title: Cytotoxicity of a new antimicrobial coating for surgical screws: an in vivo study.
abstract: BACKGROUND
  The risk of surgery-related infection is a persistent problem in orthopaedics and infections involving implants are particularly difficult to treat. This study explored the responses of bone and soft tissue to antimicrobial-coated screws. We investigated whether such screws, which have never been used to fix bony tissues, would result in a cytotoxic effect. We hypothesised that the coated screws would not be toxic to the bone and that the likelihood of infection would be reduced since bacteria are not able to grow on these screws.
  
  
  METHODS
  Titanium screws were inserted into the left supracondylar femoral regions of 16 rabbits. The screws were either uncoated (control group, n = 8) or coated with a polyvinylpyrrolidone-polyurethane interpolymer with tertiary amine functional groups (experimental group, n = 8). At Week 6, histological samples were obtained and examined. The presence of necrosis, fibrosis and inflammation in the bony tissue and the tissue surrounding the screws was recorded.
  
  
  RESULTS
  Live, cellular bone marrow was present in all the rabbits from the experimental group, but was replaced with connective tissue in four rabbits from the control group. Eight rabbits from the control group and two rabbits from the experimental group had necrosis in fatty bone marrow. Inflammation was observed in one rabbit from the experimental group and five rabbits from the control group.
  
  
  CONCLUSIONS
  Titanium surgical screws coated with polyvinylpyrrolidone-polyurethane interpolymer were associated with less necrosis than standard uncoated screws. The coated screws were also not associated with any cytotoxic side effect.
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Ordu University, Campus of Cumhuriyet, İstanbul, Turkey.
authors.forename: Yunus
authors.initials: Y
authors.lastname: Güzel
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Bezmialem Vakıf University, İstanbul, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Elmadag
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Bezmialem Vakıf University, İstanbul, Turkey.
authors.forename: Gokcer
authors.initials: G
authors.lastname: Uzer
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Bezmialem Vakıf University, İstanbul, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Yıldız
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Bezmialem Vakıf University, İstanbul, Turkey.
authors.forename: Kerem
authors.initials: K
authors.lastname: Bilsel
authors.affiliation: Department of Orthopaedics and Traumatology, School of Medicine, Bezmialem Vakıf University, İstanbul, Turkey.
authors.forename: İbrahim
authors.initials: İ
authors.lastname: Tuncay
mesh_terms: D000818:Animals; D001863:Bone Screws; D020099:Coated Materials, Biocompatible; D011140:Polyurethanes / Q000633:toxicity*; D011205:Povidone / Q000633:toxicity*; D011817:Rabbits; D013530:Surgical Wound Infection / Q000517:prevention & control*; D014025:Titanium
chemical_list: D020099:Coated Materials, Biocompatible; D011140:Polyurethanes; D014025:Titanium; D011205:Povidone
keywords: antimicrobial coating; coated screws; hydrophobic coating; implant infection