title: The saline load test of the knee redefined: a test to detect traumatic arthrotomies and rule out periarticular wounds not requiring surgical intervention.
abstract: OBJECTIVE
  To describe the use of the saline load test (SLT) using a new definition that more adequately characterizes its use in the emergency department (ED) setting.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Level I trauma center.
  
  
  METHODS
  Fifty consecutive patients who underwent an SLT of the knee in the ED and had a minimum of 14 days follow-up.
  
  
  METHODS
  Saline Load Test.
  
  
  METHODS
  Positive traumatic arthrotomy of the knee (+TAK) defined as operating room (OR) confirmation of an arthrotomy (assumed to develop a septic knee) or -SLT with follow-up revealing a septic knee. Periarticular wound equivalent to no traumatic arthrotomy of the knee [pw = (-TAK)] defined as OR evaluation revealing no arthrotomy (assumed not to develop a septic knee) or -SLT whose follow-up revealed no septic knee. Development of a septic knee was considered the gold standard for determining true positives/negatives and false positives/negatives.
  
  
  RESULTS
  The mean wound size was 3.9 ± 4.3 cm and the mean saline load volume was 74.9 ± 28.2 cm. There were 19 +SLTs of which there were 16 +TAK and 3 pw = (-TAK). The 3 pw = (-TAK) in the +SLT group were evaluated in the OR where inspection of the joint capsule revealed the absence of a traumatic arthrotomy. There were 31 -SLTs of which there were 1 +TAK and 30 pw = (-TAK). The SLT has a sensitivity of 94% and a specificity of 91% for detecting +TAKs and ruling out periarticular wounds not requiring surgical intervention [pw = (-TAK)]. The false-positive rate of the SLT to detect +TAK is 9%.
  
  
  CONCLUSIONS
  Using +TAK and pw = (-TAK) as the newly defined measures of the SLT, we report the sensitivity (94%) and specificity (91%) of the SLT in the ED setting while still maintaining the clinical relevancy of the test. Based on a small sample size, knees with small periarticular wounds and a -SLT and no other radiographic or clinical evidence of an arthrotomy appear to have an infection rate of 0% with nonoperative management.
  
  
  METHODS
  Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York 10003, USA.
authors.forename: Sanjit R
authors.initials: SR
authors.lastname: Konda
authors.forename: Daniel
authors.initials: D
authors.lastname: Howard
authors.forename: Roy I
authors.initials: RI
authors.lastname: Davidovitch
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Egol
mesh_terms: D000293:Adolescent; D000328:Adult; D003955:Diagnostic Tests, Routine / Q000379:methods*; D004636:Emergency Service, Hospital; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000453:epidemiology; D012965:Sodium Chloride; D014947:Wounds and Injuries / Q000150:complications* / Q000175:diagnosis* / Q000209:etiology*; D055815:Young Adult
chemical_list: D012965:Sodium Chloride