title: Morphological characteristics of cartilage-bone transitional structures in the human knee joint and CAD design of an osteochondral scaffold.
abstract: BACKGROUND
  There is a lack of understanding of the morphological characteristics of the cartilage-bone interface. Materials that are currently being used in tissue engineering do not adequately support the regeneration of bone and cartilage tissues. The present study aimed to explore the morphological characteristics of cartilage-bone transitional structures in the human knee joint and to design a biomimetic osteochondral scaffold based on morphological data.
  
  
  METHODS
  Histology, micro-computed tomography (micro-CT), and scanning electron microscopy (SEM) were used to investigate the microstructure of the cartilage-bone transitional structures. Morphological characteristics and their distribution were obtained and summarized into a biomimetic design. A three-dimensional model of a biomimetic osteochondral scaffold was CAD designed. A prototype of the resulting subchondral bone scaffold was constructed by stereolithography using resin.
  
  
  RESULTS
  Micro-CT revealed that subchondral bone presented a gradually changing structure from the subchondral to spongy bone tissue. The subchondral bone plate was more compact with ~20 % porosity compared with ~60 % porosity for the spongy bone. Histology and SEM showed that cartilage was stabilized on the subchondral bone plate by conjunctions, imbedding, interlocking, and binding forces generated by collagen fibers. Some scattered defects allow blood vessel invasion and nutritional supply.
  
  
  CONCLUSIONS
  The subchondral bone plate is not an intact plate between the cartilage and bone cavity, and some scattered defects exist that allow blood vessel invasion and nutritional supply. This characteristic was used to design an osteochondral scaffold. This could be used to construct an osteochondral complex that is similar to native bones.
authors.affiliation: The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Bian
authors.affiliation: State Key Lab for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Lian
authors.affiliation: State Key Lab for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China.
authors.forename: Dichen
authors.initials: D
authors.lastname: Li
authors.affiliation: The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, 710028, Shaanxi, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Lab for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China.
authors.forename: Weijie
authors.initials: W
authors.lastname: Zhang
authors.affiliation: The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, 710028, Shaanxi, China.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
authors.affiliation: The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China. qysbone@126.com.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Qiu
mesh_terms: D000328:Adult; D040761:Biomimetic Materials; D001842:Bone and Bones / Q000166:cytology* / Q000000981:diagnostic imaging; D002358:Cartilage, Articular / Q000166:cytology* / Q000000981:diagnostic imaging; D017076:Computer-Aided Design; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000166:cytology* / Q000000981:diagnostic imaging; D008297:Male; D054457:Tissue Scaffolds; D055114:X-Ray Microtomography
keywords: Cartilage-bone interface; Cartilage-bone transitional structure; Computational modeling; Human knee joint; Osteochondral scaffold; Tissue engineering