Comprehensive Guidance for the Prevention of Periprosthetic Joint Infection After Total Joint Arthroplasty and Pitfalls in the Prevention.

Total joint arthroplasty (TJA) is a surgical procedure, in which parts of damaged joints are removed and replaced with a prosthesis. The main indication of TJA is osteoarthritis, and the volume of TJA is rising annually along with the increase of aged population. Hip and knee are the most common joints, in which TJAs are performed. The TJA prosthesis is composed of metal, plastic, or ceramic device. Even though TJA is the most successful treatment for end-stage osteoarthritis, it is associated with various complications, and periprosthetic joint infection (PJI) is the most serious complication after TJA. With the increasing volume of TJAs, there is a simultaneous rise in the incidence of PJI. Contamination of the surgical wound and the adherence of bacteria to the surface of prosthetic component represent the initial step in the pathogenesis of PJI. The main sources of the contamination are 1) patient's own flora, 2) droplets in the operation room air, and 3) surgical gloves and instruments. Even though modern techniques have markedly reduced the degree of contamination, TJAs cannot be done in completely germ-free conditions and some degree of contamination is inevitable in all surgical procedures. However, not all contamination leads to PJI. It develops when the burden of contamination exceeds the immune threshold or the colony forming units (CFUs) and various factors contribute to a decrease in the CFU level. Surgeons should be aware of the germ burden/CFU concept and should monitor sources of contamination to maintain the germ burden below the CFU to prevent PJI.

The Gut Microbiome and Joint Microbiome Show Alterations in Patients with Knee Osteoarthritis Versus Controls: A Systematic Review.

PURPOSE: To assess the current scientific literature on the microbiome's relationship with knee osteoarthritis (OA), with specific focuses on the gut microbiome-joint axis and joint microbiome-joint axis. METHODS: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, searching PubMed, Embase, and Cochrane databases for relevant English-language clinical studies on the gut and/or joint microbiomes' association with knee OA in humans. Bias was evaluated using the methodological index for non-randomized studies score. RESULTS: Thirty-five thousand bacterial species comprise the gut microbiome; approximately 90% are members of the phyla Bacteroides and Firmicutes. Symbiosis between the gut microbiome and host under normal physiological conditions positively affects host growth, development, immunity, and longevity. Gut microbiome imbalance can negatively influence various physiological processes, including immune response, inflammation, metabolism, and joint health including development of knee OA. In addition, next generation gene sequencing suggests the presence of microorganisms in the synovial fluid of osteoarthritic knees, and distinct microbiome profiles detected are presumed to play a role in the development of OA. With regard to the gut microbiome, consistent alterations in microbial composition between OA patients and controls are noted, in addition to several associations between certain gut bacteria with OA-related knee pain, patient-reported outcome measure performance, imaging findings, and changes in metabolic and inflammatory pathways. Regarding the joint microbiome, studies revealed increased levels of lipopolysaccharide (LPS) and LPS-binding protein in synovial fluid are associated with activated macrophages, and correlated with worsened osteophyte severity, joint space narrowing, and pain scores in knee OA patients. In addition, studies demonstrated various microbial composition differences in OA patients compared to control, with certain joint microbes directly associated with OA pathogenesis, inflammation, and metabolic dysregulation. CONCLUSIONS: The gut microbiome-joint axis and joint microbiome shows alterations in microbial composition between osteoarthritic patients and controls. These alterations are associated with perturbations of metabolic and inflammatory pathways, imaging findings, osteoarthritis-related pain, and patient reported outcome measure performance. LEVEL OF EVIDENCE: Systematic Review; Level III.

Gloves Contamination During Revision Surgery for Periprosthetic Joint Infection.

BACKGROUND: The use of double gloving has become a standard practice for joint replacement surgeons. However, since there are limited data on how gloves are contaminated during both primary and revision arthroplasty, no precise protocol exists to direct surgeons on when, or if, to change their gloves. The goals of this preliminary study were to evaluate the contamination of gloves during total joint arthroplasties (TJAs). METHODS: We included 25 infected cases and 10 primaries, which were performed at the same institution using the same surgical protocol from 3 fellowship trained surgeons. Samples were taken every 20 minutes from the start of the surgery until the joint was irrigated. Procedural steps were noted. To evaluate cross-contamination during infected cases, we sampled gloves using blood agar plates. In primary cases, culture swabs of anterior chamfer cuts and sterile instruments on the back table were used as negative controls. Next-generation sequencing (NGS) was used as an adjunct to identify low virulence bacteria. RESULTS: In the primary cases, all samples were found culture negative but 3 (8.1%) of the 37 samples were found to have a low, unidentifiable bacterial mass via NGS testing. In the infected cases, 41 (59.4%) of the 69 samples yielded positive microbial results. The positivity rate was higher in the samples collected after the arthrotomy was performed (70%) compared to samples collected before the arthrotomy was performed (40%), and the surgeon was only dissecting superficial layers (P = .502). CONCLUSION: Gloves seem to be a common source of cross-contamination in the intraoperative field during revision TJA. Due to the higher percent of positive samples following the opening of the joint, we hypothesize that the arthrotomy allows for the spread of bacteria across the operative site. While further investigation is necessary to formulate a precise protocol for the changing of gloves during TJA, it may be beneficial to perform a thorough irrigation of the joint and change of the gloves immediately following arthrotomy.

Next-Generation Sequencing Supports Targeted Antibiotic Treatment for Culture Negative Orthopedic Infections.

The isolation of an infective pathogen can be challenging in some patients with active, clinically apparent infectious diseases. Despite efforts in the microbiology lab to improve the sensitivity of culture in orthopedic implant-associated infections, the clinically relevant information often falls short of expectations. The management of peri-prosthetic joint infections (PJI) provides an excellent example of the use and benefits of newer diagnostic technologies to supplement the often-inadequate yield of traditional culture methods as a substantial percentage of orthopedic infections are culture-negative. Next-generation sequencing (NGS) has the potential to improve upon this yield. Bringing molecular diagnostics into practice can provide critical information about the nature of the infective organisms and allow targeted therapy in these otherwise challenging situations. This review article describes the current state of knowledge related to the use and potential of NGS to diagnose infections, particularly in the setting of PJIs.

AOASM Position Statement on Esports, Active Video Gaming, and the Role of the Sports Medicine Physician.

ABSTRACT: Electronic sports, or esports, has a global audience of over 300 million fans and is increasing in popularity, resulting in projected revenue of over $1 billion by the end of this past year. The global pandemic of 2020 had little to no effect on these increasing numbers because athletes have been able to continue to engage in sports because of its electronic nature and fans have been able to follow them virtually. Esports has been recognized as an organized sport by the International Olympic Committee, the US National Collegiate Athletic Association, and several secondary school athletic associations within the United States. In addition, professional teams have been established in several major cities within the United States, Canada, Europe, and Australia. With the growth of esports, the necessity of incorporating esports medicine into the practice of sports medicine physicians has become paramount. Esports can be played on a monitor or screen and played using physical activity in what has become known as active video gaming. Within both of these platforms, there have emerged certain conditions unique to esports. There are also certain conditions seen in other sports applicable to esports athletes. This document will review the evaluation of the esports athlete, introduce conditions unique to these athletes and review common conditions seen in esports, discuss diagnostics used in the evaluation of esports athletes, introduce treatment options for conditions unique to esports and review those for commonly seen injuries in esports, discuss prevention of injuries in esports, and introduce a framework for the future development of esports medicine that can be introduced into the daily practice of the sports medicine physician.

Aspirin Administered for Venous Thromboembolism Prophylaxis May Protect Against Stiffness Following Total Knee Arthroplasty.

BACKGROUND: Aspirin has become the main agent for venous thromboembolism (VTE) prophylaxis following total knee arthroplasty (TKA). This study assessed whether aspirin is associated with less knee stiffness compared to warfarin and other chemoprophylaxis agents. METHODS: This is a retrospective review of all primary and revision TKAs performed between January 2009 and October 2020 at a high volume institution. Demographics, comorbidity data, and operative variables were extracted from medical records. VTE prophylaxis administered during this time period included aspirin, warfarin, and "others" (factor Xa, unfractionated heparin, low-molecular-weight heparin, fondaparinux, adenosine diphosphate receptor inhibitor, and direct thrombin inhibitor). The primary outcome assessed was manipulation under anesthesia (MUA) performed within 6 months of index surgery. Secondary outcome included major bleeding events. Univariate followed by multivariate regression analyses were performed. RESULTS: A total of 15,903 cases were included in the study, of which 531 (3.3%) patients developed stiffness that required MUA. The rates of MUA were 2.7% (251/9223) for patients receiving aspirin, 4.2% (238/5709) for patients receiving warfarin, and 4.3% (42/971) for all others (P's < .001). Multivariate regression analysis confirmed that aspirin is associated with lower rates of VTE compared to warfarin (adjusted odds ratio 1.423, 95% confidence interval 1.158-1.747, P < .001) and compared to other anticoagulation medications (adjusted odds ratio 1.742, 95% confidence interval 1.122-2.704, P = .013). Major bleeding events were also significantly lower in patients who received aspirin compared to the other 2 groups (P's = .001). CONCLUSION: Aspirin prophylaxis is associated with lower rates of MUA following TKA compared to warfarin and other VTE chemoprophylactic agents when grouped together.

Surgical Helmets Used During Total Joint Arthroplasty Harbor Common Pathogens: A Cautionary Note.

BACKGROUND: The use of personal-protection surgical helmet/hood systems is now a part of the standard surgical attire during arthroplasty in North America. There are no protocols for the disinfection of these helmets. METHODS: This is a prospective, single-center, observational study. Helmets worn by 44 members of the surgical team and foreheads of 44 corresponding surgical personnel were swabbed at three distinct time points. In addition, 16 helmets were treated with hypochlorite spray to determine if pathogens could be eliminated. Swabs obtained were processed for culture and next-generation sequencing (NGS). RESULTS: Of the 132 helmet samples, 97 (73%) yielded bacteria on culture and 94 (71%) had evidence of bacterial-deoxyribonucleic acid (DNA) on NGS. Of the swabs sent for bacterial identification at the three time points, at least one from each helmet was positive for a pathogen(s). Of the 132 forehead samples, 124 (93%) yielded bacteria on culture and 103 (78%) had evidence of bacterial-DNA on NGS. The most commonly identified organism from helmets was Cutibacterium acnes (86/132) on NGS and Staphylococcus epidermidis (47/132) on culture. The most commonly identified organism from the foreheads of surgical personnel was Cutibacterium acnes (100/132) on NGS and Staphylococcus epidermidis (70/132) on culture. Sanitization of helmets was totally effective; no swabs taken the following morning for culture and NGS identified any bacteria. CONCLUSION: This study demonstrates that surgical helmets worn during orthopedic procedures are contaminated with common pathogens that can potentially cause surgical site infections. The findings of this study should at the minimum compel us to develop protocols for the disinfection of these helmets.

Periprosthetic Joint Infection and the Trojan Horse Theory: Examining the Role of Gut Dysbiosis and Epithelial Integrity.

BACKGROUND: Periprosthetic joint infection (PJI) is an uncommon yet dreadful complication after total joint arthroplasty. Emerging evidence suggested a role for the gut microbiome in the pathogenesis of such infections as a reservoir of opportunistic pathogens. METHODS: A secondary analysis of an ongoing trial looking at gut dysbiosis and PJI was performed on patients that had next-generation sequencing done as part of their workup. Gut permeability and dysbiosis were measured using known biomarkers such as Zonulin. Statistical analysis consisted of descriptive statistics and logistic regression modeling. RESULTS: Among the cohort of 46 (47.8% female) patients, with a mean age of 68.47 years (range, 40 to 91) and a mean BMI 31.15 ± 6.49 kg/m2, 38 patients underwent a revision for PJI (29 chronic and 9 acute infections), and 8 patients were classified as aseptic failures. Then, a review of each of the bacteria retrieved was performed. Those known to be gut commensal based on available literature were noted. When regression modeling was performed, Zonulin levels were found to be associated with an increased probability of a similar finding (Estimate: 0.377, OR: 1.458; P = .001). CONCLUSION: In our study, we report the first clinical evidence of the translocation of bacteria from the gut to the joint in patients with PJI. In particular, when evaluating the microbiological profile of the NGS signal, a great number of known gut commensals were seen in patients with a highly permeable dysbiotic gut. Manipulation of the gut microbiome may become part of an essential and comprehensive approach for management of patients with PJI.

Aspirin Thromboprophylaxis Is Associated With Less Major Bleeding Events Following Total Joint Arthroplasty.

BACKGROUND: There is ongoing debate on what is optimal prophylactic agent to reduce venous thromboembolism (VTE) following total joint arthroplasty (TJA). Although many studies assess the efficacy of these agents in VTE prevention, no attention is given to their adverse effect on major bleeding events (MBEs). This study compared the incidence of MBE in patients receiving aspirin as VTE prophylaxis vs other chemoprophylaxis. METHODS: A single-institution, retrospective study of 35,860 patients undergoing TJA between 2009 and 2020 was conducted. Demographic variables, co-morbidities, type of chemoprophylaxis, and intraoperative factors were collected. MBE was defined using the 2010 criteria for major bleeding in surgical patients presented by the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. To enhance capture rate, comprehensive queries utilizing MBE keywords were conducted in clinical notes, physician dictations, and phone call logs. Univariate followed by multivariate regression was performed as well as propensity score matched analysis. RESULTS: Overall, 270 patients (0.75%) in this cohort developed MBE. The MBE rate was 0.5% in the aspirin group and 1.2% in the non-aspirin group. After adjusting for confounders, multiple logistic regression and propensity score matched analysis revealed almost 2 times lower odds of MBE in patients who received aspirin. Variables independently associated with increased MBE risk included increasing age, body mass index, American Society of Anesthesiologists score, revision surgery, peptic ulcer disease, coagulopathy, intraoperative blood transfusion, and active smoking. CONCLUSION: Administration of aspirin for VTE prophylaxis, compared to other chemoprophylaxis agents may have an association with lower risk of major bleeding following TJA. Future randomized controlled trials should examine these findings.

Total Hip and Knee Revisions are Really Outpatient Procedures? Implications of the Removal From the Inpatient Only List.

BACKGROUND: In 2021, the Centers for Medicare and Medicaid Services (CMS) removed over 200 procedures from the Inpatient Only (IPO) list including revision total hip (THA) and total knee arthroplasties (TKA). The purpose of this study is to determine if some revision TKA and THA procedures may be appropriate for outpatient status. METHODS: We reviewed a consecutive series of 1026 revision THA and TKA patients at our tertiary academic institution from 2015 to 2020. An outpatient procedure was defined as a length of stay of <2 midnights. We queried our prospectively collected arthroplasty database and compared demographics, comorbidities, surgical indication, type of procedure, discharge disposition, readmissions, and complications between the outpatient and inpatient groups. RESULTS: There were only 166 revision patients (16%) who met outpatient criteria. Revision THA outpatients were more likely to have a head and liner exchange (49% vs 25%, P < .001) and an indication of instability (93% vs 44%, P < .001). Revision TKA outpatients were more likely to have an isolated liner exchange (34% vs 14%, P < .001) and have an indication of instability (67% vs 25%, P < .001). Patients undergoing a revision for infection and aseptic loosening were more likely to require an inpatient stay than other revision indication (P < .05). CONCLUSION: The vast majority of revision TKA and THA patients met CMS inpatient criteria. In addition to a projected decrease in facility reimbursement, concerns exist for the safety of early discharge and access to care for these complex patients if CMS removes all revisions from the Inpatient Only list.

Many Common Pathogens are Present in the Operative Room Air During Surgery.

BACKGROUND: The main objective of this study was to assess the sanitary measures of operating theaters using next-generation sequencing. METHODS: Air was sampled from the operating room for the whole duration of 10 surgical days of "clean" (no infection cases) procedures (6 hip/knee arthroplasty and 4 spine cases). Controls consisted of samples at the beginning of the day (1 hour before the surgery started) and at the end of the day after terminal cleaning. One additional control sample, consisting of a culture swab that was opened and exposed to the air for 5 seconds, was collected at each time point. All samples were sent for next-generation sequencing analysis (16S rRNA sequencing) for bacterial identification. RESULTS: Overall, 306 samples were collected (159 controls and 147 experimental). Microbial DNA was detected in only 1 control sample, while 18 (12.2%) experimental samples were positive for microbial DNA. The most common organisms retrieved were Escherichia coli (6/18, 30%), Cutibacterium acnes (3/18, 15%), and Pseudomonas aeruginosa (2/18, 11.1%). There was no difference in positive samples between arthroplasty and spine cases (P > .05). CONCLUSION: Microbial organisms are not uncommonly present in the operating room air during hip and knee arthroplasties and spine procedures.

Commercial Synovial Antibody Testing is No Better Than Traditional Culture in Identification of Pathogen(s) Causing Periprosthetic Joint Infection.

BACKGROUND: Identification of infective organism causing periprosthetic joint infections (PJIs) is crucial to tailor the best combination of surgical and antimicrobial treatment. Traditional culture, with all its limitations, has been utilized for this purpose. A synovial fluid antibody assay against some common pathogens has been introduced by a commercial entity recently. This study aimed to determine if the antibody testing could be used as a proxy to traditional culture, and whether it provided additional information, in the setting of PJI. METHODS: A retrospective study was conducted of patients who underwent revision total hip and knee arthroplasty between January 2019 and 2020. Aspirated synovial fluid was sent for analyses including the commercial antibody testing. All patients had samples harvested for culture per standard of care. Results of the antibody testing and culture, in terms of concordance, were compared. Receiver operating characteristic curve and Youden's criterion were used to compare the 2 methods. RESULTS: A total of 419 patients were included. Using the International Consensus Meeting criteria as reference standard for PJI, antibody testing had a sensitivity and specificity of 40.5% and 93.4%, respectively. There were 59.5% false negative results with antibody testing compared with 50% for culture. Of the 12 patients who had positive results in both tests, 5 (41.7%) had discordant pathogens identified in each test. CONCLUSION: Synovial fluid antibody testing does not provide clinical benefit when compared to traditional cultures for PJI diagnosis. The antibody testing had a low sensitivity and a high rate of discordance with culture, when both tests were positive.

Comparison of Automated Ribotyping, spa Typing, and MLST in 108 Clinical Isolates of Staphylococcus aureus from Orthopedic Infections.

108 isolates of Staphylococcus aureus, belonging to six large ribogroups according to the automated Ribo-Printer® system, were studied with two highly used molecular methods for epidemiological studies, namely multi-locus sequence typing (MLST) and spa typing, followed by BURP and eBURST v3 analysis for clustering spa types and sequence (ST) types. The aim was to evaluate whether automated ribotyping could be considered a useful screening tool for identifying S. aureus genetic lineages with respect to spa typing and MLST. Clarifying the relationship of riboprinting with these typing methods and establishing whether ribogroups fit single clonal complexes were two main objectives. Further information on the genetic profile of the isolates was obtained from agr typing and the search for the mecA, tst genes, and the IS256 insertion sequence. Automated ribotyping has been shown to predict spa clonal complexes and MLST clonal complexes. The high cost and lower discriminatory power of automated ribotyping compared to spa and MSLT typing could be an obstacle to fine genotyping analyzes, especially when high discriminatory power is required. On the other hand, numerous advantages such as automation, ease and speed of execution, stability, typeability and reproducibility make ribotyping a reliable method to be juxtaposed to gold standard methods.

Fungal periprosthetic joint infection: Rare but challenging problem.

Periprosthetic joint infection (PJI) is the most difficult complication following total joint arthroplasty. Most of the etiological strains, accounting for over 98% of PJI, are bacterial species, with Staphylococcusaureus and Coagulase-negative staphylococci present in between 50% and 60% of all PJIs. Fungi, though rare, can also cause PJI in 1%-2% of cases and can be challenging to manage. The management of this uncommon but complex condition is challenging due to the absence of a consistent algorithm. Diagnosis of fungal PJI is difficult as isolation of the organisms by traditional culture may take a long time, and some of the culture-negative PJI can be caused by fungal organisms. In recent years, the introduction of next-generation sequencing has provided opportunity for isolation of the infective organisms in culture-negative PJI cases. The suggested treatment is based on consensus and includes operative and non-operative measures. Two-stage revision surgery is the most reliable surgical option for chronic PJI caused by fungi. Pharmacological therapy with antifungal agents is required for a long period of time with antibiotics and included to cover superinfections with bacterial species. The aim of this review article is to report the most up-to-date information on the diagnosis and treatment of fungal PJI with the intention of providing clear guidance to clinicians, researchers and surgeons.

High-fat diet, adipokines and low-grade inflammation are associated with disrupted tendon healing: a systematic review of preclinical studies.

BACKGROUND: The aetiopathogenesis of tendinopathy is uncertain, but inflammation may play a role in the early phase of tendinopathy and in tendon healing response. We investigated the most up-to-date evidence about the association between obesity, high-fat diet and tendinopathy, focusing on the role of adipokines, inflammatory pathways and molecular changes. SOURCES OF DATA: A systematic review was performed searching PubMed, Embase and Cochrane Library databases following the PRISMA guidelines. We included studies of any level of evidence published in peer-reviewed journals. The risk of bias (SIRCLE) was assessed, as was the methodological quality (CAMARADES) of the included studies. We excluded all the articles with a high risk of bias and/or low quality after the assessment. After applying the inclusion and exclusion criteria, we included 14 studies of medium or high quality. AREAS OF AGREEMENT: A high-fat diet negatively affects tendon quality, increasing the risk of rupture and tendinopathy. AREAS OF CONTROVERSY: Controversial evidence exists on both tendon fat infiltration secondary to a dysregulation of the lipid metabolism and of a molecular effect of inflammatory pathways. GROWING POINTS: The secretion of adipokines is strictly related to fat ingestion and body composition and can potentially act on tendon physiology and injury. AREAS TIMELY FOR DEVELOPING RESEARCH: Adipokines, low-grade inflammation and fat intake play a role in disrupting tendon healing and setting up tendinopathy. Further high-quality research is needed to better define the molecular pathways involved.

Which Socioeconomic Factors Affect Outcomes Following Total Hip and Knee Arthroplasty?

BACKGROUND: Studies have shown that lower socioeconomic status may result in adverse outcomes following total hip (THA) and total knee arthroplasty (TKA). The optimal method of defining socioeconomic status, however, continues to be debated. The purpose of this study is to determine which socioeconomic variables are associated with poor outcomes following THA and TKA. METHODS: We reviewed a consecutive series of 2770 primary THA and TKA patients from 2015 to 2018. Utilizing census data based upon the patient's ZIP code, we extracted poverty, unemployment, high school graduation, and vehicle possession rates. We collected demographics, comorbidities, discharge disposition, 90-day readmissions, and postoperative functional outcome scores for each patient. We then performed a multivariate regression analysis to identify the effect of each socioeconomic variable on postoperative outcomes. RESULTS: Patients from areas with high unemployment (P = .008) and low high school graduation rates (P = .019) had a higher age-adjusted Charlson Comorbidity Index. High poverty levels, high unemployment, lower high school graduation rate, and lower vehicle possession rates did not have a significant effect on functional outcomes (all P > .05). In the multivariate analysis, no socioeconomic variable demonstrated an increased rate of rehabilitation discharge, revision, or readmission (all P > .05). CONCLUSION: Patients undergoing THA and TKA from areas with high unemployment and lower educational levels do have more medical comorbidities. However, none of the 4 socioeconomic variables studied are independently associated with higher rates of readmission, discharge to rehabilitation, or worse functional outcomes. Patients from disadvantaged areas should not be denied access to arthroplasty care based on socioeconomic status alone.

Emergence of Antibiotic Resistance Across Two-Stage Revision for Periprosthetic Joint Infection.

BACKGROUND: The current preferred treatment for chronic hip and knee periprosthetic joint infection (PJI) involves both surgical intervention and antibiotic treatment as part of a two-stage revision. The purpose of this study is to determine how often patients who underwent a two-stage revision for chronic PJI developed a subsequent antibiotic-resistant infection. METHODS: We retrospectively reviewed the clinical records of 142 patients who underwent a two-stage revision for a chronic culture-positive PJI from January 2014 to May 2019. Demographic data and risk factors for PJI were identified. Resistance was defined in accordance with microbiology laboratory report and minimum inhibitory concentration. Statistical analysis consisted of descriptive statistics and univariate analysis. RESULTS: Only 10 of the 142 patients (7.04%) demonstrated emergence of resistance to antibiotics across their two-stage revision. At reimplantation, 25 (17.6%) patients had positive cultures. Of these, 16 patients presented with a novel organism and 9 patients had positive culture for the same organism as the initial infection. During the entire course of the two-stage revision, including spacer exchanges and irrigation and debridement procedures, 15 (10.56%) patients demonstrated persistent infections, whereas 25 (17.6%) patients presented with novel infections. 26 (18.3%) patients had reinfection of the same joint within one year. CONCLUSION: In the given cohort, there does not appear to be a major emergence of antibiotic resistant organisms in patients undergoing two-stage exchange arthroplasty and antibiotic treatment.

Leukocyte Esterase Versus ICM 2018 Criteria in the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: A leukocyte esterase (LE) test is inexpensive and provides real-time information about patients suspected of periprosthetic joint infections (PJIs). The 2018 International Consensus Meeting (ICM) recommends it as a diagnostic tool with a 2+ cutoff. There is still a lack of data revealing LE utility versus the ICM 2018 criteria for PJI. METHODS: This is a retrospective study of patients who underwent revision total hip and total knee arthroplasty at a single institution between March 2009 and December 2019. All patients underwent joint aspiration before the arthrotomy, and the LE strip test was performed on aspirated joint fluid. PJI was defined using the 2018 ICM criteria. RESULTS: As per the 2018 ICM criteria, 78 patients were diagnosed with chronic PJI and 181 were not infected. An LE test with a cutoff of ≥1+ had a sensitivity of 0.744, a specificity of 0.906, a positive predictive value of 0.773, an accuracy of 0.825 (95% confidence interval 0.772-0.878), and a negative predictive value of 0.891. The positive likelihood ratio (LR+) was 7.917. Using an LE cutoff of 2 + had a sensitivity of 0.513, a specificity of 1.000, and an accuracy of 0.756 (95% confidence interval-0.812). CONCLUSION: LE is a rapid and inexpensive test which can be performed at the bedside. Its performance is valuable as per ICM criteria. Based on the findings of this study and the given cohort, we suggest using the cutoff of LE1+ (result = negative or trace) as a point of care test to exclude infection, whereas LE at 2 + threshold has near absolute specificity for the diagnosis.

Despite Equivalent Medicare Reimbursement, Facility Costs for Outpatient Total Knee Arthroplasty Are Higher Than Unicompartmental Knee Arthroplasty.

BACKGROUND: With the recent removal of total knee arthroplasty (TKA) from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list, facility reimbursement for outpatient TKA now falls under the Outpatient Prospective Payment System at the same rate as unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare true facility costs of patients undergoing outpatient TKA with those undergoing UKA. METHODS: We reviewed a consecutive series of 2310 outpatient TKA and 231 UKA patients from 2018 to 2019. Outpatient status was defined as a hospital stay of less than 2 midnights. Facility costs were calculated using a time-driven, activity-based costing algorithm. Implants, supplies, medications, and personnel costs were compared between outpatient TKA and UKA patients. A multivariate analysis was performed to control for confounding medical and demographic variables. RESULTS: When compared with patients undergoing UKA, outpatient TKA patients had higher implant costs ($3403 vs $3081; P < .001) and overall hospital costs ($6350 vs $5594; P < .001). Outpatient TKA patients had a greater length of stay (1.2 vs 0.5 days; P < .001) and greater postoperative personnel costs ($783 vs $166; P < .001) than UKA patients. When controlling for comorbidities, outpatient TKA was associated with a $803 (P < .001) increase in overall facility costs compared with UKA. CONCLUSION: Despite equivalent reimbursement from CMS as UKA, outpatient TKA has increased facility costs to the hospital. Although implant costs can vary greatly by institution, CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs when compared with UKA.

Low-Dose Aspirin Administered for Venous Thromboembolism Prophylaxis Reduces the Incidence of Heterotopic Ossification in Total Joint Arthroplasty.

BACKGROUND: Heterotopic ossification (HO) is a common complication following total joint arthroplasty (TJA). However, the pathophysiology of HO is not entirely understood. Inflammation may play a significant role in the pathogenesis of HO as nonsteroidal anti-inflammatory drugs are effective in the prevention of HO. The purpose of this study is to examine if aspirin (ASA), when used as venous thromboembolism (VTE) prophylaxis, influenced the rate of HO formation following TJA. METHODS: We queried our longitudinally maintained database to identify all patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) for osteoarthritis between January 2016 and June 2018 with at least 3-month radiographic follow-up. In total, 1238 THAs and 1051 TKAs were included for analysis. Radiographs were reviewed and HO formation graded according to the Brooker classification. Patient demographic and VTE prophylaxis data were collected and reviewed for accuracy. Univariate and multivariate analysis was performed to evaluate the effect of ASA on HO formation. RESULTS: The overall rate of HO was 37.5% after THA and 17.4% after TKA. Patients receiving ASA were less likely to develop HO after THA (34.8% vs 45.5%; P < .001), as well as HO after TKA (13.4% vs 18.4%; P = .047) compared to patients receiving non-ASA VTE prophylaxis. The rate of HO formation trended to be lower, albeit not statistically significantly, in patients receiving low-dose ASA (81 mg) vs high-dose ASA (325 mg). CONCLUSION: Patients undergoing primary TJA receiving ASA for VTE prophylaxis were less likely to develop HO compared to patients who were administered non-ASA VTE prophylaxis.