To compare the effect of intraoperative red cell salvage on blood transfusion and cost in patients undergoing idiopathic scoliosis surgery. Retrospective. 37 patients (36 females, 1 male) underwent scoliosis surgery from February 2007 to October 2008. Intraoperative red cell salvage (Group 1) was used. They were compared with 28 patients (23 females, 5 males) operated from January 2005 to December 2006 without the use of cell salvage (Group 2). 36 patients in group 1 had posterior surgery and 1 had anterior surgery. In Group 2, 20 patients had posterior surgery, 7 anterior and 1 patient had anterior and posterior surgery. Both groups were comparable for age, number of levels fused, preoperative haemoglobin and haematocrit values. Amount of perioperative blood transfusion, costs. 14 patients (50%) in group 2 had blood transfusion whereas only 6 (16%) were transfused blood in group 1. Average blood loss in group 1 was 1076 mls (range 315-3000) and 1626mls (419-4275) in group 2. An average of 2 units of packed red blood cells per patient was processed by the cell salvage system. Postoperative haemoglobin, haematocrit and hospital stay were comparable in both groups. Cost analysis shows the use of cell salvage is cost beneficial by £116.60 per case. The use of red blood cell salvage reduces the amount of blood transfusion and is cost beneficial

Aims. The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis. Methods. Patients undergoing joint aspiration for evaluation of pain after total knee arthroplasty (TKA) or total hip arthroplasty (THA) were considered for inclusion. Synovial fluids from 99 patients (25 THA and 74 TKA) were analyzed by WBC count and PMN% analysis, AD LFA, and AD ELISA. WBC and PMN% cutoffs of ≥ 1,700 cells/mm. 3. and ≥ 65% for TKA and ≥ 3,000 cells/mm. 3. and ≥ 80% for THA were used, respectively. A panel of three physicians, all with expertise in orthopaedic infections and who were blinded to the results of AD tests, independently reviewed patient data to diagnose subjects as with or without PJI. Consensus PJI classification was used as the reference standard to evaluate test performances. Results were compared using McNemar’s test and area under the receiver operating characteristic curve (AUC) analysis. Results. Expert consensus classified 18 arthroplasies as having failed due to PJI and 81 due to aseptic failure. Using these classifications, the calculated sensitivity and specificity of AD LFA was 83.3% (95% confidence interval (CI) 58.6 to 96.4) and 93.8% (95% CI 86.2 to 98.0), respectively. Sensitivity and specificity of AD ELISA was 83.3% (95% CI 58.6 to 96.4) and 96.3% (95% CI 89.6 to 99.2), respectively. There was no statistically significant difference between sensitivity (p = 1.000) or specificity (p = 0.157) of the two AD assays. AUC for AD LFA was 0.891. In comparison, AUC for synovial WBC count, PMN%, and the combination of the two values was 0.821 (sensitivity p = 1.000, specificity p < 0.001), 0.886 (sensitivity p = 0.317, specificity p = 0.011), and 0.926 (sensitivity p = 0.317, specificity p = 0.317), respectively. Conclusion. The diagnostic accuracy of synovial AD for PJI diagnosis is comparable and not statistically superior to that of synovial WBC count plus PMN% combined. Cite this article: Bone Joint J 2021;103-B(6):1119–1126

Aim. White blood cell (WBC) scintigraphy for diagnosing fracture-related infections (FRIs) has only been investigated in small patient series. Aims of this study were (1) to establish the accuracy of WBC scintigraphy for diagnosing FRIs, and (2) to investigate whether the duration of the time interval between surgery and WBC scintigraphy influences its accuracy. Method. 192 consecutive WBC scintigraphies with . 99m. Tc-HMPAO-labelled autologous leucocytes performed for suspected peripheral FRI were included. The goldstandard was based on the outcome of microbiological investigation in case of surgery, or - when these were not available - on clinical follow-up of at least six months. The discriminative ability of the imaging modalities was quantified by several measures of diagnostic accuracy. A multivariable logistic regression analysis was performed to identify predictive variables of a false-positive or false-negative WBC scintigraphy test result. Results. WBC scintigraphy had a sensitivity of 0.79, a specificity of 0.97, a positive predicting value of 0.91, a negative predicting value of 0.93 and a diagnostic accuracy of 0.92 for detecting an FRI in the peripheral skeleton. The duration of the interval between surgery and the WBC scintigraphy did not influence its diagnostic accuracy; neither did concomitant use of antibiotics or NSAIDs. There were 11 patients with a false-negative (FN) WBC scintigraphy, the majority of these patients (n = 9, 82%) suffered from an infected nonunion. Four patients had a false-positive (FP) WBC scintigraphy. Conclusions. WBC scintigraphy showed a high diagnostic accuracy (0.92) for detecting FRIs in the peripheral skeleton. Duration of the time interval between surgery for the initial injury and the WBC did not influence the results which indicate that WBC scintigraphy is accurate shortly after surgery

Aims. The aim of this study was to perform a systematic review of the evidence for the use of intraoperative cell salvage in patients undergoing revision hip arthroplasty, and specifically to analyze the available data in order to quantify any associated reduction in the use of allogenic blood transfusion, and the volume which is used. Methods. An electronic search of MEDLINE (PubMed), Embase, Scopus, and the Cochrane Library was completed from the date of their inception to 24 February 2022, using a search strategy and protocol created in conjunction with the PRISMA statement. Inclusion criteria were patients aged > 18 years who underwent revision hip arthroplasty when cell salvage was used. Studies in which pre-donated red blood cells were used were excluded. A meta-analysis was also performed using a random effects model with significance set at p = 0.05. Results. Of the 283 studies which were identified, 11 were included in the systematic review, and nine in the meta-analysis. There was a significant difference (p < 0.001) in the proportion of patients requiring allogenic transfusion between groups, with an odds ratio of 0.331 (95% confidence interval (CI) 0.165 to 0.663) associated with the use of cell salvage. For a total of 561 patients undergoing revision hip arthroplasty who were treated with cell salvage, 247 (44.0%) required allogenic transfusion compared with 418 of 643 patients (65.0%) who were treated without cell salvage. For those treated with cell salvage, the mean volume of allogenic blood which was required was 1.95 units (390 ml) per patient (0.7 to 4.5 units), compared with 3.25 units (650 ml) per patient (1.2 to 7.0 units) in those treated without cell salvage. The mean difference of -1.91 units (95% CI -4.0 to 0.2) in the meta-analysis was also significant (p = 0.003). Conclusion. We found a a significant reduction in the need for allogenic blood transfusion when cell salvage was used in patients undergoing revision hip arthroplasty, supporting its routine use in these patients. Further research is required to determine whether this effect is associated with types of revision arthroplasty of differing complexity. Cite this article: Bone Joint J 2023;105-B(10):1038–1044

Aims. The aim of this study was to examine perioperative blood transfusion practice, and associations with clinical outcomes, in a national cohort of hip fracture patients. Methods. A retrospective cohort study was undertaken using linked data from the Scottish Hip Fracture Audit and the Scottish National Blood Transfusion Service between May 2016 and December 2020. All patients aged ≥ 50 years admitted to a Scottish hospital with a hip fracture were included. Assessment of the factors independently associated with red blood cell transfusion (RBCT) during admission was performed, alongside determination of the association between RBCT and hip fracture outcomes. Results. A total of 23,266 individual patient records from 18 hospitals were included. The overall rate of blood transfusion during admission was 28.7% (n = 6,685). There was inter-hospital variation in transfusion rate, ranging from 16.6% to 37.4%. Independent perioperative factors significantly associated with RBCT included older age (90 to 94 years, odds ratio (OR) 3.04 (95% confidence interval (CI) 2.28 to 4.04); p < 0.001), intramedullary fixation (OR 7.15 (95% CI 6.50 to 7.86); p < 0.001), and sliding hip screw constructs (OR 2.34 (95% CI 2.19 to 2.50); p < 0.001). Blood transfusion during admission was significantly associated with higher rates of 30-day mortality (OR 1.35 (95% CI 1.19 to 1.53); p < 0.001) and 60-day mortality (OR 1.54 (95% CI 1.43 to 1.67); p < 0.001), as well as delays to postoperative mobilization, higher likelihood of not returning to their home, and longer length of stay. Conclusion. Blood transfusion after hip fracture was common, although practice varied nationally. RBCT is associated with adverse outcomes, which is most likely a reflection of perioperative anaemia, rather than any causal effect. Use of RBCT does not appear to reverse this effect, highlighting the importance of perioperative blood loss reduction. Cite this article: Bone Joint J 2022;104-B(11):1266–1272

Stored red blood cells (RBCs) undergo a variety of changes that impair their post-transfusion viability, but the detrimental effect of such lesion at the clinical level is a matter of debate (1) and there is no data about the incidence of postoperative infection, a complication frequently associated with transfusion of stored RBCs (2). We reviewed 9906 patients who underwent a primary or revision arthroplasty between January 2000 and December 2012. Of these, 1153 (11.6%) received transfusion during surgery or within the first 6h after surgery (early transfusion, ET) and 920 (9.3%) received transfusion only between 24 and 96 hours after surgery (late transfusion, LT). Primary end-point was prosthetic joint infection (PJI) within the first year. Demographics, joint, type of surgery, duration of surgery, number and length of storage of transfused RBCs were collected. Ethical Committee approved the study. The median age was 74.9 (IQR:68.3–80.1) years and 1546 (74.6%) were female. There were 914 (44.1%) hip and 1117 (53.9%) knee arthroplasties and 428 (20.6%) were revision surgeries. The median duration of surgery was 105 (IQR:80–145) minutes. A total of 100 (4.8%) patients had a PJI. Figure 1 shows the PJI rate according to the number of RBC units transfused and the proportion of such units that had been stored for more than 14 days, both in the ET-group (Fig. 1A) and the LT-group (Fig. 1B). In the ET-group, the fact that >50% of transfused RBCs had been stored >14 days was an independent predictor of PJI (OR:2.50, 95%CI:1.44–4.33, Hosmer-Lemeshow test P=0.972). Stored RBC occlude the microcirculation (1), thereby precluding a good oxygenation of the surgical wound and the arrival of leukocytes and prophylactic antibiotics. Both factors are involved in the progression from wound bacterial contamination to wound infection and are particularly operative in the few hours following surgery (5). It is biologically plausible that transfusion of old RBC in this early, critical period results in more wound infections as compared to RBCs transfused later

This was an international single blind phase-III study of patients undergoing orthopaedic surgery to assess the efficacy and safety of HBOC-201. Patients who were expected to require two or more units of red blood cells (RBC) were randomised to HBOC-201 or RBC. Efficacy was defined as the proportion of patients in the HBOC-201 group who did not receive RBC. The HBOC-201 group comprised 350 patients and the RBC group 338. At randomisation, mean haemoglobin levels were similar (~9 g/dl) in the two groups (p =0.760). In the HBOC-201 group, transfusion was avoided in 337 patients (96.3%) on day one, 246 patients (70.3%) through day seven, and 208 patients (59.4%) through day 42. Fewer units of allogeneic red cell units were administered in the HBOC-201 group than in the RBC group, namely 1.4 units v 3.1 units (p < 0.001). Adverse events in the HBOC-201 group were transient and mild in intensity and did not result in discontinuation of HBOC-201. There was no significant difference in mortality between the groups (p.=0.450). The efficacy of HBOC-201 was demonstrated by the avoidance of allogeneic RBC in about 60% of patients receiving this oxygen-carrying solution over a six-week period. HBOC-201 was well tolerated and appears to be a feasible alternative to RBC

Aims

Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion.

Objectives. The objective of this study was to investigate the therapeutic effect of peripheral blood mononuclear cells (PBMNCs) treated with quality and quantity control culture (QQ-culture) to expand and fortify angiogenic cells on the acceleration of fracture healing. Methods. Human PBMNCs were cultured for seven days with the QQ-culture method using a serum-free medium containing five specific cytokines and growth factors. The QQ-cultured PBMNCs (QQMNCs) obtained were counted and characterised by flow cytometry and real-time polymerase chain reaction (RT-PCR). Angiogenic and osteo-inductive potentials were evaluated using tube formation assays and co-culture with mesenchymal stem cells with osteo-inductive medium in vitro. In order to evaluate the therapeutic potential of QQMNCs, cells were transplanted into an immunodeficient rat femur nonunion model. The rats were randomised into three groups: control; PBMNCs; and QQMNCs. The fracture healing was evaluated radiographically and histologically. Results. The total number of PBMNCs was decreased after QQ-culture, however, the number of CD34+ and CD206+ cells were found to have increased as assessed by flow cytometry analysis. In addition, gene expression of angiogenic factors was upregulated in QQMNCs. In the animal model, the rate of bone union was higher in the QQMNC group than in the other groups. Radiographic scores and bone volume were significantly associated with the enhancement of angiogenesis in the QQMNC group. Conclusion. We have demonstrated that QQMNCs have superior potential to accelerate fracture healing compared with PBMNCs. The QQMNCs could be a promising option for fracture nonunion. Cite this article: K. Mifuji, M. Ishikawa, N. Kamei, R. Tanaka, K. Arita, H. Mizuno, T. Asahara, N. Adachi, M. Ochi. Angiogenic conditioning of peripheral blood mononuclear cells promotes fracture healing. Bone Joint Res 2017;6: 489–498. DOI: 10.1302/2046-3758.68.BJR-2016-0338.R1

Introduction: The existence of circulating skeletal stem cells in the peripheral blood from different species including adult mouse and human has been found and documented. The circulating skeletal stem cells may provide a new source of stem cells that may be used for bone regeneration and tissue engineering applications. The aim of this study was to investigate the existence of circulating osteogenic stem cells in the rat peripheral blood, and to compare their osteogenic potentials with bone marrow mesenchymal stem cells (BMMSCs). Methods: Whole blood from twelve female 3-month old SD rats was harvested by cardiac puncture and bone marrows were also collected. Mononuclear cells from both bone marrow and peripheral blood (PBMNCs) were isolated by Lymphoprep density gradient centrifugation method, and plated at a density of 300000 to 400000/cm2 in flasks with á-MEM medium and 15% FCS. The colony forming efficiency (CFE) was calculated after 10–14 days culture. The osteogenic, adipogenic, and chondrogenic differentiation potential of both BMMSCs and peripheral blood mononuclear cell subset were examined and compared under different specific culture conditions. In addition, both BMMSCs and peripheral blood mononuclear cell subset were seeded into absorbable porous calcium phosphate substitute and implanted subcutaneously into SCID mice for 12 weeks, and the implants were examined histologically. Results: After 10–14 days in culture, the adherent fibroblast-like colonies were formed in the PBMNCs, with CFE ranging from 1.3 to 3.5 per 10000000 cells. Under osteogenic conditions, both BMMSCs and PBMNCs subset were positive for bone markers such as ALP, type I collagen and osteocalcin; bone nodules were formed in BMMSCs and PBMNCs subset long-term culture with positive Von Kossa and Alizarin Red S staining. Under adipogenic conditions, PBMNCs subset and BMMSCs were positive for Oil Red O and C/EBP á immunostaining. For chondrogenic differentiation studies, PBMNCs subset and BMMSCs were positive for type II collagen and they had Alcian blue positive nodules formation. After implantation with calcium phosphate substitutes in SCID mice for 12 weeks, osteoid and bony tissues were evident in the implants both loaded with PBMNCs subset and BMSCSs. Conclusions: A subset of mononuclear cells that have multi-differentiation potential similar to BMMSCs exists in the rat peripheral blood. Our present study has shown that these circulating stem cells possess osteogenic potential in vitro and in vivo. Further work is ongoing to investigate the roles of PBMNCs subset in fracture healing and their recruiting and homing mechanisms

Aims. The diagnosis of periprosthetic joint infection (PJI) can be challenging as the symptoms are similar to other conditions, and the markers used for diagnosis have limited sensitivity and specificity. Recent research has suggested using blood cell ratios, such as platelet-to-volume ratio (PVR) and platelet-to-lymphocyte ratio (PLR), to improve diagnostic accuracy. The aim of the study was to further validate the effectiveness of PVR and PLR in diagnosing PJI. Methods. A retrospective review was conducted to assess the accuracy of different marker combinations for diagnosing chronic PJI. A total of 573 patients were included in the study, of which 124 knees and 122 hips had a diagnosis of chronic PJI. Complete blood count and synovial fluid analysis were collected. Recently published blood cell ratio cut-off points were applied to receiver operating characteristic curves for all markers and combinations. The area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values were calculated. Results. The results of the analysis showed that the combination of ESR, CRP, synovial white blood cell count (Syn. WBC), and polymorphonuclear neutrophil percentage (PMN%) with PVR had the highest AUC of 0.99 for knees, with sensitivity of 97.73% and specificity of 100%. Similarly, for hips, this combination had an AUC of 0.98, sensitivity of 96.15%, and specificity of 100.00%. Conclusion. This study supports the use of PVR calculated from readily available complete blood counts, combined with established markers, to improve the accuracy in diagnosing chronic PJI in both total hip and knee arthroplasties. Cite this article: Bone Jt Open 2023;4(11):881–888

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

This edition of Cochrane Corner looks at some of the work published by the Cochrane Collaboration, covering pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic, and long bone fractures; interventions for reducing red blood cell transfusion in adults undergoing hip fracture surgery: an overview of systematic reviews; and pharmacological treatments for low back pain in adults: an overview of Cochrane Reviews

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

Aims. The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI. Methods. Periprosthetic femoral trabecular bone specimens were obtained from patients suffering from chronic PJI of the hip and knee (n = 20). Microbiological analysis was performed on preoperative joint aspirates and tissue specimens obtained during revision surgery. Microstructural and cellular bone parameters were analyzed in bone specimens by histomorphometry on undecalcified sections complemented by tartrate-resistant acid phosphatase immunohistochemistry. Data were compared with control specimens obtained during primary arthroplasty (n = 20) and aseptic revision (n = 20). Results. PJI specimens exhibited a higher bone volume, thickened trabeculae, and increased osteoid parameters compared to both control groups, suggesting an accelerated bone turnover with sclerotic microstructure. On the cellular level, osteoblast and osteoclast parameters were markedly increased in the PJI cohort. Furthermore, a positive association between serum (CRP) but not synovial (white blood cell (WBC) count) inflammatory markers and osteoclast indices could be detected. Comparison between different pathogens revealed increased osteoclastic bone resorption parameters without a concomitant increase in osteoblasts in bone specimens from patients with Staphylococcus aureus infection, compared to those with detection of Staphylococcus epidermidis and Cutibacterium spp. Conclusion. This study provides insights into the local bone metabolism in chronic PJI, demonstrating osteosclerosis with high bone turnover. The fact that Staphylococcus aureus was associated with distinctly increased osteoclast indices strongly suggests early surgical treatment to prevent periprosthetic bone alterations. Cite this article: Bone Joint Res 2023;12(10):644–653

Aims. Implant-related postoperative spondylodiscitis (IPOS) is a severe complication in spine surgery and is associated with high morbidity and mortality. With growing knowledge in the field of periprosthetic joint infection (PJI), equivalent investigations towards the management of implant-related infections of the spine are indispensable. To our knowledge, this study provides the largest description of cases of IPOS to date. Methods. Patients treated for IPOS from January 2006 to December 2020 were included. Patient demographics, parameters upon admission and discharge, radiological imaging, and microbiological results were retrieved from medical records. CT and MRI were analyzed for epidural, paravertebral, and intervertebral abscess formation, vertebral destruction, and endplate involvement. Pathogens were identified by CT-guided or intraoperative biopsy, intraoperative tissue sampling, or implant sonication. Results. A total of 32 cases of IPOS with a mean patient age of 68.7 years (37.6 to 84.1) were included. Diabetes, age > 60 years, and history of infection were identified as risk factors. Patient presentation upon admission included a mean body temperature of 36.7°C (36.1 to 38.0), back pain at rest (mean visual analogue scale (VAS) mean 5/10) and when mobile (mean VAS 6/10), as well as elevated levels of CRP (mean 76.8 mg/l (0.4 to 202.9)) and white blood cell count (mean 9.2 units/nl (2.6 to 32.8)). Pathogens were identified by CT-guided or conventional biopsy, intraoperative tissue sampling, or sonication, and Gram-positive cocci presented as the most common among them. Antibiotic therapy was established in all cases with pathogen-specific treatment in 23 (71.9%) subjects. Overall 27 (84.4%) patients received treatment by debridement, decompression, and fusion of the affected segment. Conclusion. Cases of IPOS are rare and share similarities with spontaneous spondylodiscitis. While procedures such as CT-guided biopsy and sonication are valuable tools in the diagnosis of IPOS, MRI and intraoperative tissue sampling remain the gold standard. Research on known principles of PJI such as implant retention versus implant exchange need to be expanded to the field of spine surgery. Cite this article: Bone Jt Open 2023;4(11):832–838

The covid-19 pandemic had a great impact in the daily clinical and surgical practice. Concerning patients with a femoral neck fracture, there is the need of a negative Sars-CoV-2 test or an established isolation period for the positive cases, pre-operatively. The goal of this study was to evaluate the impact of the pandemic in the management of patients with femoral neck fractures, who were submitted to surgical treatment with hemiarthroplasty, in our hospital. A retrospective, observational study was performed, analysing the patients with femoral neck fractures submitted to hip hemiarthroplasty, during the years 2019 (before the pandemic) and 2020 (first year of the pandemic). We analysed the first 5 patients operated in each month of the mentioned years. We analysed 56 and 60 patients submitted to surgery in the years 2019 and 2020, respectively. The inpatient days were, in average, 14.1 and 13.1. Patients were operated, in average, 3.0 and 3.8 days after admission (corrected to 2.5 and 3.6 days if the time of discontinuation of anticoagulants or antiplatelets needed before surgery is deducted). There were peri-operative complications in 53.6% and 46.7% of the patients, in 2019 and 2020 respectively. The most common complication in both groups was a low postoperative haemoglobin level needing red blood cell transfusion. One-year postoperative mortality rate was 17.9% and 13.3%, respectively. Despite the changes triggered by the new pandemic, there was an overall maintenance of the quality of the management of these patients, with only a slight increase in the interval between admission and surgery. Some of the remaining variables even showed an improvement when comparing the two groups of patients. Nevertheless, it is important to mention that there were patients infected with Covid-19 who died before being submitted to surgery, therefore not being present in these statistics

High doses of intra-articular (IA) antibiotics has been shown to effectively achieve a minimal biofilm eradication concentration which could mitigate the need for removal of infected but well-ingrown cementless components of a total hip arthroplasty (THA). However, there are concerns that percutaneous catheters could lead to multi-resistance or multi-organism peri-prosthetic joint infections (PJI) following single stage THA revisions for PJI. Eighteen single-stage revision procedures were performed for acute (N=9) or chronic (N=9) PJI following a primary (N=12) or revision (N=6) cementless THA. Modular and loosened components were replaced. All well ingrown components were retained. Two Hickmann catheters were placed in the joint space. Along with intravenous antibiotics, IA antibiotics were injected twice a day for two weeks, followed by 3 months of oral antibiotics. Per-operative cultures demonstrated 4 multi-bacterial PJIs. None of the patients developed post-operatively an AB related renal or systemic dysfunction. At a mean follow-up of 38 months [range, 8–72] all patients had normal erythrocyte sedimentation rate and white blood cell count. Four had a slightly elevated C-reactive protein but were completely symptom free and did not show any sign of loosening at a mean of 27 months [range, 16–59]. Addition of high doses of IA antibiotics following single-stage revision for PJI in cementless THA, is an effective and safe treatment option that allows for retention of well-ingrown components. We found no evidence for residual implant infection or catheter induced multi-resistance. Total hip arthroplasty, revision surgery, Periprosthetic Joint Infection, Intra-articular antibiotics. Level 4 (Case series)

Aim. Diagnosing low-grade periprosthetic joint infections (PJI) can be very challenging due to low-virulent microorganisms capable of forming biofilm. Clinical signs can be subtle and may be similar to those of aseptic failure. To minimize morbidity and mortality and to preserve quality of life, accurate diagnosis is essential. The aim of this study was to assess the performance of various diagnostic tests in diagnosing low-grade PJI. Methods. Patients undergoing revision surgery after total hip and knee arthroplasty were included in this retrospective cohort study. A standardized diagnostic workup was performed using the components of the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI. For statistical analyses, the respective test was excluded from the infection definition to eliminate incorporation bias. Receiver-operating-characteristic curves were used to calculate the diagnostic performance of each test, and their area-under-the-curves (AUC) were compared using the z-test. Results. 422 patients undergoing revision surgery after total hip and knee arthroplasty were included in this study. 208 cases (49.3%) were diagnosed as septic. Of those, 60 infections (28.8%) were defined as low-grade PJI (symptoms >4 weeks and caused by low-virulent microorganisms (e. g. coagulase-negative staphylococci, Cutibacterium spp., enterococci and Actinomyces)). Performances of the different test methods are listed in Table 1. Synovial fluid (SF) - WBC (white blood cell count) >3000G/L (0.902), SF - %PMN (percentage of polymorphonuclear neutrophils) > 65% (0.959), histology (0.948), and frozen section (0.925) showed the best AUCs. Conclusion. The confirmatory criteria according to the EBJIS definition showed almost ideal performances in ruling-in PJI (>99% specificity). Histology and synovial fluid cell count (SF-WBC and SF-%PMN) showed excellent accuracies for diagnosing low-grade PJI. However, a reduced immune reaction in these cases may necessitate lower cut-off values. Intraoperative frozen section may be valuable in cases with inconclusive preoperative diagnosis. For any tables or figures, please contact the authors directly

Aim. As the number of performed total hip arthroplasties (THA) and total knee arthroplasties (TKA) has increased over the years, revision surgeries are expected to increase as well. Revision surgeries are associated with a longer operating room time, prolonged length of stay (LOS), and more frequent complications. Postoperative hematomas are a major reason for wound healing disturbances and periprosthetic joint infections (PJI). We aimed to systematically assess the use and safety of a microporous polysaccharide hemosphere (MPH) in revision THA and TKA. We focused on the risk reduction of further revision surgeries in case of wound healing disorders and hematoma, transfusion of packed red blood cells (PRBC), loss of hemoglobin (hb) and mean LOS following the use of MPH. Method. Our prospective study includes 89 patients who underwent revision surgery after THA and TKA with application of MPH and were compared to 102 patients who did not receive MPH and underwent revision surgery after THA and TKA. Five grams of MPH. 1. were applied periarticular before fascia closure and to the subcutaneous soft tissue. The follow-up was conducted in daily clinical visits during the inpatient stay and three months postoperatively in our outpatient clinic. Repeated revision surgery was performed in case of prolonged secretion (>10 days) or clinical suspicion of infection. After matching the cohorts the outcomes were statistically analyzed using paired methods. Results. A significantly lower odds ratio for repeat revisions was found for the MPH cohort (OR=0.312; 95%-CI 0.090, 0.893; p=0.027). Differences between pre- and postoperative hb levels, LOS and transfusions of PRBC did not reach significance. No intra- or postoperative complications to MPH occurred. Moreover, no infection relapse occurred after applying MPH. Conclusions. Routine use of MPH in revision arthroplasty management after TKA and THA appears to be safe and an effective way to support hemostasis, with no observed adverse events related to MPH use. There were noticeably less hematomas and revision surgeries in the MPH group. 1. Arista BD, Franklin Lakes, NJ, USA