Epidemiology of surgical site infections after total hip and knee joint replacement during 2007-2009: a report from the VINCat Program

Analysis of the incidence and risk factors of blood transfusion in total knee revision: a retrospective nationwide inpatient sample database study

OBJECTIVE

This study sought to determine the incidence and risk factors of blood transfusion among patients undergoing total knee revision (TKR) using a nationwide database.

METHODS

A retrospective data analysis was conducted based on the Nationwide Inpatient Sample (NIS), enrolling patients who underwent TKR from 2010 to 2019 with complete information. The patients were divided into two groups based on whether they received blood transfusion or not. The demographic characteristics (race, sex, and age), length of stay (LOS), total charge of hospitalization, hospital characteristics (admission type, insurance type, bed size, teaching status, location, and region of hospital), hospital mortality, comorbidities, and perioperative complications were analyzed. Finally, we conducted univariate and multivariate logistic regression to identify factors that were associated with TKR patients to require blood transfusion.

RESULTS

The NIS database included 115,072 patients who underwent TKR. Among them, 14,899 patients received blood transfusion, and the incidence of blood transfusion was 13.0%. There was a dramatic decrease in the incidence over the years from 2010 to 2019, dropping from 20.4 to 6.5%. TKR patients requiring transfusions had experienced longer LOS, incurred higher total medical expenses, utilized Medicare more frequently, and had increased in-hospital mortality rates (all P < 0.001). Independent predictors for blood transfusion included advanced age, female gender, iron-deficiency anemia, rheumatoid disease, chronic blood loss anemia, congestive heart failure, coagulopathy, uncomplicated diabetes, lymphoma, fluid and electrolyte disorders, metastatic carcinoma, other neurological diseases, paralysis, peripheral vascular disorders, pulmonary circulation disorders, renal failure, valvular disease, and weight loss. In addition, risk factors for transfusion in TKR surgery included sepsis, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, gastrointestinal bleeding, heart failure, renal insufficiency, pneumonia, wound infection, lower limb nerve injury, hemorrhage/seroma/hematoma, wound rupture/non healing, urinary tract infection, acute renal failure, and postoperative delirium.

CONCLUSIONS

Our findings highlight the importance of recognizing the risk factors of blood transfusion in TKR to reduce the occurrence of adverse events.

Examining the Efficacy of Drain Tip Cultures in Predicting Postoperative Surgical Site Infections in Hip Arthroplasty: A 15-Year Retrospective Study

Background Postoperative surgical site infections (SSIs) are a significant complication of surgical procedures, leading to increased morbidity, prolonged hospital stays, and substantial healthcare costs; however, the use of drain tip cultures to diagnose SSIs in patients is controversial. The objective of this study was to evaluate the efficacy of drain tip cultures for the prediction of postoperative SSIs in patients recovering from hip arthroplasty. Methodology The data were collected from 1204 patients who underwent hip arthroplasty procedures over 15 years, and statistical analysis was performed to evaluate the diagnostic value of drain tip culture in determining surgical site infection. We also used these data to evaluate whether preexisting conditions such as hypertension or diabetes affected the probability of a patient getting an SSI. Results Drain tip cultures were positive in 12 of 1,112 cases of primary hip arthroplasty, but only one of these 12 patients was ultimately diagnosed with an SSI (sensitivity, 12.5%; specificity, 99.0%; p = 0.0834). Results from postoperative drain tip cultures performed in patients undergoing revision arthroplasty included two false positives and three false negatives; interestingly, no true positives were detected in any of the revision arthroplasty cases we evaluated (sensitivity, 0％; specificity, 97.8％; p = 0.9355). Conclusion Our results indicate that drain tip cultures have no statistically significant predictive value for the diagnosis of postoperative SSIs and thus should not be used as a primary diagnostic or predictive tool for SSIs. We recommend exploring other diagnostic tools for the postoperative diagnosis of SSIs. Standardized guidelines should therefore be established to improve the predictive value of the different methods.

Risk factors for periprosthetic joint infection after total knee arthroplasty

INTRODUCTION

Periprosthetic joint infection (PJI) is the most serious and feared complication in total knee arthroplasty (TKA) and can have catastrophic consequences. The number of total knee arthroplasties is increasing, so infections could also be greater in the future. The aim of this study is to identify the most relevant risk factors associated with infection after a total knee arthroplasty.

METHODS

This is a case-control study of patients who underwent total knee arthroplasty at the University Hospital of Salamanca. We included 66 TKA PJI patients and 66 control TKA patients. Demographic and clinical variables were collected. A descriptive and inferential analysis was performed by logistic regression and attributable risk fraction assessed.

RESULTS

Prolonged operative time (> 90') and tourniquet time (> 60') were the most relevant risk factors described (OR 40.77, AFE 0.97, p > 0.001 and OR 37.14, AFE 0.97, p < 0.001, respectively). The use of non-antibiotic-laded cement (OR 3.62), obesity (BMI > 30, OR 8.86), diabetes (OR 2.33), high ASA grade (III-IV, OR 15.30), and blood transfusion requirement (OR 4.60) were also statistically significant risk factors for TKA PJI.

CONCLUSIONS

Our study provides evidence concerning that operative time, tourniquet time, cement type, diabetes, obesity, ASA grade, and blood transfusion requirement as independently associated risk factors for TKA PJI. Modifiable risk factors were specifically relevant, so we should be able to reduce the infection rate.

Experimental study of the application of a new bone cement loaded with broad spectrum antibiotics for the treatment of bone infection

OBJECTIVES

To evaluate the in vivo behaviour of a new bone cement loaded with antibiotics, in a rabbit bone infection model.

MATERIAL AND METHODS

Sixteen New Zealand rabbits divided into 4 groups were used, depending on the cement (commercial or experimental) and the antibiotic (vancomycin or linezolid) used to control a bone infection caused by Staphylococcus aureus. The commercial cement is Palacos^® R and the experimental cement has been achieved by adding PLGA to the solid phase of Palacos^® R cement. A novel histological staging method based on bone histoarchitecture has been used. This staging allows us a global vision of bone repair capacity, in the presence of modified cement, and also allows us to correlate the damage generated with the functionality of the tissue.

RESULTS

The degree of bone destructuration found depended on the type of cement and antibiotic, and was higher in the groups with commercial cement than in the experimental group (P<.01) and in the groups with linezolid with respect to vancomycin (P=.04) The percentage of macrophages varied exclusively depending on the antibiotic used, and was higher in the vancomycin groups (P=.04).

DISCUSSION

The development of new formulations of bone cement that release more, and more prolonged, new generation antibiotics such as linezolid, present an in vivo behaviour superior to commercial cement, respecting the bone structure. This behaviour would have a clinical implication in fighting infections by increasingly resistant germs in the treatment of prosthetic infection.

Risk of Contamination in Assembled vs Disassembled Instruments in Hip Arthroplasty Surgery

BACKGROUND

Periprosthetic joint infection (PJI) is one of the most common causes of revision total hip arthroplasty (THA) and associated with higher costs, prolonged pain, and worse clinical outcomes. Many factors have been linked to increased infection rates, one being the operative equipment and instrumentation used during the surgical procedure. With few arthroplasty instruments designed for complete disassembly and increasingly complex instrument designs, this study seeks to understand the effect that instrument disassembly plays on infection using disassembled and assembled standard femoral broach handles (BHs).

METHODS

Two BHs, not designed for disassembly, were modified and then contaminated in the disassembled state with Geobacillus stearothermophilus vegetative-form bacteria and spores. Using both flash and standard sterilization cycles, the BHs were steam sterilized in the disassembled or assembled state and then analyzed for remaining bacteria and spores.

RESULTS

At all target locations after either a flash sterilization cycle or a standard sterilization cycle, complete eradication of both the vegetative-form and spore-form of G stearothermophilus was achieved.

CONCLUSION

This study demonstrates that adequate decontamination of the tested BHs can be achieved after steam sterilization in either the disassembled or assembled state, without an increased risk of infection transmission.

[Validation of the structure and resources of nosocomial infection control team in hospitals ascribed to VINCat program in Catalonia, Spain]

The main objective of this study was to validate the structure of the infection control team (ICT) in the hospitals adhered to VINCat program and secondary objective was to establish the consistency of resources of each center with the requirements established by the program. Qualitative research consisting of an ethnographic study using participant observation during the years 2008-2010. The centers were stratified in three groups by complexity and beds. The instrument was a semistructured interview to members of the ICT. The transcription of the interview was sent to informants for validation. In November 2010 a questionnaire regarding human resources and number hours dedicated to the ICT was sent. During 2008-2010, 65 centers had been adhered to VINCat program. In 2010, the ICT of Group I hospitals had a mean of two physician, one in full-time and one nurse for every 230 beds. In Group II, one physician part-time and one nurse per 180 beds and in Group III a physician and a nurse for every 98 beds, both part-time. In 2010, all hospitals had a structured ICT, an operative infection committee, and a hospital member representing the center at the program as well as enough electronic resources. The hospitals participating in the program have now VINCat an adequate surveillance structure and meet the minimum technical and human resources required to provide high-quality data. However human resources are not guaranteed.

A systematic review of the evidence for single stage and two stage revision of infected knee replacement

BACKGROUND

Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates.

METHODS

A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded.

RESULTS

63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies.

CONCLUSIONS

Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority.