Apoptotic extracellular vesicles derived from hypoxia-preconditioned mesenchymal stem cells within a modified gelatine hydrogel promote osteochondral regeneration by enhancing stem cell activity and regulating immunity.

Due to its unique structure, articular cartilage has limited abilities to undergo self-repair after injury. Additionally, the repair of articular cartilage after injury has always been a difficult problem in the field of sports medicine. Previous studies have shown that the therapeutic use of mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) has great potential for promoting cartilage repair. Recent studies have demonstrated that most transplanted stem cells undergo apoptosis in vivo, and the apoptotic EVs (ApoEVs) that are subsequently generated play crucial roles in tissue repair. Additionally, MSCs are known to exist under low-oxygen conditions in the physiological environment, and these hypoxic conditions can alter the functional and secretory properties of MSCs as well as their secretomes. This study aimed to investigate whether ApoEVs that are isolated from adipose-derived MSCs cultured under hypoxic conditions (hypoxic apoptotic EVs [H-ApoEVs]) exert greater effects on cartilage repair than those that are isolated from cells cultured under normoxic conditions. Through in vitro cell proliferation and migration experiments, we demonstrated that H-ApoEVs exerted enhanced effects on stem cell proliferation, stem cell migration, and bone marrow derived macrophages (BMDMs) M2 polarization compared to ApoEVs. Furthermore, we utilized a modified gelatine matrix/3D-printed extracellular matrix (ECM) scaffold complex as a carrier to deliver H-ApoEVs into the joint cavity, thus establishing a cartilage regeneration system. The 3D-printed ECM scaffold provided mechanical support and created a microenvironment that was conducive to cartilage regeneration, and the H-ApoEVs further enhanced the regenerative capacity of endogenous stem cells and the immunomodulatory microenvironment of the joint cavity; thus, this approach significantly promoted cartilage repair. In conclusion, this study confirmed that a ApoEVs delivery system based on a modified gelatine matrix/3D-printed ECM scaffold together with hypoxic preconditioning enhances the functionality of stem cell-derived ApoEVs and represents a promising approach for promoting cartilage regeneration.

Diagnostic efficiency of [68 Ga]Ga-DOTA-FAPI-04 in differentiating periprosthetic hip joint infection and aseptic failure.

PURPOSE: To assess the efficiency of [68 Ga]Ga-DOTA-FAPI-04 in diagnosing periprosthetic hip joint infection and establish a diagnostic standard of clinical significance based on uptake pattern. METHODS: [68 Ga]Ga-DOTA-FAPI-04 PET/CT was performed in patients with symptomatic hip arthroplasty from December 2019 to July 2022. The reference standard was based on the 2018 Evidence-Based and Validation Criteria. Two diagnostic criteria, SUVmax and uptake pattern, were used to diagnose PJI. Meanwhile, original data were imported into IKT-snap to draw the view of interest, A.K. was used to extract features of clinical cases, and unsupervised clustering analysis was applied according to the groups. RESULTS: A total of 103 patients were included, 28 of whom had PJI. The area under the curve of SUVmax was 0.898, which was better than that of all of the serological tests. The cutoff value of SUVmax was 7.53, and the sensitivity and specificity were 100 and 72%, respectively. The sensitivity, specificity and accuracy of the uptake pattern were 100, 93.1 and 95%, respectively. In radiomics analysis, the features of PJI were significantly different from those of aseptic failure. CONCLUSION: The efficiency of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in diagnosing PJI showed promising results, and the diagnostic criteria of the uptake pattern were more clinically instructive. Radiomics also showed certain application prospects in the field of PJI. TRIAL REGISTRATION NUMBER: Trial registration: ChiCTR2000041204. Registered 24 September 2019.

Characterization of periprosthetic environment microbiome in patients after total joint arthroplasty and its potential correlation with inflammation.

AIMS: Periprosthetic joint infection (PJI) is one of the most serious complications after total joint arthroplasty (TJA) but the characterization of the periprosthetic environment microbiome after TJA remains unknown. Here, we performed a prospective study based on metagenomic next-generation sequencing to explore the periprosthetic microbiota in patients with suspected PJI. METHODS: We recruited 28 patients with culture-positive PJI, 14 patients with culture-negative PJI, and 35 patients without PJI, which was followed by joint aspiration, untargeted metagenomic next-generation sequencing (mNGS), and bioinformatics analysis. Our results showed that the periprosthetic environment microbiome was significantly different between the PJI group and the non-PJI group. Then, we built a "typing system" for the periprosthetic microbiota based on the RandomForest Model. After that, the 'typing system' was verified externally. RESULTS: We found the periprosthetic microbiota can be classified into four types generally: "Staphylococcus type," "Pseudomonas type," "Escherichia type," and "Cutibacterium type." Importantly, these four types of microbiotas had different clinical signatures, and the patients with the former two microbiota types showed obvious inflammatory responses compared to the latter ones. Based on the 2014 Musculoskeletal Infection Society (MSIS) criteria, clinical PJI was more likely to be confirmed when the former two types were encountered. In addition, the Staphylococcus spp. with compositional changes were correlated with C-reactive protein levels, the erythrocyte sedimentation rate, and the synovial fluid white blood cell count and granulocyte percentage. CONCLUSIONS: Our study shed light on the characterization of the periprosthetic environment microbiome in patients after TJA. Based on the RandomForest model, we established a basic "typing system" for the microbiota in the periprosthetic environment. This work can provide a reference for future studies about the characterization of periprosthetic microbiota in periprosthetic joint infection patients.

A Nomogram That Characterizes a Patient's Odds of Developing Squeaking After Fourth-generation Ceramic-on-ceramic THA.

BACKGROUND: Although ceramic-on-ceramic (CoC) bearings result in the lowest wear rate of any bearing combination, postoperative squeaking remains worrisome. However, data concerning squeaking in long-term follow-up studies are still lacking, especially for fourth-generation CoC THA. QUESTIONS/PURPOSES: (1) After keeping the prosthesis in place for 10 years, what percentage of patients treated with fourth-generation CoC THA implants report squeaking, and are there points in time when squeaking occurs more frequently? (2) What are the characteristics, association with hip function, and factors associated with squeaking? (3) Can we create a nomogram that characterizes a patient's odds of experiencing squeaking based on the factors associated with it? METHODS: Between January 2009 and December 2011, 1050 patients received primary THAs at our institution, 97% (1017) of whom received fourth-generation CoC THAs because this was the preferred bearing during this period. Of the 1017 eligible patients, 5% (54) underwent THAs performed by low-volume surgeons, 3% (30) were implanted with cemented prostheses, 2% (22) died, 1% (10) were immobile, 1% (six) underwent revision surgery, and 17% (169) were lost to follow-up before 10 years, leaving 726 patients for analysis here at a mean of 11 ± 1 years. In the study cohort, 64% (464) were male and 36% (262) were female, with a mean age of 44 ± 13 years at primary THA. We extracted data about articular noise from follow-up records in our institutional database and used a newly developed questionnaire to ascertain the percentage of patients who reported squeaking at the latest follow-up interval. Although not validated, the questionnaire was modeled on previous studies on this topic. The longitudinal pattern for squeaking was explored to find timepoints when squeaking occurs more frequently. Based on the questionnaire data, we calculated the percentages of frequent, reproducible, and avoidable squeaking. Hip function was evaluated with the Harris Hip Score and WOMAC score and compared between the squeaking and nonsqueaking groups. Factors associated with squeaking, which were examined in a multivariate analysis, were used to develop a nomogram. RESULTS: At 10 years, 16% (116 of 726) of patients reported squeaking. Two squeaking peaks were determined, at 0 to 1 year and 8 to 10 years. Frequent, reproducible, and avoidable squeaking accounted for 42% (36 of 86), 20% (17 of 86), and 41% (35 of 86), respectively. The mean Harris Hip Score (93 ± 4 versus 94 ± 5; p = 0.81) and WOMAC score (16 ± 13 versus 15 ± 13; p = 0.23) did not differ between patients with squeaking and those without. After controlling for potential confounding variables such as etiology and head offset, we found that patients younger than 46 years (odds ratio 2.5 [95% confidence interval 1.5 to 5.0]; p < 0. 001), those who were male (OR 2.0 [95% CI 1.1 to 3.5]; p = 0.04), those having a total flexion and extension arc of less than 50° (OR 2.0 [95% CI 1.2 to 3.3]; p = 0.02), and those with the Corail hip implant (OR 4.1 [95% CI 2.1 to 7.7]; p < 0. 001) were more likely to report squeaking. We created a nomogram that can be used at the point of care that can help clinicians identify patients at a higher risk of experiencing squeaking; this nomogram had good performance (area under the receiver operating characteristic curve of 77%). CONCLUSION: As a potential late complication, squeaking after fourth-generation CoC THA is of concern and may be related to increased stripe wear. We recommend that surgeons use this nomogram to assess the odds of squeaking before selecting a bearing, especially in patients at high risk, to facilitate shared decision-making and improve patient satisfaction. Future external validation of the model is still needed to enhance its applicability.Level of Evidence Level III, therapeutic study.

It can be unnecessary to combine common synovial fluid analysis and alpha-defensin tests for periprosthetic joint infection diagnosis.

BACKGROUND: Periprosthetic joint infection is a serious complication after total joint arthroplasty. Despite that alpha-defensin was used as diagnostic test in the 2018 ICM (international consensus meeting) criteria, its position in the PJI diagnostic pipeline was controversial. Therefore, we performed a retrospective pilot study to identify whether synovial fluid alpha-defensin test was necessary when corresponding synovial fluid analysis (WBC count, PMN% and LE tests) was performed. METHODS: Between May 2015 and October 2018, a total of 90 suspected PJI patients who underwent revisions after TJA were included in this study. Based on the 2018 ICM criteria, the interobserver agreements between preoperative diagnostic results and postoperative diagnostic results and the interobserver reliability between preoperative diagnostic results and postoperative diagnostic results with or without synovial fluid alpha-defensin tests were calculated. After that, the ROC analysis, and the direct cost-effectiveness of adding alpha-defensin was performed. RESULTS: There were 48,16 and 26 patients in the PJI group, inconclusive group and non-PJI group, respectively. Adding the alpha-defensin tests into 2018 ICM criteria can't change the preoperative diagnostic results, postoperative diagnostic results, and the concordance between preoperative and postoperative diagnostic results. Moreover, the Risk-benefit Ratio is over 90 per changed decision and the direct cost-effectiveness of alpha-defensin was more than $8370($93*90) per case. CONCLUSIONS: Alpha-defensin assay exhibit high sensitivity and specificity for PJI detection as a standalone test based on the 2018 ICM criteria. However, the additional order of Alpha-defensin can't offer additional evidence for PJI diagnosis when corresponding synovial fluid analysis was performed (synovial fluid WBC count, PMN% and LE strip tests). EVIDENCE LEVEL: Level II, Diagnostic study.

Primary Total Hip Arthroplasty With Ceramic-On-Ceramic Articulations: Analysis of a Single-Center Series of 1,083 Hips at a Minimum of 10-Year Follow-Up.

BACKGROUND: There are limited long-term results of using ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) in a large number of patient cohorts. The purpose of this study was to evaluate the minimum 10-year clinical and radiological outcomes and survivorship in a single surgeon series of CoC-THA. METHODS: Among the 1,039 patients (1,391 hips) who underwent primary THA at our institution between 2008 and 2011, 49 patients (69 hips) experienced paralysis or death, and 194 patients (239 hips, 19%) were lost to follow-up. The remaining 796 patients (1,083 hips) were assessed at a mean of 11 years (range, 10 to 13 years) using the modified Harris hip score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a questionnaire on articular noises. Survival analysis was used to estimate the survivorship. Radiological evaluation was performed on 869 hips at the final follow-up. RESULTS: Survivorship at 11 years was 98.3% for revision or aseptic loosening, and 98.2% for reoperation. At the final follow-up, the mean mHHS and WOMAC scores were 93 (range, 12 to 100) and 14.4 (range, 3 to 66), respectively. There were 131 (12%) hips that experienced squeaking, but no patient required revision. No fracture of the ceramic was observed. Radiological evaluation at the final follow-up revealed that 3 (0.3%) hips exhibited loosening, 2 (0.2%) had femoral osteolysis, 81(9.3%) acquired radiolucencies, and 35 (4%) showed heterotopic ossification. CONCLUSION: This CoC bearing for THA had a high survivorship and excellent functional outcomes for at least 10 years.

Status of robot-assisted artificial total joint arthroplasty in China: a cross-sectional survey of joint surgeons.

PURPOSE: The purpose of this study is to report on the use of Robotic-assisted total joint arthroplasty (RA-TJA) in China as well as the experience and expectations of Chinese doctors regarding this technology. METHOD: A self-administered questionnaire was used to assess the current status of RA-TJA in China, the practical experience and suggestions for improvement of the technology by joint surgeons who have performed RA-TJA, and the interest and expectations of orthopaedic surgeons who have not used RA-TJA. The questionnaire was administered to all the physicians of the Chinese Association of Orthopedic Surgeons (CAOS). RESULT: A total of 372 qualified questionnaires were generated, among which 28% (n = 104) of the respondents had performed RA-TJA, among those who had performed RA-TJA. When asked how helpful the joint replacement robot was actually/expected to be, there was no significant difference between the expected and actual experience of nonusers and users (p ≥ 0.05); the biggest disadvantage of the current development of RA-TJA was perceived as additional charges to the patient by those who had used it, while those who had not used it perceived it as a limitation of their hospital, both of which were significant differences. Most respondents in both groups (used: 94.2%; not used: 91.4%) were confident in the clinical development of the joint replacement robot. CONCLUSION: This survey provides cross-sectional data on the current status of Chinese joint surgeons using or not using robots in their daily clinical practice. Improving surgical precision was the consensus of most respondents, while high surgical costs and limitations of hospital conditions were barriers to its development in China.

Role of the EM clustering method in determining the geochemical background of As and Cr in soils: a case study in the north of Changchun, China.

Determining the geochemical background for heavy metals is vital in soil management activities. Although many statistical methods for geochemical background determination have been proposed, the multi-population problem of geochemical data, primarily regional ones, derived mainly from mixing multiple populations belonging to various geological sources or processes, needs to be better addressed. In this study, the Expectation-Maximization (EM) algorithm was employed to separate multiple populations in a 1:250,000 scale regional geochemical data set of soils in a lithologically complex region in the north of Changchun, China. The data set included 3746 surface soil samples analyzed for SiO2, K2O, Al2O3, CaO, La, Rb, Y, Ti, Ce, V, Cr, and As. The potential high-risk areas of As and Cr were determined before and after the separation of multiple populations. The comparison results show that the EM clustering method can efficiently separate multiple populations and determine soil geochemical background more reasonably, thus eliminating false contamination that is easily misidentified and better revealing concealed contamination that is challenging to detect.

Comparison of serum inflammatory indicators and radiographic results in MAKO robotic-assisted versus conventional total knee arthroplasty for knee osteoarthritis: a retrospective study of Chinese patients.

BACKGROUND: The purpose of this study was to compare the serum inflammatory indicators and radiographic results of conventional manual total knee arthroplasty (CM-TKA) with those of MAKO-robotic assisted total knee arthroplasty (MA-TKA). METHODS: We retrospectively analysed 65 patients with knee osteoarthritis who underwent unilateral TKA from December 2020 to November 2021 in our department, which included 34 patients who underwent MA-TKA and 31 patients who underwent CM-TKA. The tourniquet time and estimated blood loss (EBL) were compared between the two groups. Knee function was evaluated using range of motion (ROM), functional score and pain score. Leukocytes, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), creatine kinase (CK), and neutrophil-to-lymphocyte ratio (NLR) were recorded at 3 time points (preoperative, and on the first and third postoperative days). The hip-knee-ankle angle (HKA) and the femoral and tibial component angles in the coronal and sagittal planes were used for postoperative radiographic evaluation. RESULTS: The postoperative MA-TKA group had less EBL (496.9 ± 257.8 vs. 773.0 ± 301.3 ml, p < 0.001). There was no significant difference in knee function scores at 6 weeks postoperatively (p > 0.05). IL-6 levels were significantly lower in the MA-TKA group on the 1st postoperative day (11.4 (5.2, 21.0) vs. 24.6 (86.3, 170.8), p = 0.031). This difference in inflammatory indices became more pronounced at 72 hours after the operation because CRP, ESR, IL-6, and CK values were significantly lower in the MA-TKA group on the 3rd postoperative day (72 h) (p < 0.05). Postoperative radiographic examinations performed 2 days after the MA-TKA group suggested that only 2 cases of HKA had outlier values, which was remarkably better than the 12 cases found in the CM-TKA group (5.9% vs. 38.7%, p < 0.001). The frontal femoral component was significantly closer to the expected value of 90° in the MA-TKA group (90.9 (90.5, 92.3) vs. 92.4 (91.3, 93.7), p = 0.031). The remaining imaging evaluation parameters were not significantly different between the two groups (p > 0.05). CONCLUSIONS: In Chinese patients with OA, there was a milder systemic inflammatory response in the early postoperative period after MA-TKA compared to that of CM-TKA, as well as better radiographic outcomes. However, the tourniquet time was prolonged, and no advantages were observed in terms of functional score or pain score in the short-term follow-up.

Multi-Irradiance: A Method for Simultaneous Measurement of the Temperature and Spectral Emissivity of High-Temperature Targets in SWIR.

The currently used energy methods in spectral emissivity measurement are susceptible to the difference in temperature between the target and the reference blackbody. It is also limited by the state of the observation target and observation. This paper introduces the irradiance condition, while using the correlation between the information of emission energy and reflected energy of the high-temperature target. Based on the principle of radiative transmission and energy conservation, the relationship between the emissivity and bidirectional reflectance factor (BRF) was used to perform the retrieval of emissivity and temperature. An experimental device was designed, and graphite and rock were considered to verify the feasibility of the experimental scheme. The error of emissivity and temperature of both targets were, respectively, less than 5% and 0.5%, due to the Lambertian assumption, and the systematic errors had negligible impact on the retrieval. This verifies that the experimental observation method and scheme is reasonable.

The concordance between preoperative aspiration and intraoperative synovial fluid culture results: intraoperative synovial fluid re-cultures are necessary whether the preoperative aspiration culture is positive or not.

AIMS: Preoperative aspiration culture and intraoperative cultures play pivotal roles in periprosthetic joint infection (PJI) diagnosis and pathogen identification. But the discordance between preoperative aspiration culture and intraoperative synovial fluid culture remains unknown. We aim to determine (1) the discordance between preoperative and intraoperative synovial fluid (SF) culture and. (2) compared to intraoperative synovial fluid cultures, the sensitivity of preoperative aspiration fluid culture. Then the following question is tried to be answered: Are intraoperative synovial fluid re-cultures necessary if the preoperative aspiration culture is positive? MATERIALS AND METHODS: Between 2015 and 2019, 187 PJI patients managed with surgeries were included in this study. Compared to intraoperative synovial fluid culture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of preoperative aspiration culture were calculated. Then, the discordance between preoperative aspiration culture and intraoperative SF culture was analyzed. RESULTS: The sensitivity of preoperative aspiration culture was 81.29% compared to intraoperative synovial fluid cultures. Concordance was identified in 147 PJI (78.61%) patients and culture discordance occurred in 40 patients (21.39%). In these discordant PJI patients, 24 patients (60%) were polymicrobial and no intraoperative synovial fluid culture growth was found in 16 PJI cases (40%). Preoperative monomicrobial staphylococcus results had a sensitivity of and a specificity of 80.43% and 83.16%, respectively. Preoperative polymicrobial results had the lowest sensitivity. CONCLUSIONS: The intraoperative synovial fluid re-cultures are necessary if the preoperative aspiration culture is positive and the discordance between preoperative aspiration culture and intraoperative synovial fluid culture should be noted especially when Streptococcus spp. and more than one pathogen was revealed by preoperative aspiration culture. LEVEL OF EVIDENCE: Level III.

Leukocyte esterase test and alpha-defensin test have similar accuracy for the diagnosis of periprosthetic joint infection.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) after total joint replacement remains challenging. Synovial biomarkers are recommended as the major diagnostic criteria for PJI. The purpose of this study was to test the accuracy of the alpha-defensin test and compare it with that of the leukocyte esterase (LE) test for the diagnosis of PJI. METHODS: We obtained 130 hip or knee aspirates from May 2015 to September 2018. PJI was defined according to the European Bone and Joint Infection Society (EBJIS) criteria. Synovial fluid samples were tested with the alpha-defensin ELISA and a LE strip. For the LE strip test, besides using the traditional threshold 500 (equal to ++), we are also using an improved one, with 500 (equal to ++) serving as the threshold for the tests before centrifugation and both 250 and 500 indicating positive results after centrifugation. The receiver operating characteristic (ROC) curves, sensitivity, specificity, positive predictive value, negative predictive value, and Cohen's Kappa value were calculated for the LE and alpha-defensin tests. RESULTS: The area under the curve (AUC) of alpha-defensin, LE strip test with traditional, and improved interpretation strategy were 0.875, 0.854, and 0.877, respectively. The Cohen's Kappa value for the alpha-defensin tests was 0.826 with the traditional LE interpretation strategy and 0.875 with the improved strategy. CONCLUSION: The present study shows that the use of the LE strip to test synovial fluid yielded an accuracy similar to that of the alpha-defensin immunoassay for the diagnosis of PJI; this finding supports the 2018 ICM PJI definition, which considers positive alpha-defensin and LE test results to be equivalent.

Neutrophil to lymphocyte ratio as a predictor for diagnosis of early Periprosthetic joint infection.

BACKGROUND: Periprosthetic joint infection (PJI) is a catastrophic complication after total knee or hip arthroplasty. The diagnosis of PJI is very difficult, especially in the early postoperative period. The value of the neutrophil to lymphocyte ratio (NLR) is useful for diagnosing infectious diseases. The objective of this study was to investigate the accuracy of the NLR for the diagnosis of early PJI after total knee or hip arthroplasty. METHODS: We retrospectively evaluated consecutive primary total knee or hip arthroplasty and identified the patients who readmitted within the first 90 days postoperatively between January 2011 and October 2018.There were 20 cases diagnosed early PJI and 101 uninfected cases on the basis of the modified Musculoskeletal Infection Society (MSIS) criteria. The serum parameters including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood-cell (WBC) count, NLR and interleukin-6 (IL-6) were compared between the two groups. Receiver operating characteristic curves were generated to estimate the optimal cutoff values for each parameter. The sensitivity, specificity, positive predictive value and negative predictive value for each parameter were calculated. RESULTS: The CRP, ESR, WBC, NLR and IL-6 values were all significally higher in the infected group than the uninfected group. The median of CRP was 66.6 mg/l in the infected group and 8.6 mg/l in the uninfected group (p < 0.001). The median of ESR was 34.8 mm/hr. in the infected group and 17.4 mm/hr. in the uninfected group (p < 0.001). In the infected group and uninfected group, the median of WBC was 8.2X109 /L and 6.1 X109 /L (p = 0.002), respectively; while the median of NLR was 5.2 and 2.1 (p < 0.001). The median of IL-6 was 46 pg/ml and 6.4 pg/ml (p < 0.001),respectively. The best parameter for the diagnosis of early PJI was IL-6 (AUC = 0.814) followed by the NLR (AUC =0.802), CRP (AUC =0.793), ESR (AUC =0.744) and WBC (AUC = 0.632). CONCLUSIONS: This study is the first to show that NLR values are more accurate than CRP and may be considered as useful parameters for the diagnosis of early PJI because it is a cheap and convenient parameter to be calculated in daily practice without extra costs.

Two-stage exchange Arthroplasty is a viable treatment for Periprosthetic joint infection in inflammatory diseases.

BACKGROUND: Inflammatory diseases are chronic autoimmune systemic autoimmune diseases, which may increase the risk of prosthetic joint infection (PJI) after total joint arthroplasty (TJA). However, to our best knowledge, few studies have studied the association between inflammatory diseases and subsequent failure after two-stage exchange reimplantation. The aims of this study were to identify the differences in (1) serum markers, synovial indicators and pathology results and (2) treatment outcomes following two-stage exchange arthroplasty between patients with or without inflammatory diseases. METHODS: A retrospective review of 184 patients with PJI who underwent two-stage revision from 2014 to 2018 was conducted. PJI was diagnosed by using the MSIS criteria. Serum biomarkers, synovial fluid, organism and pathology results at the time of the PJI diagnosis and reimplantation were compared between patients with or without inflammatory diseases. Treatment success was defined according to the Delphi-based consensus criteria; Kaplan-Meier survivorship curves of the patients were generated and compared. RESULTS: There was no difference in the biomarkers, pathology results or organism profile at the time of the PJI diagnosis. At reimplantation, the patients with inflammatory diseases generally had higher values of serum markers than those without inflammatory diseases. However, synovial white blood cell count was comparable in patients with inflammatory diseases (1142.8 ± 1385.3*109/mL) and group C (1315.8 ± 1849.3*109/mL, p = 0.841). The total treatment success rate was 91.3% (92% for individuals with inflammatory diseases and 91.2% for the controls). The survivorship of the inflammatory disease group was comparable with that of the control group. CONCLUSION: Two-stage exchange arthroplasty is a viable option for PJIs with inflammatory diseases. Synovial fluid analysis may be less affected by inflammatory diseases than serum markers did in the diagnosis persistent infection at reimplantation.

Source tracing of n-alkanes in Songhua Lake, based on correspondence analysis and geochemical index.

This paper analyzes the source of n-alkanes in sediments spanning 63 years since 1943 from Songhua Lake, using the method of correspondence analysis and geochemical index. The area of Songhua Lake is 554 km2, and its ecological problems affect hundreds of thousands of people in the basin. The concentration of total n-alkanes (C13-C36) in the sediments ranged from 20.39 to 168.35 µg/g, averaged at 72.58 µg/g, indicating that the Songhua Lake has an ecological risk of n-alkanes and should be taken seriously and protected. The analysis of geochemical indexes, including main carbon distributions (MH), LMW/HMW ratio, Paq, average chain length and so on, shows the n-alkanes in the Songhua Lake sediments are mainly derived from modern higher terrestrial plants, followed by human activities, and a small part from aquatic vascular plants and algae. Moreover, the source and sedimentary history of n-alkanes in Songhua Lake were carried out by corresponding analysis. And the correspondence analysis could be a feasible and effective means of source tracing.

Diagnostic criteria of periprosthetic joint infection: a prospective study protocol to validate the feasibility of the 2018 new definition for Chinese patients.

BACKGROUND: Periprosthetic joint infection (PJI) is a challenging complication following total joint arthroplasty (TJA), and the diagnostic criteria remains controversial. The 2018 new definition proposed in May 2018 consists of new diagnostic criteria for PJI. We conducted a retrospective study and demonstrated that the new definition could improve the diagnostic efficiency in Chinese patients. However, missing data led to bias in the previous retrospective study. Therefore, this prospective study is designed to further validate the feasibility of 2018 new definition (and its modified version) for Chinese patients. METHODS/DESIGN: This is a single-centre, prospective diagnostic study with 1 year of follow-up. The patients enrolled in the trial will be divided into a PJI group and an Aseptic group based on the eligibility criteria. We will recruit at least 70 patients for each group from October 2019 to October 2020. Blood samples, synovial fluid samples and intraoperative variables of all the included patients will be collected to assess various indicators. We will integrate the results of the various tests and examine the diagnostic efficiency (sensitivity and specificity) of five diagnostic criteria. DISCUSSION: We design the prospective study in the hope of reducing the bias caused by missing data. Therefore, the prospective study will further support the conclusion of our preceding retrospective study. The results of this study will be submitted to a peer-reviewed journal for publication. CONCLUSION: Through this prospective study, we will validate the feasibility of the 2018 new PJI definition (and its modified version) for Chinese patients and determine the optimal method of PJI diagnosis. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1900025395. Registered on 25 August 2019.

Synovial Fluid Viscosity Test is Promising for the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: So far there is no "gold standard" test for the diagnosis of periprosthetic joint infection (PJI), compelling clinicians to rely on several serological and synovial fluid tests with no 100% accuracy. Synovial fluid viscosity is one of the parameters defining the rheology properties of synovial fluid. We hypothesized that patients with PJI may have a different level of synovial fluid viscosity and aimed to investigate the sensitivity and specificity of synovial fluid viscosity in detecting PJI. METHODS: This prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 45 patients undergoing revision for PJI (n = 15), revision for aseptic failure (n = 15), and primary arthroplasty (n = 15). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, synovial fluid viscosity, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and plasma d-dimer levels were measured preoperatively. RESULTS: The synovial fluid viscosity level was significantly lower (P = .0011) in patients with PJI (7.93 mPa·s, range 3.0-15.0) than in patients with aseptic failure (13.11 mPa·s, range 6.3-20.4). Using Youden's index, 11.80 mPa·s was determined as the optimal threshold value for synovial fluid viscosity for the diagnosis of PJI. Synovial fluid viscosity outperformed CRP, ESR, and plasma d-dimer, with a sensitivity of 93.33% and a specificity of 66.67%. CONCLUSION: Synovial fluid viscosity seems to be on the same level of accuracy with CRP, ESR, and d-dimer regarding PJI detection and to be a promising marker for the diagnosis of PJI.

Does Use of Lidocaine Affect Culture of Synovial Fluid Obtained to Diagnose Periprosthetic Joint Infection (PJI)? An In Vitro Study.

BACKGROUND Synovial fluid culture (SFC) is recommended as one of the major diagnostic criteria by the Musculoskeletal Infection Society (MSIS) for diagnosing periprosthetic joint infection (PJI). Local anesthetic agents are used for anesthesia and analgesia in some clinical settings to relieve pain. As a local anesthetic, lidocaine is safely used in arthrocentesis to obtain synovial fluid. The goal of this study was to determine if infiltration anesthesia with additive-free lidocaine 2% has antibacterial effects that might interfere with subsequent SFC. MATERIAL AND METHODS Eight isolates of reference strains of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and Candida albicans were incubated on the plates. Each bacterial suspension was formed by 50-fold dilution before the test lidocaine 2% was added. For each strain, bacterial suspension was divided into 2 groups (5 samples each) exposed either lidocaine 2% or sterile non-bacteriostatic 0.45% saline. The antimicrobial property of lidocaine 2% was determined by measuring the bacterial density on agar plates incubated for 24 h and comparing it with controls unexposed to lidocaine 2%. RESULTS Exposure to lidocaine 2% negatively affected microbial viability in vitro. Of the lidocaine 2% exposure, reference strains but no Streptococcus pyogenes strain resulted in fewer colony-forming units compared with the sterile saline control. The antibacterial property of lidocaine 2% appears to affect the ability to culture the organism in synovial fluid. CONCLUSIONS Lidocaine 2% has strong antimicrobial activities against some commonly encountered bacterial strains in PJI. As a result, infiltration anesthesia with additive-free lidocaine 2% before the arthrocentesis procedure may affect the results of SFC. To further evaluate its potential antibacterial usefulness in clinical applications, studies are needed to assess the ability of lidocaine to reduce the risk of iatrogenic infections.

Robot-assisted vs. conventional unicompartmental knee arthroplasty : Systematic review and meta-analysis.

Numerous advances have been made in prosthesis design, instrumentation and postoperative rehabilitation for unicompartmental knee arthroplasty; however, only 70-86% of patients are satisfied with the functional outcome and revision rates range between 10% and 20%. The primary outcome for this meta-analysis was implantation accuracy of component positioning and tibiofemoral component safe zone. A total of three randomized controlled trials (RCT), three quasi-RCTs and one prospective trial were included in this review. It was found that the use of robotic-assisted systems reduces implantation errors without an increase in adverse events. There are only a few reports about clinical outcome and long-term follow-up and whether the more accurate component positioning results in a better clinical effect or a better long-term survival of the implants is unknown.

Pelvic height planning versus conventional templating in preoperative planning of acetabulum cup size for THA.

This study aimed to compare the accuracy of pelvic height planning vs. the conventional templating method for acetabulum cup measurement. A total of 200 consecutive patients undergoing primary total hip arthroplasty (THA) were randomly grouped as follows: group A, accepting conventional templating; group B, accepting pelvic height planning. Preoperative measurement of the acetabular cup was performed with conventional templating and pelvic height planning, respectively. There were 57 cases with the same size or with one type size discrepancy, 49 with two type size discrepancies, and 14 with three type size discrepancies in group A. There were 145 cases with the same size or one type size discrepancy, 20 with two type size discrepancies, and 3 type size discrepancies in group B. The mean difference between the planned size and actual cup size was 2.58 ± 0.89 mm (group A) vs. 1.38 ± 1.22 mm (group B). Therefore, pelvic height planning is reliable for use in preoperative planning compared with conventional templating.