Posts filed under ‘BIOMARCADORES’

Single-Dose Perioperative Antibiotics Do Not Increase the Risk of Surgical Site Infection in Unicompartmental Knee Arthroplasty

Journal of Arthroplasty July 2019 V.34 Supplement S327–S330


Unicompartmental knee arthroplasty (UKA) is commonly performed as an outpatient procedure. To facilitate this process, a single-dose intravenous (IV) perioperative antibiotic administration is required compared to 24-hour IV antibiotic dosing schedules that are typical of most inpatient arthroplasty procedures. There is a paucity of literature to guide surgeons on the safety of single-dose perioperative antibiotic administration for arthroplasty procedures, particularly those that will be performed in the outpatient setting. The purpose of this study is to evaluate a large series of UKA performed with single-dose vs 24-hour IV antibiotic coverage to determine the impact on risk for surgical site infection (SSI).


All UKA cases were evaluated from 2007 to 2017 performed by a single surgeon at an academic institution. There were 296 UKAs in the cohort: 40 were outpatient procedures receiving single-dose antibiotics and 256 were inpatient procedures receiving 24-hour antibiotics. No patients were prescribed adjuvant oral antibiotics. Mean age was 64 years, 50% were female, mean body mass index was 32 kg/m2, and mean follow-up was 4.1 years (range 1.0-10.4). Perioperative antibiotic regimen was evaluated and SSI, defined as occurring within 1 year of surgery, was abstracted through a prospective total joint registry and manual chart review.


SSI occurred in 2 of 296 cases (0.7%) in the entire cohort, 2 of 256 inpatient UKAs (0.8%), and 0 of 40 outpatient UKAs (0%) (P = 1.00). One SSI was a deep infection occurring 6 weeks postoperatively that required 2-stage exchange and conversion to total knee arthroplasty. The other was a superficial infection treated with 2 weeks of oral antibiotics.


This study demonstrates a low SSI risk (0.8% or less) following UKA with both single-dose and 24-hour IV antibiotics. Administering single-dose perioperative antibiotics is safe for UKA, which should alleviate that potential concern for outpatient surgery.




August 30, 2019 at 4:15 pm

Traditional Laboratory Markers Hold Low Diagnostic Utility for Immunosuppressed Patients With Periprosthetic Joint Infections

Journal of Arthroplasty July 2019 V.34 N.7 P.1441–1445


Although predictive laboratory markers and cutoffs for immunocompetent patients are well-studied, similar reference ranges and decision thresholds for immunosuppressed patients are less understood. We investigated the utility of typical laboratory markers in immunosuppressed patients undergoing aspiration of a prosthetic hip or knee joint.


A retrospective review of adult patients with an immunosuppressed state that underwent primary and revision total joint arthroplasty with a subsequent infection at our tertiary, academic institution was conducted. Infection was defined by Musculoskeletal Infection Society criteria. A multivariable analysis was used to identify independent factors associated with acute (<90 days) and chronic (>90 days) infection. Area under the receiver-operator curve (AUC) was used to determine the best supported laboratory cut points for identifying infection.


We identified 90 patients with immunosuppression states totaling 172 aspirations. Mean follow-up from aspiration was 33 months. In a multivariate analysis, only synovial fluid cell count and synovial percent neutrophils were found to be independently correlated with both acute and chronic infection. A synovial fluid cell count cutoff value of 5679 nucleated cells/mm3 maximized the AUC (0.839) for predicting acute infection, while a synovial fluid cell count cutoff value of 1293 nucleated cells/mm3 maximized the AUC (0.931) for predicting chronic infection.


Physicians should be aware of lower levels of synovial nucleated cell count and percentage of neutrophils in prosthetic joint infections of the hip or knee in patients with immunosuppression. Further investigation is necessary to identify the best means of diagnosing periprosthetic joint infection in this patient population.



August 30, 2019 at 4:10 pm

The Presence of Sinus Tract Adversely Affects the Outcome of Treatment of Periprosthetic Joint Infections

Journal of Arthroplasty June 2019 V.34 N.6 P.1227-1232


A sinus tract may be encountered in patients with periprosthetic joint infection (PJI) and constitutes a major criterion for diagnosis. The aim of this study is to identify associated factors for the presence of sinus tract and outcome of 2-stage exchange arthroplasty in these patients.


We retrospectively reviewed all patients with PJI following hip and knee arthroplasty from 2000 to 2017. Of them, 161 patients with a sinus tract had a minimum follow-up of 1 year following 2-stage exchange arthroplasty. These patients were matched 1:2 with those without sinus tract by using propensity score matching. Treatment success was assessed using the modified Delphi criteria. A multiple logistic regression analysis was performed to determine the effect of sinus tract on the outcome and associated factors for the presence of sinus tract.


Factors significantly associated with sinus tract included smoking (odds ratio [OR] = 1.83), hypothyroidism (OR = 1.62), hypoalbuminemia (OR = 1.52), hip joint involvement (OR = 1.43), and prior revision surgery (OR = 1.37). Patients with sinus tract had a significantly higher rate of failure compared to those without sinus tract (OR = 2.94).


This study demonstrates that the presence of sinus tract in patients with PJI adversely affects the outcome of treatment of these patients. The presence of sinus tract may be a proxy for other issues such as poor periarticular soft tissue, the poor nutritional status of the host, and multiple prior operations. These findings need to be borne in mind when treating patients with PJI and a concomitant sinus tract.



August 30, 2019 at 4:08 pm

Synovial Fluid Viscosity Test is Promising for the Diagnosis of Periprosthetic Joint Infection

Journal of Arthroplasty June 2019 V.34 N.6 P.1197-1200


So far there is no “gold standard” test for the diagnosis of periprosthetic joint infection (PJI), compelling clinicians to rely on several serological and synovial fluid tests with no 100% accuracy. Synovial fluid viscosity is one of the parameters defining the rheology properties of synovial fluid. We hypothesized that patients with PJI may have a different level of synovial fluid viscosity and aimed to investigate the sensitivity and specificity of synovial fluid viscosity in detecting PJI.


This prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 45 patients undergoing revision for PJI (n = 15), revision for aseptic failure (n = 15), and primary arthroplasty (n = 15). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, synovial fluid viscosity, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and plasma d-dimer levels were measured preoperatively.


The synovial fluid viscosity level was significantly lower (P = .0011) in patients with PJI (7.93 mPa·s, range 3.0-15.0) than in patients with aseptic failure (13.11 mPa·s, range 6.3-20.4). Using Youden’s index, 11.80 mPa·s was determined as the optimal threshold value for synovial fluid viscosity for the diagnosis of PJI. Synovial fluid viscosity outperformed CRP, ESR, and plasma d-dimer, with a sensitivity of 93.33% and a specificity of 66.67%.


Synovial fluid viscosity seems to be on the same level of accuracy with CRP, ESR, and d-dimer regarding PJI detection and to be a promising marker for the diagnosis of PJI.



August 30, 2019 at 4:05 pm

Fever and Erythema are Specific Findings in Detecting Infection Following Total Knee Arthroplasty.

J Bone Jt Infect. March 16, 2019 V.4 B.2 P.92-98. doi: 10.7150/jbji.30088. eCollection 2019.

Shohat N1,2, Goswami K1, Tan TL1, Henstenburg B1, Makar G1, Rondon AJ1, Parvizi J1.

1 The Rothman Institute at Thomas Jefferson University, Philadelphia, PA 19107.

2 Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel.


Current diagnostic modalities are based almost exclusively on laboratory findings and the role of clinical presentation remains unknown. The purpose of this study was to examine the diagnostic value of clinical presentation in detecting periprosthetic joint infection (PJI). This study evaluated 279 patients undergoing revision surgery for failed total knee arthroplasty (TKA) between 2001-2016. Patients were classified as undergoing septic revisions based on major MSIS criteria. Aseptic revisions were defined as cases of single stage revision that did not have suspected PJI, fulfill MSIS criteria, or subsequently fail within one year of follow-up. Clinical presentation included pain, fever, presence of joint effusion or erythema, and reduced range of motion. Serum and synovial laboratory markers were also evaluated. The diagnostic value of each test was assessed and a Fagan’s nomogram was constructed. A subset of MSIS-negative patients was used to demonstrate the value of various clinical presentations in detecting PJI. Post-test probability for infection was calculated taking into account clinical presentation together with serum and synovial markers. Our results show that fever and erythema are the most important signs for diagnosing PJI with a positive likelihood ratio (LR) of 10.78 and 8.08, respectively. Effusion had a LR of 2.42. Pain and reduced ROM were not as strongly correlated with PJI diagnosis; LR was 1.02 and 1.51. Of the 35 MSIS-negative patients treated for PJI, 33 had a post-test probability of infection greater than 90% when taking clinical presentation into account. Clinical presentation should be used to guide which future diagnostic tests should be ordered and in the interpretation of their results. Our results indicate that pain, fever, presence of joint effusion or erythema, and reduced range of motion should prompt further workup for infection. We propose a nomogram that may be used in interoperating their individual weight together with laboratory findings. Fever and erythema are highly specific findings in patients with PJI and future studies should assess whether they may be added as minor criteria to current definitions for infection.


August 28, 2019 at 3:52 pm

Is Gram staining still useful in prosthetic joint infections?

J Bone Jt Infect. January 29, 2019 V.4 N.2 P.56-59.

doi: 10.7150/jbji.31312. eCollection 2019.

Wouthuyzen-Bakker M1, Shohat N2,3, Sebillotte M4, Arvieux C4,5, Parvizi J2, Soriano A6.

1 Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, the Netherlands.

2 Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, United States.

3 Department of Orthopaedic Surgery, Tel Aviv University, Tel Aviv, Israel.

4 Department of Infectious Diseases and Intensive Care Medicine, Rennes University Hospital, Rennes, France.

5 Great West Reference centers for Complex Bone and Joint Infections (CRIOGO), France.

6 Service of Infectious Diseases, Hospital Clínic, University of Barcelona, Barcelona, Spain.


Introduction: Staphylococcus aureus is an independent risk factor for DAIR failure in patients with a late acute prosthetic joint infection (PJI). Therefore, identifying the causative microorganism in an acute setting may help to decide if revision surgery should be chosen as a first surgical approach in patients with additional risk factors for DAIR failure. The aim of our study was to determine the sensitivity of Gram staining in late acute S. aureus PJI. Material and methods: We retrospectively evaluated all consecutive patients between 2005-2015 who were diagnosed with late acute PJI due to S. aureus. Late acute PJI was defined as the development of acute symptoms and signs of PJI, at least three months after the index surgery. Symptoms existing for more than three weeks were excluded from the analysis. Gram staining was evaluated solely for synovial fluid. Results: A total of 52 cases were included in the analysis. Gram staining was positive with Gram positive cocci in clusters in 31 cases (59.6%). Patients with a C-reactive protein (CRP) > 150 mg/L at clinical presentation had a significantly higher rate of a positive Gram stain (30/39, 77%) compared to patients with a CRP ≤ 150 mg/L (4/10, 40%) (p=0.02). A positive Gram stain was not related to a higher failure rate (60.6% versus 57.9%, p 0.85). Conclusion: Gram staining may be a useful diagnostic tool in late acute PJI to identify S. aureus PJI. Whether a positive Gram stain should lead to revision surgery instead of DAIR should be determined per individual case.


August 28, 2019 at 3:51 pm

In vitro pharmacokinetics/pharmacodynamics of the combination of avibactam and aztreonam against MDR organisms.

J Antimicrob Chemother. July 2016 V.71 N.7 P.1866-80.

Sy SK1, Beaudoin ME2, Zhuang L1, Löblein KI1, Lux C1, Kissel M1, Tremmel R1, Frank C1, Strasser S1, Heuberger JA1, Mulder MB1, Schuck VJ2, Derendorf H3.

Author information

1 Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA.

2 AstraZeneca, Waltham, MA, USA.

3 Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA



The combination of aztreonam and avibactam has been proposed for the treatment of infections caused by metallo-β-lactamase-producing Gram-negative organisms, given the stability of aztreonam against metallo-β-lactamases plus the broad coverage of avibactam against AmpC β-lactamases and ESBLs. This study aimed to evaluate the efficacy of the combination against four clinical isolates with defined but diverse β-lactamase profiles.


The MICs of aztreonam were determined without and with avibactam (1, 2, 4, 8 and 16 mg/L). Using the MIC values, the static time-kill kinetic studies were designed to encompass aztreonam concentrations of 0.25, 0.5, 1, 2 and 4 times the MIC at the respective avibactam concentrations from 0 to 8 mg/L. Aztreonam and avibactam concentrations were determined by LC-MS/MS during the course of the time-kill kinetic studies to evaluate whether avibactam protects aztreonam from degradation.


Three of the four isolates had aztreonam MICs ≥128 mg/L in monotherapy. Dramatically increasing susceptibility associated with a decrease in aztreonam MIC was observed with increasing avibactam concentration. Against all isolates, the combinations resulted in greater killing with a much lower dose requirement for aztreonam. The resulting changes in base-10 logarithm of cfu/mL at both the 10 h and 24 h references (versus 0 h) were synergistic. In contrast, a significantly higher concentration of aztreonam in the monotherapy was required to produce the same kill as that in the combination therapy, due to rapid aztreonam degradation in two isolates.


The aztreonam/avibactam combination protects aztreonam from hydrolysis and provides synergy in antimicrobial activity against multiple β-lactamase-expressing strains with a wide MIC range.



August 25, 2019 at 11:36 am

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