title: Centralization of extruded medial meniscus delays cartilage degeneration in rats.
abstract: BACKGROUND
  Meniscus extrusion often observed in knee osteoarthritis has a strong correlation with the progression of cartilage degeneration and symptom in the patients. We recently reported a novel procedure "arthroscopic centralization" in which the capsule was sutured to the edge of the tibial plateau to reduce meniscus extrusion in the human knee. However, there is no animal model to study the efficacy of this procedure. The purposes of this study were [1] to establish a model of centralization for the extruded medial meniscus in a rat model; and [2] to investigate the chondroprotective effect of this procedure.
  
  
  METHODS
  Medial meniscus extrusion was induced by the release of the anterior synovial capsule and the transection of the meniscotibial ligament. Centralization was performed by the pulled-out suture technique. Alternatively, control rats had only the medial meniscus extrusion surgery. Medial meniscus extrusion was evaluated by micro-CT and macroscopic findings. Cartilage degeneration of the medial tibial plateau was evaluated macroscopically and histologically.
  
  
  RESULTS
  By micro-CT analysis, the medial meniscus extrusion was significantly improved in the centralization group in comparison to the extrusion group throughout the study. Both macroscopically and histologically, the cartilage lesion of the medial tibial plateau was prevented in the centralization group but was apparent in the control group.
  
  
  CONCLUSIONS
  We developed medial meniscus extrusion in a rat model, and centralization of the extruded medial meniscus by the pull-out suture technique improved the medial meniscus extrusion and delayed cartilage degeneration, though the effect was limited. Centralization is a promising treatment to prevent the progression of osteoarthritis.
authors.affiliation: Center for Stem Cell and Regenerative Medicine, Tokyo Medical and Dental University, Japan; Department of Orthopaedic Surgery, Yokohama City University, Japan.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Ozeki
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Muneta
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kawabata
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Koga
authors.affiliation: Center for Stem Cell and Regenerative Medicine, Tokyo Medical and Dental University, Japan; Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nakagawa
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Saito
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Mio
authors.initials: M
authors.lastname: Udo
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Yanagisawa
authors.affiliation: Department of Joint Surgery and Sports Medicine, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ohara
authors.affiliation: Department of Joint Reconstruction, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mochizuki
authors.affiliation: Department of Cartilage Regeneration, Graduate School, Tokyo Medical and Dental University, Japan.
authors.forename: Kunikazu
authors.initials: K
authors.lastname: Tsuji
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Saito
authors.affiliation: Center for Stem Cell and Regenerative Medicine, Tokyo Medical and Dental University, Japan. Electronic address: sekiya.arm@tmd.ac.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sekiya
mesh_terms: D000818:Animals; D001182:Arthroscopy / Q000379:methods; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000601:surgery; D004195:Disease Models, Animal; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging*; D051381:Rats; D011917:Rats, Inbred Lew; D000070600:Tibial Meniscus Injuries / Q000175:diagnosis* / Q000378:metabolism