title: A tissue engineering approach to meniscus regeneration in a sheep model.
abstract: OBJECTIVE
  Regeneration of the meniscal tissue occurs to a limited extent, and the loss of meniscal tissue leads to osteoarthritis. A new biomaterial consisting of hyaluronic acid and polycaprolactone was used as a meniscus substitute in sheep to evaluate the properties of the implant material with regard to size, biomechanical stability, tissue ingrowth, and integration.
  
  
  METHODS
  Eight sheep (right stifle joints) were treated with three total and three partial meniscus replacements while two meniscectomies served as empty controls. The animals were euthanized after 6 weeks. The specimens were assessed by gross inspection and histology, and compared with the nonoperated left joints.
  
  
  RESULTS
  The surgical technique was found to be feasible. The implants remained in position, did not tear, and showed excellent tissue ingrowth to the capsule. Tissue integration was also observed between the original meniscus and the implant. However, graft compression and extrusion occurred. The histological investigation revealed tissue formation, cellular infiltration and vascularization. Cartilage degeneration was more severe in the operated joints.
  
  
  CONCLUSIONS
  The present study shows promising results concerning the qualities of this biomaterial with regard to implantation technique, stability and tissue ingrowth.
authors.affiliation: Department of Orthopaedics, Medical University of Vienna, Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Chiari
authors.forename: U
authors.initials: U
authors.lastname: Koller
authors.forename: R
authors.initials: R
authors.lastname: Dorotka
authors.forename: C
authors.initials: C
authors.lastname: Eder
authors.forename: R
authors.initials: R
authors.lastname: Plasenzotti
authors.forename: S
authors.initials: S
authors.lastname: Lang
authors.forename: L
authors.initials: L
authors.lastname: Ambrosio
authors.forename: E
authors.initials: E
authors.lastname: Tognana
authors.forename: E
authors.initials: E
authors.lastname: Kon
authors.forename: D
authors.initials: D
authors.lastname: Salter
authors.forename: S
authors.initials: S
authors.lastname: Nehrer
mesh_terms: D000276:Adjuvants, Immunologic / Q000627:therapeutic use; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use; D001698:Biomedical Engineering; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000627:therapeutic use; D020007:Implants, Experimental; D008592:Menisci, Tibial / Q000601:surgery*; D011091:Polyesters / Q000627:therapeutic use; D012038:Regeneration / Q000502:physiology*; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods
chemical_list: D000276:Adjuvants, Immunologic; D001672:Biocompatible Materials; D011091:Polyesters; C016240:polycaprolactone; D006820:Hyaluronic Acid