Histomorphometric evaluation of bone ingrowth of porous titanium by a computer-assisted analyzing system

The objective of this study was to evaluate the bone ingrowth of a new vacuum plasma sprayed titanium surface (vps-ti) in comparison to cs-titanium implants in a gottinger minipig model. Fifteen gottinger minipigs each received the two implants, vacuum plasma sprayed titanium with a porosity of 50 % and a pore size of 200 pm (vps-ti) and an implant with a similar porosity but a different pore size 500 pm (cs-ti), at the proximal femur metaphysis by press-fit technique. The pigs were euthanized at three different postsurgical periods: 4, 8 and 12 weeks. Each femur was harvested and qualitative (macroscopic and microscopic) and quantitative (histomorpho-metric) histological analysis was done on histological slides. The results indicated that there was a difference in bone ingrowth between the two implants, whereas the bone ingrowth of vps-ti was superior to cs-ti after 4 and 8 weeks healing time. 12 weeks post implantationem no statistiscal difference was evident. The pore size of 200 mu m seemed superior to a pore size of 500 pm. Whether or not these effects lead to a better mechanical stability remains unanswered.