title: Interposition of the Posterior Cruciate Ligament into the Medial Compartment of the Knee Joint on Coronal Magnetic Resonance Imaging.
abstract: OBJECTIVE
  The purpose of our study was to evaluate the overall prevalence and clinical significance of interposition of the posterior cruciate ligament (PCL) into the medial compartment of the knee joint in coronal magnetic resonance imaging (MRI).
  
  
  METHODS
  We retrospectively reviewed 317 consecutive patients referred for knee MRI at our institution between October 2009 and December 2009. Interposition of the PCL into the medial compartment of the knee joint on proton coronal MRI was evaluated dichotomously (i.e., present or absent). We analyzed the interposition according to its prevalence as well as its relationship with right-left sidedness, gender, age, and disease categories (osteoarthritis, anterior cruciate ligament tear, and medial meniscus tear).
  
  
  RESULTS
  Prevalence of interposition of PCL into the medial compartment of the knee joint was 47.0% (149/317). There was no right (50.0%, 83/166) to left (43.7%, 66/151) or male (50.3%, 87/173) to female (43.1%, 62/144) differences in the prevalence. There was no significant association between the prevalence and age, or the disease categories.
  
  
  CONCLUSIONS
  Interposition of the PCL into the medial compartment of the knee joint is observed in almost half of patients on proton coronal MRI of the knee. Its presence is not associated with any particular factors including knee pathology and may be regarded as a normal MR finding.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.
authors.forename: Hyun Su
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.; Department of Medical Device Management and Research, SAIHST, Sungkyunkwan University, Seoul 06351, Korea.
authors.forename: Young Cheol
authors.initials: YC
authors.lastname: Yoon
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.
authors.forename: Ki Jeong
authors.initials: KJ
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Wang
authors.affiliation: Department of Preventive Medicine, Kyung Hee University School of Medicine, Seoul 02454, Korea.
authors.forename: Bong-Keun
authors.initials: BK
authors.lastname: Choe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging; D008875:Middle Aged; D010003:Osteoarthritis / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D016119:Posterior Cruciate Ligament / Q000000981:diagnostic imaging*; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult
keywords: Anatomic variation; Knee; Magnetic resonance imaging; Posterior cruciate ligament