title: Normal and acutely torn posterior cruciate ligament of the knee at US evaluation: preliminary experience.
abstract: OBJECTIVE
  To determine the ultrasonographic (US) findings of normal and acutely torn posterior cruciate ligament (PCL) of the knee and evaluate the usefulness of US in the injured PCL.
  
  
  METHODS
  US images were obtained in 30 knees in 15 asymptomatic volunteers as a control group and in 35 patients clinically suspected of having an acute PCL injury. Only the distal half of the PCL was evaluated. Of the 35 patients, 28 had their PCL status confirmed: 13 had a normal PCL at magnetic resonance (MR) imaging plus clinical examination, and 15 had a torn PCL at either MR imaging and surgery or MR imaging and clinical follow-up.
  
  
  RESULTS
  Normal PCLs were homogeneously hypoechoic, with a well-defined posterior border. Torn PCLs were heterogeneously hypoechoic (12 [80%] of 15 patients), with an indistinct posterior margin (11 [73%] of 15 patients). Torn PCLs were significantly thicker (range, 12.0-20.0 mm; mean, 15.6 mm +/- 2.5 [SD]; P <.01), as compared with normal PCLs in 13 patients (range, 3.8-5.8 mm; mean, 4.6 mm +/- 1.0; P <.01) and in the volunteers (range, 3.7-6.2 mm; mean, 4.5 mm +/- 1.2; P <.01).
  
  
  CONCLUSIONS
  An acutely torn PCL thickens (>10 mm), loses its sharply defined posterior border, and has a heterogeneously hypoechoic appearance. US may be useful as a screening examination for patients suspected of having PCL injury and for deciding whether to perform more expensive MR imaging or surgical intervention.
authors.affiliation: Department of Diagnostic Radiology, Yeungnam University Medical Center, College of Medicine, 317-1 Daemyung-Dong, Nam-Ku, Taegu 705-717, Korea. khcho@medical.yeungnam.ac.kr
authors.forename: K H
authors.initials: KH
authors.lastname: Cho
authors.forename: D C
authors.initials: DC
authors.lastname: Lee
authors.forename: R K
authors.initials: RK
authors.lastname: Chhem
authors.forename: S D
authors.initials: SD
authors.lastname: Kim
authors.forename: J A
authors.initials: JA
authors.lastname: Bouffard
authors.forename: E
authors.initials: E
authors.lastname: Cardinal
authors.forename: B H
authors.initials: BH
authors.lastname: Park
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis / Q000000981:diagnostic imaging; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000000981:diagnostic imaging* / Q000293:injuries* / Q000473:pathology; D014463:Ultrasonography