title: Tissue engineering for total meniscal substitution: animal study in sheep model.
abstract: OBJECTIVE
  The aim of the study was to investigate the use of a novel hyaluronic acid/polycaprolactone material for meniscal tissue engineering and to evaluate the tissue regeneration after the augmentation of the implant with expanded autologous chondrocytes. Two different surgical implantation techniques in a sheep model were evaluated.
  
  
  METHODS
  Twenty-four skeletally mature sheep were treated with total medial meniscus replacements, while two meniscectomies served as empty controls. The animals were divided into two groups: cell-free scaffold and scaffold seeded with autologous chondrocytes. Two different surgical techniques were compared: in 12 animals, the implant was sutured to the capsule and to the meniscal ligament; in the other 12 animals, also a transtibial fixation of the horns was used. The animals were euthanized after 4 months. The specimens were assessed by gross inspection and histology.
  
  
  RESULTS
  All implants showed excellent capsular ingrowth at the periphery. Macroscopically, no difference was observed between cell-seeded and cell-free groups. Better implant appearance and integrity was observed in the group without transosseous horns fixation. Using the latter implantation technique, lower joint degeneration was observed in the cell-seeded group with respect to cell-free implants. The histological analysis indicated cellular infiltration and vascularization throughout the implanted constructs. Cartilaginous tissue formation was significantly more frequent in the cell-seeded constructs.
  
  
  CONCLUSIONS
  The current study supports the potential of a novel HYAFF/polycaprolactone scaffold for total meniscal substitution. Seeding of the scaffolds with autologous chondrocytes provides some benefit in the extent of fibrocartilaginous tissue repair.
authors.affiliation: Laboratorio di Biomeccanica, Rizzoli Orthopedic Institute, Bologna, Italy. e.kon@biomec.ior.it
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Kon
authors.forename: Catharina
authors.initials: C
authors.lastname: Chiari
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
authors.forename: Marco
authors.initials: M
authors.lastname: Delcogliano
authors.forename: Donald M
authors.initials: DM
authors.lastname: Salter
authors.forename: Ivan
authors.initials: I
authors.lastname: Martin
authors.forename: Luigi
authors.initials: L
authors.lastname: Ambrosio
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Matilde
authors.initials: M
authors.lastname: Tschon
authors.forename: Enrico
authors.initials: E
authors.lastname: Tognana
authors.forename: Roberto
authors.initials: R
authors.lastname: Plasenzotti
authors.forename: Stefan
authors.initials: S
authors.lastname: Nehrer
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000637:transplantation; D019902:Chondrocytes / Q000637:transplantation; D005260:Female; D020007:Implants, Experimental; D007596:Joints / Q000473:pathology; D008592:Menisci, Tibial / Q000502:physiology* / Q000601:surgery*; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D016062:Porosity; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds