title: Evaluating posterior cruciate ligament injury by using two-dimensional ultrasonography and sonoelastography.
abstract: OBJECTIVE
  This study aimed to elucidate the diagnostic criteria for posterior cruciate ligament (PCL) injury using ultrasonography.
  
  
  METHODS
  Thirty-three patients with clinically suspected PCL injuries and 30 normal control subjects were recruited. Both groups were assessed using sonographic examination with reliability testing. Patients also underwent posterior stress radiography and magnetic resonance imaging (MRI). PCL thickness on two-dimensional ultrasonography (2D US), pixel intensity on sonoelastography, displacement on posterior stress view, and severity grading using MRI were analysed. Receiver operating characteristic (ROC) curves were plotted using MRI as the gold standard. Correlation coefficients among variables were calculated.
  
  
  RESULTS
  Good to excellent reliabilities were noted for 2D US and red pixel intensity on sonoelastography. In injured knees, PCL thicknesses were significantly greater, and red pixel intensities were significantly lower, compared to non-injured knees of patients and healthy controls. This indicates increased swelling and softness in injured PCLs. The area under the PCL thickness ROC curve was 0.917 (p < 0.001), and the best diagnostic criterion was a thickness ≥6.5 mm (90.6 % sensitivity and 86.7 % specificity). Thickness correlated with red pixel intensity, International Knee Documentation Committee examination grade, and MRI severity grading. In addition, effusions were detected on 2D US in all knees with "tears" of other structures on MRI.
  
  
  CONCLUSIONS
  2D US is a useful tool to diagnose PCL injury, and PCL thickness ≥6.5 mm is the recommended diagnostic criterion.
  
  
  METHODS
  II.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung City, Taiwan, ROC.|Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC.|Medical Mechatronic Engineering Program, Cheng Shiu University, Kaohsiung City, Taiwan, ROC.
authors.forename: Lin-Yi
authors.initials: LY
authors.lastname: Wang
authors.affiliation: Department of Physical Medicine and Rehabilitation, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung City, Taiwan, ROC.|Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC.
authors.forename: Tsung-Hsun
authors.initials: TH
authors.lastname: Yang
authors.affiliation: Department of Physical Medicine and Rehabilitation, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung City, Taiwan, ROC.|Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC.
authors.forename: Yu-Chi
authors.initials: YC
authors.lastname: Huang
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC.|Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, 123, Dapi Road, Niaosong District, Kaohsiung City, Taiwan, ROC.|Medical Mechatronic Engineering Program, Cheng Shiu University, Kaohsiung City, Taiwan, ROC.
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Chou
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC. cchcgmh@cgmh.org.tw.|Department of Diagnostic Radiology, Kaohsiung Chang Gung Memorial Hospital, 123, Dapi Road, Niaosong District, Kaohsiung City, Taiwan, ROC. cchcgmh@cgmh.org.tw.
authors.forename: Chung-Cheng
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC. w281211@cgmh.org.tw.|Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, 123, Dapi Road, Niaosong District, Kaohsiung City, Taiwan, ROC. w281211@cgmh.org.tw.
authors.forename: Ching-Jen
authors.initials: CJ
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000000981:diagnostic imaging* / Q000293:injuries*; D012372:ROC Curve; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult
keywords: Diagnosis; MRI; Posterior cruciate ligament; Sonoelastography; Ultrasonography