This study was designed to present the effect of alendronate sodium on prevention of osteolysis after arthroplasty by suppression of macrophage.

Submicron-sized titanium particles were made from TiAlV cylinder and plate after milling, and by repeated washing, centrifugation and floating method. 12 dogs were given alendronate by oral administration for 3 months and blood was sampled at 3 weeks, 6 weeks and 3 months. Monocytes were separated from canine blood by isopycnic centrifugation with Percoll solution and cultured in media with LPS, L-NMA, TiAlV particle (x1 SAR and x5 SAR) for 24 hours. Nitric Oxide (NO) assay by Mendelow's method and MTT assay as a cell viability test were performed.

Average diameter of TiAlV particles was 1.1±0.8 m (from 0.17 to 4.0 m). Particles less than 1.0 m were 55% and 3.0 m, 96%. Compared with control group, there was slight decrease of NO production in 3 weeks group with no statistic difference, but there was significant decrease in 6 weeks and 3 months group statistically.

Administration of alendronate for more than 6 weeks may be effective in suppression of macrophage, prevention of osteolysis after arthroplasty.