Aims. Multiligament knee injuries (MLKI) are devastating injuries that can result in significant morbidity and time away from sport. There remains considerable variation in strategies employed for investigation, indications for operative intervention, outcome reporting, and rehabilitation following these injuries. At present no study has yet provided a comprehensive overview evaluating the extent, range, and overall summary of the published literature pertaining to MLKI. Our aim is to perform a methodologically rigorous scoping review, mapping the literature evaluating the diagnosis and management of MLKI. Methods. This scoping review will address three aims: firstly, to map the current extent and nature of evidence for diagnosis and management of MLKI; secondly, to summarize and disseminate existing research findings to practitioners; and thirdly, to highlight gaps in current literature. A three-step search strategy as described by accepted methodology will be employed to identify peer-reviewed literature including reviews, technical notes, opinion pieces, and original research. An initial limited search will be performed to determine suitable search terms, followed by an expanded search of four electronic databases (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and Web of Science). Two reviewers will independently screen identified studies for final inclusion. Dissemination. We will map key concepts and evidence, and disseminate existing research findings to the wider orthopaedic and sports medicine community, through both peer-reviewed and non-peer-reviewed literature, and conference and in-person communications. We will highlight gaps in the current literature and determine future priorities for further research. Cite this article: Bone Jt Open 2022;3(11):894–897

Introduction. Lumbosacral transitional vertebrae (LSTV) are increasingly recognized as a common anatomical variant and is the most common congenital anomaly of the lumbosacral spine. Patients can have symptomatic LSTV, known as Bertolotti's Syndrome, where transitional anatomy can cause back, L5 distribution leg, hip, and groin pain. We propose an outline for diagnosis and treatment of Bertolotti's Syndrome. Methods. We retrospectively reviewed over 500 patients presenting to the primary author with low back, buttock, hip, groin and/or leg pain from April 2009 through April 2024. Patients with radiographic findings of an LSTV and clinical presentation underwent diagnostic injections to confirm diagnosis of Bertolotti's syndrome. Treatment was determined based on patient's LSTV classification. 157 patients with confirmed Bertolotti's syndrome underwent surgical treatment. Results. Over 500 patients presented with an appropriate clinical presentation and radiographic findings of an LSTV. Diagnostic injections were targeted into the transitional anatomy confirming the LSTV as the primary pain generator to make the diagnosis of Bertolotti's syndrome. The decision in the type of surgical intervention, resection or fusion, was made based on patient's LSTV anatomy. 157 patients with confirmed Bertolotti's Syndrome underwent surgical treatment (121 fusions (77%), 36 resections (23%)). The classification system and surgical outcomes, in part, have been previously published in World Neurosurgery. Conclusion. We have outlined the best practice of diagnosis and treatment selection for Bertolotti's syndrome. We have shown significant improvement in outcomes based on this method. We hope to aid in both patient education and provide an outline on how clinicians can become knowledgeable on Bertolotti's syndrome. Conflicts of interest. No conflicts of interest. Sources of funding. No funding obtained

Introduction. Fracture related infection (FRI) is a challenging complication to manage in an orthoplastic setting. Consensus guidelines have been created to standardise the diagnosis of FRI and comprise confirmatory and suggestive criteria. In this study, the aim is to assess the diagnostic criteria and management of FRI with a particular focus on soft tissue reconstruction. Materials & Methods. A retrospective study to identify the outcomes of FRI in the lower limb over a five year period at a Major Trauma Centre. Fracture specific information that was analysed includes: open versus closed, fractured bone(s) and site, initial fracture management, method of diagnosis and soft tissue management. Results. A total of 40 patients were identified, 80% of whom were male (n= 32). The mean age for FRI diagnosis was 54 years (range 18–83 years). In our patient cohort, 10% were immunosuppressed and another 12.5% had a formal diagnosis of Diabetes Mellitus. A diagnosis of acute FRI (i.e. < six weeks from time of injury) was made in 9 patients (22.5%). Chronic FRI was noted in 25 patients (62.5%). There was equal incidence of FRI in patients with closed fractures and open fractures (42.5%). Tibia and fibula fractures were most common (87.5%, n=35). Regardless of fractured bone(s), the more distal the fracture the higher the incidence of FRI (60% distal versus 12.5% proximal). Gram-positive cocci were the most commonly identified pathogens, identified in 25% of patients. Five patients underwent free flap reconstruction, two patients received pedicled muscle flaps and another two patients received split thickness skin grafts. Conclusions. The diagnosis of FRI can be confirmed through the presence of a combination of confirmatory and suggestive criteria. We advocate a staged approach in the management of FRI with radical wound excision and temporary coverage followed by definitive soft tissue reconstruction

Background. The diagnosis of periprosthetic joint infection (PJI) remains a challenge in clinical practice and the analysis of synovial fluid (SF) is a useful diagnostic tool. Recently, two synovial biomarkers (leukocyte esterase (LE) strip test, alpha-defensin (AD)) have been introduced into the MSIS (MusculoSkeletal Infection Society) algorithm for the diagnosis of PJI. AD, although promising with high sensitivity and specificity, remains expensive. Calprotectin is another protein released upon activation of articular neutrophils. The determination of calprotectin and joint CRP is feasible in a routine laboratory practice with low cost. Purpose. Our objective was to evaluate different synovial biomarkers (calprotectin, LE, CRP) for the diagnosis of PJI. Methods. In this monocentric study, we collected SF from hip, knee, ankle and shoulder joints of 42 patients who underwent revision or puncture for diagnostic purposes. Exclusion criteria included a joint surgery in the previous 3 months and a diagnosis of a systemic inflammatory disease. PJI was diagnosed in a multidisciplinary consultation meeting (RCP) of the Reference Centers for Osteoarticular Infections of the Great West (CRIOGO). SF was analysed for LE, CRP and calprotectin. The cut-off values used were 50 mg/L for calprotectin, 8.8 mg/L for CRP and 125 WBC/µL for LE. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for these different synovial markers. Results. Of the 42 patients included, 28 were considered as infected and 14 uninfected. The statistical parameters are presented in Table 1. Conclusion. The present study shows that the synovial calprotectin assay has an excellent sensitivity and a 100% NPV for the diagnosis of PJI, suggesting that a result < 50 mg/L could exclude PJI. This promising study suggests that calprotectin should be included with synovial CRP in a new decision algorithm for the diagnosis of PJI. For any tables or figures, please contact the authors directly

Aims. This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%). Methods. In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared. Results. The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI. Conclusion. SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly. Cite this article: Bone Joint Res 2023;12(2):113–120

Introduction:. Most of the published papers on AI based diagnosis have focused on the algorithm's diagnostic performance in a ‘binary’ setting (i.e. disease vs no disease). However, no study evaluated the actual value for the clinicians of an AI based approach in diagnostic. Detection of Traumatic thoracolumbar (TL) fractures is challenging on planar radiographs, resulting in significant rates of missed diagnoses (30-60%), thus constituting a field in which a performance improvement is needed. Aim of this study is therefore to evaluate the value provided by AI generated saliency maps (SM), i.e. the maps that highlight the AI identified region of interests. Methods:. An AI model aimed at identifying TL fractures on plain radiographs was trained and tested on 567 single vertebrae images. Three expert spine surgeons established the Ground Truth (GT) using CT and MRI to confirm the presence of the fracture. From the test set, 12 cases (6 with a GT of fracture and 6 with a GT of no fracture, associated with varying levels of algorithm confidence) were selected and the corresponding SMs were generated and shown to 7 independent evaluators with different grade of experience; the evaluators were requested to: (1) identify the presence or absence of a fracture before and after the saliency map was shown; (2) grade, with a score from 1 (low) to 6 (high) the pertinency (correlation between the map and the human diagnosis), and the utility (the perceived utility in confirming or not the initial diagnosis) of the SM. Furthermore, the usefulness of the SM was evaluated through the rate of correct change in diagnosis after the maps had been shown. Finally, the obtained scores were correlated with the algorithm confidence for the specific case. Results:. Of the selected maps, 8 had an agreement between the AI diagnosis and the GT, while in 4 the diagnosis was discordant (67% accuracy). The pertinency of the map was found higher when the AI diagnosis was the same as the GT and the human diagnosis (respectively p-value = .021 and <.000). A positive and significant correlation between the AI confidence score and the perceived utility (Spearman: 27%, p-value=.0-27) was found. Furthermore, evaluator with experience < 5 year found the maps more useful than the experts (z-score=2.004; p-value=.0455). Among the 84 evaluation we found 12 diagnostic errors in respect to the GT, 6 (50%) of which were reverted after the saliency map evaluation (z statistic = 1.25 and p-value = .21). Discussion:. The perceived utility of AI generated SM correlate with the model confidence in the diagnosis. This highlights the fact that to be considered helpful, the AI must provide not only the diagnosis but also the case specific confidence. Furthermore, the perceived utility was higher among less experienced users, but overall, the SM were useful in improving the human diagnostic accuracy. Therefore, in this setting, the AI enhanced approach provides value in improving the human performance

Aim. Synovial fluid D-lactate may be useful for diagnosing septic arthritis (SA) as this biomarker is almost exclusively produced by bacteria. We evaluated the performance of synovial fluid D-lactate and determined its optimal cut-off value for diagnosing SA. Method. Consecutive patients with suspicion of septic arthritis were prospectively included. They underwent joint aspiration and synovial fluid was collected for culture, leukocyte count and D-lactate concentration (by spectrophotometry). Youden's J statistic was used for determining optimal D-lactate cut-off value on the receiver operating characteristic (ROC) curve by maximizing sensitivity and specificity. Results. A total of 155 patients were included. Using institutional criteria, 21 patients (14%) were diagnosed with SA and 134 (86%) patients with aseptic arthropathy, out of which 43 (27%) had osteoarthrosis, 80 (52%) had rheumatic arthropathy and 11 (7%) reactive arthritis. The optimal cut-off of synovial fluid D-lactate to differentiate SA from aseptic cases was 0,035 mmol/l. Synovial fluid D-lactate had a sensitivity 90% (95% CI: 70–99%) and specificity 87% (95% CI: 80–92%) compared to leukocyte count with sensitivity 81% (95% CI: 60–95%) and specificity 83% (95% CI: 76–90%). Culture was positive in only 17 (80%) out of 21 patients with SA. Conclusions. The synovial fluid D-lactate showed high sensitivity and specificity for diagnosis of SA which was higher than the current gold standard of diagnosis (culture and leukocyte count). The high sensitivity makes this biomarker useful as a point-of-care screening test for SA

Aims. The International Consensus Meeting on Musculoskeletal Infection (ICM, Philadelphia 2018) recommended histology as one of the diagnostic tests although this is not routinely used in a number of UK hospitals. This study aims to explore the role of histology in the diagnosis of infection and whether it is of practical use in those cases where the microbiology samples are either diagnostically unclear or do not correspond to the pre-operative diagnosis or the clinical picture. Patients and Methods. We identified 85 patients who underwent revision knee arthroplasty for either septic or aseptic loosening and for whom both microbiology and histology samples were taken. The procedures were performed by the senior experienced surgeons specialised in revision knee arthroplasty in two centres from Liverpool. Each patient had a minimum of five tissue samples taken, using separate knife and forceps and each sample was divided in half and sent for microbiology and histology in different containers. Fifty-four patients (63.5%) underwent a single-staged revision; ten patients (11.8%) underwent the 1. st. stage of a two staged revision; eleven patients (12.9%) underwent the 2. nd. stage of a two staged revision; one patient (1.2%) underwent an additional revision stage; three patients (3.5%) were treated with a DAIR; three patients (3.5%) had a 2-in-1 revision; two patients (2.4%) had a debridement and polyethylene exchange; and one patient (1.2%) had an arthroscopy biopsy of knee replacement. The cost to process five microbiology samples for each patient was £122.45 on average and for the five histology samples was £130. Results. In 63.5% (n=54) the histology and microbiology confirmed an aseptic joint as suspected beforehand. In 8.2% (n=7) the histology result was the same as the microbiology result confirming infection as suspected beforehand. In 15.3% (n=13) where asepsis was suspected beforehand, one of the five microbiology samples unexpectedly grew an organism but all the histological samples showed no evidence of infection. In these cases, the histology result supported the diagnosis of the likelihood of a contaminant. In 5.9% (n=5) we found differences in the microbiology and histology in one sample and in 7.1% (n=6) the histology was different to the microbiology in more than one sample. Conclusions. In cases where the diagnosis of sepsis within a knee replacement is not in doubt due to pre-operative microbiology, we found no benefit in additional histology sampling. In 28.3% of the cases, the histology was of use in the diagnosis of infection in complex cases and a useful tool in the decision process for further management. In over half of the cases where the revision was for aseptic loosening, the histology result did not alter the management but 28.3% of cases that were thought to be aseptic, microbiology revealed at least one positive sample hence the histology was of use in making a final diagnosis, be that of infection, contamination or to rule out infection. Whilst histology is of use in the latter groups but not the aseptic group, these outcomes are not predictable until after the post-operative period hence histology is required in all these cases. Overall, the histology is a cheap test which is of benefit in the diagnosis of complex peri-prosthetic joint infection in one–third of cases and we support the ICM recommendation

Our understanding of pre-arthritic hip disease has evolved tremendously but challenges remain in categorizing diagnosis, which ultimately impacts choice of treatments and clinical outcomes. This study aims to report patient reported outcome measures (PROMs) comparing four different condition groups within hip preservation surgery by a group of fellowship-trained surgeons. From 2018 to 2021, 380 patients underwent hip preservation surgery at our center and were classified into five condition groups: dysplasia: 82 (21.6%), femoro-acetabular impingement (FAI): 173 (45.4%), isolated labral tear: 103 (27.1%), failed hip preservation: 20 (5.3%) and history of childhood disease/other: 2 (0.5%). International hip outcomes Tool 12 (IHOT-12), numeric pain score and patient-reported outcomes measurement information system (PROMIS) were collected pre-operatively and at 3 months and 1 year post-operatively, with 94% and 82% follow-up rate respectively. Arthroscopy (75.5%) was the most common procedure followed by peri-acetabular osteotomy (PAO) (22.4%) and surgical dislocation (2.1%). Re-operation rate were respectively 18.3% (15), 5.8% (10), 4.9% (5), 30% (6) and 0%. There were 36 re-operations in the cohort, 14 (39%) for unintended consequences of initial surgery, 10 (28%) for mal-correction leading to a repeat operation, 8 (22%) progression of arthritis, and 4 (11%) for incorrect initial diagnosis/intervention. Most common re-operations were hardware removal 31% (7 PAO, 3 surgical hip dislocation and 1 femoral de-rotational osteotomy), arthroscopy 31% (11) and arthroplasty 28% (10). All groups had significant improvements in their IHOT-12 as well as PROMIS physical and numerical pain scales, except those with failed hip preservation. Dysplasia group showed a slower recovery. Overall, this study demonstrated a clear relation between the condition groups, their respective intervention and the significant improvements in PROMs with isolated labral pathology being a valid diagnosis. Establishing tertiary referral centers for hip preservation and longer follow-up is needed to monitor the overall survivorship of these various procedures

Introduction. It is generally held that blood tests are not particularly helpful in establishing the diagnosis of bone tumours but may be useful in prognosis. We reviewed the results of blood tests taken at the time of diagnosis to establish the frequency of abnormalities in common blood tests and whether this was significant in staging or prognosis. Method. Blood test results on all newly diagnosed patients with bone tumours from 2005 – 2010 were exported and abnormalities identified. This was matched to diagnosis, clinical features and prognosis. Results. There were 541 patients included in the analysis of whom 221 had osteosarcoma, 167 chondrosarcoma, 87 Ewing's, and 66 other bone tumours. 340 were adults, 103 children (under 14) and 98 TYA. The most frequently abnormal blood test was a low haemoglobin (⋋13) in 56%, raised alkaline phosphatase in 40%, and raised ESR and CRP in 32%. Patients with metastases at diagnosis tended to have higher levels of ESR (p⋋0.0001) but there was no other significant difference overall. Older patients tended to have a greater number of abnormal results apart from the CRP which was highest in the TYA group. No single blood test was related to prognosis. Conclusion. Abnormal blood tests are common in patients at the time of diagnosis of bone tumours. None are either particularly diagnostic or prognostic

Aim. Diagnosing periprosthetic joint infections (PJI) can be very challenging, especially infections caused by low virulence microorganisms. No single test with a 100% accuracy is available yet. Hence, different infection definitions were introduced to improve the diagnostic confidence and quality of research articles. Due to constant developments in this field, infection definitions are adopted continuously. The aim of our study was to find the most sensitive currently available infection definition among three currently used criteria (International Consensus Meeting – criteria 2018 (ICM), Infectious Diseases Society of America - criteria 2013 (IDSA), and European Bone and Joint Infection Society – criteria 2021 (EBJIS)) for the diagnosis of PJI. Method. Between 2015 and 2020, patients with an indicated revision surgery due to septic or aseptic failure after a total hip or knee replacement were included in this retrospective analysis of prospectively collected data. A standardized diagnostic workup was done in all patients. The components of the IDSA-, ICM-, and EBJIS- criteria for the diagnosis of PJI were identified in each patient. Results. Overall, 206 patients (hip: n=104 (50%); knee: n=102 (50%)) with a median age of 74 years (IQR 65 – 80y) were included. 101 patients (49%) were diagnosed with PJI when using the EBJIS- criteria. Based on the IDSA- and ICM- criteria, 99 patients (48%, IDSA) and 86 patients (42%, ICM) were classified as septic. Based on all three criteria, 84 cases (41%) had an infection. 15 septic cases (n=15/206; 7%) were only identified by the IDSA- and EBJIS- criteria. In 2 patients (n=2/206, 1%), an infection was present based on only the ICM and EBJIS criteria. No case was classified as infected by one infection definition alone. A statistically significant higher number of inconclusive cases was observed when the ICM criteria (n=30/206; 15%) were used in comparison to the EBJIS criteria (likely infections: n=16/206; 8%) (Fisher's exact test, p=0.041). The EBJIS definition showed a better preoperative performance in comparison to the other two definitions (p<0.0001). Conclusions. The most sensitive infection definition seems to be the novel EBJIS– criteria covering all infections diagnosed by the IDSA- and ICM-criteria without detecting any further infection. In addition, less inconclusive (infection likely) cases were detected by the EBJIS-criteria in comparison with the ICM-criteria reducing the so called ‘grey zone’ significantly which is of utmost importance in clinical routine

In the last decades, the use of artificial intelligence (AI) has been increasingly investigated in intervertebral disc degeneration (IDD) and chronic low back pain (LBP) research. To date, several AI-based cutting-edge technologies, such as computer vision, computer-assisted diagnosis, decision support system and natural language processing have been utilized to optimize LBP prevention, diagnosis, and treatment. This talk will provide an outline on contemporary AI applications to IDD and LBP research, with a particular attention towards actual knowledge gaps and promising innovative tools

Aims. To investigate the optimal thresholds and diagnostic efficacy of commonly used serological and synovial fluid detection indexes for diagnosing periprosthetic joint infection (PJI) in patients who have rheumatoid arthritis (RA). Methods. The data from 348 patients who had RA or osteoarthritis (OA) and had previously undergone a total knee (TKA) and/or a total hip arthroplasty (THA) (including RA-PJI: 60 cases, RA-non-PJI: 80 cases; OA-PJI: 104 cases, OA-non-PJI: 104 cases) were retrospectively analyzed. A receiver operating characteristic curve was used to determine the optimal thresholds of the CRP, ESR, synovial fluid white blood cell count (WBC), and polymorphonuclear neutrophil percentage (PMN%) for diagnosing RA-PJI and OA-PJI. The diagnostic efficacy was evaluated by comparing the area under the curve (AUC) of each index and applying the results of the combined index diagnostic test. Results. For PJI prediction, the results of serological and synovial fluid indexes were different between the RA-PJI and OA-PJI groups. The optimal cutoff value of CRP for diagnosing RA-PJI was 12.5 mg/l, ESR was 39 mm/hour, synovial fluid WBC was 3,654/μl, and PMN% was 65.9%; and those of OA-PJI were 8.2 mg/l, 31 mm/hour, 2,673/μl, and 62.0%, respectively. In the RA-PJI group, the specificity (94.4%), positive predictive value (97.1%), and AUC (0.916) of synovial fluid WBC were higher than those of the other indexes. The optimal cutoff values of synovial fluid WBC and PMN% for diagnosing RA-PJI after THA were significantly higher than those of TKA. The specificity and positive predictive value of the combined index were 100%. Conclusion. Serum inflammatory and synovial fluid indexes can be used for diagnosing RA-PJI, for which synovial fluid WBC is the best detection index. Combining multiple detection indexes can provide a reference basis for the early and accurate diagnosis of RA-PJI. Cite this article: Bone Joint Res 2023;12(9):559–570

Aim. Differentiation of infected (INF) nonunion from aseptic (AS) nonunion is crucial for the choice of intra- and postoperative treatment. Preoperative diagnosis of infected nonunion is challenging, especially in case of low-grade infection lacking clinical signs of infection. Standard blood markers such as C-reactive protein or leucocyte count do not aid in preoperative diagnosis. Proteomic profiling has shown promising results for differentiation of numerous chronic disease states, and in this study was applied to preoperative blood samples of patients with nonunion in an attempt to identify potential biomarkers. Method. This prospective multicenter study enrolled patients undergoing revision surgery of femur or tibia nonunion. Patients with implant removal after regular fracture healing (HEAL) were included as a control-group. Preoperative blood samples, intraoperative tissue samples, sonication of osteosynthesis material and 1-year-follow-up questionnaire were taken. Nonunion patients were grouped into INF or AS after assessing bacterial culture and histopathology of retrieved samples. Diagnosis of infection followed the fracture related infection consensus group criteria, with additional consideration of healing one year after revision surgery. Targeted proteomics was used to investigate a predefined panel of 45 cytokines in preoperative blood samples. Statistical differences were calculated with Kruskal Wallis and Dunn's post hoc test. Cytokines with less than 80% of samples being above the lower limit of detection range (LLDR) were excluded for this study. Results. We recruited 62 AS, 43 INF and 32 HEAL patients. Patients in the two nonunion groups (INF and AS) did not differ concerning smoking, diabetes or initial open or closed fracture. Thirty-two cytokines were above LLDR in >80% of patients. INF patients showed a significant difference in expression of 8 cytokines compared to AS, with greatest differences observed for Macrophage Colony Stimulating Factor 1 (MCSF-1) and Hepatocyte Growth Factor (HGF) (p<0.01). In comparing AS with HEAL patients, 9 cytokines displayed significant differences, including interleukin (IL)-6, Vascular Endothelial Growth Factor A (VEGFA), Matrix Metalloproteinase 1 (MMP-1). Comparison of INF with HEAL patients revealed significantly different expression of 20 cytokines, including. IL-6, IL-18, VEGFA or MMP-1. Conclusions. Our study revealed differences in plasma cytokine profile of blood samples from INF and AS patients. Although no single biomarker is sufficient to differentiate these patients preoperatively in isolation, future multivariant analysis of this cytokine data in combination with clinical characteristics may provide valuable diagnostic insights. Funded by German Social Accident Insurance (FF-FR 0276) and AO Trauma (AR2021_04)

Aim. While 16S rRNA PCR - Sanger sequencing has paved the way for the diagnosis of culture-negative bacterial infections, it does not provide the composition of polymicrobial infections. We aimed to evaluate the performance of the Nanopore-based 16S rRNA metagenomic approach using partial-length amplification of the gene, and to explore its feasibility and suitability as a routine diagnostic tool for bone and joint infections (BJI) in a clinical laboratory. Method. Sixty-two clinical samples from patients with BJI were sequenced on MinION* using the in-house partial amplification of the 16S rRNA gene. BJI were defined based on the ICM Philly 2018 and EBJIS 2021 criteria. Among the 62 samples, 16 (26%) were culture-positive, including 6 polymicrobial infections, and 46 (74%) were culture-negative from mono- and polymicrobial infections based on Sanger-sequencing. Contamination, background noise definition, bacterial identification, and time-effectiveness issues were addressed. Results. Results were obtained within one day. Setting a threshold at 1% of total reads overcame the background noise issue and eased interpretation of clinical samples. The partial 16S rRNA metagenomics approach had a greater sensitivity compared both to the culture method and the Sanger sequencing. All the 16 culture-positive samples were confirmed with the metagenomic sequencing. Bacterial DNA was detected in 32 culture-negative samples (70%), with pathogens consistent with BJI. The 14 Nanopore negative samples included 7 negative results confirmed after implementation of other molecular techniques and 7 false-negative MinION results: 3 Kingella kingae infections detected after targeted-PCR only, 2 Staphylococcus aureus infections and 2 Pseudomonas aeruginosa infections sterile on agar plate media and detected only after implementation of blood culture media, advocating for the very low inoculum. Conclusions. The results discriminated polymicrobial samples, and gave accurate bacterial identifications compared to Sanger-based results. They confirmed that Nanopore technology is user-friendly as well as cost- and time-effective. They also indicated that 16S rRNA targeted metagenomics is a suitable approach to be implemented for routine diagnosis of culture-negative samples in clinical laboratories. * Oxford Nanopore Technologies

Aim. The analysis of synovial fluid has proved to be of crucial importance in the diagnostic process of prosthetic joint infections (PJI), suggesting the presence of an infection before the microbiological culture results. In this context, several studies illustrated the efficacy of synovial calprotectin in supporting the diagnosis of PJI [1, 2]. However, several testing methods have been explored to detect synovial calprotectin levels, emphasizing the need to use a standardized, rapid and rapid test. In this study, synovial calprotectin was analyzed by means of a commercial stool test [3] to explore whether the detected levels might predict PJIs and, therefore, being a promising tool for the fast and reliable diagnosis of this complication. Method. The synovial fluid of 55 patients underwent to revision of the prosthetic implant were analyzed. The measurement of calprotectin was carried out by of commercial stool test, following the protocol for liquid samples. Calprotectin levels were then compared to other synovial biomarkers of PJI such as leucocyte esterase and count and percentage of polymorphonuclear cells. Data analysis were performed using R software v4.1.1 (R Core Team) and package “pROC” [4]. Receiver operator characteristics curves were designed using culture test as gold standard to evaluate the area under curve (AUC) of each method (with DeLong method for confidence-interval calculation). Thresholds were calculated to maximize Youden's index; sensitivity and specificity were reported. One-to-one Pearson's correlations coefficient were calculated for each pair of methods. P value <0.05 were considered statistically significant. Results. Of the 55 synovial fluids analyzed, 13 patients were diagnosed with PJI and 42 with an aseptic failure of the implant. The specificity, sensitivity, and AUC of calprotectin resulted 0.90, 0.85, and 0.86 (95%CI: 0.72–0.99), respectively with a set threshold of 226.5 µg/g. The values of calprotectin had a moderate and statistically relevant correlation with the synovial leucocyte counts (r. s. = 0.54, p = 0.0003) and the percentage of polymorphonuclear cells (r. s. = 0.68, p = 0.0000). Conclusions. From this analysis, it can be concluded that synovial calprotectin is a valuable biomarker that correlates with other established indicator of local infection, delivering a rapid and reliable results and supporting the diagnostic process of PJI

Background. The identification of novel biomarker which is highly specific and sensitive for periprosthetic joint (PJI) have the potential to improve diagnostic accuracy and ultimately improve patient outcomes. Thus, the aim of this systemic review is to identify and evaluate novel biomarkers for the preoperative diagnostics of PJI. Methods. MEDLINE, EMBASE, PubMed and Cochrane Library databases identified from 1. st. of January 2018 to 30. th. of September. 2022. We used “periprosthetic joint infection” OR “prosthetic joint infection” OR “periprosthetic infection” as the diagnosis of interest and the target index applied AND “marker”. To focus on novel biomarkers already used biomarkers of the established PJI diagnostic criteria of MSIS, ICM and EBJIS were not included in the analysis. These three criteria were considered the reference standard during quality assessment. Results. A total of 19 studies were included. In these, fourteen different novel biomarkers were analyzed. Fifteen studies (79%) had prospective designs and the other four (22%) were retrospective studies. Six studies (33%) included only periprosthetic knee infections and thirteen (67%) included periprosthetic knee and hip infections. Proteins were analyzed in most cases (nine studies), followed by molecules (three studies), exosome (two studies) as well as DNA (two studies), interleukin (one study) and lysosome (one study). One novel and promising marker that had been frequently analyzed is calprotectin. Conclusion. No marker demonstrated higher sensitivity and specificity than already known parameters used for standardized treatment based on established PJI definitions. Further studies are needed to elucidate the benefit and usefulness of implementing new biomarkers in diagnostic PJI settings

Aim. Despite the availability of numerous tests, the diagnosis of periprosthetic infection (PJI) continues to be complex. Although several studies have suggested that coagulation-related markers, such as D-dimer and fibrinogen, may be promising tools in the diagnosis of prosthetic infections, their role is still controversial. The aim of this study is to evaluate the diagnostic accuracy of serum D-dimer and fibrinogen in patients with painful total knee replacement. Method. 83 patients with painful total knee replacement and suspected peri-prosthetic infection were included. All patients underwent pre-operative blood tests to evaluate inflammation indices (ESR and CRP) and serum D-Dimer and Fibrinogen levels. The diagnostic performance of the tests was assessed using the ICM definition as the gold standard. The diagnostic accuracy of the D-dimer and fibrinogen was measured by assessing sensitivity, specificity and by calculating the area under the ROC curve. Results. The definition of prosthetic infection based on the ICM criteria has made it possible to classify 40 peri-prosthetic infections and 43 aseptic failures. The mean value of fibrinogen, D-Dimer, VES and PCR observed in patients with prosthetic infection was significantly higher than in patients with aseptic failure [fibrinogen 468 mg / dl vs 331 mg / dl, p <0.001; D-Dimero 2177 ng/mL vs. 875 ng / mL, p <0.005], ESR 49 mm / hr vs 24 mm/h, p <0.001; PCR 25.5 mg /L vs 8.9 mg/L, p <0.001]. The optimal threshold value of the fibrinogen indicative of the presence of infection was 418 mg/dl, with a sensitivity of 72% and a specificity of 88%. The serum concentration of d-dimer greater than 945 ng / ml showed a sensitivity of 72.5% and a specificity of 76.7%. Conclusions. Although in this multicenter prospective study we found that serum D-dimer may have significantly higher statistical values in PJI than aseptic failures, its diagnostic power appears however limited when compared with other markers including plasma fibrinogen. Fibrinogen is regularly analyzed before surgery, the evaluation of this marker does not involve additional costs. The diagnostic accuracy appears to be similar to that of classic markers such as the level of PCR and VES. Plasma D-dimer may have a limited value in the diagnosis of PJI unlike plasma fibrinogen which has shown moderate sensitivity and excellent specificity. However, in our limited series of cases, both tests cannot be used alone in the diagnosis of infection but could contribute to the diagnosis if contextualized to ves and pcr

Aim. The diagnosis of septic arthritis mostly relies on clinical examination, several blood parameters including white blood cell count, C-reactive protein, sedimentation, and the analysis of the joint aspiration. However, the diagnosis can be difficult when the symptoms are vague and the information obtained from laboratory might be insufficient for definitive diagnosis. This study aimed to evaluate several ratios obtained from routine blood tests for a possible use in the diagnosis of septic arthritis. Method. The adult patients who were operated in our clinic due to septic arthritis between 2014–2020 were identified and retrospectively evaluated. The patients with any blood disorders or missing file information were excluded. A total of 36 patients were found to be eligible for inclusion. The control group included 40 patients without any sign of infection who underwent total knee arthroplasty due to knee osteoarthritis. Preoperative blood tests of each patients were examined. In addition to CRP and sedimentation values, neutrophil-lymphocyte, monocyte-lymphocyte, platelet-lymphocyte, and platelet count-mean platelet volume were calculated and receiving operating characteristics (ROC) curve analysis was made to determine the sensitivity, specificity and area under curve (AUC) values of these parameters. Results. The distribution of affected joint in septic arthritis group was as follow; 22 knees, 6 hips, 4 shoulders, 2 elbows, 1 wrist and 1 ankle. The cultures of joint aspiration yielded positive result in 19 patients while the cultures were negative in 17 patients. All of the analyzed parameters were significantly different between the groups (p<0.001). ROC curve analysis results are given in detail, in Table 1 and Figure 1. The AUC value was 97.3 when only CRP and sedimentation values were used but increased to 98.6 when neutrophile/ lymphocyte ratio was added and increased to 100 when all analyzed parameters were included. Conclusions. The analyzed parameters were found to increase the overall sensitivity and specificity when used together with acute phase reactants. However, when evaluated separately, CRP and sedimentation were still found as the most valuable parameters in the diagnosis of septic arthritis. In the diagnosis of septic arthritis, 35 mm/hr cut-off value for sedimentation and 10 mg/L cut-off value for CRP were found more sensitive and specific compared to standard laboratory cut-off values of 20 mm/hr and 5 mg/L. For any tables or figures, please contact the authors directly

Aim. The aim of this study was to investigate the metabolomic profile of synovial fluid in periprosthetic joint infection (PJI) cases regarding a possible diagnostic approach. Also, further information about the metabolic composition of synovial fluid in PJI may point to future diagnostic and therapeutic approaches. Method. Patients with a clinical suspicion of a prosthesis infection who underwent a joint puncture in our outpatient department or ward were included. After sample preparation, the nuclear magnetic resonance (NMR) experiments were performed at 310 K on an AVANCE™ NeoBruker Ultrashield 600 MHz spectrometer. Bruker Topspin version 4.0.2 was used for NMR data acquisition. The spectra for all samples were automatically processed (exponential line broadening of 0.3 Hz), phased, and referenced using TSP at 0.0 ppm. In total, 37 metabolites were analysed using a volume of 200 µl per synovial sample. The PJI and aseptic cases were assigned according to the EBJIS criteria. Results. In total, 76 samples were included in the final analysis with 48 PJI cases and 28 aseptic cases. Five measured metabolites have shown an area under the curve (AUC) over 0.8, with Taurine (AUC 0.8558, p<0.0001) and Glutamine (AUC 0.8333, p<0.0001) showing the best diagnostic performance. When combining two metabolites, the AUC indicated even higher diagnostic performance: Glucose/Glycogen (AUC 0.9073, p<0.0001), Taurine/Mannose (AUC 0.9073, p<0.0001), Mannose/Glycogen (AUC 0.8992, p<0.0001) and Taurine/Glucose (AUC 0.8956, p<0.0001). Conclusions. While NMR as a method in PJI diagnostics is currently not broadly available for daily clinical work, our results indicate that certain synovial metabolites and their combinations can be used for PJI diagnosis