Microbiology of Periprosthetic Hip and Knee Infections in Surgically Revised Cases from 34 Centers in Mainland China.

BACKGROUND AND AIM: Periprosthetic joint infection (PJI) is one of the most devastating complications after total joint arthroplasty (TJA). However, the antibiotic resistance of infecting pathogens can significantly vary in different parts of the country. In the current study, we analyzed the demographic and microbiological profiles of knee and hip PJI over three years and compared the microbiological differences between them. METHODS: A multicenter retrospective study of PJI patients in 34 referral medical centers in mainland China from January 2015 to November 2017 was performed. RESULTS: A total of 925 PJI patients were recruited, 452 were identified as knee PJIs, and 473 were hip PJIs. The most common causative pathogens were Staphylococcus aureus (26.5%) and coagulase-negative staphylococci (14.3%). Methicillin-resistant staphylococci were involved in 25.6% (237/925) of all PJI cases. Mycobacterium and fungus only accounted for 6.5% (61) of all cases. Enteric gram-negative bacilli, anaerobes, and polymicrobial pathogens were more common in hip joint prostheses than in knee PJI (P = 0.014; P = 0.006; P = 0.002, respectively). CONCLUSION: While the majority of causative pathogens in PJI cases are staphylococcal species, the prevalence of atypical organisms and resistant pathogens should also be given attention and warrant the need for empiric antibiotic treatment.

Medium-Term Clinical Results of High-Flexion Knee Prostheses in Patients with Rheumatoid Arthritis.

OBJECTIVE: This study was performed to evaluate the function and satisfaction outcome of patients with rheumatoid arthritis (RA) who underwent total knee arthroplasty (TKA) with high-flexion prostheses. MATERIALS AND METHODS: Twenty-two patients (35 knees) using high-flexion prostheses (Zimmer, Warsaw, IN) were followed up for a period of 7-11 years from February 2007 to December 2009. Clinical and radiographic follow-up was performed using Hospital for Special Surgery (HSS), Short-Form 36 scores (SF-36), American Knee Society score (KSS), and Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. Patient satisfaction assessments took place at the final follow-up sessions using the Marsh Satisfaction Questionnaire. RESULTS: The average ROM improved from preoperative 68.43° ± 33.78° to 95.54° ± 7.03° at the final follow-up. The HSS score and KSS score for pain improved from (46.49 ± 12.73) points to (85.46 ± 3.90) points and from 20.57 ± 5.91 points to 47.43 ± 3.51 points at the follow-up evaluation, respectively. Physical Component Summary(PCS) and Physical Component Summary (MCS) scores were 45.38 and 52.56, respectively by the end of follow-up. Deep venous thrombosis developed in one patient and one patient required surgical revision due to infection. There were no instances of prosthetic loosening. The satisfaction rate of patients was 95.5%. CONCLUSION: Although this particular model of TKA did not yield high-flexion angles (ie, 140°) required for kneeling, squatting, or rising from the floor, significant clinical and radiographic gains were evident in these patients with RA.

[Spatial distribution of cladoceran assemblages in surface sediments of shallow lakes in Yunnan.] / æµ æ°´æ¹–æ³Šè¡¨å±‚æ²‰ç§¯ç‰©è®°å½•çš„æžè§’ç±»ç¾¤è½ç©ºé—´åˆ†å¸ƒç‰¹å¾.

Shallow lakes, sensitive to environmental changes due to low environmental carrying capacity, generally experience decreases in ecosystem function and even regime shifts after over-exploitation. Surface sediments of 18 shallow lakes in Yunnan were collected and analyzed to identify the spatial pattern and the influencing factors of cladoceran communities. The results showed that there was significant heterogeneity in the spatial distribution of cladocera in those lakes. For example, the cladoceran community was generally dominated by benthic taxa in alpine lakes, while there was a clear replacement of benthic cladocerans by planktonic ones with increasing nutrient levels across lakes from Southeast Yunnan. Altitude and total phosphorus were the main driving factors, which independently explained 22.0% and 7.7% of the change in cladocera communities, respectively. The altitude gradient and related changes in climate and catchment features were the main factors in structuring cladocerans for shallow lakes of Yunnan, while the anthropogenic impacts on cladoceran distribution was significant via the processes such as catchment development, pollutant input and macrophyte changes. Meanwhile, the interaction between elevation and total phosphorus explained 26.3% of the total variance in cladoceran community shift, indicating that the increase in human activity intensity in lakes at lower altitudes would have stronger impact on cladocerans through anthropogenic nutrient inputs.

[Spatial distributions and environmental control of diatom functional groups in sediments of Haixi Lake, Southwest China.] / åŸºäºŽç¡ è—»åŠŸèƒ½ç¾¤ç‰¹å¾æ­ç¤ºæµ·è¥¿æµ·è¿‘çŽ°ä»£ç”Ÿæ€çŽ¯å¢ƒå˜åŒ–.

Functional group classification based on the morphological, physiological and ecological characteristics of diatoms is advanced in describing the tolerance and sensibility of diatoms to environmental stressors. In this study, we examined the spatial distribution of diatom functional groups in surface sediments of Haixi Lake and explored the relationships between diatom distributions and environmental variables using multivariate analyses. Principal components analysis (PCA) and redundancy analysis (RDA) results showed that water depth and total nitrogen (TN) were the key drivers for the heterogeneous distribution of diatom functional groups. Water depth of ca. 8 m was the threshold depth in influencing diatom functional group structures linking with thermal stratification. These results provided a basis for fossil record interpretation of the short core. Diatom functional groups fluctuated over the last century, in keeping with mean annual temperature, sediment TN, and median grain size. Climate warming, accelerated nutrient enrichment and intensified hydrological changes led to the dominance of functional group D, MP and P. Additionally, climate warming and nutrient enrichment led to increased diatom functional group diversity, while increased water depth (led by damming and reservoir reinforcement) contributed to diversity loss around 1957 and 1990 AD, respectively.

Bottom-Up Electrodeposition of Large-Scale Nanotwinned Copper within 3D Through Silicon Via.

This paper is the first to report a large-scale directcurrent electrodeposition of columnar nanotwinned copper within through silicon via (TSV) with a high aspect ratio (~4). With this newly developed technique, void-free nanotwinned copper array could be fabricated in low current density (30 mA/cm²) and convection conditions (300 rpm), which are the preconditions for copper deposition with a uniform deep-hole microstructure. The microstructure of a whole cross-section of deposited copper array was made up of (111) orientated columnar grains with parallel nanoscale twins that had thicknesses of about 22 nm. The hardness was also uniform along the growth direction, with 2.34 and 2.68 GPa for the top and bottom of the TSV, respectively. The gelatin additive is also first reported hereas a key factor in forming nanoscale twins by adsorbing on the cathode surface, in order to enhance the overpotential for cathodic reaction during the copper deposition process.

Prevalence and risk factors for diabetic retinopathy: the Beijing Communities Diabetes Study 6.

BACKGROUND: To examine prevalence and associated factors of diabetic retinopathy in patients with Type 2 diabetes mellitus in urban communities of Beijing. METHODS: The community health care center-based study included subjects with diabetes mellitus and an age of 20 years to 80 years, who were recruited from 15 community health centers in urban Beijing. Diabetes mellitus was defined using the World Health Organization criteria. Fundus photographs were graded using the modified Airlie House classification system. RESULTS: Of 2,642 eligible patients, 2,007 (76.0%) subjects (1,199 women) with a mean age of 64.1 ± 9.0 years participated. The overall prevalence of diabetic retinopathy was 24.7 ± 1.0% (95% confidence interval [CI], 22.8-26.6). In binary logistic analysis, presence of diabetic retinopathy was associated with younger age (odds ratio [OR], 0.97; 95% CI, 0.95-0.98), longer duration of diabetes (OR, 1.10; 95% CI, 1.08-1.12), higher concentration of glycosylated hemoglobin HbA1c (OR, 1.23; 95% CI, 1.14-1.33), higher systolic blood pressure (OR, 1.01; 95% CI, 1.01-1.02), lower body mass index (OR, 0.95; 95% CI, 0.92-0.98), and elevated blood urea concentration (OR, 1.01; 95% CI, 1.00-1.01). Microalbuminuria was an additional associated factor (OR, 1.55; 95% CI, 1.16-2.08). Patients with microalbuminuria were 4.7 times more likely to have a severe or proliferating diabetic retinopathy than those without microalbuminuria. CONCLUSION: In the urban population of Beijing, prevalence of diabetic retinopathy in diabetic patients was 25%. As in whites, increased blood pressure besides elevated plasma glucose concentrations was highly significantly associated with diabetic retinopathy in Chinese. It suggests that in Chinese as also in whites, blood pressure control beside control of plasma glucose levels is important to prevent development or progression of diabetic retinopathy.

[Anterolateral minimally-invasive total hip arthroplasty: a clinical comparative study of 110 cases].

OBJECTIVE: To explore the indications and key points of anterolateral minimally-invasive total hip arthroplasty. METHODS: 110 baseline indexes matched patients admitted for unilateral total hip arthroplasty were randomly assigned to 2 equal groups to undergo surgery through a short anterolateral incision of < or = 10 cm or a standard posterolateral incision. All operations were done by the same surgeon. The demographic data, perioperative indexes, and postoperative function indexes were recorded and statistically analyzed. RESULTS: No significant differences were detected with respect to operation time, abduction angle, anteversion angle, stem alignment, and stem fixation between these 2 groups. The incision length, blood loss, perioperative transfusion, and 100 - mm visual analogue pain scale (VAS) score at the first 24 hours of the anterolateral approach group were (7.49 +/- 0.86) cm, (376.18 +/- 168.30) ml, (410.09 +/- 136.46) ml, and (30.76 +/- 21.77) respectively, all significantly shorter, less, or lower than those of the standard posterolateral approach group [(15.2 +/- 1.8) cm, (605.0 +/- 225.1) ml, (629.5 +/- 232.9) ml, and (50.3 +/- 13.7) respectively, all P < 0.01]. The Harris hip score and Barthel index 3 months after operation of the anterolateral approach group were (83.80 +/- 5.64) and (93.45 +/- 6.37) respectively, both significantly higher than those of the standard posterolateral approach group [(75.0 +/- 7.5) and (94.6 +/- 7.5) respectively, both P < 0.01)], however, there were not significant differences in the Harris hip score and Barthel index 3 years after operation between these 2 groups. CONCLUSIONS: Fewer traumas, less blood loss and rapid recovery can be obtained through this new total hip arthroplasty approach. But experienced doctors and special instruments are prerequisite.

Orthopedic trauma of limbs associated with vascular injuries.

OBJECTIVE: To evaluate the treatment for patients with major vascular injuries associated with traumatic orthopedic injuries. METHODS: A total of 196 patients, aged from 4-67 years with the mean age of 29.88 years, had major vascular injuries associated with traumatic orthopedic injuries and were treated in our hospital in a period of 44 years. The most common mechanism of trauma was blunt trauma (67.3%), open injuries accounted for 32.4% and 54.5% of the injuries were located in the lower extremities. The vascular injury frequently happened in the femoral artery (26.7%) and popliteal artery (20.3%). The treatment principle consisted of aggressive resuscitation, Doppler imaging and stable bone internal fixation with subsequent vascular repair and debridement. The vascular repair for injuries included end-to-end anastomosis (80 cases, 39.6%), interpositional vein graft (94, 46.5%), vascular decompression through fracture distraction (18, 8.9%), arterial ligation (6, 3.0%), vein patch (2, 1.0%), bypass graft (2, 1.0%), venous repair including autogenous vein graft (9, 24.3%) and ligation (28, 75.7%) and prophylactical fasciotomy (15, 7.4%). Postoperative amputation was performed in 16 cases (16.3%). RESULTS: No intraoperative death was observed and all fractures united within 6 months. Limbs were salvaged in 180 patients (91.8%). Among these patients, early complications were found in 19 patients (9.7%) and late complications were observed in 8 patients (4.1%). CONCLUSIONS: A well-organized approach, based on a specific treatment principle, not only improves clinical outcome but also does good to excellent functional recovery for patients with severe orthopedic injuries and concomitant vascular lesion.

Biomechanical effect of major extremity vessels in choosing repair methods for peripheral artery injury.

OBJECTIVE: To investigate the biomechanical effect of major extremity vessels to choose appropriate repair methods for vascular injuries of the extremities. METHODS: The data of 385 patients (337 males and 48 females, aged 18-71 years, mean=32.6 years) including 403 injured vessels, who suffered from vascular injuries of the extremities and were treated in our hospital from October 1960 to August 2005, were studied retrospectively in this article. We compared the results of different repair methods for the defect of vessels and evaluated different injured vessels for repairing arterial injuries with anastomosis and venous graft, respectively. RESULTS: A significant difference was found between the defect lengths of the arteries repaired with anastomosis and venous graft (P less than 0.0001). The upper limits of the confidence interval in the defect lengths of the brachial artery, the femoral artery and the popliteal artery were 3.43 cm, 2.38 cm and 2.42 cm, respectively, when repaired with anastomosis. The lower limits were 2.16 cm, 2.16 cm and 1.63 cm, respectively, when repaired with venous graft. The defect length of each artery repaired with venous graft had linear correlation with the graft length. CONCLUSION: Because of the longitudinal biomechanical difference of human peripheral vessels, different options of repair are necessary for different arterial injuries.

Amelioration of osteoarthritis by intra-articular hyaluronan synthase 2 gene therapy.

Osteoarthritis (OA) is a chronic, degenerative disorder of multifactorial aetiology, characterized by loss of articular cartilage and periarticular bone remodelling. Goals of managing OA include controlling pain, maintaining and improving function and health-related quality of life, and limiting functional impairment. Although several managements had been proved to ameliorate the symptoms of osteoarthritis, no methods could cure it thoroughly. High-molecular-weight hyaluronan (HMW-HA) is a major component of synovial joint fluids which physically acts as a viscous lubricant for slow joint movements and as an elastic shock absorber during rapid movements. It also has a variety of biologic effects in vivo, such as inhibiting the release of inflammatory factors and suppressing the degradation of cartilage matrix. Intra-articular injection of synthetic HMW-HA has been used as viscosupplement for knee OA and its therapeutic efficacy has been verified. However, repeated injections of HMW-HA which is needed to control symptoms increase the probability of infection and sometimes there will have acute joint pain with effusion, which requires aspiration to exclude sepsis. In order to overcome the disadvantages of repeated injections of HMW-HA, novel strategies should be developed. As HMW-HA is synthesized by hyaluronan synthase-2 (HAS2), we postulate that HAS2 gene could be delivered into intra-articular cells by methods of gene therapy to achieve long-lasting synthesis of HMW-HA. In our opinion, this strategy seems to hold interesting future prospects for the treatment of OA.

Morphological changes of roof of subacromial bursa in patients with rotator cuff tear.

OBJECTIVE: To investigate the morphological changes of the roof of the subacromial bursa (SAB) and its involvement extent after rotator cuff tear. METHODS: In the experimental group, the roof of SAB was obtained from 30 cases of rotator cuff tear both at the tear site and a site 2.5-3.0 cm distal to the tear site during rotator cuff repair. In the control group, the roof of SAB was obtained from the exposed site of recurrently dislocated shoulder or fractured humeral shaft of 8 cases. The specimens were stained with hematoxylin and eosin and observed under a transmission electron microscope. The cell number was quantitated through counting the blue-stained nucleus in SAB with a computer image analysis system. RESULTS: The number of cells increased significantly in the roof of SAB in the experimental group compared with that of the control group. However, no difference of the bursal reaction was found among the type of rotator cuff tear, the bursa thickness and the presence of fluid in the bursa. The great majority of cells were type B cells observed under the transmission electron microscope. CONCLUSIONS: The increase in cell number in the roof of SAB in the experimental group is a reactive increase rather than an inflammatory process and the involvement of SAB is not limited in extent. The change of the roof of SAB is a secondary reaction to the rotator cuff tear.

[Construction and identification of recombinant adenovirus vector containing Tet-on adjustable NT3 and BDNF genes].

AIM: To construct Tetracycline(tet) inducible recombinant adenovirus vectors containing human neurotrophin 3(NT3) and brain-derived neurotrophic factor(BDNF) genes, respectively and perform PCR and restrictive enzyme digestion analysis. METHODS: Full length NT3 and BDNF cDNAs were subcloned into pIND vector, followed by being cloned into pTRE-shuttle2 vector. The NT3 and BDNF gene fragments resulted from the pTRE-shuttle2-NT3 and pTRE-shuttle2-BDNF digested with I-Ceu I and PI-Sce I were linked to the linear adeno-X virus DNA. The recombinant adenovirus vectors were confirmed by PCR and restriction enzyme digestion analysis. RESULTS: The PCR identification showed that a given band with 312 bp, and predictive fragments proved by restriction enzyme digestion analysis were exhibited. All the above results indicated that human NT3 and BDNF genes had been connected with pAdeno-X vectors correctly. CONCLUSION: Tet inducible recombinant adenovirus vector of Human NT3 and BDNF genes have been constructed successfully, which upon packaged in HEK293 cells, will be used to introduce the target genes into Schwann's cells in-vitro or in-vivo.

Expression of adenovirus-mediated neurotrophin-3 gene in Schwann cells of sciatic nerve in rats.

OBJECTIVE: To investigate the expression of neurotrophin-3 (NT-3) gene in Schwann cells of rat sciatic nerve introduced by an adenovirus vector in vivo. METHODS: A recombinant adenovirus vector for NT-3 (Ad-NT-3) was propagated in 293 packaging cells and titered with tissue culture infectious dose(50) (TCID(50)). Ad-NT-3 was injected directly into the rat sciatic nerve after transection and immediate repair. Immunohistochemical staining was employed to determine the expression of NT-3 in Schwann cells in rat sciatic nerve and the expressive intensity of the tissue slices of the sciatic nerve was measured with LEICA M550 image analysis system. RESULTS: On the 2nd day after injection of Ad-NT-3, positive stain in the Schwann cells was apparent in the vicinity of anastomosis. NT-3 expression increased significantly on the 7th day (P<0.01) and then decreased 14-28 days after injection (P<0.01). There was no significant difference of NT-3 expression between the 14th and 28th day groups (P<0.05). Compared with the 2nd day group, the 14th and 28th day groups still maintained a relatively high level of NT-3 (P<0.01). Intact and repaired nerves, which were injected with adenovirus encoding LacZ genes (Ad-LacZ) or physiological saline served as controls, showed no NT-3-positive Schwann cells. CONCLUSIONS: An adenovirus vector can be used to induce efficiently the expression of NT-3 gene in Schwann cells of rat peripheral nerves following nerve injury and repair, which suggests that neurotrophic factors can be introduced into Schwann cells with an adenovirus vector to promote peripheral nerve regeneration.

[Effects of simulated weightlessness on pressure-volume relationships of femoral vein of New Zealand Rabbits].

Objective. To observe the changes of pressure-volume relationships of rabbit femoral veins and their structural changes caused by simulated weightlessness. Method. Head-Down Tilt (HDT) -20 degrees rabbit model was used to simulate weightlessness. Twenty four healthy male New Zealand Rabbits were randomly divided into 21 d HDT group,10 d HDT group and control group, (8 in each group). Pressure-volume (P-V) relationship of rabbits femoral veins was measured and the microstructure of the veins was observed. Result. The femoral vein P-V relationship curves of HDT groups showed a larger volume change ratio than that of control group. This change was that 21 d HDT group was even more obvious than that of HDT-10 d group. B1 and B2 in quadratic equations of 21 d HDT group were significantly higher than the values of both 10 d HDT group and control group during expansion (inflow) and collapse (outflow) (P<0.01). The result of histological examination showed that the contents and structure of femoral vein wall of HDT-rabbits changed significantly. Endothelial cells of femoral vein became short and columnar or cubic, some of which fell off. Smooth muscle layer became thinner. Conclusion. Femoral venous compliance increased after weightlessness-simulation and the femoral venous compliance in 21 d-HDT rabbits increased more obviously than that in 10 d-HDT rabbits. The structure of femoral vein wall had changed obviously.