title: Posterior medial meniscus root ligament lesions: MRI classification and associated findings.
abstract: OBJECTIVE
  The purposes of this study were to determine the prevalence of altered MRI appearances of "posterior medial meniscus root ligament (PMMRL)" lesions, introduce a classification of lesion types, and report associated findings.
  
  
  METHODS
  We retrospectively reviewed 419 knee MRI studies to identify the presence of PMMRL lesions. Classification was established on the basis of lesions encountered. The medial compartment was assessed for medial meniscal tears in the meniscus proper, medial meniscal extrusion, insertional PMMRL osseous changes, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament abnormality.
  
  
  RESULTS
  PMMRL abnormalities occurred in 28.6% (120/419) of the studies: degeneration, 14.3% (60/419) and tear, 14.3% (60/419). Our classification system included degeneration and tearing. Tearing was categorized as partial or complete with delineation of the point of failure as entheseal, midsubstance, or junction to meniscus. Of all tears, 93.3% (56/60) occurred at the meniscal junction. Univariate analysis revealed significant differences between the knees with and without PMMRL lesions in age, medial meniscal tear, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture (p=0.017), and cruciate ligament degeneration (p<0.001).
  
  
  CONCLUSIONS
  PMMRL lesions are commonly detected in symptomatic patients. We have introduced an MRI classification system. PMMRL lesions are significantly associated with age, medial meniscal tears, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament degeneration.
authors.affiliation: 1 Department of Radiology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Chang
authors.forename: Guilherme M
authors.initials: GM
authors.lastname: Cunha
authors.forename: Monica
authors.initials: M
authors.lastname: Tafur
authors.forename: Sheronda
authors.initials: S
authors.lastname: Statum
authors.forename: Christine B
authors.initials: CB
authors.lastname: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002357:Cartilage Diseases / Q000145:classification / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000145:classification / Q000473:pathology*; D008023:Ligaments, Articular / Q000293:injuries* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000070600:Tibial Meniscus Injuries; D055815:Young Adult
keywords: MRI; medial meniscus tear; posterior root ligament