Aims. The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA). Methods. In this retrospective cohort study, 147 consecutive patients with acute or chronic complaints following THA and TKA were included. Diagnosis of PJI was established based on the 2018 International Consensus Meeting criteria. A total of 39 patients diagnosed with PJI (32 chronic and seven acute) and 108 patients with aseptic complications were surgically revised. Results. Using receiver operating characteristic curves and calculating the area under the curve (AUC), an optimal synovial cut-off value of 2,000 PMN/µl was determined (AUC 0.978 (95% confidence interval (CI) 0.946 to 1)). Using this cut-off, sensitivity and specificity of absolute synovial PMN count for PJI were 97.4% (95% CI 91.2 to 100) and 93.5% (95% CI 88.9 to 98.1), respectively. Positive and negative predictive value were 84.4% (95% CI 72.7 to 93.9) and 99.0% (95% CI 96.7 to 100), respectively. Exclusion of 20 patients with acute complications improved specificity to 97.9% (95% CI 94.6 to 100). Different cut-off values for THA (< 3,600 PMN/µl) and TKA (< 2,000 PMN/µl) were identified. Absolute synovial PMN count correlated strongly with synovial alpha-defensin (AD) (r = 0.759; p < 0.001). With a positive AD result, no additional PJI could be identified in any case. Conclusion. Absolute synovial PMN count is a widely available, rapid, cost-effective, and accurate marker in PJI diagnostics, whereas synovial AD appears to be a surrogate parameter of absolute synovial PMN count. Despite limitations in the early postoperative phase, wear, and rheumatic diseases in confirming PJI, an absolute synovial PMN count below 2,000/µl is highly suitable for ruling out PJI, with specific cut-off values for THA and TKA. Cite this article: Bone Joint J 2023;105-B(4):373–381

Aims. We aim to evaluate the usefulness of postoperative blood tests by investigating the incidence of abnormal results following total joint replacement (TJR), as well as identifying preoperative risk factors for abnormal blood test results postoperatively, especially pertaining to anaemia and acute kidney injury (AKI). Methods. This is a retrospective cohort study of patients who had elective TJR between January and December 2019 at a tertiary centre. Data gathered included age at time of surgery, sex, BMI, American Society of Anesthesiologists (ASA) grade, preoperative and postoperative laboratory test results, haemoglobin (Hgb), white blood count (WBC), haematocrit (Hct), platelets (Plts), sodium (Na. +. ), potassium (K. +. ), creatinine (Cr), estimated glomerular filtration rate (eGFR), and Ferritin (ug/l). Abnormal blood tests, AKI, electrolyte imbalance, anaemia, transfusion, reoperation, and readmission within one year were reported. Results. The study included 2,721 patients with a mean age of 69 years, of whom 1,266 (46.6%) were male. Abnormal postoperative bloods were identified in 444 (16.3%) patients. We identified age (≥ 65 years), female sex, and ASA grade ≥ III as risk factors for developing abnormal postoperative blood tests. Preoperative haemoglobin (≤ 127 g/dl) and packed cell volume (≤ 0.395 l/l) were noted to be significant risk factors for postoperative anaemia, and potassium (≤ 3.7 mmol/l) was noted to be a significant risk factor for AKI. Conclusion. The costs outweigh the benefits of ordering routine postoperative blood tests in TJR patients. Clinicians should risk-stratify their patients and have a lower threshold for ordering blood tests in patients with abnormal preoperative haemoglobin (≤ 127 g/l), blood loss > 300 ml, chronic kidney disease, ASA grade ≥ III, and clinical concern. Cite this article: Bone Jt Open 2023;4(11):899–905

Aims. To investigate whether chronic kidney disease (CKD) is associated with the risk of all-cause revision or revision due to a periprosthetic joint infection (PJI) after primary hip or knee arthroplasty. Methods. This retrospective cohort study comprised 18,979 consecutive hip and knee arthroplasties from a single high-volume academic hospital. At a median of 5.6 years (interquartile range (IQR) 3.5 to 8.1), all deaths and revisions were counted. To overcome the competing risk of death, competing risk analysis using the cumulative incidence function (CIF) was applied to analyze the association between different stages of CKD and revisions. Confounding factors such as diabetes and BMI were considered using either a stratified CIF or the Fine and Gray model. Results. There were 2,111 deaths (11.1%) and 677 revisions (3.6%) during the follow-up period. PJI was the reason for revision in 162 cases (0.9%). For hip arthroplasty, 3.5% of patients with CKD stage 1 (i.e. normal kidney function, NKF), 3.8% with CKD stage 2, 4.2% with CKD stage 3, and 0% with CKD stage 4 to 5 had undergone revision within eight years. For knee arthroplasty, 4.7% with NKF, 2.7% with CKD stage 2, 2.4% with CKD stage 3, and 7% of CKD stage 4 to 5 had had undergone revision. With the exception of knee arthroplasty patients in whom normal kidney function was associated with a greater probability of all-cause revision, there were no major differences in the rates of all-cause revisions or revisions due to PJIs between different CKD stages. The results remained unchanged when diabetes and BMI were considered. Conclusion. We found no strong evidence that CKD was associated with an increased risk of all-cause or PJI-related revision. Selection bias probably explains the increased amount of all-cause revision operations in knee arthroplasty patients with normal kidney function. The effect of stage 4 to 5 CKD was difficult to evaluate because of the small number of patients. Cite this article: Bone Joint J 2021;103-B(4):689–695

Aims. As the first wave of the COVID-19 pandemic began to dip, restarting elective orthopaedics became a challenge. Protocols including surgery at ‘green’ sites, self-isolation for 14 days, and COVID-19 testing were developed to minimize the risk of transmission. In this study, we look at risk effects of 14-day self-isolation on the incidence of venous thromboembolism (VTE) in our green site hospital among patients undergoing total joint replacement (TJR). Methods. This retrospective cohort study included 50 patients who underwent TJR. Basic demographic data was collected including, age, sex, American Society of Anesthesiologists (ASA) grade, body mass index (BMI), type of surgery, and complications at two and four weeks. Univariate and multivariate analysis were used to identify risk factors associated with an increased risk of VTE. Results. A total of 50 patients were included in our study, with 24 males and 26 females. The mean age was 67.86 (SD 11.803). Overall, 8% of patients suffered a VTE complication; symptomatic non-fatal pulmoary embolism was confirmed in 6% of patients (n = 3) as an inpatient, and symptomatic deep vein thrombosis was diagnosed in 2% of patients (n = 1) within two weeks of their operation. All patients were found to be female (p < 0.001), had a BMI > 30 (p = 0.317), and were immobile prior to their operation using walking aids (p = 0.016). Conclusion. The incidence we report is much higher than the reported incidence in the literature, which we believe is related to the 14-day self-isolation period and immobility prior to their operation. We recommend that all patients undergoing TJR that require a period of self-isolation, are pre-assessed prior to self-isolation for their risk of VTE, potentially using mechanical and chemical prophylaxis to reduce the likelihood of developing VTE. Cite this article: Bone Jt Open 2020;1-12:751–756

Aims. The success rates of two-stage revision arthroplasty for infection have evolved since their early description. The implementation of internationally accepted outcome criteria led to the readjustment of such rates. However, patients who do not undergo reimplantation are usually set aside from these calculations. The aim of this study was to investigate the outcomes of two-stage revision arthroplasty when considering those who do not undergo reimplantation, and to investigate the characteristics of this subgroup. Methods. A retrospective cohort study was conducted. Patients with chronic hip or knee periprosthetic joint infection (PJI) treated with two-stage revision between January 2010 and October 2018, with a minimum follow-up of one year, were included. Variables including demography, morbidity, microbiology, and outcome were collected. The primary endpoint was the eradication of infection. Patients who did not undergo reimplantation were analyzed in order to characterize this subgroup better. Results. A total of 162 chronic PJIs were included in the study. After a mean follow-up of 57.3 months (12.1 to 115.7), 18 patients (11.1%) did not undergo reimplantation, due either to medical issues (10), the patient’s choice (4), or death (4). When only considering those who underwent reimplantation, the success rate was 80.6%. However, when those who did not undergo reimplantation were included, the success rate dropped to 71.6%. Advanced age, American Society of Anesthesiologists grade ≥ III, McPherson’s C host, and Gram-negative related PJI were independent risk factors for retention of the spacer. The mortality was higher in the non-reimplanted group. Conclusion. The real success rate of two-stage revision may not be as high as previously reported. The exclusion of patients who do not undergo reimplantation resulted in a 9% overestimation of the success rate in this series. Many comorbidity-related risk factors for retention of the spacer were identified, as well as higher death rates in this group. Efforts should be made to optimize these patients medically in order to increase reimplantation and success rates, while decreasing mortality. Cite this article: Bone Joint J 2020;102-B(12):1682–1688

Aims. Positive cultures are not uncommon in cases of revision total knee and hip arthroplasty (TKA and THA) for presumed aseptic causes. The purpose of this study was to assess the incidence of positive intra-operative cultures in presumed aseptic revision of TKA and THA, and to determine whether the presence of intra-operative positive cultures results in inferior survival in such cases. Patients and Methods. A retrospective cohort study was assembled with 679 patients undergoing revision knee (340 cases) or hip arthroplasty (339 cases) for presumed aseptic causes. For all patients three or more separate intra-operative cultures were obtained. Patients were diagnosed with a previously unsuspected prosthetic joint infection (PJI) if two or more cultures were positive with the same organism. Records were reviewed for demographic details, pre-operative laboratory results and culture results. The primary outcome measure was infection-free implant survival at two years. Results. The incidence of unsuspected PJI was 27 out of 340 (7.9%) in TKA and 41 out of 339 (12.1%) in THA. Following revision TKA, the rate of infection-free implant survival in patients with an unsuspected PJI was 88% (95% confidence intervals (CI) 60 to 97) at two years compared with 98% (95% CI 94 to 99) in patients without PJI (p = 0.001). After THA, the rate of survival was similar in those with unsuspected PJI (92% (95% CI 73 to 98) at two years) and those without (94% (95% CI 89 to 97), p = 0.31). Conclusion. Following revision of TKA and THA for aseptic diagnoses, around 10% of cases were found to have positive cultures. In the knee, such cases had inferior infection-free survival at two years compared with those with negative cultures; there was no difference between the groups following THA. Cite this article: Bone Joint J 2017;99-B:1482–9

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The present study aimed to investigate whether patients with inflammatory bowel disease (IBD) undergoing joint arthroplasty have a higher incidence of adverse outcomes than those without IBD.

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Our aim was to estimate the total costs of all hospitalizations for treating periprosthetic joint infection (PJI) by main management strategy within 24 months post-diagnosis using activity-based costing. Additionally, we investigated the influence of individual PJI treatment pathways on hospital costs within the first 24 months.

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A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients.

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This study aimed to evaluate whether an enhanced recovery protocol (ERP) for arthroplasty established during the COVID-19 pandemic at a safety net hospital can be associated with a decrease in hospital length of stay (LOS) and an increase in same-day discharges (SDDs) without increasing acute adverse events.

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While preoperative bloodwork is routinely ordered, its value in determining which patients are at risk of postoperative readmission following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is unclear. The objective of this study was to determine which routinely ordered preoperative blood markers have the strongest association with acute hospital readmission for patients undergoing elective TKA and THA.

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Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI.

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Periprosthetic fracture is a significant complication of total hip and knee arthroplasty. This study aimed to describe the survival of patients sustaining periprosthetic femoral fractures and compare this with that of the general population, as well as to identify the factors that influence survival.

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To investigate the outcomes of treatment of streptococcal periprosthetic joint infection (PJI) involving total knee and hip arthroplasties.