title: The role of computed tomography in the assessment of open periarticular fractures associated with deep knee wounds.
abstract: OBJECTIVE
  To (1) determine the incidence and injury profile of open periarticular fractures about the knee joint in a cohort of patients presenting to the emergency department with a deep periarticular knee wound and to (2) determine the effectiveness of computed tomography (CT) scan to detect and guide management of these open fractures compared with plain radiographs (XRs).
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Level I trauma center.
  
  
  METHODS
  Seventy-eight patients (79 knees) with deep periarticular knee wounds of which 62 patients (63 knees) received both a XR and a CT scan of the knee.
  
  
  METHODS
  XR and CT scan of the injured knee.
  
  
  METHODS
  Comparison of OTA fracture classification and surgeon produced management plan as determined by XRs versus CT scans. CT scan was considered the gold standard test to detect a fracture.
  
  
  RESULTS
  Twenty-one (27%, 21/79) knees had an open periarticular fracture of the knee, and 95% (20/21) of these knees had intra-articular air indicative of an associated traumatic arthrotomy. Of 41 (52%, 41/79) knees with a traumatic arthrotomy, 51% (21/41) had an associated open periarticular fracture of the knee. XRs detected 18 fractures in 17 knees (of which 1 fracture was later determined to not be a true fracture), whereas CT scans detected 26 fractures in 21 knees. Overall, CT scans detected 9 additional fractures in 6 knees. The specificity, sensitivity, and positive and negative predictive values of XRs to detect and rule out a fracture were 98%/65% and 94%/82%, respectively. Compared with XRs, CT scan altered the fracture classification in 48% of patients and altered the management plan in 43% of patients, respectively. Gunshot wounds to the knee had a 48% (12/25) incidence of an associated open periarticular fracture compared with a 17% (9/54) incidence for all other injury mechanisms combined (P < 0.01).
  
  
  CONCLUSIONS
  Patients with a periarticular knee wound have a high incidence of open periarticular fractures, and the incidence is even higher if the mechanism of injury is a gunshot wound or there is associated traumatic arthrotomy. CT scan improves detection and management of open fractures of the knee compared with XRs. Consideration should be given to routinely using CT scan to evaluate knees with deep periarticular wounds that present to the emergency department, especially if secondary to gunshot injuries, given the high incidence of open periarticular fractures of the knee.
  
  
  METHODS
  Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
authors: NYU Hospital for Joint Diseases, New York, NY, 10003, USA.
authors: Sanjit R
authors: SR
authors: Konda
authors: Daniel
authors: D
authors: Howard
authors: Roy I
authors: RI
authors: Davidovitch
authors: Kenneth A
authors: KA
authors: Egol
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D004636:Emergency Service, Hospital; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D008297:Male; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014947:Wounds and Injuries / Q000150:complications*; D014965:X-Rays; D055815:Young Adult