title: Painful knee prosthesis: can we help with bone SPECT/CT?
abstract: OBJECTIVE
  The aim of the study was to evaluate the value of single-photon emission computerized tomography/computed tomography (SPECT/CT) in the clinical assessment of painful knee prostheses.
  
  
  METHODS
  Between 2009 and 2011 we identified 105 patients who had undergone Tc-hydroxydiphosphonate SPECT/CT for painful knee prosthesis. Complete follow-up data were available for 69 patients (50 women and 19 men; mean age, 71 years) with painful knee prostheses (59 total, nine unicompartmental, one patellofemoral) and clinical suspicion of infection or loosening. The imaging test report in conjunction with the clinical data from the patient's notes was used to gauge how useful the test had been in terms of patient management.
  
  
  RESULTS
  SPECT/CT confirmed the suspected clinical diagnosis of loosening in nine patients (13%) and of infection in two (2.9%) and identified other causes in 43 patients (62.3%). In 85.5% of patients, SPECT/CT was clinically useful (both positive and negative results), whereas in 14.5% it had no clinical impact on patient management. Revision surgery was performed in 24/69 (34.8%) patients and confirmed the SPECT/CT diagnosis in 21 patients (seven loosening, one infection, two subchondral fractures, two postoperative inflammation and nine patellofemoral osteoarthritis).
  
  
  CONCLUSIONS
  SPECT/CT is a useful tool for the evaluation of painful knee prosthesis in 85.5% of cases and helps in confirming mechanical loosening and in excluding other causes such as infection and patellofemoral osteoarthritis.
authors.affiliation: Department of Nuclear Medicine, T5, University College London Hospital NHS Foundation Trust, London, UK.
authors.forename: Khalsa
authors.initials: K
authors.lastname: Al-Nabhani
authors.forename: Sofia
authors.initials: S
authors.lastname: Michopoulou
authors.forename: Rayjanah
authors.initials: R
authors.lastname: Allie
authors.forename: Jokha
authors.initials: J
authors.lastname: Alkalbani
authors.forename: Ziauddin
authors.initials: Z
authors.lastname: Saad
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sajjan
authors.forename: Rizwan
authors.initials: R
authors.lastname: Syed
authors.forename: Jamshed
authors.initials: J
authors.lastname: Bomanji
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010146:Pain / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D059408:Pain Management; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed