title: Partial tear of the anterior cruciate ligament of the knee: injury patterns on MR imaging.
abstract: OBJECTIVE
  To describe rupture patterns of partial anterior cruciate ligament (ACL) tears on magnetic resonance (MR) imaging.
  
  
  METHODS
  MR images of 51 patients with a surgically confirmed partial ACL tear were retrospectively and independently interpreted by 2 experienced, blinded radiologists. Using previously described MR criteria, ACLs were categorized as follows: complete tear, partial tear, isolated anteromedial or posterolateral bundle tear, mucoid degeneration or normal ACL. MR interpretations were compared with the arthroscopic results as the standard of reference. Inter- and intraobserver agreements were determined using kappa (к) coefficients.
  
  
  RESULTS
  On MR imaging, ACL injuries were categorized as complete tears (16-23%), partial tears (20-47%), mucoid degeneration (12-27%) or normal ACLs (18-23%). Isolated ACL bundle tears were diagnosed on MR in 6% of our patients. Accuracy of MR for the diagnosis of partial ACL tears was 25-53%. Interobserver agreement was moderate (к = 0.48-0.56). Intraobserver agreement was good (к = 0.72-0.76).
  
  
  CONCLUSIONS
  MR diagnosis of a partial ACL tear is difficult because various tear patterns may be seen. Many partial tears demonstrate MR features that are indistinguishable from complete ACL tear, mucoid ACL degeneration or normal ACL. An isolated ACL bundle tear is infrequently detected on MR images.
authors.affiliation: Department of Radiology, University Hospital Antwerp and University of Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium. pieter.van.dyck@uza.be
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Dyck
authors.forename: Eline
authors.initials: E
authors.lastname: De Smet
authors.forename: Jan
authors.initials: J
authors.lastname: Veryser
authors.forename: Valérie
authors.initials: V
authors.lastname: Lambrecht
authors.forename: Jan L
authors.initials: JL
authors.lastname: Gielen
authors.forename: Filip M
authors.initials: FM
authors.lastname: Vanhoenacker
authors.forename: Lieven
authors.initials: L
authors.lastname: Dossche
authors.forename: Paul M
authors.initials: PM
authors.lastname: Parizel
mesh_terms: D000328:Adult; D000368:Aged; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D016037:Single-Blind Method