Author/Editor		Cimerman, Matej
Title		Mikrostrukturna analiza stične ploskve med kostjo in kovinskimi vsadki s hidroksiapatitnim kritjem
Type		monografija
Place		Ljubljana
Publisher		Univerza v Ljubljani, Medicinska fakulteta
Publication year		2004
Volume		str. 69
Language		slo
Abstract		The use of metallic implants in orthopedic surgery is very common. The implant and the bone should act integrally in permanent and temporary use. Loosening of the implants in the bone always represent a serious complication. Bioactive coating of metallic implants has been recently introduced to improve bone-implant interface. Plasma sprayed hydroxyapatite (HA) is the most frequently used coating material. Such HA coated metallic implants are relatively common in orthopedic surgery, but rarely used in fracture surgery. The aim of the study was to compare pin-bone interface micro structural characteristics of HA coated and standard, stainless steel Shanz screws, after 2, 4 and 6 months of implantation in a sheep model. HA coating microstructure and composition was analyzed using scanning electron microscope (SEM) and XRD analysis. 12 coated and 12 uncoated screws were implanted into both femora of three sheep, each sheep receiving eight screws. After surgery and euthanasia, radiographs, blood samples and screws together with bone samples were taken. Polished bone-screws specimens were morphometrically analyzed using scanning electron (SEM) and light microscope. HA coating was before the implantation 40 micro m thick, the grain size ranged from 5 to 40 pm, with pores less than 20 pm. The atomic ratio of Ca/P was 1.62. SEM micrographs showed that the implant-bone contact was much better for HA coated implants compared to the uncoated ones. The ingrowth of the bone in the HA coating was clearly seen. Morphometric analysis showed good contact between bone and implant in 65.1 (±24.6)% in HA coated and 32.0 (±23.3)% in uncoated implants (p<0.001). The relative gap surface was 20.8 (±11.2) pm2 for coated and 61.5 (±37.1) micro m2 for the uncoated group (p<0.001). (Abstract truncated at 2000 characters).
Descriptors		FEMUR BONE SCREWS IMPLANTS, ARTIFICIAL STAINLESS STEEL HYDROXYAPATITES MICROSCOPY, ELECTRON, SCANNING X-RAY DIFFRACTION FEMORAL FRACTURES FRACTURE FIXATION, INTERNAL DISEASE MODELS, ANIMAL SHEEP