Osseous implants are used for the rigid fixation of complex fractures in modern medicine. Resorbable materials represent a considerable improvement of this technology, since a second surgery to remove the implant after completed osseous healing is no longer necessary. The aim of this study was, to investigate the effect of an anti-inflammatory additive on bone regeneration around the resorbable implants in an animal experiment. The implants which were used in this study are made of polylactide-co-Glycolid(PLGA). Diclofenac, a nonsteroidal antiphlogistic, was added to the implants. Therefore, 36 rats were divided into two groups. In one group, rods containing Diclofenac were implanted in the shaft of the femur, in the other group, untreated rods were used. The animals of both groups were sacrificed after a treatment duration of three, six and twelve weeks.
After that, ground thin sections were made according to the method of Donath (1988). Finally, a histomorphometric evaluation was conducted to asses the amount of newly formed bone and to analyze the result statistically. Four Regions of Interest were defined (marrow space dorsal/ventral, area near to cortical bone dorsal/ventral) and new bone formation after 3, 6 and 12 weeks were compared. There were no significant differences regarding the amount of newly formed bone between groups with and without Diclofenac treatment after the same treatment duration. But there was a significant difference in the time course of bone healing. A decline in the amount of bone was found in the group without Diclofenac between the third and sixth week whereas this decrease occurred in the group with Diclofenac between the 6. and 12. week. These differences were only seen in the dorsal marrow space. The results in this experiment conducted in rats showed that there were no significant differences in the amount of newly formed bone around resorbable implants with and without Diclofenac. It seems possible that in the group with Diclofenac, there could be a time-delayed transformation of the regenerated bone tissue.