title: Effect of hydroxyapatite coating and polymethylmethacrylate on stainless steel implant-site infection with Staphylococcus epidermidis in a sheep model.
abstract: We aimed to study the influence of hydroxyapatite (HA) coating and polymethylmethacrylate (PMMA) cement on the risk of development of stainless steel implant-site infection with Staphylococcus epidermidis in a sheep model. Uncoated, HA-coated, and PMMA-cemented stainless steel implants were inserted in the left femur of 30 sheep. For each type of implant, sheep were inoculated with S. epidermidis in the intramedullary canal and one non-inoculated group was used as control. After 6 weeks, infection was evaluated using clinical, radiological, bacteriological, and histological criteria. Radiological and clinical results were normal. Cultures were negative in the control sheep. In the inoculated sheep, interposition tissue and bone cultures were positive in 2 of 6 uncoated, 6 of 6 HA, and 6 of 6 PMMA implants with a mean bacteria count of 5.2 +/- 1.17, 3.5 +/- 0.7, and 3.9 +/- 0.9 log10 cfu/g, respectively (NS), for interposition tissue, and 4 +/- 0.01, 2.9 +/- 0.6, and 2.5 +/- 1.3 log10 cfu/g, respectively (NS) for bone. The polymorphonuclear leukocyte (PMN) score (mean number of PMN per 10 different microscopic high-power fields >or=5) in interposition tissue was >or=3 in 6 of 6 HA, significantly different from uncoated (3 of 6) and PMMA (2 of 6) groups (p = 0.04). The HA and PMMA inoculated groups had a higher infection rate than the uncoated inoculated group (p = 0.06). In this experimental sheep model of S. epidermidis infection at the bone-biomaterial interface, HA seems to be at higher risk of infection compared with uncoated or PMMA-cemented stainless steel, when inoculation is intramedullary and contemporary with implantation.
authors.affiliation: Université François Rabelais, Faculté de Médecine de Tours, 2bis Boulevard Tonnellé, 37000 Tours, France. laure@med.univ-tours.fr
authors.forename: Boris
authors.initials: B
authors.lastname: Laure
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Besnier
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Bergemer-Fouquet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Marquet-Van Der Mee
authors.forename: Frédérik
authors.initials: F
authors.lastname: Damie
authors.forename: Roland
authors.initials: R
authors.lastname: Quentin
authors.forename: Luc
authors.initials: L
authors.lastname: Favard
authors.forename: Philippe
authors.initials: P
authors.lastname: Rosset
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000382:microbiology; D004195:Disease Models, Animal; D017886:Durapatite / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D019736:Prostheses and Implants / Q000009:adverse effects*; D012756:Sheep; D013193:Stainless Steel / Q000737:chemistry*; D013203:Staphylococcal Infections / Q000473:pathology*; D013212:Staphylococcus epidermidis / Q000502:physiology*; D013583:Synovial Membrane / Q000382:microbiology
chemical_list: D013193:Stainless Steel; D019904:Polymethyl Methacrylate; D017886:Durapatite