title: Rapid prototyping of anatomically shaped, tissue-engineered implants for restoring congruent articulating surfaces in small joints.
abstract: BACKGROUND
  Preliminary studies investigated advanced scaffold design and tissue engineering approaches towards restoring congruent articulating surfaces in small joints.
  
  
  METHODS
  Anatomical femoral and tibial cartilage constructs, fabricated by three-dimensional fibre deposition (3DF) or compression moulding/particulate leaching (CM), were evaluated in vitro and in vivo in an autologous rabbit model. Effects of scaffold pore architecture on rabbit chondrocyte differentiation and mechanical properties were evaluated following in vitro culture and subcutaneous implantation in nude mice. After femoral and tibial osteotomy and autologous implantation of tissue-engineered constructs in rabbit knee joints, implant fixation and joint articulation were evaluated.
  
  
  RESULTS
  Rapid prototyping of 3DF architectures with 100% interconnecting pores promoted homogeneous distribution of viable cells, glycosaminoglycan (GAG) and collagen type II; significantly greater GAG content and differentiation capacity (GAG/DNA) in vitro compared to CM architectures; and higher mechanical equilibrium modulus and dynamic stiffness (at 0.1 Hz). Six weeks after implantation, femoral and tibial constructs had integrated with rabbit bone and knee flexion/extension and partial load bearing were regained. Histology demonstrated articulating surfaces between femoral and tibial constructs for CM and 3DF architectures; however, repair tissue appeared fibrocartilage-like and did not resemble implanted cartilage.
  
  
  CONCLUSIONS
  Anatomically shaped, tissue-engineered constructs with designed mechanical properties and internal pore architectures may offer alternatives for reconstruction or restoration of congruent articulating surfaces in small joints.
authors.affiliation: Institute for Biomedical Technology, University of Twente, Enschede, The Netherlands. tim.woodfield@otago.ac.nz
authors.forename: T B F
authors.initials: TB
authors.lastname: Woodfield
authors.forename: M
authors.initials: M
authors.lastname: Guggenheim
authors.forename: B
authors.initials: B
authors.lastname: von Rechenberg
authors.forename: J
authors.initials: J
authors.lastname: Riesle
authors.forename: C A
authors.initials: CA
authors.lastname: van Blitterswijk
authors.forename: V
authors.initials: V
authors.lastname: Wedler
mesh_terms: D000818:Animals; D002356:Cartilage / Q000033:anatomy & histology / Q000166:cytology; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D019902:Chondrocytes / Q000737:chemistry / Q000166:cytology* / Q000637:transplantation*; D004247:DNA / Q000032:analysis; D005269:Femur / Q000033:anatomy & histology / Q000166:cytology; D006025:Glycosaminoglycans / Q000032:analysis; D007596:Joints / Q000033:anatomy & histology / Q000166:cytology; D008422:Materials Testing; D055595:Mechanical Phenomena; D051379:Mice; D008819:Mice, Nude; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D013977:Tibia / Q000033:anatomy & histology / Q000166:cytology; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014182:Transplantation, Autologous
chemical_list: D006025:Glycosaminoglycans; D004247:DNA