title: Pathologic characteristics of the torn human meniscus.
abstract: BACKGROUND
  Acellular meniscus tissue is at a high risk for degeneration and retear. Information that would help surgeons predict, preoperatively, or intraoperatively which torn menisci had few viable cells could be useful in deciding which patients might be at increased risk for retear and failure of surgical repair.
  
  
  OBJECTIVE
  Patient age, length of time since injury, and tear type are predictors of the cellularity of meniscus tissue.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Gross and histologic evaluation of torn meniscus tissue from 44 patients and 10 control menisci was performed.
  
  
  RESULTS
  The patient factors of age, time since injury, and tear type all had significant effects on the pathologic characteristics of the torn meniscus. Patients older than 40 years had lower cellularity in the torn menisci than did patients younger than 40 years (P < .01). As time since injury increased, so did the rates of DNA fragmentation in the midsubstance of the meniscus and rates of Outerbridge II changes in the adjacent cartilage. Worse meniscal histologic scores were found in menisci with degenerative and radial tear types.
  
  
  CONCLUSIONS
  Patient age had a significant effect on the cellularity of the torn meniscus, with patients older than 40 years having significantly fewer meniscus cells than did those younger than 40 years. Further studies are needed to define the relative importance of the individual histologic findings in the clinical setting of meniscus tear and repair.
  
  
  CONCLUSIONS
  In light of their decreased cellularity, menisci from patients older than 40 years may be more vulnerable to degeneration and retear after repair than are menisci of younger patients.
authors.affiliation: Department of Orthopaedic Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Mena
authors.initials: M
authors.lastname: Mesiha
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.forename: Jamil
authors.initials: J
authors.lastname: Soriano
authors.forename: Jason H
authors.initials: JH
authors.lastname: Nielson
authors.forename: Bertram
authors.initials: B
authors.lastname: Zarins
authors.forename: Martha M
authors.initials: MM
authors.lastname: Murray
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D049109:Cell Proliferation; D053938:DNA Fragmentation; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D020287:In Situ Nick-End Labeling; D016015:Logistic Models; D008297:Male; D008592:Menisci, Tibial / Q000166:cytology / Q000473:pathology*; D008875:Middle Aged; D000070600:Tibial Meniscus Injuries; D014945:Wound Healing / Q000502:physiology