title: Larger medial femoral to tibial condylar dimension may trigger posterior root tear of medial meniscus.
abstract: OBJECTIVE
  The major meniscal functions are load bearing, load distribution, and shock absorption by increasing the tibiofemoral joint (TFJ) contact area and dissipating axial loads by conversion into hoop stresses. The increased hoop strain stretches the meniscus in outward direction towards radius, causing extrusion, which is associated with the root tear and resultant degenerative osteoarthritis. Since the larger contact area of medial TFJ may increase the hoop stresses, we hypothesized that the larger medial femoral to tibial condylar dimension would contribute to the development of medial meniscus posterior root tear (MMPRT). Thus, the purpose of the study was to assess the relationship between MMPRT and medial femoral to tibial condylar dimension.
  
  
  METHODS
  A case-control study was conducted to compare medial femoral to tibial condylar dimensions of patients with complete MMPRT (n = 59) with those of demography-matched controls (n = 59) during the period from 2010 to 2013. In each patient, MRIs were reviewed and several parameters were measured including articulation width of medial femoral condyle (MFC) at 0°, 30°, 60°, and 90°, medial tibial condyle (MTC) width, degree of meniscal extrusion, and medial femoral to tibial condylar width ratio (MFC/MTC) at 0°, 30°, 60°, and 90°, respectively. Demographic and radiographic data were assessed.
  
  
  RESULTS
  A larger medial femoral to tibial condylar dimension was associated with MMPRT at 0° and 30° knee angles. Patients with MFC/MTC greater than 0.9 at 0° also showed about 2.5-fold increase in the chance of MMPRT. Those with meniscal extrusion greater than 3 mm also had about 17.1 times greater chance for the presence of MMPRT accordingly.
  
  
  CONCLUSIONS
  A larger medial femoral to tibial condylar dimension may be considered as one of the regional contributors to the outbreak of MMPRT, and medial femoral to tibial condylar width ratio greater than 0.9 at 0° knee angle may be considered as a significant risk factor for MMPRT.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Chung
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Hyung Keun
authors.initials: HK
authors.lastname: Song
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Myung Kuk
authors.initials: MK
authors.lastname: Jung
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Hyeong Tak
authors.initials: HT
authors.lastname: Oh
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea.
authors.forename: Ji-Sang
authors.initials: JS
authors.lastname: Yoon
authors.affiliation: Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchon-dong, Youngtong-gu, Suwon, 443-380, Korea. bhmin@ajou.ac.kr.|Department of Molecular Science and Technology, Ajou University, Suwon, Korea. bhmin@ajou.ac.kr.
authors.forename: Byoung-Hyun
authors.initials: BH
authors.lastname: Min
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging; D007719:Knee Joint / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging*; D008875:Middle Aged; D012307:Risk Factors; D012421:Rupture; D013977:Tibia / Q000000981:diagnostic imaging*; D000070600:Tibial Meniscus Injuries / Q000000981:diagnostic imaging* / Q000209:etiology*
keywords: Condyle; Knee; Meniscus; Root tear