title: Accuracy of CT-guided joint aspiration in patients with suspected infection status post-total hip arthroplasty.
abstract: OBJECTIVE
  To determine the accuracy of guided computed tomography aspiration in the detection of septic hip prosthesis before surgery.
  
  
  METHODS
  Sixty-three patients (35 women and 28 men; age range, 29-86 years; mean age, 71 years) with clinically suspected septic hip prosthesis were prospectively studied with independent review board (IRB) approval. Volume and microbiological cultures of aspirated fluid and several computed tomography imaging findings such as periprosthetic fluid collections, prosthetic acetabular malposition, and heterotopic ossification were analyzed. All patients underwent revision surgery and infection was finally diagnosed in 33 patients.
  
  
  RESULTS
  Statistical comparative analysis was performed comparing computed tomography aspiration and surgical findings (95% CI; level of significance at P=0.05 two-sided) with 70% sensitivity, 100% specificity, 84% accuracy, 100% positive predictive value, and 75% negative predictive value. Using Fisher's exact test, the presence of periprosthetic fluid collections (P=0.001), prosthetic acetabular malposition (P=0.025) and aspirated fluid volume (P=0.009) were significantly higher in infected than in non-infected prostheses, whereas heterotopic ossification was not (P=0.429).
  
  
  CONCLUSIONS
  Computed tomography aspiration is accurate to preoperatively diagnose septic hip prosthesis on the basis of volume and bacterial cultures of aspirated joint fluid. Furthermore, imaging findings such as periprosthetic fluid collections and prosthetic acetabular malposition strongly suggest infected prosthesis.
authors.affiliation: Department of Radiology, Hospital Clinic, Universidad de Barcelona, Villarroel 170, Barcelona, 08036, Spain. xtomas61@gmail.com
authors.forename: Xavier
authors.initials: X
authors.lastname: Tomas
authors.forename: Guillem
authors.initials: G
authors.lastname: Bori
authors.forename: Sebastián
authors.initials: S
authors.lastname: Garcia
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Garcia-Diez
authors.forename: Jaime
authors.initials: J
authors.lastname: Pomes
authors.forename: Alex
authors.initials: A
authors.lastname: Soriano
authors.forename: Jose
authors.initials: J
authors.lastname: Ríos
authors.forename: Manel
authors.initials: M
authors.lastname: Almela
authors.forename: Josep
authors.initials: J
authors.lastname: Mensa
authors.forename: Xavier
authors.initials: X
authors.lastname: Gallart
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Martinez
authors.forename: Josep
authors.initials: J
authors.lastname: Riba
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging / Q000628:therapy*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
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