title: Coating of titanium implants with copolymer supports bone regeneration: a comparative in vivo study in rabbits.
abstract: OBJECTIVE
  In modern orthopedics aseptic loosening caused by the formation of micro-wear particles remains a problem for endoprosthetic joint replacements as revision surgery is necessary with corresponding costs and exertions by patients. This study is devoted to the question of how the osseous ingrowth of implants can be supported. It was investigated whether the developed copolymer, p-VBP-co-GMA, coated on the surface of the implants, supports bone healing. In addition, it was analyzed whether covalent linkage of Bone Morphogenetic Protein 2 (BMP-2) to the copolymer layer enhances bone formation.
  
  
  METHODS
  Eight adult New Zealand White Rabbits were implanted with four different foils (control, copolymer, copolymer + BMP-2, control + BMP-2) each. The histomorphometric analysis of all samples was made 28 days after implantation.
  
  
  RESULTS
  The copolymer had a positive effect on bone remodeling compared to the control group. We observed that the copolymer group had a significantly increased bone volume per tissue volume ratio and bone density to the control group. In contrast, this in-vivo study showed that the immobilization of BMP-2 onto the copolymer layer did not enhance bone healing. The bone volume per tissue volume ratio was decreased as well as the bone density compared to control + BMP-2 group.
  
  
  CONCLUSIONS
  The analysis showed that the bone remodeling process in the copolymer + BMP-2-group is in an early phase comparable to the control group. These results suggest that the coating with the developed copolymer has major potential for medical use as it enhances bone mass around the implant.
authors: Department of Orthopedic Surgery, Hannover Medical School, Germany. fritz.thorey@ddh-gruppe.de
authors: Fritz
authors: F
authors: Thorey
authors: Kerstin
authors: K
authors: Weinert
authors: Andreas
authors: A
authors: Weizbauer
authors: Frank
authors: F
authors: Witte
authors: Elmar
authors: E
authors: Willbold
authors: Ivonne
authors: I
authors: Bartsch
authors: Andrea
authors: A
authors: Hoffmann
authors: Gerhard
authors: G
authors: Gross
authors: Corinna
authors: C
authors: Lorenz
authors: Henning
authors: H
authors: Menzel
authors: Henning
authors: H
authors: Windhagen