title: Effect of pore size of D, L-polylactic acid as bone repair material on bone regeneration.
abstract: OBJECTIVE
  To study the bone regeneration behavior in porous D,L-polylactic acid (D,L-PLA) with different pore sizes.
  
  
  METHODS
  A particulate-leaching method was employed to prepare porous biodegradable D,L-PLA with different pore sizes (75, 250, 400, 750 micrometer) and with porosity of 75% as the materials to repair bone defects in rabbits. The materials were then implanted at random into 40 rabbits with bilateral radius bone defect, leaving another 10 rabbits without implantation as blank control. Gross observation and X-ray and histomorphological examination as well as assessment of the biomechanics of the implants were performed in 2, 4, 8 and 12 weeks respectively after the operation.
  
  
  RESULTS
  New bone tissue occurred around the implanted materials with pore sizes of 250, 400 or 750 micrometer 12 weeks after the operation. In the control group and in the rabbits with implants with pore size of 75 micrometer, the bone defect was filled with connective tissues. The implants with 250-micrometer pores had the strongest biomechanical strengths of all the materials (P<0.01) at 8 weeks and 12 weeks after the operation.
  
  
  CONCLUSIONS
  The pore size of the porous implants decides the behavior of bone regeneration, and D, L-PLA polymer with 250-micrometer pores produces the most desired effects.
authors.affiliation: Department of Orthopaedics, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: An-Min
authors.initials: AM
authors.lastname: Jin
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Guo
authors.forename: Shao-Xiong
authors.initials: SX
authors.lastname: Min
authors.forename: Da-Ping
authors.initials: DP
authors.lastname: Quan
authors.forename: Ze-Jian
authors.initials: ZJ
authors.lastname: Lu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology*; D016025:Bone Transplantation; D019344:Lactic Acid / Q000737:chemistry / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology*; D016062:Porosity; D011817:Rabbits; D011884:Radius / Q000187:drug effects / Q000601:surgery; D013237:Stereoisomerism
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)