincer and mixed-type deformities were significantly more common among veterans than civilians. The forces borne by the hip during military training exceed normal physiologic conditions. In addition, the time between symptom onset and surgical correction may be 10–12 months longer for active military personnel than for civilians. The combination of increased physical demands and a protracted time to treatment highlights the need for better recognition of FAI in military members. Future studies are necessary to determine whether earlier intervention may prevent or delay the progression to end-stage OA and the need for total hip arthroplasty.展开更多
Objective Total knee arthroplasty is one of the most common orthopedic surgeries.Readmission due to severe complications after total knee arthroplasty is a grave concern to surgeons.In this study,we evaluated the risk...Objective Total knee arthroplasty is one of the most common orthopedic surgeries.Readmission due to severe complications after total knee arthroplasty is a grave concern to surgeons.In this study,we evaluated the risk factors for severe complications after primary total knee arthroplasty.Methods We retrospectively collected clinical data of 2,974 patients who underwent primary total knee arthroplasty from July 2013 to June 2019 in our hospital.Postoperative complication≥gradeⅢwas defined as severe complication according to Clavien-Dindo classification system.Binary logistic regression was used to identify the predictive risk factors for severe complications.Results The complication rate after primary total knee arthroplasty was 6.8%and severe complication rate was 2.5%.Male(OR=2.178,95%CI:1.324-3.585,P=0.002),individuals above 75 years old(OR=1.936,95%CI:1.155-3.244,P=0.012),arrhythmia(OR=2.913,95%CI:1.350-6.285,P=0.006)and cerebrovascular disease(OR=2.804,95%CI:1.432-5.489,P=0.003)were predictive risk factors for severe complications after primary total knee arthroplasty.Conclusion Advanced age,male,arrhythmia,and cerebrovascular disease might be patients-related risk factors for postoperative severe complications after primary total knee arthroplasty.Special attention should be paid to patients with risk factors.展开更多
The arterial supply of the genicular meniscus was studied with macro-microanatomical and histological examinations,translucent preparations and scanning electronmicroscopy.It was found that the menisci were supplied b...The arterial supply of the genicular meniscus was studied with macro-microanatomical and histological examinations,translucent preparations and scanning electronmicroscopy.It was found that the menisci were supplied by the articular branches of thepopliteal artery except the lateral superior genicular branch and the descending genicularartery.Among them there were two genicular branches with independent stems from thepopliteal artery,named as the posterior medial and posterior lateral genicular artery,whichsupplied the posterior part of the corresponding meniscus.The genicular branchesanastomosed with each other to form a vascular circle around the menisci,and minutebranches from the circle formed an arterial network around the menisci and terminated incapillaries in 3 types of anastomotic forms.The surgical approach to the menisci and theprognosis of an injured meniscus were discussed on the basis of the arterial distributionsinside and outside of the menisci.展开更多
Adult New Zealand white rabbits were used in this study. The knee joint of rabbits was experimentally traumatized. 2% solution of chitosan was applied in the experimental group (group A). The rabbits of the control gr...Adult New Zealand white rabbits were used in this study. The knee joint of rabbits was experimentally traumatized. 2% solution of chitosan was applied in the experimental group (group A). The rabbits of the control group (group B) were not treated with chitosan. The hind limb of the rabbits was immobilized with plaster cast from toe to groin. After 3 or 6 weeks,the animals were killed and the specimens were observed. The results showed that the degree of angular movement of the knee joint in group A was greater than that of group B (P<0.01). Adhesion in group B was more severe than that in group A (P<0. 01). Histological studies indicated slight synovium,little connective tissue in suprapatellar sac and collagenous fiber in matrix,and normal shape and size of the synovial cell in group A. The results of this study suggest that chitosan can prevent or alleviate post-traumatic adhesion of joint.展开更多
The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improve...The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.展开更多
The influences of different design factors,as well as dummy posture,on an occupants' knee slider compression,were studied in this paper.Based on the vehicle geometry data,the simulation model,including both the mu...The influences of different design factors,as well as dummy posture,on an occupants' knee slider compression,were studied in this paper.Based on the vehicle geometry data,the simulation model,including both the multi-rigid-body and finite element(FE)part,was built up and validated with China New Car Assessment Program(C-NCAP)full impact to ensure the accuracy of the model.By adjusting the design parameters and the posture of the femur and lower leg,different factors affecting the passengers' knee slider compression were evaluated,with the help of MAthematical DYnamic MOdel(MADYMO)simulations.The study indicated that the leg posture,the stiffness of the IP and angles of the carpet have significant effects on the knee slider compression in this case.By decreasing the angle between the femur and lower leg from 133° to 124°,the maximum knee slider compression was decreased by 17.3% and by scaling the IP stiffness from 1 to 0.7,it could be decreased by 18.6%.Also,decreasing the angles of the carpet from 28° to 37°can help reduce the knee slider compression by 18.3%.展开更多
Sixteen patients with osteoarthritis (13 knees and 3 hips), 3 patients with rheumatoid arthritis (RA) and 4 cadaver were studied for evidence of immune complex in the destroyed articular cartilage tissues. Frozen sect...Sixteen patients with osteoarthritis (13 knees and 3 hips), 3 patients with rheumatoid arthritis (RA) and 4 cadaver were studied for evidence of immune complex in the destroyed articular cartilage tissues. Frozen sections of the articular cartilage from arthroplasty were stained with fluoresceinated antibodies to human immunoglobulins IgG, IgA, IgM and complement C3. The results showed: 1. There were immune complexes linear deposited in the surface of the irregular articular cartilage tissues and on some chondro- cytes remained in most patients with osteoarthritis (14/16). The patterns of immune complexes are IgA, complement C3, IgG and IgM, their percentage is 81. 25%, 75%, 75% and 50% respectively. 2. In all of 3 patients with RA, the surfaces of articular tissues were seen with patchy diffusely positive areas for IgA, IgG, IgM (excepting negative in I case) and complement C3. 3. There were no immune complexes deposited in the surfaces of 4 cases of normal articular tissues. The presence of immune complexes in the cartilages suggested that an autoimmune reaction participated in the pathological process of osteoarthritis and that the autoimmunity may be responsible for the continuous degeneration of the osteoarthritis.展开更多
基金Supported by the National Key Technologenetic Research Development Program during the 10th Five-year Planning(No.2004-BA702B06)
文摘Objective:To explore the prevalence rate of knee joint osteoarthritis and its pathogenetic fea- tures among the middle-aged and old aged people in the urban and rural area of Xi'an.Methods:From May to October 2005,1538 Han nationality above 40 years in Xi'an were investigated according to strati- fied and cluster random sampling.The same questionnaire was delivered to subjects who had been given normotopia and lateral position radiographic examination in both knees.Excluded from etiological arthri- tis,some subjects with clinical symptoms and a radiographic grade (beyond Kellgren & Lawrence gradeⅡ) were finally diagnosed as spontaneous knee joint osteoarthritis.All analyses were performed with SPSS 13.0 and t test,U test.Single factor analysis and multiple logistic regression analysis were used to analyze dates.Results:The total prevalence of spontaneous knee joint osteoarthritis was 12.1% with 2.5% and 2.1% for right and left knees,respectively.The prevalence of knee joint osteoarthritis in wom- en was 2.5 times of that in men (17.2% vs 6.8%,P=0.000).the osteophyte prevalence in women was 2.3 times of that in men (26.5% vs 11.4%,P=0.000).The prevalence of knee joint osteoarthritis and osteophyte increased with the growth of age.So did the symptomatic knee,except for the age group of 56- 60 years and 66-70 years.The prevalence of symptomatic knee joint for urban area was significantly higher than that for rural area (56.3% vs 45.3%,P=0.003).In women,the prevalence of knee joint os- teoarthritis increased significantly with the increasing of body mass index,which had not been observed in men.Female and obesity are the risk factors for osteoarthritis,but bean and its products and meat could prevent the osteoarthritis.Conclusion:Old age,female and obesity serve as risk factors for knee joint os- teoarthritis.
文摘Objective To investigate the influence of gender on osteoarthritic knee rehabilitation outcome of osteoarthritis patient undergoing total knee arthroplasty(TKA).Methods We prospectively studied thirty male and thirty female knee primary osteoarthritis patients receiving unilateral TKA with posterior stable-fixed plateau prosthesis at our hospital from March 2003 to March 2008.The age and body mass index of male and female patients were matched.The surgical and rehabilitation clinical factors were compared between two groups.Results There was no significant difference in postoperative hospitalization time,surgical tourniquet time,and wound drainage volume between two groups(P>0.05).The extension/flexion degrees of knee joint before operation,1-week,2-week and 1-year after operation for male patients were 6.0 ± 3.3 degrees/ 114.0 ± 10.0 degrees,2.0 ± 1.6 degrees/93.0 ± 7.4 degrees,0.6 ± 0.6 degrees/104.0 ± 9.9 degrees and 0.3 ± 0.5 degrees/125.0 ± 8.8 degrees,for female patients were 7.0 ± 3.4 degrees/112.0 ± 14.0 degrees,2.0 ± 1.3 degrees/89.0 ± 10.9 degrees,0.9 ± 0.8 degrees/101.0 ± 11.8 degrees,0.4 ± 0.5 degrees/124.0 ± 7.1 degrees.The range of motion before operation,1-week,2-week,and 1-year after operation for male patients was 108.0 ± 9.5 degrees,91.0 ± 7.1 degrees,103.0 ± 9.9 degrees,and 125.0 ± 8.9 degrees,for female patients was 105.0 ± 14.1 degrees,87.0 ± 11.4 degrees,100.0±11.9 degrees,and 124.0 ± 7.0 degrees.The preoperative and 1-year postoperative HSS scores were 55.8 ± 13.3 and 89.6 ± 6.7 for males and 54.5 ± 13.8 and 89.2 ± 4.1 for females.No significant statistical difference was observed between two gender groups in regards to degree of extension and flexion,range of motion and HSS score(P>0.05).Conclusions Gender does not influence postoperative knee function of osteoarthritis patients.TKA significantly improves knee joint function and relieve osteoarthritis-related pain.
文摘ABSTRACT:Knee osteoarthritis(KOA),a complicated peripheral joint disorder,can be caused by non-modifiable and modifiable risk factors.At present,the treatment for osteoarthritis is mainly to manage symptoms and improve quality of life.Although some patients with osteoarthritis may choose pharmacological agents for pain relief,it has been confirmed that a variety of preparations and doses of pharmacological agents were ineffective.In recent years,Traditional Chinese medicine(TCM)has been shown unique superiorities in the treatment of osteoarthritis,including KOA.Therefore,this article primarily investigated the key points of common syndromes,TCM nursing methods and healthy guidance of KOA,aiming at maintaining and developing the strengths of TCM,improving its efficacy and standardizing its behavior.
基金financial support of the Russian Foundation for Basic Research,grant No.20-08-00818(simulation results)the Government research assignment for ISPMS SB RAS,project FWRW-2021-009(in-house software development)。
文摘Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of the knee joint.Non-invasive methods based on mechanical action are also used for the rehabilitation of a patient after arthroplasty.This paper presents numerical models of the knee joint with degenerative OA changes and arthroplasty.Using these models,a computational study was made of the influence of the intensity of shock-wave exposure on the conditioning for the regeneration of bone and cartilage tissues.Based on the modeling results,it was found that in the knee joint with degenerative OA changes,conditions for the regeneration of cartilage and meniscus tissues were fulfilled under medium and highintensity loading.Under high-intensity loading(up to 0.9 m J/mm^(2)),the stress level was significantly below the ultimate value required for fracture.At knee arthroplasty,the conditions for bone tissue regeneration around the tibia component are fulfilled only under high-intensity loading.
基金Supported by the National Natural Science Foundation of China(No.81672219No.81601936)the Science and Technology Support Program of Sichuan province(No.2014SZ0023-2)
文摘Objective To investigate the expression of miRNA-140 in chondrocytes and synovial fluid of osteoarthritis(OA) patients, and explore the relationship between the miRNA-140 expression and OA severity. Methods This study enrolled 30 OA patients who underwent total knee arthroplasty for chondrocytes sampling and 30 OA patients who underwent intra-articular injection for synovial fluid sampling. All OA patients were grouped into mild [Kellgren and Lawrence(KL) grade 1-2], moderate(KL grade 3) and severe(KL grade 4), with 10 in each subgroups for each sampling purposes. 7 non-OA patients and 10 patients with knee injury were collected for cartilage and synovial fluid sampling respectively as control groups. Chondrocytes were isolated from the cartilage tissue and cultured in vitro. Quantitative real time PCR for miRNA-140 in chondrocytes and synovial fluid were performed, and the U6 sn RNA was used as internal control. The expression difference of miRNA-140 among groups and correlation between the expression and the KL grade of OA were analysed using one-way ANOVA and Spearman test respectively. Results The expression of miRNA-140 in chondrocytes of knees in OA patients was reduced than that in normal knees, and the between-group difference was statistically significant(F=305.464, P<0.001). miRNA-140 could be detected in synovial fluid of both normal knees and OA knees, its relative expression level was reduced in synovial fluid of OA group compared with normal group, and the between-group difference was statistically significant as well(F=314.245, P<0.001). The relative expression level of miRNA-140 in both chondrocytes and synovial fluid were negatively correlated with the KL grade of OA(r=-0.969, P<0.001; r=-0.970, P<0.001). Conclusion miRNA-140 could be detected in chondrocytes and synovial fluid of OA patients, and its expression was negatively correlated with the severity of OA.
文摘Objective To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). Methods A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen for this 17-week, randomized, double-dummy, diclofenac sodium-controlled trial, with diacerein dosage of 100 mg/d and diclofenac sodium of 75mg/d. Efficacy and safety of both drugs were evaluated. Results Totally 106 patients in the diacerein group and 107 patients in the diclofenac group were considered qualified for the evaluation. After 12 weeks of treatment, the total effective rates of patients/physicians’ overall assessment in diacerein and diclofenac groups were 65.4%/61.6% and 61.2%/61.2%, respectively (P>0.05). The primary efficacy parameter [visual analog scale (VAS) assessment of pain on 20 metres walking] and the secondary efficacy parameters [tenderness on palpation, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short-Form (SF-36) Health Survey] significantly improved compared with baseline in both groups (P<0.05). In the follow-up period, there were no obvious changes in above parameters in diacerein group. However, in diclofenac group, pain on 20 metres walking, tenderness on palpation, and WOMAC became aggravated after withdrawing the drug for 4 weeks (P<0.05). Moreover, the consumption of paracetamol was significantly lower in diacerein group than in diclofenac group during follow-up (P<0.001). The incidences of related adverse events were 35.7% in diacerein and 45.1% in diclofenac group, respectively. Mild-to-moderate gastrointestinal disorders were the most frequent adverse events. Conclusions Diacerein is as effective as diclofenac sodium in treating patients with knee OA. Furthermore, it has better extended effect and a good safety profile. It is generally well tolerated and has no severe adverse effect.
文摘Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral postoperative joint alignment. However, contemporary approaches, such as kinematic alignments and hybrid techniques including adjusted mechanical, restricted kinematic, inverse kinematic, and functional alignments, are gaining attention for their ability to restore native joint kinematics and anatomical alignment, potentially leading to enhanced functional outcomes and greater patient satisfaction. The ongoing debate on optimal alignment strategies considers the following factors: long-term implant durability, functional improvement, and resolution of individual anatomical variations. Furthermore, advancements of computer-navigated and robotic-assisted surgery have augmented the precision in implant positioning and objective measurements of soft tissue balance. Despite ongoing debates on balancing implant longevity and functional outcomes, there is an increasing advocacy for personalized alignment strategies that are tailored to individual anatomical variations. This review evaluates the spectrum of various alignment techniques in TKA, including mechanical alignment, patient-specific kinematic approaches, and emerging hybrid methods. Each technique is scrutinized based on its fundamental principles, procedural techniques, inherent advantages, and potential limitations, while identifying significant clinical gaps that underscore the need for further investigation.
基金supported by RGC Themebased Research Scheme of Hong Kong (T13-402/17N)National Natural Science Foundation of China (81802152)+5 种基金Natural Science Foundation of Guangdong Province (2019A1515012224)RGC Areas of Excellence (AoE/M-402/20)RGC Collaborative Research Fund (C4026-17WF)General Research Fund (14121918 and 14173917)the Innovation and Technology Commission Funding (ITS/208/18FX)Key-Area Research and Development Program of Guangdong Province (2019B010941001)。
文摘Osteoarthritis is the most prevalent chronic and debilitating joint disease,resulting in huge medical and socioeconomic burdens.Intra-articular administration of agents is clinically used for pain management.However,the effectiveness is inapparent caused by the rapid clearance of agents.To overcome this issue,nanoparticles as delivery systems hold considerable promise for local control of the pharmacokinetics of therapeutic agents.Given the therapeutic programs are inseparable from pathological progress of osteoarthritis,an ideal delivery system should allow the release of therapeutic agents upon specific features of disorders.In this review,we firstly introduce the pathological features of osteoarthritis and the design concept for accurate localization within cartilage for sustained drug release.Then,we review the interactions of nanoparticles with cartilage microenvironment and the rational design.Furthermore,we highlight advances in the therapeutic schemes according to the pathology signals.Finally,armed with an updated understanding of the pathological mechanisms,we place an emphasis on the development of“smart”bioresponsive and multiple modality nanoparticles on the near horizon to interact with the pathological signals.We anticipate that the exploration of nanoparticles by balancing the efficacy,safety,and complexity will lay down a solid foundation tangible for clinical translation.
基金the National Health and Family Planning Commission of the People’s Republic of China(CN)program(201302007).
文摘Background:Postoperative care has been evolving since the concept of enhanced recovery after surgery(ERAS)was introduced in China.This study aimed to evaluate the effects of early ambulation within 24h after unilateral total knee arthroplasty(TKA)on postoperative rehabilitation and costs in a Chinese population.Methods:This cohort study of patients with knee osteoarthritis who had undergone TKA at 24 large teaching hospitals between January 2014 and November 2016 involved 2687 patients who began ambulating within 24h(Group A)and 3761 patients who began ambulating later than 24h(Group B).The outcome measurements,such as length of stay(LOS),total hospitalization costs,dynamic pain level,knee flexion range of motion(ROM),results of the 12-Item Short Form Survey(SF-12),incidence of thromboembolic events and other complications,were recorded and compared.Results:The early ambulation group(Group A)had a shorter LOS and lower hospitalization costs and pain levels than the late ambulation group(Group B).There was a favorable effect in enhancing ROM for patients in Group A compared with patients in Group B.In Group A,patients had significantly higher postoperative SF-12 scores than those in Group B.The incidence of deep venous thrombosis(DVT)and pulmonary infection was significantly lower in Group A than in Group B.The incidence of pulmonary embolism(PE)and other complications did not differ between the two groups.Conclusions:Early ambulation within 24h after TKA was associated with reduced LOS,improved knee function,lower hospitalization costs and lower incidence of DVT and pulmonary infection in the Chinese population.
文摘Objective To assess the effects of suction drainage versus nondrainage on the post-operative rehabilitation of patients receiving primary bilateral total knee arthroplasties(TKA).Methods A prospective study including 40 patients was conducted.These patients were diagnosed with osteoarthritis and underwent primary bilateral TKA between October 2007 and September 2009 with the same operation team.A suction drainage was placed by randomization in only one knee for each patient,while the other knee as self-control.Pain visual analogue scale score,extremity swelling,wound healing,range of motion and incidence of early post-operative complications between the drained and nondrained group were compared statistically.Results Each patient was followed up for 12 months.Placing drainage did not relieve the pain,extremity swelling,ecchymosis,or reduce the incidence of early complications(all P>0.05).Conclusions Suction drainage in TKA does not exhibit substantial advantages in promoting post-operative rehabilitation after unsophisticated TKA,compared with nondrainage.On the other hand,it might complicate the surgical operation,and increase the incidence of post-operative hemorrhage and retrograde infection.Thus we do not recommend suction drainage in unsophisticated TKA.
基金supported by the National Natural Science Foundation of China (52103184, 82102593)the China Postdoctoral Science Foundation (XJ2021051, 2020TQ0129, 2021M693960)+3 种基金the"Young Talent Support Plan"and Funding for Basic Scientific Research of Xi’an Jiaotong Universitysupported by a Grant from Science Foundation Ireland (SFI)co-funded under the European Regional Development Fund (13/RC/2073_P2)the funds received from European Union Horizon 2020 Programme (H2020-MSCA-IF-2017) under the Marie Sklodowska-Curie Individual Fellowship (797716).
文摘Osteoarthritis(OA)is the most common type of degenerative joint disease which affects 7%of the global population and more than 500 million people worldwide.One research frontier is the development of hydrogels for OA treatment,which operate either as functional scaffolds of tissue engineering or as delivery vehicles of functional additives.Both approaches address the big challenge:establishing stable integration of such delivery systems or implants.Adhesive hydrogels provide possible solutions to this challenge.However,few studies have described the current advances in using adhesive hydrogel for OA treatment.This review summarizes the commonly used hydrogels with their adhesion mechanisms and components.Additionally,recognizing that OA is a complex disease involving different biological mechanisms,the bioactive therapeutic strategies are also presented.By presenting the adhesive hydrogels in an interdisciplinary way,including both the fields of chemistry and biology,this review will attempt to provide a comprehensive insight for designing novel bioadhesive systems for OA therapy.
基金supported by Science and Technology Programme of Shaanxi Province(2020SF-076)Science Research Project of Education Department of Shaanxi Province(19JS015)Healthcare Research Fund from Health Commission of Shaanxi Province(2018A019).
文摘Objective Iodothyronine deiodinases(DIOs)are important selenoproteins that play a key role in the bone and joint diseases.Osteoarthritis(OA)is the most prevalent joint disease especially in elders.This bioinformatic analysis was performed to explore the role of DIOs in OA pathogenesis.Methods The biological functions of selenoprotein DIOs were analyzed by bioinformatic techniques,mcluding GenCLip 3.0,Database for Annotation,Visualization and Integrated Discovery(DAVID),STRING,Cytoscape,and Network Analyst.The expression of DIOs in the healthy individuals and OA patients was determined by mining OA-related microarray data in the gene expression omnibus(GEO)database of National Center for Biotechnology Information and performing a Meta-analysis of the data with Review Manager 5.3.Results Cluster analysis revealed that the function of the DIOs was associated with thyroid hormone receptor and iodothyronine;GO analysis showed that DIOs were mainly involved in biological processes,such as ethanol metabolism and phenol-containing compound metabolism and primarily involved in the cytochrome P450 metabolism of exogenous organisms and thyroid hormone signaling;SULT1A1 was the core node of the PPI network;miRNAs and thyroid hormones had some iterations with DIO1 and DI02;Meta-analysis showed that DIO3 expression was significantly up-regulated in OA patients(SMD=0.31,95%CI:0.03,0.59,P=0.03).Conclusions The main biological functions of DIOs were closely associated with the regulation of thyroid hormone.And the up-regulated expression of DIO3 may have crucial impact on the occurrence of OA.
基金Supported by Science and Research Foundation of Shanghai Municipal Health Bureau (200537103)
文摘Objective: To examine the changes of mu-opioid receptors (MORs) expression in human chronic inflamed knee joint synovium tissue. Methods:Knee joint synovium tissues were taken from 21 patients with chronic arthritis (inflamed group) and 6 fresh bodies with normal knee joints (control group). And the expression of MORs was detected by using immunohistochemistry. flow cytometry(FCM) and reverse-transcription polymerase chain reaction (RT-PCR). Results: The expression of MORs in the inflamed group was significantly higher than that in the normal group by using the 3 techniques(P<0. 05). Conclusion: Chronic inflammation enhances the up-regulation of MORs in human knee joint synovium tissue.
文摘Background: The purpose of this study was to compare the frequency of femoroacetabular impingement(FAI) between matched groups of military veterans and civilian patients with end-stage hip osteoarthritis(OA).Methods: Patients who underwent a primary total hip arthroplasty(THA) between January 1, 2015 and December 31, 2015 at a single Veteran’s Affairs Hospital were identified. Veterans were then matched 1:2 with civilian patients from our prospective outcome registry. The alpha angle and lateral center-edge angle(LCEA) were measured by a single evaluator. Independent t-tests were used to compare joint angles, and Fisher exact tests were used to compare the prevalence of cam(alpha angle ≥60°), pincer(LCEA ≥40°), or mixed-type pathologies.Results: Twenty-one veterans were matched 1:2 with civilian patients. The mean alpha angle did not significantly differ between groups(P=0.33) nor did the prevalence of cam deformities(P=0.79). The LCEAs were significantly greater in veterans than in civilians(P=0.04), and veterans also demonstrated a significantly greater prevalence of pincer and mixed-type deformities than civilians(P=0.025 and P=0.004, respectively).Conclusions: These results suggest that FAI is perhaps a more common mechanism in the progression of OA in a veteran population than in a civilian population, as pincer and mixed-type deformities were significantly more common among veterans than civilians. The forces borne by the hip during military training exceed normal physiologic conditions. In addition, the time between symptom onset and surgical correction may be 10–12 months longer for active military personnel than for civilians. The combination of increased physical demands and a protracted time to treatment highlights the need for better recognition of FAI in military members. Future studies are necessary to determine whether earlier intervention may prevent or delay the progression to end-stage OA and the need for total hip arthroplasty.
文摘Objective Total knee arthroplasty is one of the most common orthopedic surgeries.Readmission due to severe complications after total knee arthroplasty is a grave concern to surgeons.In this study,we evaluated the risk factors for severe complications after primary total knee arthroplasty.Methods We retrospectively collected clinical data of 2,974 patients who underwent primary total knee arthroplasty from July 2013 to June 2019 in our hospital.Postoperative complication≥gradeⅢwas defined as severe complication according to Clavien-Dindo classification system.Binary logistic regression was used to identify the predictive risk factors for severe complications.Results The complication rate after primary total knee arthroplasty was 6.8%and severe complication rate was 2.5%.Male(OR=2.178,95%CI:1.324-3.585,P=0.002),individuals above 75 years old(OR=1.936,95%CI:1.155-3.244,P=0.012),arrhythmia(OR=2.913,95%CI:1.350-6.285,P=0.006)and cerebrovascular disease(OR=2.804,95%CI:1.432-5.489,P=0.003)were predictive risk factors for severe complications after primary total knee arthroplasty.Conclusion Advanced age,male,arrhythmia,and cerebrovascular disease might be patients-related risk factors for postoperative severe complications after primary total knee arthroplasty.Special attention should be paid to patients with risk factors.
文摘The arterial supply of the genicular meniscus was studied with macro-microanatomical and histological examinations,translucent preparations and scanning electronmicroscopy.It was found that the menisci were supplied by the articular branches of thepopliteal artery except the lateral superior genicular branch and the descending genicularartery.Among them there were two genicular branches with independent stems from thepopliteal artery,named as the posterior medial and posterior lateral genicular artery,whichsupplied the posterior part of the corresponding meniscus.The genicular branchesanastomosed with each other to form a vascular circle around the menisci,and minutebranches from the circle formed an arterial network around the menisci and terminated incapillaries in 3 types of anastomotic forms.The surgical approach to the menisci and theprognosis of an injured meniscus were discussed on the basis of the arterial distributionsinside and outside of the menisci.
文摘Adult New Zealand white rabbits were used in this study. The knee joint of rabbits was experimentally traumatized. 2% solution of chitosan was applied in the experimental group (group A). The rabbits of the control group (group B) were not treated with chitosan. The hind limb of the rabbits was immobilized with plaster cast from toe to groin. After 3 or 6 weeks,the animals were killed and the specimens were observed. The results showed that the degree of angular movement of the knee joint in group A was greater than that of group B (P<0.01). Adhesion in group B was more severe than that in group A (P<0. 01). Histological studies indicated slight synovium,little connective tissue in suprapatellar sac and collagenous fiber in matrix,and normal shape and size of the synovial cell in group A. The results of this study suggest that chitosan can prevent or alleviate post-traumatic adhesion of joint.
文摘The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.
基金Supported by the National Natural Science Foundation of China(51405050)Key Laboratory of Advanced Manufacturing Technology for Automobile Parts,Ministry of Education(2016KLMT03)Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ1500912)
文摘The influences of different design factors,as well as dummy posture,on an occupants' knee slider compression,were studied in this paper.Based on the vehicle geometry data,the simulation model,including both the multi-rigid-body and finite element(FE)part,was built up and validated with China New Car Assessment Program(C-NCAP)full impact to ensure the accuracy of the model.By adjusting the design parameters and the posture of the femur and lower leg,different factors affecting the passengers' knee slider compression were evaluated,with the help of MAthematical DYnamic MOdel(MADYMO)simulations.The study indicated that the leg posture,the stiffness of the IP and angles of the carpet have significant effects on the knee slider compression in this case.By decreasing the angle between the femur and lower leg from 133° to 124°,the maximum knee slider compression was decreased by 17.3% and by scaling the IP stiffness from 1 to 0.7,it could be decreased by 18.6%.Also,decreasing the angles of the carpet from 28° to 37°can help reduce the knee slider compression by 18.3%.
文摘Sixteen patients with osteoarthritis (13 knees and 3 hips), 3 patients with rheumatoid arthritis (RA) and 4 cadaver were studied for evidence of immune complex in the destroyed articular cartilage tissues. Frozen sections of the articular cartilage from arthroplasty were stained with fluoresceinated antibodies to human immunoglobulins IgG, IgA, IgM and complement C3. The results showed: 1. There were immune complexes linear deposited in the surface of the irregular articular cartilage tissues and on some chondro- cytes remained in most patients with osteoarthritis (14/16). The patterns of immune complexes are IgA, complement C3, IgG and IgM, their percentage is 81. 25%, 75%, 75% and 50% respectively. 2. In all of 3 patients with RA, the surfaces of articular tissues were seen with patchy diffusely positive areas for IgA, IgG, IgM (excepting negative in I case) and complement C3. 3. There were no immune complexes deposited in the surfaces of 4 cases of normal articular tissues. The presence of immune complexes in the cartilages suggested that an autoimmune reaction participated in the pathological process of osteoarthritis and that the autoimmunity may be responsible for the continuous degeneration of the osteoarthritis.
