title: The incidence of hematoma formation in patients with continuous femoral catheters following total knee arthroplasty while receiving rivaroxaban as thromboprophylaxis: an observational study.
abstract: OBJECTIVE
  Multimodal analgesia, including continuous femoral block, is often used to manage postoperative pain following total knee arthroplasty. To reduce the risk of deep vein thrombosis and pulmonary embolus formation, anticoagulation is also a part of the care for patients who undergo total knee arthroplasty. However, the concurrent use of continuous peripheral nerve block and anticoagulation can lead to hematoma formation. This prospective, single-center, observational study investigated the incidence of hematoma formation, causing neurovascular compromise, for patients with femoral catheters while taking the oral anticoagulant rivaroxaban.
  
  
  METHODS
  Five hundred four eligible patients consented to participate in this study. A femoral nerve block catheter was inserted before surgery, and a continuous infusion of local anesthetic was continued for 36 to 48 hours postoperatively. Rivaroxaban 10 mg was administered daily, and the femoral catheter was removed 20 hours after a dose of rivaroxaban. Participants were assessed daily to postoperative day 3 for the presence of a hematoma causing neurovascular compromise or ecchymosis formation at the femoral catheter site; sensory and motor functions of the femoral nerve were also assessed.
  
  
  RESULTS
  No participant presented with a hematoma causing neurovascular compromise at the femoral catheter site or groin area (upper confidence limit, 3.7). The most common complication was an ecchymosis in the groin or upper thigh, with the highest incidence of ecchymosis formation occurring on postoperative day 3.
  
  
  CONCLUSIONS
  In this prospective observational study, the concurrent administration of continuous femoral nerve block, the once-daily administration of the anticoagulant rivaroxaban, and the timed removal of the femoral catheter were not associated with hematoma formation resulting in neurovascular compromise at the femoral catheter insertion site or groin area.
authors.affiliation: From the *Medical-Dental-Midwifery Staff Association, Acute Pain Service, and Department of Anaesthesiology, Sunnybrook Health Sciences Centre, Toronto; †School of Nursing, Queens University, Kingston, and North York General Hospital, Toronto; ‡Department of Anaesthesiology and the Holland Orthopaedic and Arthritic Centre, Sunnybrook Health Sciences Centre; and §Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Idestrup
authors.forename: Mona
authors.initials: M
authors.lastname: Sawhney
authors.forename: Catherine
authors.initials: C
authors.lastname: Nix
authors.forename: Alex
authors.initials: A
authors.lastname: Kiss
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D002406:Catheterization, Peripheral / Q000009:adverse effects*; D057785:Catheters / Q000009:adverse effects*; D004438:Ecchymosis / Q000209:etiology; D005260:Female; D005267:Femoral Nerve; D006406:Hematoma / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000009:adverse effects* / Q000627:therapeutic use; D009407:Nerve Block / Q000009:adverse effects*; D011446:Prospective Studies; D000069552:Rivaroxaban; D013876:Thiophenes / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D009025:Morpholines; D013876:Thiophenes; D000069552:Rivaroxaban