Effect of pore size of D, L-polylactic acid as bone repair material on bone regeneration.
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.
Zhang
Liang
L
Department of Orthopaedics, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
Jin
An-Min
AM
Guo
Zhi-Min
ZM
Min
Shao-Xiong
SX
Quan
Da-Ping
DP
Lu
Ze-Jian
ZJ
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
D001672:Biocompatible Materials; D018786:Bone Substitutes; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)