title: Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty--a new dimension of diagnostics?
abstract: BACKGROUND
  The purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).
  
  
  METHODS
  Twenty-three painful knees in patients following primary TKA were assessed using Tc-99m-HDP-SPECT/CT. Rotational, sagittal and coronal position of the TKA was assessed on 3D-CT reconstructions. The level of the SPECT-tracer uptake (0-10) and its anatomical distribution was mapped using a validated localization scheme. Univariate analysis (Wilcoxon-Mann-Whitney, Spearmean's-rho test, p < 0.05) was performed to identify any correlations between component position, tracer uptake and diagnosis.
  
  
  RESULTS
  SPECT/CT imaging changed the suspected diagnosis and the proposed treatment in 19/23 (83%) knees. Progression of patellofemoral OA (n = 11), loosening of the tibial (n = 3) and loosening of the femoral component (n = 2) were identified as the leading causes of pain after TKA.Patients with externally rotated tibial trays showed higher tracer uptake in the medial patellar facet (p = 0.049) and in the femur (p = 0.051). Patients with knee pain due to patellofemoral OA showed significantly higher tracer uptake in the patella than others (p < 0.001).
  
  
  CONCLUSIONS
  SPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA.
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Kantonsspital Bruderholz, CH-4101 Bruderholz, Switzerland. michael.hirschmann@ksbh.ch
authors.forename: Michael T
authors.initials: MT
authors.lastname: Hirschmann
authors.forename: Praveen
authors.initials: P
authors.lastname: Konala
authors.forename: Farhad
authors.initials: F
authors.lastname: Iranpour
authors.forename: Anna
authors.initials: A
authors.lastname: Kerner
authors.forename: Helmut
authors.initials: H
authors.lastname: Rasch
authors.forename: Niklaus F
authors.initials: NF
authors.lastname: Friederich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D010149:Postoperative Pain / Q000175:diagnosis / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*