Do trabecular metal and cancellous titanium implants reduce the risk of late haematogenous infection? An experimental study in rabbits.

Abstract

This study evaluated the late resistance to haematogenous contamination by microbial pathogens of implants and bone-implant interface and the development of late clinical infection when cementless components with different surface or structural properties are implanted. 50 adult male New Zealand white rabbits were divided into 5 groups of 10 animals each. In Group A smooth titanium, in Group B grit blasted titanium, in Group C HA-coated titanium, in Group D trabecular metal and in group E cancellous titanium rods were implanted in the right proximal tibia. Four weeks later, 1 ml of inoculum of a standardised CA-MRSA strain (3 × 108 cfu/ml) was injected through a femoral artery catheter (groups B, C, D, E) while in group A, 1 ml of sterile saline was injected in a similar way (control group). Subjects were killed 8 weeks after the initial procedure and 3 samples of each tibial specimen were subjected to conventional cultures and PCR studies. The number of the specimens (conventional cultures and PCR studies) contaminated by the standardized pathogen was as follows: Group A: 0/10, Group B: 7/10, Group C: 6/10, Group D; 5/10 and Group E: 5/10. Comparing the number of colony form units isolated from the implant samples, Group B (GB titanium) showed statistically significantly higher values (Mann-Whitney test) compared to Group C (p = 0.044), Group D (p = 0.040) and Group E (p = 0.038). Local active infection was observed in 6 animals: 3 in Group B; 1 in Group C, 1 in Group D, and 1 in Group E. Modern cementless implants (trabecular metal and cancellous titanium) showed a lower risk of implant contamination and late clinical haematogenous infection.