title: Incidence and Risk Factor Analysis of Symptomatic Venous Thromboembolism After Knee Arthroscopy.
abstract: OBJECTIVE
  To (1) determine the incidence of symptomatic venous thromboembolic events (VTEs) after knee arthroscopy and arthroscopy-assisted procedures at a single institution and (2) determine associated risk factors for VTEs in these patients.
  
  
  METHODS
  The records of patients who underwent knee arthroscopy at a single institution between 1988 and 2008 were reviewed. Chemoprophylaxis was not routinely used. Confirmed VTEs occurring within 4 weeks after the index arthroscopy procedure were included. A 2:1 matched control group was generated to include patients in whom knee arthroscopy was performed by the same surgeon either on the same day or immediately before each case resulting in a VTE. Preoperative and perioperative data were collected with respect to demographic data, medical history, medications, and surgical and anesthesia data. Univariate and multivariate analyses were performed.
  
  
  RESULTS
  During the study period, 12,595 patients underwent knee arthroscopy. Among these patients, 43 cases of VTEs (35 deep venous thromboses [DVTs], 5 pulmonary embolisms [PEs], and 3 DVTs that progressed to PEs) occurred, resulting in an incidence of 0.30% (95% confidence interval [CI], 0.22% to 0.41%) for DVT, 0.06% (95% CI, 0.03% to 0.12%) for PE, and 0.34% (95% CI, 0.25% to 0.46%) for VTEs overall. Factors associated with an elevated risk of symptomatic postoperative VTEs included a history of malignancy (P = .01; odds ratio [OR], 6.3), a history of VTEs (P = .02; OR, 5.2), or the presence of more than 2 classic risk factors for VTEs (P = .01; OR, 13.6).
  
  
  CONCLUSIONS
  In this study, symptomatic VTEs were rare and occurred infrequently, with an incidence of 0.34% (95% CI, 0.25% to 0.46%), after knee arthroscopy and arthroscopy-assisted cases in the absence of routine chemoprophylaxis. Patients with a history of VTEs, a history of malignancy, or 2 or more classic risk factors are at increased risk of VTEs after knee arthroscopy, and chemoprophylaxis should be considered in these select patients.
  
  
  METHODS
  Level III, case-control study.
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Krych
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Sousa
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Morgan
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Levy
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stuart
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota, U.S.A.. Electronic address: Dahm.Diane@mayo.edu.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Dahm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D011183:Postoperative Complications; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000209:etiology*; D055815:Young Adult