title: Bone scintigraphy for osteonecrosis of the knee in patients with non-traumatic osteonecrosis of the femoral head: comparison with magnetic resonance imaging.
abstract: OBJECTIVE
  To determine whether technetium bone scintigraphy (BS) is useful for screening of non-traumatic osteonecrosis of the knee (ONK), which was a major affected site, secondary to the femoral head, among multiple osteonecrosis, in patients with non-traumatic osteonecrosis of the femoral head (ONFH).
  
  
  METHODS
  A total of 214 knee joints in 107 patients with ONFH were evaluated by BS and a comparison made with magnetic resonance imaging (MRI). ONK was classified into five sites, including the femoral condyles (ONFC), distal femoral metaphysis (ONFM), tibial plateau (ONTP), proximal tibial metaphysis (ONTM), and patella (ONP).
  
  
  RESULTS
  Based on the diagnosis by MRI, ONK was detected in 103 knees of 62 patients (48%). ONFC was most common (86 knees, 40%), ONFM (15%), followed by ONTM (10%), ONP (3%), and ONTP (0.9%). Sensitivity, specificity, and accuracy of BS for ONFC detection were 63%, 71%, and 68%, respectively. When the ONFC lesions on the coronal views of MRI were large or medium sized and occupied two thirds, or the entire anteroposterior joint surface on the sagittal views, the sensitivity of BS for ONFC detection increased to 89% (34/38 knees). The sensitivity of BS for ONFM, ONTM, and ONP detection was 3%, 0%, and 0%, respectively, but these lesions showed a low likelihood of collapse.
  
  
  CONCLUSIONS
  BS is useful for screening large ONK in patients with ONFH given that 89% of patients with ONFC who had a high risk of collapse of the knee were identified.
authors: Department of Orthopaedic Surgery, Osaka University Medical School, Osaka, Japan. tsakai@ort.med.osaka-u.ac.jp
authors: T
authors: T
authors: Sakai
authors: N
authors: N
authors: Sugano
authors: T
authors: T
authors: Nishii
authors: K
authors: K
authors: Haraguchi
authors: H
authors: H
authors: Yoshikawa
authors: K
authors: K
authors: Ohzono
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013669:Technetium Tc 99m Medronate
chemical_list: D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate