Low-molecular-weight heparin followed by rivaroxaban or not for the prevention of deep venous thromboembolism after total knee arthroplasty

Utility of D-dimer in total joint arthroplasty

As the number of patients receiving total joint replacements continues to rise, considerable attention has been directed towards the early detection and prevention of postoperative complications. While D-dimer has long been studied as a diagnostic tool in venous thromboembolism (VTE), this assay has recently received considerable attention in the diagnosis of periprosthetic joint infection (PJI). D-dimer values are substantially elevated in the acute postoperative period after total joint arthroplasty, with levels often exceeding the standard institutional cutoff for VTE (500 µg/L). The utility of D-dimer in detecting VTE after total joint replacement is currently limited, and more research to assess its value in the setting of contemporary prophylaxis protocols is warranted. Recent literature supports D-dimer as a good to excellent biomarker for the diagnosis of chronic PJI, especially when using serum sample technique. Providers should exercise caution when interpreting D-dimer levels in patients with inflammatory and hypercoagulability disorders, as the diagnostic value is decreased. The updated 2018 Musculoskeletal Infection Society criteria, which includes D-dimer levels > 860 µg/L as a minor criterion, may be the most accurate for diagnosing chronic PJI to date. Larger prospective trials with transparent lab testing protocols are needed to establish best assay practices and optimal cutoff values for D-dimer in the diagnosis of PJI. This review summarizes the most current literature on the value of D-dimer in total joint arthroplasty and elucidates areas for future progress.

Permeation-Enhancing Nanoparticle Formulation to Enable Oral Absorption of Enoxaparin

This study tests the hypothesis that association complexes formed between enoxaparin and cetyltrimethylammonium bromide (CTAB) augment permeation across the gastrointestinal mucosa due to improved encapsulation of this hydrophilic macromolecule within biocompatible poly (lactide-co-glycolide, PLGA RG 503) nanoparticles. When compared with free enoxaparin, association with CTAB increased drug encapsulation efficiency within PLGA nanoparticles from 40.3 ± 3.4 to 99.1 ± 1.0%. Drug release from enoxaparin/CTAB PLGA nanoparticles was assessed in HBSS, pH 7.4 and FASSIFV2, pH 6.5, suggesting effective protection of PLGA-encapsulated enoxaparin from unfavorable intestinal conditions. The stability of the enoxaparin/CTAB ion pair complex was pH-dependent, resulting in more rapid dissociation under simulated plasma conditions (i.e., pH 7.4) than in the presence of a mild acidic gastrointestinal environment (i.e., pH 6.5). The intestinal flux of enoxaparin complexes across in vitro Caco-2 cell monolayers was greater when encapsulated within PLGA nanoparticles. Limited changes in transepithelial transport of PLGA-encapsulated enoxaparin complexes in the presence of increasing CTAB concentrations suggest a significant contribution of size-dependent passive diffusion as the predominant transport mechanism facilitating intestinal absorption. Graphical abstract.