title: Diagnostic value of bone scintigraphy for aseptic loosening after total knee arthroplasty.
abstract: BACKGROUND
  Despite technical improvements, aseptic loosening after total knee arthroplasty (TKA) remains a frequent complication. A one-stage revision arthroplasty is the most common therapeutic pathway.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the diagnostic value of bone scintigraphy in detecting aseptic loosening after TKA.
  
  
  METHODS
  We retrospectively identified 46 cases of one-stage revision TKA performed between January 2011 and December 2012. In each case a bone scintigraphy was performed at least one year after the primary TKA and 3.2 ± 2.2 month prior to revision arthroplasty. Additionally, we evaluated the rate of satisfaction and pain level 16.2 ± 5.4 months after one-stage revision arthroplasty.
  
  
  RESULTS
  Bone scintigraphy indicated aseptic loosening in 28 cases. Intraoperative aseptic loosening was verified in 34 cases. Bone scintigraphy had a sensitivity of 0.76 and a specificity of 0.83 in detecting aseptic loosening. The positive predictive value was 0.93, and the negative predictive value 0.56. At follow-up consultation, 35 patients were very satisfied or satisfied, and 31 patients had no pain or occasional pain.
  
  
  CONCLUSIONS
  Bone scintigraphy is a helpful tool in detecting aseptic loosening after TKA. Nevertheless, the results from bone scintigraphy should be compared with clinical findings and patients' disorders.
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Leif
authors.initials: L
authors.lastname: Claassen
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Ettinger
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Plaass
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Kiriakos
authors.initials: K
authors.lastname: Daniilidis
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Calliess
authors.affiliation: Orthopedic Department, Hannover Medical School, Hannover, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Ezechieli
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011475:Prosthesis Failure / Q000009:adverse effects*; D011877:Radionuclide Imaging / Q000379:methods*; D012086:Reoperation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Aseptic loosening; one-stage revision arthroplasty; total knee arthroplasty