title: The effects of meniscus injury on the development of knee osteoarthritis: data from the osteoarthritis initiative.
abstract: BACKGROUND
  Osteoarthritis (OA) is a leading cause of pain and disability, and the knee is one of the most commonly affected joints. Many have speculated that injury to the meniscus may play a key role in the development of knee OA; however, the exact relationship of meniscus injury and knee OA is unknown.
  
  
  OBJECTIVE
  To examine the rate of meniscus injuries in patients with and without incident radiographic knee OA and to explore how the type, size, and location of the meniscus injury affects the development of OA.
  
  
  METHODS
  Case-control study; Level of evidence, 3.
  
  
  METHODS
  A secondary case-control analysis was conducted of the Knee Osteoarthritis Initiative (OAI) database, which is a prospective, longitudinal, multicenter cohort study of knee health in patients at risk for knee OA. Eligible patients included those without radiographic OA at baseline in 1 knee. Thirty-two patients who developed radiographic OA in a previously unaffected knee after 2 years of follow-up were matched to 64 age-, sex-, and body mass index-matched patients who did not develop OA. The study analyzed the relationship between the development of OA and the presence of a meniscus tear or degenerative signal, meniscus extrusion, tear type, and size of injury on the baseline magnetic resonance imaging scans. Conditional logistic regression was used to identify significant predictors of OA.
  
  
  RESULTS
  The rate of medial meniscus lesions (tear or degeneration) was not significantly higher in those who developed incident OA (85%) compared with the control patients (68%; P = .07). However, medial meniscus extrusion (odds ratio [OR], 3.03; 95% confidence interval [CI], 1.4-6.5), complex tears (OR, 5.0; 95% CI, 1.0-25), and tears with large radial involvement (OR, 5.92; 95% CI, 1.7-7.5) were more common at baseline in cases compared with controls.
  
  
  CONCLUSIONS
  Knees with meniscus tears with greater radial involvement and extrusion are at greater risk for later development of radiographic OA.
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Jayshiv T
authors.initials: JT
authors.lastname: Badlani
authors.forename: Camilo
authors.initials: C
authors.lastname: Borrero
authors.forename: Saraswati
authors.initials: S
authors.lastname: Golla
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Harner
authors.forename: James J
authors.initials: JJ
authors.lastname: Irrgang
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000453:epidemiology* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology*; D010865:Pilot Projects; D011859:Radiography; D012189:Retrospective Studies; D000070600:Tibial Meniscus Injuries
keywords: knee; meniscus; meniscus injury; osteoarthritis; prognosis