Noam Shohat

Prevention of periprosthetic joint infection: new guidelines

The World Health Organization (WHO) and the Centre for Disease Control and Prevention (CDC) recently published guidelines for the prevention of surgical site infection. The WHO guidelines, if implemented worldwide, could have an immense impact on our practices and those of the CDC have implications for healthcare policy in the United States. Our aim was to review the strategies for prevention of periprosthetic joint infection in light of these and other recent guidelines. Cite this article: Bone Joint J 2017;99-B(4 Supple B):3-10.

Prevention of Periprosthetic Joint Infection: Examining the Recent Guidelines

BACKGROUND The global rise in infectious disease has led the Center for Disease Control and Prevention and the World Health Organization to release new guidelines for the prevention of surgical site infection. METHODS In this article, we summarize current recommendations based on level of evidence, review unresolved and unaddressed issues, and supplement them with new literature. RESULTS Although the guidelines discuss major issues in reducing surgical site infection, many questions remain unanswered. CONCLUSION These guidelines will hopefully help in setting a standard of care based on best evidence available and focus investigators on areas where evidence is lacking.

The Long-term Outcome After Varus Derotational Osteotomy for Legg-calvé-perthes Disease: A Mean Follow-up of 42 Years

BACKGROUND Varus derotational osteotomy (VDRO) is one of the most common surgical treatments for Legg-Calvé-Perthes disease, yet its long-term results have not been fully assessed. We aimed to determine the long-term clinical and radiographic outcomes following VDRO. METHODS Forty patients (43 hips) who underwent VDRO for Legg-Calvé-Perthes disease at our institution from 1959 to 1983, and participated in a follow-up study completed 10 years earlier, were approached for the present study. Clinical examination and radiographs were evaluated. Hip status and well-being were assessed with the Harris hip score and the Short Form-36 (SF-36). RESULTS Thirty-five patients (37 hips) participated in the study. Information regarding the need for an arthroplasty was gathered on 4 additional hips from the previous study. The mean follow-up was 42.5 years (range, 32.4 to 56.5 years), with a mean patient age of 50.2 years (range, 35.9 to 67.8 years). In total, 7 patients (7 hips; 17% of 41 hips for which information was available, including 1 hip from the original cohort of 40 patients [43 hips]), underwent a total hip arthroplasty for hip pain. Excluding patients who had undergone an arthroplasty, the mean Harris hip and SF-36 scores were 79.8 points (range, 23.1 to 100 points) and 74.8 (range, 15.1 to 100), respectively. Twenty (64.5%) of the 31 hips that had not been replaced achieved a good or excellent Harris hip score (≥80 points). Sixteen (57.1%) of 28 hips with follow-up radiographs had no, or minimal, signs of osteoarthritis. The Stulberg classification was associated with the Harris hip score, the SF-36 score, hip pain, a Trendelenburg sign, coxa magna, and the Tönnis grade. In a multivariate analysis, the Stulberg classification was the only factor associated with fair or poor outcomes (a Harris hip score of <80 points). Patients with a Stulberg class-III or IV hip had significant deterioration with respect to the Harris hip score and Tönnis grade during the 10-year period since the last follow-up. CONCLUSIONS A long-term follow-up of patients who were operatively treated for Legg-Calvé-Perthes disease revealed that a low proportion underwent total hip arthroplasty and a relatively high proportion maintained good clinical and radiographic outcomes. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Environment of care: Is it time to reassess microbial contamination of the operating room air as a risk factor for surgical site infection in total joint arthroplasty?

&NA; In the modern operating room (OR), traditional surgical mask, frequent air exchanges, and architectural barriers are viewed as effective in reducing airborne microbial populations. Intraoperative sampling of airborne particulates is rarely performed in the OR because of technical difficulties associated with sampling methodologies and a common belief that airborne contamination is infrequently associated with surgical site infections (SSIs). Recent studies suggest that viable airborne particulates are readily disseminated throughout the OR, placing patients at risk for postoperative SSI. In 2017, virtually all surgical disciplines are engaged in the implantation of selective biomedical devices, and these implants have been documented to be at high risk for intraoperative contamination. Approximately 1.2 million arthroplasties are performed annually in the United States, and that number is expected to increase to 3.8 million by the year 2030. The incidence of periprosthetic joint infection is perceived to be low (<2.5%); however, the personal and fiscal morbidity is significant. Although the pharmaceutic and computer industries enforce stringent air quality standards on their manufacturing processes, there is currently no U.S. standard for acceptable air quality within the OR environment. This review documents the contribution of air contamination to the etiology of periprosthetic joint infection, and evidence for selective innovative strategies to reduce the risk of intraoperative microbial aerosols.

Can next generation sequencing play a role in detecting pathogens in synovial fluid

Aims The diagnosis of periprosthetic joint infection can be difficult due to the high rate of culturenegative infections. The aim of this study was to assess the use of next‐generation sequencing for detecting organisms in synovial fluid. Materials and Methods In this prospective, single‐blinded study, 86 anonymized samples of synovial fluid were obtained from patients undergoing aspiration of the hip or knee as part of the investigation of a periprosthetic infection. A panel of synovial fluid tests, including levels of C‐reactive protein, human neutrophil elastase, total neutrophil count, alpha‐defensin, and culture were performed prior to next‐generation sequencing. Results Of these 86 samples, 30 were alpha‐defensin‐positive and culture‐positive (Group I), 24 were alpha‐defensin‐positive and culture‐negative (Group II) and 32 were alpha‐defensin‐negative and culture‐negative (Group III). Next‐generation sequencing was concordant with 25 results for Group I. In four of these, it detected antibiotic resistant bacteria whereas culture did not. In another four samples with relatively low levels of inflammatory biomarkers, culture was positive but next‐generation sequencing was negative. A total of ten samples had a positive next‐generation sequencing result and a negative culture. In five of these, alpha‐defensin was positive and the levels of inflammatory markers were high. In the other five, alpha‐defensin was negative and the levels of inflammatory markers were low. While next‐generation sequencing detected several organisms in each sample, in most samples with a higher probability of infection, there was a predominant organism present, while in those presumed not to be infected, many organisms were identified with no predominant organism. Conclusion Pathogens causing periprosthetic infection in both culture‐positive and culture‐negative samples of synovial fluid could be identified by next‐generation sequencing.

Diagnosis of Streptococcus canis periprosthetic joint infection: the utility of next-generation sequencing

A 62-year-old man who had undergone a primary knee arthroplasty 3 years earlier, presented to the emergency department with an infected prosthesis. He underwent prosthesis resection. All cultures failed to identify the infecting organism. Analysis of the intraoperative samples by next-generation sequencing revealed Streptococcus canis (an organism that resides in the oral cavity of dogs). It was later discovered that the patient had sustained a dog scratch injury several days earlier. The patient reports that his dog had licked the scratch. Treatment was delivered based on the sensitivity of S. canis, and the patient has since undergone reimplantation arthroplasty.

All Patients Should Be Screened for Diabetes Before Total Joint Arthroplasty

BACKGROUND Diabetes is highly prevalent in patients with osteoarthritis before total joint arthroplasty and presents a higher risk of adverse postoperative outcomes. However, the rate of diabetes in this population and optimal screening strategies remain unknown. METHODS We prospectively screened patients undergoing elective total joint arthroplasty for diabetes using glycated hemoglobin (HbA1c) and fasting blood glucose (FBG) levels. Screening was conducted within 2 time periods between 2012 and 2017. The prevalence of diabetes was assessed using a previous diagnosis of diabetes or, in the absence of diagnosis, by measuring if HbA1c ≥ 6.5% or FBG ≥ 126 mg/dL. Prediabetes was defined as 5.7% ≤ HbA1c ≤ 6.4% or 100 mg/dL ≤ FBG ≤ 125 mg/dL. Occurrence of a 90-day periprosthetic joint infection and wound complications was noted. RESULTS A total of 1461 patients were included in the study. The prevalence of diabetes was 20.6%; 178 patients (59.1%) had diagnosed diabetes, and 123 patients (40.9%) had undiagnosed diabetes. Prediabetes was identified in 559 patients (38.3%), resulting in a combined total of 860 (58.9%) patients with diabetes and prediabetes. Total diabetic rates were significantly higher in patients aged >65 years, of nonwhite ethnicity, and undergoing total knee arthroplasty. No significant differences in periprosthetic joint infection and wound complications were observed while comparing patients with diagnosed and undiagnosed diabetes. CONCLUSION A significant proportion of patients with undiagnosed diabetes and prediabetes were identified. Preadmission testing provides an opportunity to identify and address this condition, potentially reducing short-term arthroplasty-related complications and avoiding long-term systemic diabetic complications. We strongly recommend universal glycemic screening to all elective arthroplasty patients.

Serum Fructosamine: A Simple and Inexpensive Test for Assessing Preoperative Glycemic Control

Background: Although the medical community acknowledges the importance of preoperative glycemic control, the literature is inconclusive and the proper metric for assessment of glycemic control remains unclear. Serum fructosamine reflects the mean glycemic control in a shorter time period compared with glycated hemoglobin (HbA1c). Our aim was to examine its role in predicting adverse outcomes following total joint arthroplasty. Methods: Between 2012 and 2013, we screened all patients undergoing total joint arthroplasty preoperatively using serum HbA1c, fructosamine, and blood glucose levels. On the basis of the recommendations of the American Diabetes Association, 7% was chosen as the cutoff for HbA1c being indicative of poor glycemic control. This threshold correlated with a fructosamine level of 292 &mgr;mol/L. All patients were followed and total joint arthroplasty complications were evaluated. We were particularly interested in retrieving details on surgical-site infection (superficial and deep). Patients with fructosamine levels of ≥292 &mgr;mol/L were compared with those with fructosamine levels of <292 &mgr;mol/L. Complications were evaluated in a univariate analysis followed by a stepwise logistic regression analysis. Results: A total of 829 patients undergoing primary total joint arthroplasty were included in the present study. There were 119 patients (14.4%) with a history of diabetes and 308 patients (37.2%) with HbA1c levels in the prediabetic range. Overall, 51 patients had fructosamine levels of ≥292 &mgr;mol/L. Twenty patients (39.2%) had a fructosamine level of ≥292 &mgr;mol/L but did not have an HbA1c level of ≥7%. Patients with fructosamine levels of ≥292 &mgr;mol/L had a significantly higher risk for deep infection (adjusted odds ratio [OR], 6.2 [95% confidence interval (CI), 1.6 to 24.0]; p = 0.009), readmission (adjusted OR, 3.0 [95% CI, 1.1 to 8.1]; p = 0.03), and reoperation (adjusted OR, 3.4 [95% CI, 1.2 to 9.2]; p = 0.02). In the current study with the given sample size, HbA1c levels of ≥7% failed to show any significant correlation with deep infection (p = 0.14), readmission (p = 1.0), or reoperation (p = 0.7). Conclusions: Serum fructosamine is a simple and inexpensive test that appears to be a good predictor of adverse outcome in patients with known diabetes and those with unrecognized diabetes or hyperglycemia. Our findings suggest that fructosamine can serve as an alternative to HbA1c in the setting of preoperative glycemic assessment. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Increased postoperative glucose variability is associated with adverse outcomes following orthopaedic surgery

Aims The aim of this study was to examine the association between postoperative glycaemic variability and adverse outcomes following orthopaedic surgery. Patients and Methods This retrospective study analyzed data on 12 978 patients (1361 with two operations) who underwent orthopaedic surgery at a single institution between 2001 and 2017. Patients with a minimum of either two postoperative measurements of blood glucose levels per day, or more than three measurements overall, were included in the study. Glycaemic variability was assessed using a coefficient of variation (CV). The length of stay (LOS), in‐hospital complications, and 90‐day readmission and mortality rates were examined. Data were analyzed with linear and generalized linear mixed models for linear and binary outcomes, adjusting for various covariates. Results The cohort included 14 339 admissions, of which 3302 (23.0%) involved diabetic patients. Patients with CV values in the upper tertile were twice as likely to have an in‐hospital complication compared with patients in the lowest tertile (19.4% versus 9.0%, p < 0.001), and almost five times more likely to die compared with those in the lowest tertile (2.8% versus 0.6%, p < 0.001). Results of the adjusted analyses indicated that the mean LOS was 1.28 days longer in the highest versus the lowest CV tertile (p < 0.001), and the odds of an in‐hospital complication and 90‐day mortality in the highest CV tertile were respectively 1.91 (p < 0.001) and 2.10 (p = 0.001) times larger than the odds of these events in the lowest CV tertile. These associations were significant even for non‐diabetic patients. After adjusting for hypoglycaemia, the relationships remained significant, except that the CV tertile no longer predicted mortality in diabetics. Conclusion These results indicate that higher glycaemic variability is associated with longer LOS and inhospital complications. Glycaemic variability also predicted death, although that primarily held for non‐diabetic patients in the highest CV tertile following orthopaedic surgery. Prospective studies should examine whether ensuring low postoperative glycaemic variability may reduce complication rates and mortality. Cite this article: Bone Joint J 2018;100‐B:1125–32.

Majority of Total Joint Arthroplasties Are Subtherapeutic on Warfarin at Time of Discharge: Another Reason to Avoid Warfarin as a Venous Thromboembolism Prophylaxis?

BACKGROUND Warfarin has been used as prophylaxis against venous thromboembolism (VTE) after total joint arthroplasty (TJA) for over 60 years. With trends of shorter hospital stays for TJA patients, it is important to examine how many patients achieve therapeutic international normalized ratio (INR) at time of discharge. We aimed at elucidating the proportion of patients discharged at therapeutic INR and whether this is affected by inpatient specialty anticoagulation management service (AMS) involvement. METHODS We conducted a retrospective review of 2927 primary TJA patients who received warfarin as postoperative VTE chemoprophylaxis from 2011 to 2016. An electronic chart query determined AMS input, length of stay (LOS), INR at discharge, and in-hospital complications. INR results were categorized as subtherapeutic (INR < 2.0), therapeutic (2.0 ≤ INR < 3.0), and supratherapeutic (INR ≥ 3.0). Descriptive statistics, chi-square, and t-tests were performed for analysis. RESULTS At discharge, 93.9% of patients had subtherapeutic INR. Average INR was 1.41 with average LOS of 2.53 days. Factors associated with being subtherapeutic included male gender, shorter LOS, fewer comorbidities, reduced in-hospital complications, and higher body mass index. AMS supervised postoperative warfarin dosing in 64.9% of patients. Patients managed by AMS were less likely to be subtherapeutic at discharge compared to those without AMS input; however, the absolute difference in INR may not be clinically significant. There were 19 VTEs, of which 13 had prolonged hospitalization to achieve therapeutic INR. CONCLUSION The majority of patients are discharged at subtherapeutic INR levels despite management by AMS. Patients may not be adequately anticoagulated with warfarin at time of discharge, raising significant patient safety concerns as well as medicolegal implications.