Comparison among three different biocoatings for orthopaedic prostheses. An experimental animal study

One-hundred-eighty cylindrical monocortical titanium implants, 4mm diameter and 12mm long, with three different coatings: fluorohydroxyapatite (group A), hydroxyapatite (group B), and titanium oxide (group C), all applied by vacuum plasma spray were bilaterally, randomly implanted into the femurs and tibiae of twelve adult mongrel sheep. The sheep were divided into four groups (1, 2, 3 and 4) numbering three sheep each. Sheep of groups 1, 2, 3 and 4 were euthanized at two weeks, one month, three and nine months after implantation, respectively Biomechanical and histomorphological analysis were performed. Extraction torque increased over time in all groups until the nine months period. At all the studied periods, the bone-implant contact was higher in Groups A and B compared to Group C. However, only at nine months did this difference reach statistical significance (p<0.005 comparing Groups A and B to C). The results of this study show that all the three coatings could be recommended for clinical applications.